The double cantilever beam (DCB) is widely used for fracture toughness testing and it has become popular
for opening-mode (mode I) delamination testing of laminated composites. Delamination is a crack that
forms between the adjacent plies of a composite laminate at the brittle polymer resin. This study was
conducted to emphasize the need for a better understanding of the DCB specimen of different fabric
reinforced systems (carbon fibers) with a thermoplastic matrix (EP, PEI), by using the extended finite
element method (X-FEM). It is well known that in fabric reinforced composites fracture mechanisms
include microcracking in front of the crack tip, fiber bridging and multiple cracking, and both contribute
considerably to the high interlaminar fracture toughness measured. That means, the interlaminar fracture
toughness of a composite is not controlled by a single material parameter, but is a result of a complex
interaction of resin, fiber and interface properties.
USING ADVANCED INSPECTION METHOD (THREE-DIMENSIONAL ULTRASONIC)IN RECOGNITION...msejjournal
In this study, using Harfang Code 32 device, the slag catcher pipelines in one of the South Pars phases
were tested. In radiography method of these lines, no clear defect was observed in radiographic films due
to the high thickness of 40 mm. However, marvelous results were obtained using advanced ultrasonic.
Review and analysis of the results will result in high potential of three-dimensional ultrasonic method in
identifying defects in pipelines with high thicknesses and preventing financial and life-threatening risks
during the use of these refineries in the future.
Fractal characterization of dynamic systems sectional imagesAlexander Decker
This document discusses using fractal analysis to characterize sectional images of dynamic systems. It simulates three systems - a hollow sphere, transmissibility ratio, and Lorenz weather model. For each system, it generates the governing equations, simulates the surface, takes 200 sectional images by passing a plane through the surface, and uses fractal disk dimension to characterize the roughness of each image. It finds the hollow sphere surface is smoothest, transmissibility ratio is rougher, and Lorenz weather model is roughest, indicating fractal analysis can distinguish linear from nonlinear system surfaces. The study demonstrates fractals' potential for image characterization in engineering applications.
3D EBSD Overview - Metallurgical Mater Trans A Vol 39 A (2008) 374Dierk Raabe
This document describes a new technique for 3D characterization of crystalline microstructures using serial sectioning with a focused ion beam and electron backscatter diffraction (EBSD) in a scanning electron microscope. Key points:
- Serial sectioning is used to cut thin sections from the sample, which are then characterized using EBSD orientation microscopy to determine crystal orientations in 3D.
- This allows full crystallographic characterization of microstructural features like interfaces that is not possible with conventional 2D analysis.
- The technique achieves resolutions as fine as 50x50x50 nm3 and can characterize sample volumes up to 50x50x50 μm3.
- Examples demonstrate applications to characterize microstructures like
Nano Scale Surface Characterization of Poly Ethyleneterephthalate Silicon Rub...ijtsrd
Atomic force microscopy has been used to investigated the surface properties of different materials, in this paper it is used to measure the surface roughness and surface adhesive force of three different membrane samples Poly ethyleneterephthalate PET , Silicon Rubber SR and PET SRcopolymers. This analytical method allows images representing the topography and adhesive force Phase image of the surface to be captured simultaneously at a molecular nanometer resolution. The distribution of hydrophilic polar groups and the surface roughness on the investigated surfaces ofthese membrane samples influences the subsequent processing of polymeric membrane manufacture as well as their performance. From the results a clear distinction was observed between the three samples in both images the topography surface roughness images and adhesive force images. Promising result were obtained for the PET SRcopolymer samples to be a good candidate in membrane separation applications. This study may also help to explain the differences in membrane performances and efficiency during applications in the separation process. Dr. Abduelmaged Abduallah | Dr. Kamal M. Sassi | Dr. Mustafa T. Yagub "Nano-Scale Surface Characterization of Poly (Ethyleneterephthalate) - Silicon Rubber Copolymers using Atomic Force Microscopy" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd43688.pdf Paper URL: https://www.ijtsrd.comengineering/chemical-engineering/43688/nanoscale-surface-characterization-of-poly--ethyleneterephthalate--silicon-rubber-copolymers-using-atomic-force-microscopy/dr-abduelmaged-abduallah
Luigi Giubbolini | Microwave Nondestructive Testing of Composite MaterialsLuigi Giubbolini
Microwave Nondestructive Testing (MNDT) techniques have advantages over other NDT methods (such as radiography, ultrasonics, and eddy current) regarding low cost, good penetration in nonmetallic materials, good resolution and contactless feature of the microwave sensor (antenna).
RESULTS OF FINITE ELEMENT ANALYSIS FOR INTERLAMINAR FRACTURE REINFORCED THERM...MSEJjournal1
The double cantilever beam (DCB) is widely used for fracture toughness testing and it has become popular
for opening-mode (mode I) delamination testing of laminated composites. Delamination is a crack that
forms between the adjacent plies of a composite laminate at the brittle polymer resin. This study was
conducted to emphasize the need for a better understanding of the DCB specimen of different fabric
reinforced systems (carbon fibers) with a thermoplastic matrix (EP, PEI), by using the extended finite
element method (X-FEM). It is well known that in fabric reinforced composites fracture mechanisms
include microcracking in front of the crack tip, fiber bridging and multiple cracking, and both contribute
considerably to the high interlaminar fracture toughness measured. That means, the interlaminar fracture
toughness of a composite is not controlled by a single material parameter, but is a result of a complex
interaction of resin, fiber and interface properties.
1. The study developed a methodology to investigate micromechanical deformation in two-phase titanium alloys using electron backscatter diffraction (EBSD) characterization and focused ion beam micropillar compression testing.
2. EBSD was used to select regions of interest with comparable grain structures between alloy variants, and to inform micropillar fabrication targeting specific slip systems.
3. Results showed the deformation behavior depends on slip system and morphology, and one alloy exhibited slip-system dependent strain rate sensitivity while the other was slip-system independent.
Electron backscatter diffraction in materialsImtiaz Ali
This document provides an overview of electron backscatter diffraction (EBSD), including its history, working principles, applications, strengths, and limitations. EBSD uses electron diffraction patterns captured in a scanning electron microscope to determine grain morphology, crystallographic orientation, and phase composition of materials. The technique has been improved over time through automation and integration with other characterization methods. It provides fast, reliable microstructural characterization of crystalline materials and is widely used in materials science research and industry.
USING ADVANCED INSPECTION METHOD (THREE-DIMENSIONAL ULTRASONIC)IN RECOGNITION...msejjournal
In this study, using Harfang Code 32 device, the slag catcher pipelines in one of the South Pars phases
were tested. In radiography method of these lines, no clear defect was observed in radiographic films due
to the high thickness of 40 mm. However, marvelous results were obtained using advanced ultrasonic.
Review and analysis of the results will result in high potential of three-dimensional ultrasonic method in
identifying defects in pipelines with high thicknesses and preventing financial and life-threatening risks
during the use of these refineries in the future.
Fractal characterization of dynamic systems sectional imagesAlexander Decker
This document discusses using fractal analysis to characterize sectional images of dynamic systems. It simulates three systems - a hollow sphere, transmissibility ratio, and Lorenz weather model. For each system, it generates the governing equations, simulates the surface, takes 200 sectional images by passing a plane through the surface, and uses fractal disk dimension to characterize the roughness of each image. It finds the hollow sphere surface is smoothest, transmissibility ratio is rougher, and Lorenz weather model is roughest, indicating fractal analysis can distinguish linear from nonlinear system surfaces. The study demonstrates fractals' potential for image characterization in engineering applications.
3D EBSD Overview - Metallurgical Mater Trans A Vol 39 A (2008) 374Dierk Raabe
This document describes a new technique for 3D characterization of crystalline microstructures using serial sectioning with a focused ion beam and electron backscatter diffraction (EBSD) in a scanning electron microscope. Key points:
- Serial sectioning is used to cut thin sections from the sample, which are then characterized using EBSD orientation microscopy to determine crystal orientations in 3D.
- This allows full crystallographic characterization of microstructural features like interfaces that is not possible with conventional 2D analysis.
- The technique achieves resolutions as fine as 50x50x50 nm3 and can characterize sample volumes up to 50x50x50 μm3.
- Examples demonstrate applications to characterize microstructures like
Nano Scale Surface Characterization of Poly Ethyleneterephthalate Silicon Rub...ijtsrd
Atomic force microscopy has been used to investigated the surface properties of different materials, in this paper it is used to measure the surface roughness and surface adhesive force of three different membrane samples Poly ethyleneterephthalate PET , Silicon Rubber SR and PET SRcopolymers. This analytical method allows images representing the topography and adhesive force Phase image of the surface to be captured simultaneously at a molecular nanometer resolution. The distribution of hydrophilic polar groups and the surface roughness on the investigated surfaces ofthese membrane samples influences the subsequent processing of polymeric membrane manufacture as well as their performance. From the results a clear distinction was observed between the three samples in both images the topography surface roughness images and adhesive force images. Promising result were obtained for the PET SRcopolymer samples to be a good candidate in membrane separation applications. This study may also help to explain the differences in membrane performances and efficiency during applications in the separation process. Dr. Abduelmaged Abduallah | Dr. Kamal M. Sassi | Dr. Mustafa T. Yagub "Nano-Scale Surface Characterization of Poly (Ethyleneterephthalate) - Silicon Rubber Copolymers using Atomic Force Microscopy" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd43688.pdf Paper URL: https://www.ijtsrd.comengineering/chemical-engineering/43688/nanoscale-surface-characterization-of-poly--ethyleneterephthalate--silicon-rubber-copolymers-using-atomic-force-microscopy/dr-abduelmaged-abduallah
Luigi Giubbolini | Microwave Nondestructive Testing of Composite MaterialsLuigi Giubbolini
Microwave Nondestructive Testing (MNDT) techniques have advantages over other NDT methods (such as radiography, ultrasonics, and eddy current) regarding low cost, good penetration in nonmetallic materials, good resolution and contactless feature of the microwave sensor (antenna).
RESULTS OF FINITE ELEMENT ANALYSIS FOR INTERLAMINAR FRACTURE REINFORCED THERM...MSEJjournal1
The double cantilever beam (DCB) is widely used for fracture toughness testing and it has become popular
for opening-mode (mode I) delamination testing of laminated composites. Delamination is a crack that
forms between the adjacent plies of a composite laminate at the brittle polymer resin. This study was
conducted to emphasize the need for a better understanding of the DCB specimen of different fabric
reinforced systems (carbon fibers) with a thermoplastic matrix (EP, PEI), by using the extended finite
element method (X-FEM). It is well known that in fabric reinforced composites fracture mechanisms
include microcracking in front of the crack tip, fiber bridging and multiple cracking, and both contribute
considerably to the high interlaminar fracture toughness measured. That means, the interlaminar fracture
toughness of a composite is not controlled by a single material parameter, but is a result of a complex
interaction of resin, fiber and interface properties.
1. The study developed a methodology to investigate micromechanical deformation in two-phase titanium alloys using electron backscatter diffraction (EBSD) characterization and focused ion beam micropillar compression testing.
2. EBSD was used to select regions of interest with comparable grain structures between alloy variants, and to inform micropillar fabrication targeting specific slip systems.
3. Results showed the deformation behavior depends on slip system and morphology, and one alloy exhibited slip-system dependent strain rate sensitivity while the other was slip-system independent.
Electron backscatter diffraction in materialsImtiaz Ali
This document provides an overview of electron backscatter diffraction (EBSD), including its history, working principles, applications, strengths, and limitations. EBSD uses electron diffraction patterns captured in a scanning electron microscope to determine grain morphology, crystallographic orientation, and phase composition of materials. The technique has been improved over time through automation and integration with other characterization methods. It provides fast, reliable microstructural characterization of crystalline materials and is widely used in materials science research and industry.
Fabrication and characterization of Polymer laminate composites reinforced wi...IJERA Editor
The present paper evaluate slaminatedcarbonbi-wove fibers Reinforced with vinyl ester composites. Vinyl ester was used as a matrix to prepare composites by in situ polymerization technique. Four planar layers were made simultaneously by keeping one over the other and each layer made sure to be weighed off by 15% which was maintained in all layers with different orientations. Pre-assumed Layer-1 is (50/50)50%,0º; Layer-2 is (35/35/30) 35% 0º, 35% +45º,30%,0;Layer-3is (25/50/25) 25% 0º, 50%+45º,25-45º; and Layer-4is (25/25/25/25) (25% 0º, 25% +45º,25% -45º,25% 90º.The composite was prepared with the help of hand layup technique. Test ready specimens were tested with the help of shearing machine in accordance with ASTM Standards .It was observed that vinyl ester made good interface with parent fiber material. Flexural strength and Tensile strength have improved up to 3rd layer and decreased afterwards whereas Flexural modulus and Tensile modulus have linearly increased up to 4th layer. Thermal stability and Glass transition temperature have also been found to be satisfactory for all the laminated layers. Chemical resistance was good for the entire chemicals except sodium hydroxide.
This paper addresses the fracture toughness ( ), or also known as critical stress intensity Factor, according to
conditions of Lineal Elastic Fracture Mechanics (LEFM). The characterization of the mechanical properties in
tensile and fracture toughness of structural steel pipes API-5L used in hydrocarbons transportation was
performed. For fracture toughness, the material was tested through fatigue crack propagation on standardized
compact specimen (CT) according to ASTM E-399 norm. A thickness (B) equal to and a crack size (a) equal
to 0.5w were used. With the porpoise of establishing the adequate conditions at the crack tip, the specimens were
subjected to fatigue pre-cracking by application of repeated cycles of load in tensile-tensile and constant load
amplitude with a load ratio of R = 0.1. The experimental Compliance method was used based on data obtained
from load vs. Crack Mouth Opening Displacement (CMOD). The results show a Stress Intensity factor of 35.88
MPa√m for a 25 mm crack size specimen. The device used for testing is a MTS-810 machine with capacity of
100KN and 6 kHz sampling rate, which meets the conditions of the ASTM E-399 standard. The cracking
susceptibility of steel is influenced by the size, morphology and distribution of non-metallic inclusions,
thermochemical interaction with the environment and microstructure.
This document presents a novel method for quantifying surface modifications of glass fibre-reinforced polyester composites exposed to UV radiation. The method involves staining the composites with methylene blue dye after UV exposure. Colour analysis of digital images of the stained composites is then used to assess degradation, as degradation leads to increased dye adsorption and darker staining. The colour changes correlated well with FTIR spectroscopy and microscopy results. The method is presented as being easier, faster and cheaper than traditional analysis techniques for evaluating UV degradation of such composites.
IRJET-Crack Assessment in Structural Members: A Review on Recent ParadigmsIRJET Journal
This document reviews recent methods for crack assessment in structural members. It discusses how vibration-based techniques have gained popularity for early crack detection by analyzing changes in dynamic properties as cracks form. Specifically, cracks can cause reductions in natural frequencies and changes to mode shapes. The document reviews several crack detection techniques including microwave imaging to identify cracks as small as 5mm in concrete, and frequency-based methods using natural frequency shifts to detect cracks in steel beams. It also summarizes several studies analyzing the use of vibration data and modal analysis to monitor cracks over time in bridges. In conclusion, the review finds various effective crack detection methods exist but that more research is still needed.
This document discusses the design and analysis of an airborne radome. It begins with an abstract that outlines the purpose of radomes to protect microwave subsystems from environmental effects while maintaining electromagnetic transparency. It then provides a table of contents and overview of the various chapters that will analyze radome design using Creo and ANSYS software, composite materials testing and analysis, and structural analysis including dynamic analysis and pressure testing. The document focuses on the design, analysis, and testing of a composite material radome.
IRJET- Melanoma Detection using Feed Forward Neural Network and Therapeutic S...IRJET Journal
This document describes a proposed method for detecting melanoma using a feed forward neural network and suggesting appropriate treatment. The method involves preprocessing skin images using median filtering to remove noise, segmenting the affected skin cells using an improved k-means clustering algorithm, extracting features using texture and color analysis, and classifying images as melanoma or nevus using a neural network classifier. The results will be tested on a medical image dataset to evaluate the accuracy of the proposed melanoma detection system.
This study used atomic force microscopy (AFM) to characterize the interaction between polyester yarn and a silicone gel matrix. AFM was used to image the topography, measure the phase, and map the mechanical properties via force-distance spectroscopy. The results showed that the polyester yarn was about 100 times harder than the surrounding silicone gel matrix. By understanding these mechanical property differences, this study provides insights that could inform the design of novel composite materials like next-generation fabrics.
Image analysis and Laser Particle Diffraction study of ProRoot-MTA, Portland ...CrimsonPublishersRDMS
Image analysis and Laser Particle Diffraction study of ProRoot-MTA, Portland cement and Bismuth Oxide-A comparative study by MMA Rafique* in Crimson Publishers: Peer Reviewed Material Science Journals
This document summarizes a study that investigated using deep learning to classify x-ray images of quarantine items. Researchers collected x-ray image data of 21 quarantine item classes and used it to train a convolutional neural network model. The model achieved an overall accuracy of 25.5% on the test set, with higher accuracy for some classes like banana and dracaena, and lower accuracy for others like tree ear mushroom and asparagus that had poorer visibility in x-rays. While the overall accuracy was low, the confusion matrix showed the model could differentiate between classes to some degree. Improving the model would require more image data per scan type to better generalize object shapes and labels.
Modal Analysis of Fibre Reinforced Composite Beams with a Transverse Crack U...IJMER
In many structures like high speed machineries, aircrafts and light weight structures
composite beams and beam like structures are main constituent elements. Cracks induced in these
structural elements cause serious failure and monitoring of these cracks is essential. The presence of
these cracks influences the dynamic characteristics of the structural elements. Hence the changes in
natural frequencies and mode shapes have been the subject of interest of many investigations. In the
present work two Fiber- Reinforced Plastic (FRP) materials, Graphite Fibre Reinforced Polyamide
and E-Glass Fibre Reinforced Polymer have been selected as beam materials for modal analysis using
ANSYS 13.0. The analysis is carried out for these two beams in different ways. Initially the analysis is
carried out for different orientation of fibres for two beams. Later the effect of dimensions is analyzed
by varying one dimension of the beam at a time by keeping the other two constant. In the next step the
analysis is performed for constant dimensions of each beam for same layer orientation and constant
volume fraction of fibre by introducing transverse cracks of different depths at various positions along
the length of the beam. The results obtained are analyzed.
Laboratory X-ray CT Applied to the Characterisation of Tubular Composite Spec...Fabien Léonard
This study used X-ray computed tomography (XCT) to characterize defects in a tubular composite specimen. Standard measurements found voids made up 3.1% of the specimen volume. Advanced analysis mapped voids spatially, finding they were concentrated in three radial locations. Vertical cracks near the inner surface were attributed to removal from the manufacturing mandrel, while circumferential cracks further out were linked to thermal stresses during manufacturing. Overall, the study demonstrated how XCT can provide both standard and advanced 3D characterization of defects in tubular composites.
Comparative Analysis of Composite Materials based on Stress and Vibration by ...IRJET Journal
This document summarizes research on comparing the stress and vibration characteristics of different composite materials through experimental analysis. Specifically, it analyzes the natural frequency and mode shapes of cantilever beams made of steel, E-glass epoxy, and fiber reinforced plastic (FRP) composites using a fast Fourier transformer analyzer and stress testing with a universal testing machine. The study found that E-glass epoxy composite material performed better than steel and FRP materials with higher natural frequencies and was better able to withstand stresses. The behavior of vibrating structures obtained through experimental modal analysis can be used to validate results from finite element modeling of mode shapes.
Polymers Characterisation, Polymerisation Techniques & Their ApplicationsShilpi Saxena
This presentation is about the various characterization methods of polymers, polymerization techniques and various applications of these polymers in Pharmacy
Digging deeper into data processing with emphasis on computational and micros...Liza Charalambous
The document discusses using machine learning techniques to analyze compositional and microstructure data from archaeology. It describes the archaeological process and different types of data generated, including compositional data from elemental analysis and microstructure data from microscopy. For compositional data, the document examines pre-processing practices like transformation and discusses a case study on ceramics. For microstructure data, it discusses analyzing properties like annealing temperature, vitrification, and porosity using techniques like texture analysis and shape factors. Throughout, it emphasizes the challenges of archaeological data like inconsistencies and the need for standardized preprocessing.
Advances on Microwave Ceramic Filters for Wireless Communications (Review Pap...IJECEIAES
A review of the technological developments on ceramic monoblock filters and duplexers over the years is presented in this work. Early designs based on simulated and measured data are presented along with later designs based on accurate equivalent circuits as well as the use of evolution algorithms for optimal design.
This document summarizes research on using a nanosecond ytterbium fiber laser to micro-texture titanium surfaces for biomedical applications. The researchers investigated how laser process parameters like power, frequency, speed and spot size affect the generation of micro-scale self-assembled structures on titanium surfaces. Scanning electron microscopy and profilometry analysis showed that surface roughness between 1-2 microns, suitable for osteoblast tissue integration, could be achieved by adjusting the laser parameters. In particular, a spot size of 284-410 microns at 17 watts power, 20 kHz frequency and 2 mm/s speed produced the desired roughness. The study demonstrated the potential of this laser for controlled micro-texturing of titanium implants.
A Review on Detection of Cracks Present in Composite Cantilever Beam by using...ijtsrd
The aim of this paper is to discuss various techniques used by various researchers for vibration based crack detection in cracked composite structures. In aeronautical, mechanical and civil engineering fields various structural systems are likely to damage and deterioration during their working period. So it is very important to find damage and deterioration in structural member by an effective and reliable methodology. Interest in various damage detection methods has considerably increased in last few decades. A local flexibility is introduced in structural member due to the presence of crack that would affect the vibration response of structure. Due to the presence of crack there is reduction in stiffness of structure and increase in damping of the structure. Since there are changes in physical properties there are reductions in natural frequencies and deviation in mode shapes. Therefore by measuring the vibration parameters it is possible to predict crack depth and crack location in structural member. In this paper effect of various parameters like crack depth, crack location on natural frequency of beam is studied.Presence of crack in a beam decreases the natural frequency which is more pronounced when the crack is near the fixed support and the crack depth is more. Mr. Kadam Satish P | Dr. Kachare P.S."A Review on Detection of Cracks Present in Composite Cantilever Beam by using Vibration Analysis Technique" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-6 , October 2017, URL: http://www.ijtsrd.com/papers/ijtsrd4617.pdf http://www.ijtsrd.com/engineering/mechanical-engineering/4617/a-review-on-detection-of-cracks-present-in-composite-cantilever-beam-by-using-vibration-analysis-technique/mr-kadam-satish-p
Effect of lamination angle on maximum deflection of simply supported composit...RAVI KUMAR
In this project a composite laminated beam is studied with glass-epoxy and graphite-epoxy combination. The beam is composed of four layers of different combination of composite material (glass epoxy and graphite epoxy composite). The beam is simply supported at both the ends and is subjected to uniformly distributed load along the length. Transverse deflection is computed for different lamination angle (0^0-〖90〗^0) by using Euler- Bernoulli’s theory (or CLPT). Maximum transverse deflection analysis is carried out using derived analytical expressions. The research carried out in this project will enable to determine the beam strength due to bending loads. The importance of fibre reinforcement in the manufacturing of the beam is studied in terms of bending strength of the beam. MATLAB codes are generated to implement analytical expiations of the composite beam.
The main objective of the paper is to find out the lamination angle at which minimum deflection is obtained & to find out the effect of lamination angle on maximum transverse deflection of the beam.
This document summarizes an experimental study on the flexural fatigue behavior of carbon/epoxy angle ply laminates. Flexural fatigue tests were conducted on laminate composites with different fiber orientations: [00]4, [±450]4, [±550]4, and [00, 900]4. The tests measured the stiffness degradation of the laminates as a function of the number of load cycles applied. The results showed that stiffness reduced rapidly at first as the top and bottom layers were damaged, then the rate of reduction slowed as a "pivoting effect" limited further damage. Numerical models were able to describe the stiffness degradation curves.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Fabrication and characterization of Polymer laminate composites reinforced wi...IJERA Editor
The present paper evaluate slaminatedcarbonbi-wove fibers Reinforced with vinyl ester composites. Vinyl ester was used as a matrix to prepare composites by in situ polymerization technique. Four planar layers were made simultaneously by keeping one over the other and each layer made sure to be weighed off by 15% which was maintained in all layers with different orientations. Pre-assumed Layer-1 is (50/50)50%,0º; Layer-2 is (35/35/30) 35% 0º, 35% +45º,30%,0;Layer-3is (25/50/25) 25% 0º, 50%+45º,25-45º; and Layer-4is (25/25/25/25) (25% 0º, 25% +45º,25% -45º,25% 90º.The composite was prepared with the help of hand layup technique. Test ready specimens were tested with the help of shearing machine in accordance with ASTM Standards .It was observed that vinyl ester made good interface with parent fiber material. Flexural strength and Tensile strength have improved up to 3rd layer and decreased afterwards whereas Flexural modulus and Tensile modulus have linearly increased up to 4th layer. Thermal stability and Glass transition temperature have also been found to be satisfactory for all the laminated layers. Chemical resistance was good for the entire chemicals except sodium hydroxide.
This paper addresses the fracture toughness ( ), or also known as critical stress intensity Factor, according to
conditions of Lineal Elastic Fracture Mechanics (LEFM). The characterization of the mechanical properties in
tensile and fracture toughness of structural steel pipes API-5L used in hydrocarbons transportation was
performed. For fracture toughness, the material was tested through fatigue crack propagation on standardized
compact specimen (CT) according to ASTM E-399 norm. A thickness (B) equal to and a crack size (a) equal
to 0.5w were used. With the porpoise of establishing the adequate conditions at the crack tip, the specimens were
subjected to fatigue pre-cracking by application of repeated cycles of load in tensile-tensile and constant load
amplitude with a load ratio of R = 0.1. The experimental Compliance method was used based on data obtained
from load vs. Crack Mouth Opening Displacement (CMOD). The results show a Stress Intensity factor of 35.88
MPa√m for a 25 mm crack size specimen. The device used for testing is a MTS-810 machine with capacity of
100KN and 6 kHz sampling rate, which meets the conditions of the ASTM E-399 standard. The cracking
susceptibility of steel is influenced by the size, morphology and distribution of non-metallic inclusions,
thermochemical interaction with the environment and microstructure.
This document presents a novel method for quantifying surface modifications of glass fibre-reinforced polyester composites exposed to UV radiation. The method involves staining the composites with methylene blue dye after UV exposure. Colour analysis of digital images of the stained composites is then used to assess degradation, as degradation leads to increased dye adsorption and darker staining. The colour changes correlated well with FTIR spectroscopy and microscopy results. The method is presented as being easier, faster and cheaper than traditional analysis techniques for evaluating UV degradation of such composites.
IRJET-Crack Assessment in Structural Members: A Review on Recent ParadigmsIRJET Journal
This document reviews recent methods for crack assessment in structural members. It discusses how vibration-based techniques have gained popularity for early crack detection by analyzing changes in dynamic properties as cracks form. Specifically, cracks can cause reductions in natural frequencies and changes to mode shapes. The document reviews several crack detection techniques including microwave imaging to identify cracks as small as 5mm in concrete, and frequency-based methods using natural frequency shifts to detect cracks in steel beams. It also summarizes several studies analyzing the use of vibration data and modal analysis to monitor cracks over time in bridges. In conclusion, the review finds various effective crack detection methods exist but that more research is still needed.
This document discusses the design and analysis of an airborne radome. It begins with an abstract that outlines the purpose of radomes to protect microwave subsystems from environmental effects while maintaining electromagnetic transparency. It then provides a table of contents and overview of the various chapters that will analyze radome design using Creo and ANSYS software, composite materials testing and analysis, and structural analysis including dynamic analysis and pressure testing. The document focuses on the design, analysis, and testing of a composite material radome.
IRJET- Melanoma Detection using Feed Forward Neural Network and Therapeutic S...IRJET Journal
This document describes a proposed method for detecting melanoma using a feed forward neural network and suggesting appropriate treatment. The method involves preprocessing skin images using median filtering to remove noise, segmenting the affected skin cells using an improved k-means clustering algorithm, extracting features using texture and color analysis, and classifying images as melanoma or nevus using a neural network classifier. The results will be tested on a medical image dataset to evaluate the accuracy of the proposed melanoma detection system.
This study used atomic force microscopy (AFM) to characterize the interaction between polyester yarn and a silicone gel matrix. AFM was used to image the topography, measure the phase, and map the mechanical properties via force-distance spectroscopy. The results showed that the polyester yarn was about 100 times harder than the surrounding silicone gel matrix. By understanding these mechanical property differences, this study provides insights that could inform the design of novel composite materials like next-generation fabrics.
Image analysis and Laser Particle Diffraction study of ProRoot-MTA, Portland ...CrimsonPublishersRDMS
Image analysis and Laser Particle Diffraction study of ProRoot-MTA, Portland cement and Bismuth Oxide-A comparative study by MMA Rafique* in Crimson Publishers: Peer Reviewed Material Science Journals
This document summarizes a study that investigated using deep learning to classify x-ray images of quarantine items. Researchers collected x-ray image data of 21 quarantine item classes and used it to train a convolutional neural network model. The model achieved an overall accuracy of 25.5% on the test set, with higher accuracy for some classes like banana and dracaena, and lower accuracy for others like tree ear mushroom and asparagus that had poorer visibility in x-rays. While the overall accuracy was low, the confusion matrix showed the model could differentiate between classes to some degree. Improving the model would require more image data per scan type to better generalize object shapes and labels.
Modal Analysis of Fibre Reinforced Composite Beams with a Transverse Crack U...IJMER
In many structures like high speed machineries, aircrafts and light weight structures
composite beams and beam like structures are main constituent elements. Cracks induced in these
structural elements cause serious failure and monitoring of these cracks is essential. The presence of
these cracks influences the dynamic characteristics of the structural elements. Hence the changes in
natural frequencies and mode shapes have been the subject of interest of many investigations. In the
present work two Fiber- Reinforced Plastic (FRP) materials, Graphite Fibre Reinforced Polyamide
and E-Glass Fibre Reinforced Polymer have been selected as beam materials for modal analysis using
ANSYS 13.0. The analysis is carried out for these two beams in different ways. Initially the analysis is
carried out for different orientation of fibres for two beams. Later the effect of dimensions is analyzed
by varying one dimension of the beam at a time by keeping the other two constant. In the next step the
analysis is performed for constant dimensions of each beam for same layer orientation and constant
volume fraction of fibre by introducing transverse cracks of different depths at various positions along
the length of the beam. The results obtained are analyzed.
Laboratory X-ray CT Applied to the Characterisation of Tubular Composite Spec...Fabien Léonard
This study used X-ray computed tomography (XCT) to characterize defects in a tubular composite specimen. Standard measurements found voids made up 3.1% of the specimen volume. Advanced analysis mapped voids spatially, finding they were concentrated in three radial locations. Vertical cracks near the inner surface were attributed to removal from the manufacturing mandrel, while circumferential cracks further out were linked to thermal stresses during manufacturing. Overall, the study demonstrated how XCT can provide both standard and advanced 3D characterization of defects in tubular composites.
Comparative Analysis of Composite Materials based on Stress and Vibration by ...IRJET Journal
This document summarizes research on comparing the stress and vibration characteristics of different composite materials through experimental analysis. Specifically, it analyzes the natural frequency and mode shapes of cantilever beams made of steel, E-glass epoxy, and fiber reinforced plastic (FRP) composites using a fast Fourier transformer analyzer and stress testing with a universal testing machine. The study found that E-glass epoxy composite material performed better than steel and FRP materials with higher natural frequencies and was better able to withstand stresses. The behavior of vibrating structures obtained through experimental modal analysis can be used to validate results from finite element modeling of mode shapes.
Polymers Characterisation, Polymerisation Techniques & Their ApplicationsShilpi Saxena
This presentation is about the various characterization methods of polymers, polymerization techniques and various applications of these polymers in Pharmacy
Digging deeper into data processing with emphasis on computational and micros...Liza Charalambous
The document discusses using machine learning techniques to analyze compositional and microstructure data from archaeology. It describes the archaeological process and different types of data generated, including compositional data from elemental analysis and microstructure data from microscopy. For compositional data, the document examines pre-processing practices like transformation and discusses a case study on ceramics. For microstructure data, it discusses analyzing properties like annealing temperature, vitrification, and porosity using techniques like texture analysis and shape factors. Throughout, it emphasizes the challenges of archaeological data like inconsistencies and the need for standardized preprocessing.
Advances on Microwave Ceramic Filters for Wireless Communications (Review Pap...IJECEIAES
A review of the technological developments on ceramic monoblock filters and duplexers over the years is presented in this work. Early designs based on simulated and measured data are presented along with later designs based on accurate equivalent circuits as well as the use of evolution algorithms for optimal design.
This document summarizes research on using a nanosecond ytterbium fiber laser to micro-texture titanium surfaces for biomedical applications. The researchers investigated how laser process parameters like power, frequency, speed and spot size affect the generation of micro-scale self-assembled structures on titanium surfaces. Scanning electron microscopy and profilometry analysis showed that surface roughness between 1-2 microns, suitable for osteoblast tissue integration, could be achieved by adjusting the laser parameters. In particular, a spot size of 284-410 microns at 17 watts power, 20 kHz frequency and 2 mm/s speed produced the desired roughness. The study demonstrated the potential of this laser for controlled micro-texturing of titanium implants.
A Review on Detection of Cracks Present in Composite Cantilever Beam by using...ijtsrd
The aim of this paper is to discuss various techniques used by various researchers for vibration based crack detection in cracked composite structures. In aeronautical, mechanical and civil engineering fields various structural systems are likely to damage and deterioration during their working period. So it is very important to find damage and deterioration in structural member by an effective and reliable methodology. Interest in various damage detection methods has considerably increased in last few decades. A local flexibility is introduced in structural member due to the presence of crack that would affect the vibration response of structure. Due to the presence of crack there is reduction in stiffness of structure and increase in damping of the structure. Since there are changes in physical properties there are reductions in natural frequencies and deviation in mode shapes. Therefore by measuring the vibration parameters it is possible to predict crack depth and crack location in structural member. In this paper effect of various parameters like crack depth, crack location on natural frequency of beam is studied.Presence of crack in a beam decreases the natural frequency which is more pronounced when the crack is near the fixed support and the crack depth is more. Mr. Kadam Satish P | Dr. Kachare P.S."A Review on Detection of Cracks Present in Composite Cantilever Beam by using Vibration Analysis Technique" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-6 , October 2017, URL: http://www.ijtsrd.com/papers/ijtsrd4617.pdf http://www.ijtsrd.com/engineering/mechanical-engineering/4617/a-review-on-detection-of-cracks-present-in-composite-cantilever-beam-by-using-vibration-analysis-technique/mr-kadam-satish-p
Effect of lamination angle on maximum deflection of simply supported composit...RAVI KUMAR
In this project a composite laminated beam is studied with glass-epoxy and graphite-epoxy combination. The beam is composed of four layers of different combination of composite material (glass epoxy and graphite epoxy composite). The beam is simply supported at both the ends and is subjected to uniformly distributed load along the length. Transverse deflection is computed for different lamination angle (0^0-〖90〗^0) by using Euler- Bernoulli’s theory (or CLPT). Maximum transverse deflection analysis is carried out using derived analytical expressions. The research carried out in this project will enable to determine the beam strength due to bending loads. The importance of fibre reinforcement in the manufacturing of the beam is studied in terms of bending strength of the beam. MATLAB codes are generated to implement analytical expiations of the composite beam.
The main objective of the paper is to find out the lamination angle at which minimum deflection is obtained & to find out the effect of lamination angle on maximum transverse deflection of the beam.
This document summarizes an experimental study on the flexural fatigue behavior of carbon/epoxy angle ply laminates. Flexural fatigue tests were conducted on laminate composites with different fiber orientations: [00]4, [±450]4, [±550]4, and [00, 900]4. The tests measured the stiffness degradation of the laminates as a function of the number of load cycles applied. The results showed that stiffness reduced rapidly at first as the top and bottom layers were damaged, then the rate of reduction slowed as a "pivoting effect" limited further damage. Numerical models were able to describe the stiffness degradation curves.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
The document describes an extension to the brittle cracking concrete material model in ABAQUS. The extension adds nonlinear compressive behavior using a user subroutine. The extended model is validated by comparing it to the original brittle cracking model and damaged plasticity model under uniaxial loading. The extended model is also shown to capture strain rate effects observed in experiments. Finally, the extended model is used to simulate benchmark cases including a notched concrete beam, demonstrating its ability to model tensile failure of concrete structures.
This document summarizes research on developing a multi-scale modeling approach to predict the structural behavior of carbon fiber reinforced composite pipes used for offshore oil and gas risers. The approach models the pipe behavior at the micro, meso, and macro scales and links the scales together. Experiments were conducted to validate the modeling approach and determine material properties at each scale. Results showed good agreement between predicted and experimental properties and structural response at different loading conditions. The multi-scale modeling approach shows promise for designing composite risers while addressing current limitations in experience, standards, and design methodologies.
This document discusses a finite element analysis of plastic behavior in metal matrix composite laminates. It aims to study stress fields around fibers at free edges of laminates under thermal and mechanical loads, and how damage from plastic deformation affects stresses. The analysis uses micromechanical models of cross-ply laminates with fibers in different orientations. Results on stress distributions with and without considering plasticity and damage are presented and compared to previous research. The goal is to better understand delamination in composites and how fiber/matrix debonding at free edges relates to the overlapping hypothesis of thermal stress generation at fiber ends.
FRACTURE MECHANICS OF NANO-SILICA PARTICLES IN REINFORCED EPOXIES Jordan Suls
This document summarizes a study that used finite element modeling to examine how different levels of particle dispersion (evenly dispersed, moderately clumped, and severely clumped) affect the fracture mechanics of nanosilica particle reinforced epoxies. Three models were created in Abaqus with the different dispersion levels and subjected to tensile loading. The results found that the evenly dispersed model had the highest fracture toughness, as indicated by its ability to withstand a greater force at similar displacements. This was because the clumped models developed large stress regions around the clumps that caused earlier debonding of the particle-matrix interfaces and faster crack propagation.
Abstract The present research work is to determine buckling load per unit length in rectangular plate with circular cut-outs under bi-axial compression using 2D finite element analysis. The commercial finite element analysis software ANSYS has been successfully executed. The buckling factors are evaluated by changing the position of the holes, length to thickness ratio. The effect of changing the position of holes, a/b ratio, b/t ratio and buckling load per unit length is discussed. The results shows that buckling load per unit length is in clamped-clamped boundary conditions and buckling load is more at top positioned hole, decreases with increase in aspect ratio, decrease with increase breadth to thickness ratio. Keywords: Buckling analysis, Finite element method, Buckling load per unit length , carbon/epoxy composite plate, aspect ratio, b/t ratio, and Biaxial load.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
W. Phippen Deisgn Optmization of CFRP Satellite Solar Panel Structures - MECH461William Phippen
The document describes the design optimization of a carbon fiber reinforced polymer (CFRP) satellite solar panel structure using Altair's HyperWorks software. The goal was to maximize stiffness while minimizing cost and meeting stress and deflection constraints. The model was optimized over 4 iterations for CFRP properties and loading cases of launch and orbital deployment. The final design yielded a 71.2% mass reduction while satisfying all constraints.
This document discusses several applications of slope stability analysis using the finite element method. It begins by introducing slope stability analysis and some traditional limit equilibrium methods. It then discusses two main advantages of the finite element method: it does not require assumptions about the failure surface shape or location, and it can model complex geometries and soil properties. The document presents several examples of applying the finite element method to analyze slope stability under various conditions, including accounting for drainage, brittle soil behavior, and engineering interventions. It compares results to traditional methods and notes the additional data on stresses, strains, and progressive failure that finite element analysis can provide.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
This document reviews several studies that analyzed bolted joints in composite laminates. It discusses how clamping force and laminate stacking sequence can affect failure mechanisms and strength. The review examines both experimental and modeling/simulation approaches. Studies investigated topics like bearing strength, fatigue characteristics, stress distributions, and the effects of parameters like bolt-hole clearance and clamping loads. Overall, the review indicates that while modeling techniques have improved understanding, further work is still needed to optimize bolted joint design given composites' brittle failure modes.
cohesive zone modeling of laminated composite beam under mixed modeNEERAJKUMAR1898
This document summarizes a study that uses finite element modeling to analyze debonding and delamination in laminated composite beams under mixed mode bending loads. It discusses how laminate thickness and initial crack length can affect stresses, deflection, and interface health. The study models an AS4/PEEK composite beam in COMSOL and applies mixed mode bending loads. It finds that increasing laminate thickness significantly increases von Mises stresses, leading to more rapid delamination propagation. It also finds that initial crack length affects transverse beam deflection, with lower initial crack lengths producing greater deflection. The document provides background on delamination and debonding failure modes in composites and details the finite element formulation, beam geometry, materials properties
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
We conducted molecular dynamics simulations to investigate the atomistic edge crack vacancy interactions in graphene. We demonstrate that the crack tip stress field of an existing crack in graphene can be effectively tailored (reduced by over 50% or increased by over 70%) by the strategic placement of atomic vacancies of varied shapes, locations, and orientations near its tip. The crack vacancy interactions result in a remarkable improvement (over 65%) in the fracture strength of graphene. Moreover, at reduced stiffness of graphene, due to a distribution of atomic vacancies, a drastic difference (~60%) was observed between the fracture strengths of two principal crack configurations (i.e. armchair and zigzag). Our numerical simulations provide a remarkable insight into the applicability of the well-established continuum models of crack microdefect interactions for the corresponding atomic scale problems. Furthermore, we demonstrate that the presence of atomic vacancies in close proximity to the crack tip leads to a multiple stage crack growth and, more interestingly, the propagating cracks can be completely healed even under a significantly high applied tensile stress level (~5 GPa). Our numerical experiments offer a substantial contribution to the existing literature on the fracture behavior of two dimensional nanomaterials.
Prediction of Deflection and Stresses of Laminated Composite Plate with Arti...IJMER
A true understanding of their structural behaviour is required, such as the deflections, buckling loads
and modal characteristics, the through thickness distributions of stresses and strains, the large deflection
behaviour and, of extreme importance for obtaining strong, reliable multi-layered structures, the failure
characteristics. In the past, the structural behaviour of plates and shells using the finite element method has been
studied by a variety of approaches. Choudhary and Tungikaranalyzed the geometrically nonlinear behavior of
laminated composite plates using the finite element analysis.
1. The document analyzes the stress distribution over a hybrid composite material with carbon and glass fibers and epoxy, with a central circular hole, under tensile loading.
2. Three specimens were experimentally tested according to ASTM standards and found to have a maximum stress concentration near the central hole.
3. Finite element analysis was also conducted and found the results to match the experimental values, with maximum stress occurring near the central hole.
This thesis aims to develop multiphase voxel finite elements (MVEs) that can accurately predict the stiffness tensor of woven fiber composite laminates. The MVEs allow the construction of a mesh independent of the complex internal geometry by applying material properties at integration points.
Two novel MVEs are proposed - the Tensile Modulus Corrected MVE (TMC-MVE) and the Stiffness Tensor Corrected MVE (STC-MVE). These are compared to an Average Stiffness Element and a Basic MVE through tests on simple geometries. The MVEs are then used to analyze plain, satin and twill weave composites, with results compared to finite element
This document summarizes research on a low-rise concentrically braced frame building equipped with dissipative pin connections. It describes:
1) Experimental testing of a single-pin connection that dissipates energy through flexure of the pin, allowing braces to behave elastically.
2) Computer modeling using OpenSees of a one-story braced frame with these connections, validated against experimental results.
3) A comparative study of the braced frame's seismic response with and without dissipative connections.
Similar to RESULTS OF FINITE ELEMENT ANALYSIS FOR INTERLAMINAR FRACTURE REINFORCED THERMOPLASTIC COMPOSITES (20)
Modelling and Simulation of Composition and Mechanical Properties of High Ent...msejjournal
Magnesium alloys are high potential materials for application in the aerospace and automotive industries
due to their lightweight properties. They can help to lower dead weight and fuel consumption to contribute
to sustainability and efficiency. It is possible to achieve high specific strength and high stiffness of the
alloys by varying compositions of alloying elements. Applications of magnesium are limited due to its low
strength and relatively low stiffness. This research focuses on a recipe of multi component alloys of
magnesium with varied percentages of Mg, Al, Cu, Mn and Zn obtained from literature and optimizes the
percentage compositions to obtain for high specific strength and specific stiffness. Relationships among
percentage constituents of the alloy components are examined in Matlab R2022b using multiple linear
regression. Optimization is achieved using genetic algorithm to determine the specific strengths and
stiffness. The resulting optimal alloy component percentages by weight are used for microstructure
simulation of thermodynamic properties, diffusion and phase transformations of proposed alloy is done in
MatCalc software version 6.04. Results show potential for improved mechanical properties resulting from
disordered structure in the high entropy magnesium alloy. Future research should focus on production and
characterization of the proposed alloy.
Thermal and Metrological Studies on YTTRIA Stabilized Zirconia Thermal Barrie...msejjournal
Thermal Barrier Coatings (TBCs), routinely prepared from Ceramic based compositions (typically
8%Y2O3-ZrO2or 8YSZ) are being engineered to protect the metallic components from degradation in
applications like gas turbines, jet and automotive engines. With a goal of finding improved TBC materials
a wide variety of ceramics are being researched worldwide. Before physically preparing the TBCs of
uncommon compositions in the laboratory, their suitability to perform can be predicted. Limited
accessibility to detailed and realistic information on the influence of newer compositions (other than 8YSZ)
on TBCs warrants methods to obtain this information.
In this paper, 8YSZ TBCs coated onto aluminium substratesare studied for thermal fatigue, thermal barrier
and materials characteristics to determine the reliability of the coating configuration to withstand the
harshness of test conditions under the framework of experiments. Thereafter, the results have been used to
corroboratethe developed simulation model. Results obtained via thermal tests confirm the suitability of the
model and we can predict the thermal barrier effects of TBCs when prepared from materials other than
YSZ.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly peer-reviewed journal that publishes articles on theoretical and practical aspects of materials science and engineering. The goal of the journal is to bring together researchers and practitioners from academia and industry to focus on advancements in materials science and engineering and establish new collaborations. Original research papers and review articles are invited for publication in areas including biomaterials, composites, nanomaterials, and polymers.
New Experiment System for the Interaction Between Soft Rock and Water : A Cas...msejjournal
The strength of rock strongly depends on the water content especially when the rocks contain clay
materials. The interaction between soft rock and water always threaten the soft rock engineering projects.
For this problem, new sets of laboratory experiment systems are developed to simulate the interaction
between soft rock and water or vapor. In this paper, the principles of experiment systems are introduced
with particular reference to the application on soft rock in Mogao Grottoes, one of the world famous
ancient sites in China. Two kinds of rock samples, the sandstone and muddy sandstone, are obtained by insitu sampling system. Then the laboratory experiments are performed under different environment
conditions. By the specific boundary conditions design, the physical-chemical effect and mechanic effect on
water absorption of rock samples are separated for further mechanism study by the experiment system, and
the different hydrological actions of water and vapor under variable experiment environment are obtained.
The interaction mechanism is discussed with assistant methods, such as SEM (Scanning Electron
Microscope), mercury injection test, X-ray diffraction analysis and etc. With the relation between water
content and soft rock strength, the study may provide guidance and basis for the soft rock engineering in
the future.
International Conference on Embedded Systems and VLSI (EMVL 2023)msejjournal
International Conference on Embedded Systems and VLSI (EMVL 2023) will provide an excellent International forum for sharing knowledge and results in theory, methodology and applications of Embedded Systems.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
Modeling, Analyzing and Safety Aspects of Torsion and Noise Effects on Round ...msejjournal
Each material has its own effect and behavior on external impacts like heat, force, tension, compression,
torsion etc. It is important to study and analyze these behaviors before selecting a material for an
engineering application in the design aspects itself. If predicted values analyzed by both mathematical and
software are available it is easy to get the reliable details in the pre design itself. By this one can ensure the
safety of the component and the system also. In this investigation, the effects of torsional loads on mild steel
round shafts with various diameters and lengths have been analyzed. The additional effects like angle of
rotation, rpm and duration also considered to find the optimum predicted value. The data observed by
various experiments are analyzed by design of experiments especially by response surface methodology.
Minitab software is used for canalization. The data are tabulated and kept for future reference. Noise effect
due to the gradual torsional load performed in the gear box and other rotating components is also studied
for healthy working environment. The nature and characteristics of material also be explained by this noise
analysis.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on Materials Science and Engineering advancements, and establishing new collaborations in these areas. Original research papers, state-of-the-art reviews are invited for publication in all areas of Materials Science and Engineering.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
On Decreasing of Dimensions of Field-Effect Transistors with Several Sourcesmsejjournal
We analyzed mass and heat transport during manufacturing field-effect heterotransistors with several
sources to decrease their dimensions. Framework the result of manufacturing it is necessary to manufacture
heterostructure with specific configuration. After that it is necessary to dope required areas of the heterostructure by diffusion or ion implantation to manufacture the required type of conductivity (p or n). After
the doping it is necessary to do optimize annealing. We introduce an analytical approach to prognosis mass
and heat transport during technological processes. Using the approach leads to take into account nonlinearity of mass and heat transport and variation in space and time (at one time) physical parameters of these
processes
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on Materials Science and Engineering advancements, and establishing new collaborations in these areas. Original research papers, state-of-the-art reviews are invited for publication in all areas of Materials Science and Engineering.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on Materials Science and Engineering advancements, and establishing new collaborations in these areas. Original research papers, state-of-the-art reviews are invited for publication in all areas of Materials Science and Engineering.
Using Advanced Inspection Method (Three-Dimensional Ultrasonic) in Recognitio...msejjournal
In this study, using Harfang Code 32 device, the slag catcher pipelines in one of the South Pars phases
were tested. In radiography method of these lines, no clear defect was observed in radiographic films due
to the high thickness of 40 mm. However, marvelous results were obtained using advanced ultrasonic.
Review and analysis of the results will result in high potential of three-dimensional ultrasonic method in
identifying defects in pipelines with high thicknesses and preventing financial and life-threatening risks
during the use of these refineries in the future.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
RESULTS OF FINITE ELEMENT ANALYSIS FOR INTERLAMINAR FRACTURE REINFORCED THERM...msejjournal
The double cantilever beam (DCB) is widely used for fracture toughness testing and it has become popular
for opening-mode (mode I) delamination testing of laminated composites. Delamination is a crack that
forms between the adjacent plies of a composite laminate at the brittle polymer resin. This study was
conducted to emphasize the need for a better understanding of the DCB specimen of different fabric
reinforced systems (carbon fibers) with a thermoplastic matrix (EP, PEI), by using the extended finite
element method (X-FEM). It is well known that in fabric reinforced composites fracture mechanisms
include microcracking in front of the crack tip, fiber bridging and multiple cracking, and both contribute
considerably to the high interlaminar fracture toughness measured. That means, the interlaminar fracture
toughness of a composite is not controlled by a single material parameter, but is a result of a complex
interaction of resin, fiber and interface properties.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on Materials Science and Engineering advancements, and establishing new collaborations in these areas. Original research papers, state-of-the-art reviews are invited for publication in all areas of Materials Science and Engineering.
Flammability Characteristics of Chemical Treated Woven Hemp Fabricmsejjournal
Woven hemp fabric was treated with sodium hydroxide, commercial flame retardant chemical, and
combination of both to increase its fire-retardant properties. Treatments of fire-retardant changed the
properties of woven hemp fabric such as increased its fabric shrinkage and density of fibres which ranges
from 0.67 to 5% and 1.43 to 1.53 g/cm3
respectively. After the treatment, the fire retardancy of the fabric
increased tremendously which was observed by the burning, thermogravimetry and limiting oxygen index
tests. Some of the samples were not burnt when exposed to flame source and the burning rate needed to be
measured under exaggeration of flame at longer time. The limiting oxygen index value increased from 18.6
to 51 after the treatments which explained the scenario happened in the burning tests. Nevertheless, its
mechanical properties decreased slightly that ranges from 18 to 32% and 23 to 39% for warp and weft
respectively compared to untreated fibre.
Advances in Materials Science and Engineering: An International Journal (MSEJ) msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on Materials Science and Engineering advancements, and establishing new collaborations in these areas. Original research papers, state-of-the-art reviews are invited for publication in all areas of Materials Science and Engineering.
Advances in Materials Science and Engineering: An International Journal (MSEJ) msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on Materials Science and Engineering advancements, and establishing new collaborations in these areas. Original research papers, state-of-the-art reviews are invited for publication in all areas of Materials Science and Engineering.
Advances in Materials Science and Engineering: An International Journal (MSEJ)msejjournal
Advances in Materials Science and Engineering: An International Journal (MSEJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Materials Science and Engineering. The journal is devoted to the publication of high quality papers on theoretical and practical aspects of Materials Science and Engineering.
The goal of this journal is to bring together researchers and practitioners from academia and industry to focus on Materials Science and Engineering advancements, and establishing new collaborations in these areas. Original research papers, state-of-the-art reviews are invited for publication in all areas of Materials Science and Engineering.
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
RESULTS OF FINITE ELEMENT ANALYSIS FOR INTERLAMINAR FRACTURE REINFORCED THERMOPLASTIC COMPOSITES
1. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
DOI:10.5121/msej.2017.4301 1
RESULTS OF FINITE ELEMENT ANALYSIS FOR
INTERLAMINAR FRACTURE REINFORCED
THERMOPLASTIC COMPOSITES
P.J. Charitidis
Center of Orthopaedic Research (C.O.RE) at Center for Interdisciplinary Research and
Innovation-Aristotle University of Thessaloniki ( CIRI-AUTH), Greece
ABSTRACT
The double cantilever beam (DCB) is widely used for fracture toughness testing and it has become popular
for opening-mode (mode I) delamination testing of laminated composites. Delamination is a crack that
forms between the adjacent plies of a composite laminate at the brittle polymer resin. This study was
conducted to emphasize the need for a better understanding of the DCB specimen of different fabric
reinforced systems (carbon fibers) with a thermoplastic matrix (EP, PEI), by using the extended finite
element method (X-FEM). It is well known that in fabric reinforced composites fracture mechanisms
include microcracking in front of the crack tip, fiber bridging and multiple cracking, and both contribute
considerably to the high interlaminar fracture toughness measured. That means, the interlaminar fracture
toughness of a composite is not controlled by a single material parameter, but is a result of a complex
interaction of resin, fiber and interface properties.
KEYWORDS:
double cantilever beam, FEA, fabric reinforced composites, thermoplastic matrix, X-FEM
1. INTRODUCTION
A unidirectional continuous fiber reinforcement in high performance composite materials leads to
high specific strength and stiffness in fiber direction but very low properties transverse to it.
Usually laminates made of plies with different fiber orientation or of plies with woven fabric fiber
reinforcement are used in structures to overcome this problem in three dimensions. A critical
failure mode of these laminates is the interlaminar fracture or the delamination [1-4]. Delamination
can occur during the manufacturing process due to contaminated reinforcing fibers, insufficient
wetting of fibers, machining and mechanical loading such as impact loading. Delamination can
also occur due to the lack of reinforcement in the thickness direction and, also, since interlaminar
stresses exist in the boundary layer of laminates under transverse loading [5,6,7]. Components
made of epoxy-based materials have provided out- standing mechanical, thermal, and electrical
properties [8]. The laminated fiber-reinforced composite materials such as carbon fiber epoxy
composites are widely applied in packaging, coating, electronics, automotive, and aerospace
industries [9,10]. They have high strength-to-weight and stiffness-to-weight ratios. These
composites have unique advantages over monolithic materials, such as high strength, high
stiffness, long fatigue life, low density, corrosion resistance, wear resistance, and environmental
stability [11]. Mechanical properties of epoxy polymeric composites can be enhanced through the
improvement of the interlaminar properties by toughening resin matrix [12,13], and fiber
reinforcement [14, 15]. In unidirectional carbon and glass fibre with epoxy matrices, typical values
of interlaminar fracture toughness GIc are in the range 200-400 J/m2
. Modification of the epoxy
matrix with rubber particles leads to improvement in GIc up to approximately 800-1000 J/m2
. For
composites reinforce by woven glass fibres typical values of the fracture toughness are ≈1000 J/m2
2. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
2
[16]. A lot of investigations have been published so far dealing with the measurement of the
critical energy to cause delamination and to characterize the materials by means of this property.
However, most of these studies were carried out using unidirectional reinforced laminate
specimens and were focused on the test procedure, geometry and data reduction methods. In order
to predict delamination onset or growth for two-dimensional problems, these calculated G
components are compared to interlaminar fracture toughness properties measured over a range
from pure mode I loading to pure mode II loading [17, 18]. Simulating the propagation of cracks
by using finite element method is quite challenging because the topology of the domain changes
continuously. For this reason, the extended finite element method (XFEM) is being used to model
cracks because the mesh can be created independent from the crack geometry. Actually, XFEM
lies in applying the appropriate enrichment function locally in the domain of interest using the
partition of unity. This method was first proposed by Belytschko et al. [19], where they applied the
partition of unity methods to the problem of using finite elements with discontinuous basis
functions. Further on, Moes, et. al. [20], used XFEM to create a technique for simulating crack
propagation in two dimensions without remeshing the domain, while the extension to three
dimensions was begun by Sukumar et al. [21], where they used the two dimensional enrichment
functions for planar cracks, and then extended in [22-26]. XFEM has demonstrated more accurate
and stable solutions while the conventional finite element results were rough or highly oscillatory
[27, 28]. In this study we trying to analyzing stress distribution for the local region ahead the crack
tip for a very thin resin layer by using extended finite element method (Abaqus). This thickness
which is almost 0.0004mm, was "received" by the experimental procedure [29, 30], which
indicates a very thin resin-rich layer between neighboring plies.
2. ANALYTICAL THEORIES
2.1 SIMPLE BEAM THEORY
The simple beam theory expression for the compliance of a perfectly built-in DCB specimen
results in the following equation for GIc:
where P and δ are the load and displacement values, respectively calculated from the P-δ curve
at the point of deviation from linearity, determined by drawing a straight line from the origin
but ignoring any initial deviations due to take-up of play in the loading system [31].
Furthermore, B is the specimen width and α the initial crack length.
2.2 CORRECTED BEAM THEORY
The above expression will underestimate the compliance as the beam is not perfectly built-in
[32]. Thus, a correcting factor ∆ is introduced assuming that the real crack is slightly longer
(α+∆) than the one measured experimentally. ∆ may be found experimentally as the deviation
from the origin by plotting the cube root of the compliance as a function of crack length.
3. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
3
while the compliance C is given by,
where E is the Young's modulus. A constant value for ∆ is assumed during the whole crack
propagation procedure.
2.3 EXPERIMENTAL COMPLIANCE METHOD
This is the most accurate method, and could be characterized as an alternative method which is
to plot compliance versus crack length. It is the most popular theory one in literature [33, 34],
where the compliance values are obtained directly from the measured load and displacement
values (C=δ/P versus an
). Actually, is a two parameter approach according to,
where n is the slope of the plot.
2.4 THE AREA METHOD
In this method, the crack extension is related directly to the area enclosed between loading and
unloading curves. To be more specific, the energy release rate is calculated from the energy
consumed by the crack extension divided by the area of the new crack surface [35, 36]. Thus,
where ∆Α is the area enclosed by the loading-unloading path.
2.5 MODIFIED MODEL PROPOSED BY BISHOPP AND DRUCKER
Thin composite specimens, very often used for DCB tests, result in large deflections and
rotations due to their low flexural rigidity. The correction to linear beam theory for these
factors, introduced by Bishopp and Drucker [37], has recently been developed further by Devitt
et al. [38] and applied to a series of glass/epoxy composites of three different thicknesses. Good
agreement between predicted and experimental values for the three different thicknesses was
observed when a constant average value of EI was used for each laminate.
2.6 MODIFIED MODEL PROPOSED BY FREEMAN
A finite displacement analysis for the DCB test method was first introduced by Freeman [39].
Williams [40] has developed this model further, to include the effects of end blocks. This
formulation is valid for any type of anisotropic elastic behaviour of the beam, since it is based
on slender beam analysis and ignores transverse stresses. According to Freeman, the final
expression for GIc, ignoring the end block effects, is:
4. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
4
where P is the applied load, B the width of the DCB specimen and φο, the end slope of the
cantilever. The analysis was successfully applied to experimental results.
2.7 THE PROPOSED APPROACH
All the above theories are based on certain assumptions, such as: (1) homogeneity and isotropy;
(2) certain geometric conditions are respected; (3) St. Venant's principle applies; and (4) plane
sections remain plane after loading. However, these assumptions are hardly ever fullfilled in
practice. In that case, it is proposed the following approach [41]. According to the geometry
(figure 1),
Figure 1. Double Cantilever Beam (Dcb) Geometry.
And
where δ is the displacement, P the load, α the crack length, E the bending modulus, B the
specimen's width, h the thickness and C the compliance. From equation (2), we calculate the
crack length,
while from the definition of GIc it follows that:
5. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
5
By introducing expression (3) into (4) we finally find:
where A=Bh is the cross-sectional area of the bending beam. Thus, according to equation (5)
the parameters for evaluation of GIc are P, A, C, E, and B which are all completely defined by
the experimental procedure applied and the specimen's geometry.
3. MATERIAL AND METHOD
3.1 JOINT CONFIGURATION AND MATERIAL
The DCB specimen is often used to determine the mode I interlaminar fracture toughness, GIc,
and it is widely used on unidirectional reinforced laminates. In this finite element study the
specimen is composed of two uniform thickness sub laminates with 0 degree composite material
plies (CF/Ep). In figure 1 a schematic overviews of a DCB specimen is shown, while the
analyzed materials are shown in table 1 [42, 43, 44].
Table 1. Double Cantilever Beam (DCB) geometry.
3.2 EFFECT OF THE FIBER REINFORCEMENT AND MATRIX
The strengthening ingredient material in a composite is the fiber, which mainly carries the load
through the composite laminate. The fiber maintains the rigidity of the composite while impeding
crack or damage propagation and can be arranged in many different types of reinforcement.
Depending on the type of reinforcement, the fibres can be oriented randomly, all in one direction
(unidirectional or UD), or in a number of different directions [45]. Carbon fibres are one of the
most advanced and promising engineering materials, and are most commonly used as
reinforcements in advanced polymer-matrix composites [46] due to its many unique properties. In
6. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
6
figure 2, it can be seen the effect of different fiber reinforcements in a brittle epoxy and a tough
polyetherimide matrix. The CF(UD) reinforcements results in comparison to a fabric CF
reinforcement in much lower values for GIc, due to inhomogeneity and waviness of the fabric
reinforcement which causes a more complex failure and rougher fracture surface profile [47].
Thus the surface per unit crack length becomes larger in fabric reinforced composites. The
fiber/matrix bonding can be responsible for different interlaminar fracture toughnesses measured.
On the other hand, the tougher the matrix material is, the higher are the values of the interlaminar
fracture toughness (figure 3). For the neat polymers, the fracture energy values roughly vary
between GIc =0.1kJ/m2
for EP and 2.5 kJ/m2
for PEI [48]. This means, that the ratio of interlaminar
composite toughness to neat resin toughness is high in the case of an EP-matrix, but very low in
cases of PEI matrices [47].
Figure 2. Fiber reinforcement, GIc.
Figure 3. Matrix reinforcement, GIc
7. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
7
4. MATERIAL AND METHODS
Finite element analysis were carried out by using Abaqus. The analysis were based on two
dimensional finite element models, by using extended finite element method (XFEM), which
simplify the solution of problems such as, (a) the propagation of cracks, the evolution of
dislocations, (c) the modeling of grain boundaries and the (d) evolution of phase boundaries.
Figure 1 shows the DCB specimen configuration and loading analyzed in this study. The specimen
dimensions and materials were selected to represent those typical of currently used test specimens.
The CPS4, a 4-node bilinear plane stress quadrilateral was used for two dimensional modeling of
the specimen. The size of elements in the specimen was 0.042 mm using maximum principal
stress of 58 MPa (Maxps Damage) and displacement at failure at 5mm (Damage evolution). It
should be noted that the response after peak load in not as sensitive to mesh refinement.
Parametric analysis was performed with a loading displacement (δ=3 and 5 mm) which was
applied at the upper and lower corner of the specimen (Figure 1). In order to ensure a smooth
propagation, a very small increment values were considered. As, for boundary conditions the left
edges of the specimen were restricted as shown in figure 1 (point C), while the initial crack (point
AB=30mm) as well as the thickness of the resin in all cases was kept constant (0.0004mm).
5. FINITE ELEMENT AND ANALYTICAL RESULTS
5.1 FINITE ELEMENT RESULTS
The stress distributions ahead of the crack tip are analyzed for DCB specimen using carbon/epoxy
(CF/EP UD), carbon epoxy fabric (CF/EP) and carbon / polyethermide (CF/PEI). We started by
investigating the P-δ curves, obtained from the numerical model (figure 4 and 5). Once the
maximum force is attained, a stable crack propagation accompanied by a decrease in the force,
which is in a very good agreement with the experimental results (figure 6a). Moreover, the load
decreased at slow rate after a maximum, sometimes with localized stick-slip instabilities [49]
occurs. In that case, the critical strain energy release rate could be determined by using parameters
such as force, displacement and initial crack length. During the analysis, it was found that the
force-displacement curve is dependent on the choice of maximum principal stress. For instance,
changing the maximum principal stress (Maxps) values of 50MPa to 10MPa in the case of CF/PEI,
the maximum reaction force would be decreased by 11.47%. That means, the crack length for a
given displacement will be decreased.
However, for the same loading displacement, the maximum reaction force was found in the case of
the CF/Epoxy (UD). The crack was increased by 2.95mm and 4.95mm for loading displacement 3
and 5mm, respectively (figure 7). On the other hand, the minimum crack growth was found in the
case of CF/PEI (1.07 and 1.70mm). This is true, because PEI increase the viscosity of the resin
mixture, which reduces the rate of phase separation [50, 51]. Furthermore, has more resistance
towards deformation by an applied force, thus posses high stiffness [52]. Now, if the crack reaches
the tougher region, it slows down until the rate of release of elastic stored energy is sufficient to
propagate the crack through the tougher region. The release rate of stored energy is then more
than that required for stable growth. The crack then accelerates and unstable fracture occurs.
Generally, Mode I interlaminar fracture toughness for the satin woven fabric composites greatly
depended on both the interfacial properties and weave structure (figure 6b). At last, but not least,
for the case of the CF/PEI, the load instantly dropped at several points during the delamination
propagation in the load displacement curves, followed by a further increase of the load (figure 6b,
detail squared region). This behaviour was referred to as “stick-slip” crack propagation [53],
8. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
8
accompanying a series of unstable crack propagation and arrest. Again, the finite element results
are in good agreement with the experimental results [54].
Figure 4. Reaction force displacement relationship (δ=3mm).
Figure 5. Reaction force displacement relationship (δ=5mm).
9. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
9
Figure 6. (a) Useful comparisons between FEA vs Experimental results for (a) CF/Epoxy (UD) and (b)
CF/Epoxy (Fabric) for δ=5mm.
A closer look at the crack length results indicates that CF/PEI exhibits lower values (for all cases),
even when in this material is applied the maximum loading displacement compared to the
minimum loading displacement (figure 7).
Figure 7. Maximum crack length.
10. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
10
Further on, figures 8-9 and 10-11 shown the σx and σy distributions along the interface, where the
maximum values are found at the crack tip. The most dominant stress for the opening mode is σy.
It can be seen from figures 8 and 9, that σy remains tensile from the crack tip and no compressive.
The CF/PEI (UD) curve shows an elevation at the crack tip. It is clear that the differences in the σy
distributions related to the differences in the elastic properties as well as in the thickness of the
specimens. The higher value of young modulus (E2), produced higher stresses. The two fabric
materials, have an E2 that is about almost seven and six times more than the CF/EP (UD). In that
case, the σy distributions appears to be influenced by the adherends stiffness in the thickness
direction and does not seem to be influenced by the adherend stiffness in the longitudinal direction
[55]. Furthermore, the ductile matrices to deform plastically is restricted due to the preferential
occurance of unstable crack propagation in the woven fabric laminates (figures 12 and 13). As for
the critical strain energy release, depends from matrix toughness and the crack initiation region
which is usually associated with a slow stable crack growth [56].
0 5 10 15 20 25 30
0
200
400
600
800
1000
1200
σ
x
(Pa)
True Distance (mm)
CF/Epoxy (UD)
CF/Epoxy (Fabric)
CF/PEI (Fabric)
Crack tip
Figure 8. Stress distribution (σx) at the interface of substrate and resin (δ=3mm).
0 5 10 15 20 25 30
0
200
400
600
800
1000
1200
1400
1600
1800
σ
x
(Pa)
True Distance (mm)
CF/Epoxy (UD)
CF/Epoxy (Fabric)
CF/PEI (Fabric)
Crack tip
Figure 9. Stress distribution (σx) at the interface of substrate and resin (δ=5mm).
11. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
11
0 5 10 15 20 25 30
-5
0
5
10
15
20
25
30
35
40
45
σ
y
(Pa)
True Distance (mm)
CF/Epoxy (UD)
CF/Epoxy (Fabric)
CF/PEI (Fabric)
Crack tip
Figure 10. Stress distribution (σy) at the interface of substrate and resin (δ=3mm).
0 5 10 15 20 25 30
-5
0
5
10
15
20
25
30
35
40
45
50
55
σ
y
(Pa)
True Distance (mm)
CF/Epoxy (UD)
CF/Epoxy (Fabric)
CF/PEI (Fabric)
Crack tip
Figure 11. Stress distribution (σy) at the interface of substrate and resin (δ=5mm).
0.0 0.5 1.0 1.5 2.0 2.5 3.0
35
40
45
50
55
60
65
70
75
σ
y
(Pa)
Crack length (mm)
CF/Epoxy (UD)
CF/Epoxy (Fabric)
CF/PEI (Fabric)
Figure 12. Stress distribution (σy) at the interface after the 30mm (δ=3mm).
12. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
12
0 1 2 3 4 5
-30
-15
0
15
30
45
60
75
90
σ
y
(Pa)
Crack length (mm)
CF/Epoxy (UD)
CF/Epoxy (Fabric)
CF/PEI (Fabric)
Figure 13. Stress distribution (σy) at the interface after the 30mm (δ=5mm).
Other parameters such as the specimen width and the effect of adherend transverse thickness
appears to had a small effect on the DCB critical strain energy release rate GIc.
5.2 ANALYTICAL RESULTS
It is well known that in mode I tests, three basic regions appeared in the load-displacement curves,
these corresponding to linear elastic, non-linear elastic and non-linear inelastic behaviour. By
using the finite element method, it was observed that non-linear elastic behaviour was found after
the 30mm length (fig. 12 and 13), and this could be as a result of low flexural rigidity, as well as
fibre bridging mechanism. During crack propagation some of the fibers were pulled out, these
caused the extensive fiber bridging between the crack faces. This feature increased the resistance
to delamination, and consequently, a higher load value was required for the crack advance.
Therefore, further work is required to clarify these results. it should be mentioned that compliance
callibration method is the only data reduction technique, which considers the effect of fiber-
bridging, but it is sensitive to the accuracy of the displacement measurement.
Another parameter which is important to examine is the crosshead speed. Papanicolaou et al. [41],
shows that independently of the displacement rate applied, the linear elastic region is followed by
a large non-linear elastic region and this in turn by an inelastic response. The low flexural rigidity
of the specimens is mainly due to their low thickness (2h = 3.3-4.6mm). Thus large displacements
and rotations occur, leading to a non-linear elastic response.
Furthermore, results that comes from the above theories (analytical), are summarized in tables 2
and 3. In all cases, the modified model proposed by Freeman gives the highest values, while the
end slope of the cantilever (φo) ranges between 5.20-8.96o
. In all cases, crack initiation took
place well within the non-linear part (fig. 12 and 13).
13. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
13
Table 2. Analytical results (J/m2
) for different theories (δ=3mm).
Table 3. Analytical results (J/m2
) for different theories (δ=5mm).
It seems that both beam and corrected beam theory underestimates GIc values. Generally, GIc
increases as δ increases, but most of the energy supplied to the specimen is therefore consumed
in the development of secondary cracks in front of the crack tip, this further splitting resulting
in higher GIc values (fig. 14). As already mentioned, in the above theories-methods the fracture
toughness values depend on the specific data-reduction method applied. But in our case, the
corrected beam theory and the area method is impossible.
Figure 14: Primary and Secondary Cracks
6. CONCLUSIONS
A finite element formulation for double cantilever beam is presented and analyzed the distribution
of the stresses ahead of the crack tip using the extended finite element code (XFEM) in ABAQUS.
XFEM is a partition of unity based method which is able to incorporate functions, typically non-
polynomials into the standard finite element approximating space. The method relies on an
enhancement of the approximating space with enrichment functions. Based on the results, it can
be concluded that the correct crack path is imperative for determining the true failure strength of
the material. The strength will be affected by three parameters such as the length of the initial
crack, the mesh refinement and the domain for interaction integral. As it can be seen from the
above figures, the maximum stresses are found to increase as the crack grows more than 30mm.
It is also expected, that (a) the tougher the composite laminate is, the greater becomes the effect
14. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
14
of different kinds of precracks on the crack initiation, and the greater is the difference in crack
initiation and propagation values for GIc, and (b) fabric reinforced composite laminates result in
higher interlaminar fracture toughnesses than unidirectional reinforced materials, because of a
more complex fracture behavior. As already mentioned, the load instantly dropped at several
points during the delamination propagation in the load displacement curves, followed by a further
increase of the load (CF/Ep. and CF/PEI fabrics).
Furthermore, it is important to combine analytical-experimental approach in order to investigate
the fiber bridging effect in unidirectional mode I double cantilever beam specimens with
midplane delaminations. The bridging law was composed by the product of two terms: the fiber
force and the number of bridging fibers per unit area of crack face. The functions of these two
parameters were determined based on experiments. The bridging fibers enhance the resistance to
delamination and usually the energy release rate increases with the crack length (Resistance-curve
effect).
STATEMENT
This research received no specific grant from any funding agency in the public, commercial, or
not for-profit sectors.
REFERENCES
[1] Garg, AC, (1988) “Delamination - A damage mode in composite structures. Engineering Fracture
Mechanics”, Vol. 29, pp. 557-584.
[2] Bolotin, VV, (1996) “Delaminations in composite structures: Its origin, buckling, growth and
stability”, Composites Part B: Engineering. Vol 27B, pp. 129-145.
[3] Tay, TE, (2003) “Characterization and analysis of delamination fracture in composites-An overview
of developments from 1990 to 2001”, Journal of Applied Mechanics. Vol. 56, pp. 1-32.
[4] O'Brien, TK, (1982), “Characterization of delamination onset and growth in a composite laminate, in
damage in composite materials”,ASTM STP 775, pp. 140-167.
[5] Ghasemnejad, H., Blackman, BRK., Hadavinia, H et al., (2008), “Experimental studies on fracture
characterisation and energy absorption of GFRP composite box structure”, Composite Structures. Vol.
88, pp. 253-261.
[6] Blackman, BRK, Hadavinia H, Kinloch AJ, et al., (2003), “The use of cohesive zone model to study
the fracture of fiber composite and adhesively-bonded joints”, International Journal of Fracture. Vol.
119, pp. 25-46.
[7] Li, S, Thouless, MD, Waas, AM., Schroeder, JA., et al., (2005), “ Use of a cohesive-zone model to
analyze the fracture of a fiber-reinforced polymer-matrix composite”, Engineering Fracture
Mechanics. Vol. 65, pp. 537-549.
[8] Broughton, W.R., Koukoulas, T, Woolliams, P., et al., (2013) , “Assessment of nanoparticle loading
and dispersion in polymeric materials using optical coherence tomography”, Polymer Testing. Vol.
32, pp. 1290–1298.
[9] Tehrani, M, Boroujeni, A.Y., Hartman, TB, et al. (2013), “Mechanical characterization and impact
damage assessment of a woven carbon fiber reinforced carbon nano-tube-epoxy composite”,
Composites Science and Technology. Vol. 75, pp. 42–48.
[10] Shams, SS, El-Hajjar, RF, (2013), “Overlay patch repair of scratch damage in carbon fiber/epoxy
laminated composites”, Composites Part A: Applied Science and Manufacturing. Vol. 49, pp. 148–
156.
15. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
15
[11] Tserpes, K.I., Labeas, G.N. (2009). Mesomechanical analysis of non-crimp fabric composite
structural parts”, Composite Structures, vol. 87, p 358–369.
[12] Lecomte-Grosbras, P, Paluch, B, Brieu, M. (2013) , “Characterization of free edge effects: Influence
of mechanical properties, microstructure and structure effects”, Journal of Composite Materials. Vol.
47, pp. 2823–2834.
[13] Quddos, A, Khan, MB, Khan, RN., et al., (2012) , “Investigation of fiber-reinforced modified epoxy
resin composites”, Key Engineering Materials. pp. 510-511: 577–584.
[14] Shokrieh, MM, Daneshvar, A, Akbari, S, et al. (2013) , “ The use of carbon nanofibers for thermal
residual stress reduction in carbon fiber/epoxy laminated composites”, Carbon. Vol. 59, pp. 255–263.
[15] Kinloch, AJ, Mohammed, RD, Taylor, AC, et al. (2006), “The interlaminar toughness of carbon-fibre
reinforced plastic composites using ‘hybrid-toughened’ matrices”, Journal of Material Science. Vol.
41, pp. 5043–5046.
[16] Bazhenov, SL, (1995) , “ Interlaminar and intralaminar fracture modes in 0/90 cross-ply glass/epoxy
laminate”, Composites. Vol. 26 No.2 , pp. 125-133.
[17] ASTM D 6671-01. (2000) , “Standard test method for mixed mode I-mode II interlaminar fracture
toughness of unidirectional fiber reinforced polymer matrix composites”, in annual book of ASTM
Stds, pp. 15.03.
[18] ASTM D 5528-94a. (2000), “ Standard test method for mode I interlaminar fracture toughness of
unidirectional fiber-reinforced polymer matrix composites”, in annual book of ASTM Stds, pp.
15.03.
[19] Belytschko, T, Black, T, (1999), “Elastic crack growth in finite elements with minimal remeshing”,
International Journal for Numerical Methods in Engineering. Vol. 45, pp. 602-620.
[20] Moës, N, Dolbow, J, Belytschko, T, (1999), “A finite element method for crack growth without
remeshing”, International Journal for Numerical Methods in Engineering. Vol. 46, pp. 131-150.
[21] Sukumar, N, Moës, N, Moran, B, et al., (2000) , “ Extended finite element method for three-
dimensional crack modeling”, Journal for Numerical Methods in Engineering. Vol. 48, pp. 1549-
1570.
[22] Areias, P, Belytschko, T. (2005) , “ Analysis of three-dimensional crack initiation and propagation
using the extended finite element method”, Journal for Numerical Methods in Engineering. Vol. 63,
pp.760–788.
[23] de Borst, R, Gutirrez, M, Wells, G., Remmers, J, et al. (2004), “ Cohesive zone models, higher-order
continuum theories and reliability methods for computational failure analysis”, Journal for Numerical
Methods in Engineering. Vol. 60, pp. 289–315.
[24] de Borst, R, Remmers, JJ, Needleman, A, (2006), “ Mesh-independent discrete numerical
representations of cohesive-zone models”, Engineering Fracture Mechanics. Vol. 73 No. 2, pp. 160–
177.
[25] Mariani, S, Perego, U, (2003) , “Extended finite element method for quasi-brittle fracture”, Journal
for Numerical Methods in Engineering. Vol. 58, pp.103–126.
[26] Asferg, J, Poulsen, P, Nielsen, L. (2007) , “A consistent partly cracked xfem element for cohesive
crack growth”, Journal for Numerical Methods in Engineering. Vol. 72, pp. 464–485.
[27] Moёs, N, Belytschko, T, (2002), “Extended finite element method for cohesive crack growth”,
Engineering Fracture Mechanics. Vol. 69 No. 1, pp. 813-833.
[28] El-Sayed, S, Sridharan, S, (2001), “Predicting and tracking interlaminar crack growth in composites
using a cohesive layer model”, Composites Part B: Engineering. Vol. 32, pp. 545:553.
16. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
16
[29] Chai, H, (1986) , “ Bond thickness in adhesive joints and its significance for mode I interlaminar
fracture of composites”, Composite Material: Design and Testing (Seventh Conference). ASTM STP
893, pp.209- 231.
[30] Crews, JH, Shivakumar, Jr KN, Raju, IS, (1986), “Factors influencing elastic stresses in double
cantilever beam specimens”, NASA TM-89033, November.
[31] Protocol for Interlaminar fracture Testing No. 1’. European Group on Fracture (EGF), March 1992.
[32] Morais, de AB, Moura, de MF, Marques, AT and Castro, de PT, (2002) , “Mode-I interlaminar
fracture of carbon/epoxy cross-ply composites”, Composites Science and Technology. Vol. 62, pp.
679-686.
[33] Dahlen, C, Springer, GS, (1994), “Delamination growth in composites under cyclic loads”, Journal of
Composite Materials. Vol. 28, pp. 732-781.
[34] Ozdil, F, Carlsson, LA, Davies, P, (1998), “Beam analysis of angle-ply laminate end notched flexure
specimens”, Composites Science and Technology. Vol. 58, pp. 1929-1938.
[35] Yang, Z, Sun, CT, (2000), “Interlaminar fracture toughness of a graphite/epoxy multidirectional
composite”, Journal of Engineering Material and Technology. Vol. 122, pp. 428-433.
[36] Shindo, Y, Horiguchi, K, Wang, R, et al., (2001), “Double cantilever beam measurement and finite
element analysis of cryogenic mode I interlaminar fracture toughness of glass-cloth/epoxy laminates”,
Journal of Engineering Material and Technology. Vol. 123, pp. 191-197.
[37] Bishopp, KE., Drucker, DC, (1945), “Large deflections of cantilever beams”, Quartely of Applied
Mathematics. Vol. 3, p. 212.
[38] Devitt, DF, Shapery RA, Bradley, WL, (1990), “A method for determining the mode-1 delamination
fracture toughness of elastic and viscoelastic composite materials”, Journal of Composite Materials.
Vol. 14, p. 270
[39] Freeman JC., Phil. Mug. 1946, pp. 37- 855
[40] Williams, JG, (1987), “Large displacement and end block effects in the DCB interlaminar test in
modes I and II”, Journal of Composite Materials. Vol. 21, pp. 330
[41] Papanicolaou, GC, Bakos, D, (1996), “Interlaminar fracture behaviour of sandwich structures”,
Journal of Composites Part A: Applied Science and Manufacturing. Vol. 27A, pp. 165-173.
[42] Hemanth, R, Naresh, B, (2014), “Delamination behavior and experimental validation of glass fabric
/epoxy matrix and carbon fabric/epoxy composites in mode-I loading”, Mechanical Engineering: An
International Journal (MEIJ). Vol. 1(1).
[43] Haidar, F, AL-Qrimli., Fadhil, A, Mahdi, Firas, B, Ismail. (2015), “Carbon/epoxy woven composite
experimental and numerical simulation to predict tensile performance”, Advanced Materials Sciences
and Applications. Vol. 4 No.2, pp. 33-41.
[44] Kim, Ki-Young, Ye, Lin, Yan, Cheng. (2005), “Fracture behavior of polyetherimide (PEI) and
interlaminar fracture of CF/PEI laminates at elevated temperatures”, Polymer Composites. Vol. 26
No. 1,pp. 20-28.
[45] Lassila, LJ, Vallittu, PK, (2004), “The effect of fiber position and polymerization condition on the
flexural properties of fiber –reinforced composite”, Journal of Contemporary Dental Practice. Vol.
5(2).
[46] Mallick, PK, (2007) , “ Fiber reinforced composites materials, Manufacturing, and Design”, Taylor
and Francis Group, 3rd ed., ISBN 10987654321.
[47] Wittich, H, Friedrich, K, Stange, N, (1990), “Interlaminar fracture of fabric reinforced thermoplastic
composites. Advanced Composites in Emerging Technologies”, Third International Symposium
COMP' 90, University of Patras, Greece, August.
17. Advances in Materials Science and Engineering: An International Journal (MSEJ), Vol. 4, No. 1/2/3, September2017
17
[48] Chang, IY, Lees, JK, (1988), “Recent development in thermoplastic composites: a review of matrix
systems and processing methods”, Journal of Composite Materials. Vol. 1, pp. 277-296.
[49] de Morais, AB, Pereira, AB, (2007) , “ Application of the effective crack method to mode I and mode
II interlaminar fracture of carbon/epoxy unidirectional laminates”, Composites Part A: Applied
Science and Manufacturing. Vol. 38, pp. 785-794.
[50] Cho, JB, Hwang, JW, Cho, K, et al., (1993), “Effects of morphology on toughening of tetrafunctional
epoxy resins with poly(etherimide) ”, Polymer. Vol. 34 No.23, pp. 4832-4836.
[51] Yamanaka, K, Inoue, T, (1989), “Structure development in epoxy resin modified with poly(ether
sulphone) ”, Polymer. Vol. 30 No. 4, pp. 662-667.
[52] Kandpal, J, Yadaw, SB, Nagpal, AK, (2013), “Mechanical properties of multifunctional epoxy
resin/glass fiber reinforced composites modified with poly(etherimide)”, Advanced Materials Letters.
Vol. 4 No. 3, pp. 241-249.
[53] Gillespie, JW, Carlsson, Jr LA, Smiley, AJ, (1987), “Rate-Dependent Mode-I Interlaminar in
Graphite/Epoxy and Graphite/PEEK”, Composites Science and Technology.Vol. 28, pp. 1–15.
[54] Pegoretti, A, Cristelli, I, Migliaresi, C, (2008), “Experimental optimization of the impact energy
absorption of epoxy–carbon laminates through controlled delamination”, Composites Science and
Technology. Vol. 68, pp. 2653-2662.
[55] Crews, HJ, Shivakumar, KN, (1986), “Factors influencing elastic stresses in double cantilever beam
specimens”, NASA Technical Memorandum (TM) 89033.November.
[56] Lee, LH, Mandell, JF, McGarry, FJ, (1987) , “Fracture toughness and crack instability in tough
polymers under plane strain conditions”, Polymer Engineering and Science. Vol. 27, pp. 1128-1136.
AUTHOR
Panagiotis Charitidis is researcher at the Center of Orthopaedic Research(C.O.RE) at
Center for Interdisciplinary Research and Innovation-Aristotle University of Thessaloniki (
CIRI-AUTH)). He holds Ph.D in applied mechanics from the University of Patras. During
this period, he is professor at Democritus University of Xanthi (Greece).