This paper deals with investigation of fracture energy (GF) of concrete. The study involves experimental determination of fracture energy (GF) by testing three point bend concrete beams of same size but varying notch to depth ratios. RILEM fracture energy (GF) and Stress Intensity factor values is determined
Finite Element Analysis of honeycomb using AbaqusUdayan Ghosh
Prepared 3D CAD model of honeycomb in SolidWorks; studied structural behavior for static and dynamic loading
Performed mesh refinement, verification, validation and error analysis for the FEA
International Journal of Engineering Research and Development (IJERD)IJERD Editor
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
Finite Element Analysis of honeycomb using AbaqusUdayan Ghosh
Prepared 3D CAD model of honeycomb in SolidWorks; studied structural behavior for static and dynamic loading
Performed mesh refinement, verification, validation and error analysis for the FEA
International Journal of Engineering Research and Development (IJERD)IJERD Editor
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
The present investigation deals with the static analysis of adhesively bonded inner tapered double lap joint in laminated FRP composites subjected to transverse loading using three-dimensional theory of elasticity based finite element method. Many researchers studied the influences of various parameters on the failure behaviour on the composites. In those studies, the typical bonding parameters are surface conditions, fillet, bond line thickness, and environmental conditions. In the present study the stresses and deformation characteristics of adhesively bonded inner tapered double lap joint made of generally and especially orthotropic laminates (FRP) subjected to transverse loading for the three different adhesive angles, three different adhesive thicknesses with different fibre angle orientations, i.e. the adhesive angles from 350 to 450 increased in steps of 50. The variation in stresses and deflection are studied when the fibre angle orientation is varied from 00 to 900 in steps of 150. The adhesive thickness varies from 0.05 to 0.15 insteps of 0.05mm. In all the above cases stresses and displacements at various locations are evaluated for the static boundary conditions
Review on the Effect of Shear Connectors on Composite Deck SlabsIJAEMSJORNAL
This paper presents a review on the effect of shear connectors on composite deck slabs. Composite deck slabs consist of profile deck sheet and concrete. Several researchers have been studying the behaviour of composite slab but due to its complex behaviour yet it is not completely understood. The behaviour of composite slab directly depends on the deformability and contact strength. Here, some important literature reviews regarding composite slab behavior incorporating different profiles were discussed.
Improving the Properties of Self-compacted Concrete with Using Combined Silic...Pouyan Fakharian
The viscosity is the main property of self- compacted concrete (SCC) and using of pozzolan material such as metakaolin (MK) and Silica fume (SF) can help to achieve that goal. The effect of simultaneous substitution of MK and SF instead of cement on the rheological and mechanical properties of self-compacted concrete was experimentally investigated in this paper. Seventeen mix designs were cast with a substitution weight percentage (5, 10, 15, 20 %) in water to adhesive material ratio equal 0.32. All mixes were examined by compressive, tensile strengths and water absorption tests with an appropriate fluidity, without having signs of segregation or instability. The test results were indicated that the SCC mixes containing MK and SF had higher compressive and tensile strengths in comparison with no-pozzolan concrete. The comparison of linear multiple regression techniques (LMRT) and nonlinear multiple regression technique outputs with experimental results showed an appropriate similarity.
Shear Strength Prediction of Reinforced Concrete Shear Wall Using ANN, GMDH-N...Pouyan Fakharian
To provide lateral resistance in structures as well as buildings, there are some types of structural systems such as shear walls. The utilization of lateral loads occurs on a plate on the wall's vertical dimension. Conventionally, these sorts of loads are transferred to the wall collectors. There is a significant resistance between concrete shear walls and lateral seismic loading. To guarantee the building's seismic security, the shear strength of the walls has to be prognosticated by using models. This paper aims to predict shear strength by using Artificial Neural Network (ANN), Neural Network-Based Group Method of Data Handling (GMDH-NN), and Gene Expression Programming (GEP). The concrete's compressive strength, the yield strength of transverse reinforcement, the yield strength of vertical reinforcement, the axial load, the aspect ratio of the dimensions, the wall length, the thickness of the reinforced concrete shear wall, the transverse reinforcement ratio, and the vertical reinforcement ratio are the input parameters for the neural network model. And the shear strength of the reinforced concrete shear wall is considered as the target parameter of the ANN model. The results validate the capability of the models predicted by ANN, GMDH-NN, and GEP, which are suitable for use as a tool for predicting the shear strength of concrete shear walls with high accuracy.
A Review of Masonry Buckling CharacteristicsIJERA Editor
Masonry load bearing wall subjected to vertical concentric and eccentric loading may collapse through instability. In this Paper the buckling behaviour of masonry load bearing wall of different slenderness ratio were investigated by many researcher has been reviewed via testing a series of scale masonry wall subjected to concentric and eccentric vertical loading. It is also observed that buckling behaviour is greatly influenced by the material properties of units, mortar and units-mortar interface. The influence of nonlinear behaviour of interface element, slenderness ratio and various end conditions have been investigated together with the effect of different end eccentricity of vertical load
LABORATORY MODEL TESTS TO EFFECT OF DENSITY TO FILL MATERIAL ON THE PERFORMAN...IAEME Publication
The effective functioning of reinforced earth structures is very much dependent on the quality of materials and construction. Many times, due to poor quality of the materials used and poor quality control measures exercised, the density of the reinforced soil fill is not up to the design requirements, leading to underperformance or distress of the reinforced soil walls. Therefore, it becomes necessary to evaluate the level of underperformance vis-à-vis that of relative compaction. In view of this, in the present study, a series of laboratory experiments were carried out on a model soil wall of 300 mm high with vertical face, prepared at different density states of 95%, 80% and 70% of MDD of IS HCT. The wall was subjected to monotonic load applied through a model square footing of size (B) equal to 50 mm on the surface at an offset distance of 1(B). Similar tests were carried out on the soil wall reinforced with a Woven Geotextile in wrap around form; to study the effect of density on the performance of reinforced soil wall. The results indicated proportionality between relative compaction level and performance of soil wall without and with reinforcement.
When a ductile material with a crack is loaded in
tension, the deformation energy builds up around the crack tip
and it is understood that at a certain critical condition voids are
formed ahead of the crack tip. The crack extension occurs by
coalescence of voids with the crack tip. The “characteristic
distance” (Lc) defined as the distance b/w the crack tip & the void
responsible for eventual coalescence with the crack tip. Nucleation
of these voids is generally associated with the presence of second
phase particles or grain boundaries in the vicinity of the crack tip.
Although approximate, Lc assumes a special significance since it
links the fracture toughness to the microscopic mechanism
considered responsible for ductile fracture. The knowledge of the
“characteristic distance” is also crucial for designing the size of
mesh in the finite element simulations of material crack growth
using damage mechanics principles. There is not much work
(experimental as well as numerical) available in the literature
related to the dependency of “characteristic distance” on the
fracture specimen geometry. The present research work is an
attempt to understand numerically, the geometry dependency of
“characteristic distance” using three-dimensional FEM analysis.
The variation of “characteristic distance” parameter due to the
change of temperature across the fracture specimen thickness was
also studied. The work also studied the variation of “characteristic
distance”, due to the change in fracture specimen thickness.
Finally, the ASTM requirement of fracture specimen thickness
criteria is evaluated for the “characteristic distance” fracture
parameter. “Characteristic distance” is found to vary across the
fracture specimen thickness. It is dependent on fracture specimen
thickness and it converges after a specified thickness of fracture
specimen. “Characteristic distance” value is also dependent on the
temperature of ductile material. In Armco iron material, it is
found to decrease with the increase in temperature.
Dynamic Analysis of Double-Skin Composite Steel PlatesIOSR Journals
Double Skin Composite (DSC) plates are subjected to impact required to cause complete perforation and the accompanied failure modes are investigated. The amount of energy absorbed is calculated by capturing the residual velocity of penetrator after perforating the lower plate. The difference in initial kinetic energy and residual kinetic energy is the amount of energy absorbed by the panel. In the present paper a non-linear three-dimensional finite element models for Double Skin Composite panels subjected to dynamic loading is introduced. Pilot model is used to investigate the failure pattern in the composite panel when subjected to impact loads by rigid steel penetrator, while the other models are used to analyze the energy absorption capacity of such system when perforated. Results showed that such elements have good ability of absorbing energy when subjected to perforation, due to ductility of lower plate skin and vertical stiffness of lower shear studs.
Some Studies on Mode-II Fracture of Light Weight Blended Aggregate ConcreteIOSR Journals
Blended aggregate in concrete and arriving at the structural properties of blended aggregate
concrete is a thrust area. Pumice is very light and porous igneous rock that is formed during volcanic
eruptions.Cinder is a waste material obtained from steel manufacturing units. Shear strength is a property of
major significance for wide range of civil engineering materials and structures. Shear and punching shear
failures particularly in deep beams, in corbels and in concrete flat slabs are considered to be more critical and
catastrophic than other types of failures. This area has received greater attention in recent years. For
investigating shear type of failures, from the literature it is found that double central notched (DCN) specimen
geometry proposed by Prakash Desai and V.Bhaskar Desai is supposed the best suited geometry. In this present
experimental investigation an attempt is made to study the Mode-II fracture property of light weight blended
aggregate cement concrete combining both the pumice and cinder in different proportions, and making use of
DCN test specimen geometry . By blending the pumice and cinder in different percentages of 0, 25, 50, 75 and
100 by volumeof concrete, a blended light weight aggregate concrete is prepared. By using this the property
such as in plane shear strength is studied. Finally an analysis is carried out regarding Mode-II fracture
properties of blended concrete. It is concluded that the Ultimate load in Mode-II is found to decrease
continuously with the percentage increase in Pumice aggregate content. It is also observed that the ultimate
stress in Mode II is found to increase continuously with percentage increase in cinder aggregate content.
Low cycle biaxial fatigue behavior of direct aged Nickel-based 718 superalloy IJERA Editor
In recent years, significant advances in the fabrication process of nickel-base supperalloy leading to grain size
reduction have been made in order to improve fatigue properties of aircraft turbine discs. Indeed, a change in
particle size affects the initiation mode of fatigue cracks as well as the fatigue life of the material. The present
study aims to investigate the fatigue behavior of a newly developed nickel-based superalloy under biaxial-planar
loading. Low Cycle Fatigue (LCF) tests are performed at different stress ratios to study the influence of the
multiaxial stress state on the fatigue life of the material. Full-field displacement and strain measurements as well
as crack initiation detection are obtained using Digital Image Correlation (DIC) techniques. Results related to
different load ratios are presented and an appropriate biaxial lifetime prediction is given. Crack detection, strain
amplitude and number of cycles to crack initiation vs. triaxial stress ratio for each loading case are mentionned.
From fractographic investigations by scanning electron microscopy it is found that the mechanism of fatigue
crack initiation does not depend on the triaxial stress ratio and that most fatigue cracks initiate from subsurface
carbides.
Analysing The Composite Structure Of Riverted ,Hybrid And Bonded JointsIJERA Editor
Composite materials have been widely used as structural elements in aircraft structures due to their superior
properties. Aircraft structure is a huge assembly of skins, spars, frames etc. The structure consists of an
assembly of sub-structures properly arranged and connected to form a load transmission path. Such load
transmission path is achieved using joints. Joints constitute the weakest zones in the structure. Failure may occur
due to various reasons such as stress concentrations, excessive deflections etc. or a combination of these.
Therefore, to utilize the full potential of composite materials, the strength and stress distribution in the joints has
to be understood so that suitable configuration can be chosen for various applications
Finite Elements Modeling and Analysis of Double Skin Composite PlatesIOSR Journals
Abstract: Double skin composite (DSC) is a form of “steel/concrete/steel” sandwich structure; the steel plates
are connected to a sandwiched concrete core with welded stud shear connectors. In the present paper, a finite
element model for Double Skin Composite (DSC) panels subjected to quasi-static loading is developed. A series
of quasi-static finite elements models are used to analyze deformation and energy absorption capacity of such
system, when perforated by rigid penetrator with conical nose shape. Pilot test model is used to investigate the
failure pattern in the composite panel. The obtained results are compared to the experimental results; good
agreements are obtained between finite element and previous experimental results. Results show that such
elements have great ability of absorbing energy when subjected to perforation due to ductility of lower plate
skin and vertical stiffness of lower shear studs.
NUMERICAL INVESTIGATION ON THE PUNCHING BEHAVIOR OF RC FLAT SLABS STRENGTHENI...IAEME Publication
In this paper, the effectiveness of textile-reinforced mortar (TRM) and fiberreinforced
polymer (FRP), as a means of improving the punching behavior of
reinforced concrete flat slabs were numerically investigated. Finite element (FE)
model using ABAQUS computer program was developed to analyze eight half-scaled
slabs, in terms of load-carrying capacity, ductility, stiffness, and crack patterns. These
eight specimens were divided into two groups (G1 and G2) with four specimens for
each of them. Specimens of G1 was similar to that of G2 in all details but differ in the
eccentricity of the applied load. Specimens of G1 were tested with concentric load,
while these of G2 were tested with 150 mm eccentricity. For each group, one specimen
was built as control (unstrengthened), one was strengthened by FRP-sheet, and the
other two was strengthened by TRM-jacket with two different mesh opening (10 and
20 mm). The results obtained from FE analysis showed that the efficiency of TRM in
increasing the punching shear capacity of strengthened slabs was less than that of
FRP. In addition, the slabs strengthened by TRM showed stiffer behavior than that
strengthened by FRP, but lesser ductile. TRM effectiveness was sensitive to the mesh
size of the textile. When the mesh size decreased, stiffness was increased and ductility
was decreased.
Analysis of Economic Growth Quality to Improve Society Welfare in Southeast S...theijes
This study entitled "Analysis of Economic Growth Quality to Improve Society Welfare in Southeast Sulawesi". The research activities carried out as an effort to help the government of Southeast Sulawesi in solving economic problems is based on the economic growth achieved over the value of the national average but has not been able to provide overall welfare for the people. The aims to be achieved in this research is to investigate and analyze the impact economic growth quality to improve society welfare in Southeast Sulawesi. The research was conducted by taking samples at six districts and two cities in Southeast Sulawesi. The data used is quantitative data that is processed by the research model that had been developed by using statistical analysis econometric approach with panel data regression.The results showed that economic growth quality have significant impact with a positive direction to rate of society welfare in several districts / cities in Southeast Sulawesi. This means that economic growth quality that proxy with the pace of GDP growth, Gini Ratio Index , Williamson Index, the percentage decline in poverty and unemployment were able to improve society welfare in some districts / cities in Southeast Sulawesi which proxy with income per capita and Human Development Index during the period from 2006 until 2015
Non-woven fabric filters integrated with decentralized system for domestic wa...theijes
Pilot plant composed of fabric filters integrated with the decentralized treatment plant ZECUwas tested for its ability to remove the suspended solids and organic matters presented as TSS, CODt and CODs from wastewater. The filters were made from scrim polyester non-woven fabrics and were tested on gravity driven pressure. The investigation was executed on two phases. In the first phase; the flux rates were changed from 3.5-15 L/m2 /hr and the differential hydraulic head was 1.5 m, average TSS, CODt and CODs effluent concentrations 40 mg/l, 177 mg/l and 119 mg/l respectively. In the second phase the differential hydraulic head was changed to be 2.5 m, average TSS, CODt and CODs effluent concentrations were 43.6 mg/l, 133.7 mg/l and 105.3 mg/l respectively. The potential removal mechanism for the suspended solids by fabric filters is straining or sieving by filter pores. The potential removal mechanism for dissolved organic matters is dynamic membrane layer formed on the fabric filters surface and was able to remove soluble organic matters with CODs average removal efficiencies of 21.25% and 18.9%inphase (1) andphase (2) respectively.
A General-Purpose Architectural Approach to Energy Efficiency for Greendroid ...theijes
Mobile application processors are soon to replace desktop processors as the focus of innovation in microprocessor technology. Already, these processors have largely caught up to their more power hungry cousins, supporting out-of order execution and multicore processing. In the near future, the exponentially worsening problem of dark silicon is going to be the primary force that dictates the evolution of these designs. We have argued that the natural evolution of mobile application processors is to use this dark silicon to create hundreds of automatically generated energy-saving cores are called conservation cores, which can reduce energy consumption by an order of magnitude. Conservation cores(C-cores) try to solve utilization wall and consequently Dark Silicon issues.Greendroid is a development library for the android platform. It is intended to make UI developments easier and consistent through your applications. This paper describes Greendroid, a research prototype that demonstrates the use of such cores to save energy broadly across the hotspots in the android mobile phone software stack.
The present investigation deals with the static analysis of adhesively bonded inner tapered double lap joint in laminated FRP composites subjected to transverse loading using three-dimensional theory of elasticity based finite element method. Many researchers studied the influences of various parameters on the failure behaviour on the composites. In those studies, the typical bonding parameters are surface conditions, fillet, bond line thickness, and environmental conditions. In the present study the stresses and deformation characteristics of adhesively bonded inner tapered double lap joint made of generally and especially orthotropic laminates (FRP) subjected to transverse loading for the three different adhesive angles, three different adhesive thicknesses with different fibre angle orientations, i.e. the adhesive angles from 350 to 450 increased in steps of 50. The variation in stresses and deflection are studied when the fibre angle orientation is varied from 00 to 900 in steps of 150. The adhesive thickness varies from 0.05 to 0.15 insteps of 0.05mm. In all the above cases stresses and displacements at various locations are evaluated for the static boundary conditions
Review on the Effect of Shear Connectors on Composite Deck SlabsIJAEMSJORNAL
This paper presents a review on the effect of shear connectors on composite deck slabs. Composite deck slabs consist of profile deck sheet and concrete. Several researchers have been studying the behaviour of composite slab but due to its complex behaviour yet it is not completely understood. The behaviour of composite slab directly depends on the deformability and contact strength. Here, some important literature reviews regarding composite slab behavior incorporating different profiles were discussed.
Improving the Properties of Self-compacted Concrete with Using Combined Silic...Pouyan Fakharian
The viscosity is the main property of self- compacted concrete (SCC) and using of pozzolan material such as metakaolin (MK) and Silica fume (SF) can help to achieve that goal. The effect of simultaneous substitution of MK and SF instead of cement on the rheological and mechanical properties of self-compacted concrete was experimentally investigated in this paper. Seventeen mix designs were cast with a substitution weight percentage (5, 10, 15, 20 %) in water to adhesive material ratio equal 0.32. All mixes were examined by compressive, tensile strengths and water absorption tests with an appropriate fluidity, without having signs of segregation or instability. The test results were indicated that the SCC mixes containing MK and SF had higher compressive and tensile strengths in comparison with no-pozzolan concrete. The comparison of linear multiple regression techniques (LMRT) and nonlinear multiple regression technique outputs with experimental results showed an appropriate similarity.
Shear Strength Prediction of Reinforced Concrete Shear Wall Using ANN, GMDH-N...Pouyan Fakharian
To provide lateral resistance in structures as well as buildings, there are some types of structural systems such as shear walls. The utilization of lateral loads occurs on a plate on the wall's vertical dimension. Conventionally, these sorts of loads are transferred to the wall collectors. There is a significant resistance between concrete shear walls and lateral seismic loading. To guarantee the building's seismic security, the shear strength of the walls has to be prognosticated by using models. This paper aims to predict shear strength by using Artificial Neural Network (ANN), Neural Network-Based Group Method of Data Handling (GMDH-NN), and Gene Expression Programming (GEP). The concrete's compressive strength, the yield strength of transverse reinforcement, the yield strength of vertical reinforcement, the axial load, the aspect ratio of the dimensions, the wall length, the thickness of the reinforced concrete shear wall, the transverse reinforcement ratio, and the vertical reinforcement ratio are the input parameters for the neural network model. And the shear strength of the reinforced concrete shear wall is considered as the target parameter of the ANN model. The results validate the capability of the models predicted by ANN, GMDH-NN, and GEP, which are suitable for use as a tool for predicting the shear strength of concrete shear walls with high accuracy.
A Review of Masonry Buckling CharacteristicsIJERA Editor
Masonry load bearing wall subjected to vertical concentric and eccentric loading may collapse through instability. In this Paper the buckling behaviour of masonry load bearing wall of different slenderness ratio were investigated by many researcher has been reviewed via testing a series of scale masonry wall subjected to concentric and eccentric vertical loading. It is also observed that buckling behaviour is greatly influenced by the material properties of units, mortar and units-mortar interface. The influence of nonlinear behaviour of interface element, slenderness ratio and various end conditions have been investigated together with the effect of different end eccentricity of vertical load
LABORATORY MODEL TESTS TO EFFECT OF DENSITY TO FILL MATERIAL ON THE PERFORMAN...IAEME Publication
The effective functioning of reinforced earth structures is very much dependent on the quality of materials and construction. Many times, due to poor quality of the materials used and poor quality control measures exercised, the density of the reinforced soil fill is not up to the design requirements, leading to underperformance or distress of the reinforced soil walls. Therefore, it becomes necessary to evaluate the level of underperformance vis-à-vis that of relative compaction. In view of this, in the present study, a series of laboratory experiments were carried out on a model soil wall of 300 mm high with vertical face, prepared at different density states of 95%, 80% and 70% of MDD of IS HCT. The wall was subjected to monotonic load applied through a model square footing of size (B) equal to 50 mm on the surface at an offset distance of 1(B). Similar tests were carried out on the soil wall reinforced with a Woven Geotextile in wrap around form; to study the effect of density on the performance of reinforced soil wall. The results indicated proportionality between relative compaction level and performance of soil wall without and with reinforcement.
When a ductile material with a crack is loaded in
tension, the deformation energy builds up around the crack tip
and it is understood that at a certain critical condition voids are
formed ahead of the crack tip. The crack extension occurs by
coalescence of voids with the crack tip. The “characteristic
distance” (Lc) defined as the distance b/w the crack tip & the void
responsible for eventual coalescence with the crack tip. Nucleation
of these voids is generally associated with the presence of second
phase particles or grain boundaries in the vicinity of the crack tip.
Although approximate, Lc assumes a special significance since it
links the fracture toughness to the microscopic mechanism
considered responsible for ductile fracture. The knowledge of the
“characteristic distance” is also crucial for designing the size of
mesh in the finite element simulations of material crack growth
using damage mechanics principles. There is not much work
(experimental as well as numerical) available in the literature
related to the dependency of “characteristic distance” on the
fracture specimen geometry. The present research work is an
attempt to understand numerically, the geometry dependency of
“characteristic distance” using three-dimensional FEM analysis.
The variation of “characteristic distance” parameter due to the
change of temperature across the fracture specimen thickness was
also studied. The work also studied the variation of “characteristic
distance”, due to the change in fracture specimen thickness.
Finally, the ASTM requirement of fracture specimen thickness
criteria is evaluated for the “characteristic distance” fracture
parameter. “Characteristic distance” is found to vary across the
fracture specimen thickness. It is dependent on fracture specimen
thickness and it converges after a specified thickness of fracture
specimen. “Characteristic distance” value is also dependent on the
temperature of ductile material. In Armco iron material, it is
found to decrease with the increase in temperature.
Dynamic Analysis of Double-Skin Composite Steel PlatesIOSR Journals
Double Skin Composite (DSC) plates are subjected to impact required to cause complete perforation and the accompanied failure modes are investigated. The amount of energy absorbed is calculated by capturing the residual velocity of penetrator after perforating the lower plate. The difference in initial kinetic energy and residual kinetic energy is the amount of energy absorbed by the panel. In the present paper a non-linear three-dimensional finite element models for Double Skin Composite panels subjected to dynamic loading is introduced. Pilot model is used to investigate the failure pattern in the composite panel when subjected to impact loads by rigid steel penetrator, while the other models are used to analyze the energy absorption capacity of such system when perforated. Results showed that such elements have good ability of absorbing energy when subjected to perforation, due to ductility of lower plate skin and vertical stiffness of lower shear studs.
Some Studies on Mode-II Fracture of Light Weight Blended Aggregate ConcreteIOSR Journals
Blended aggregate in concrete and arriving at the structural properties of blended aggregate
concrete is a thrust area. Pumice is very light and porous igneous rock that is formed during volcanic
eruptions.Cinder is a waste material obtained from steel manufacturing units. Shear strength is a property of
major significance for wide range of civil engineering materials and structures. Shear and punching shear
failures particularly in deep beams, in corbels and in concrete flat slabs are considered to be more critical and
catastrophic than other types of failures. This area has received greater attention in recent years. For
investigating shear type of failures, from the literature it is found that double central notched (DCN) specimen
geometry proposed by Prakash Desai and V.Bhaskar Desai is supposed the best suited geometry. In this present
experimental investigation an attempt is made to study the Mode-II fracture property of light weight blended
aggregate cement concrete combining both the pumice and cinder in different proportions, and making use of
DCN test specimen geometry . By blending the pumice and cinder in different percentages of 0, 25, 50, 75 and
100 by volumeof concrete, a blended light weight aggregate concrete is prepared. By using this the property
such as in plane shear strength is studied. Finally an analysis is carried out regarding Mode-II fracture
properties of blended concrete. It is concluded that the Ultimate load in Mode-II is found to decrease
continuously with the percentage increase in Pumice aggregate content. It is also observed that the ultimate
stress in Mode II is found to increase continuously with percentage increase in cinder aggregate content.
Low cycle biaxial fatigue behavior of direct aged Nickel-based 718 superalloy IJERA Editor
In recent years, significant advances in the fabrication process of nickel-base supperalloy leading to grain size
reduction have been made in order to improve fatigue properties of aircraft turbine discs. Indeed, a change in
particle size affects the initiation mode of fatigue cracks as well as the fatigue life of the material. The present
study aims to investigate the fatigue behavior of a newly developed nickel-based superalloy under biaxial-planar
loading. Low Cycle Fatigue (LCF) tests are performed at different stress ratios to study the influence of the
multiaxial stress state on the fatigue life of the material. Full-field displacement and strain measurements as well
as crack initiation detection are obtained using Digital Image Correlation (DIC) techniques. Results related to
different load ratios are presented and an appropriate biaxial lifetime prediction is given. Crack detection, strain
amplitude and number of cycles to crack initiation vs. triaxial stress ratio for each loading case are mentionned.
From fractographic investigations by scanning electron microscopy it is found that the mechanism of fatigue
crack initiation does not depend on the triaxial stress ratio and that most fatigue cracks initiate from subsurface
carbides.
Analysing The Composite Structure Of Riverted ,Hybrid And Bonded JointsIJERA Editor
Composite materials have been widely used as structural elements in aircraft structures due to their superior
properties. Aircraft structure is a huge assembly of skins, spars, frames etc. The structure consists of an
assembly of sub-structures properly arranged and connected to form a load transmission path. Such load
transmission path is achieved using joints. Joints constitute the weakest zones in the structure. Failure may occur
due to various reasons such as stress concentrations, excessive deflections etc. or a combination of these.
Therefore, to utilize the full potential of composite materials, the strength and stress distribution in the joints has
to be understood so that suitable configuration can be chosen for various applications
Finite Elements Modeling and Analysis of Double Skin Composite PlatesIOSR Journals
Abstract: Double skin composite (DSC) is a form of “steel/concrete/steel” sandwich structure; the steel plates
are connected to a sandwiched concrete core with welded stud shear connectors. In the present paper, a finite
element model for Double Skin Composite (DSC) panels subjected to quasi-static loading is developed. A series
of quasi-static finite elements models are used to analyze deformation and energy absorption capacity of such
system, when perforated by rigid penetrator with conical nose shape. Pilot test model is used to investigate the
failure pattern in the composite panel. The obtained results are compared to the experimental results; good
agreements are obtained between finite element and previous experimental results. Results show that such
elements have great ability of absorbing energy when subjected to perforation due to ductility of lower plate
skin and vertical stiffness of lower shear studs.
NUMERICAL INVESTIGATION ON THE PUNCHING BEHAVIOR OF RC FLAT SLABS STRENGTHENI...IAEME Publication
In this paper, the effectiveness of textile-reinforced mortar (TRM) and fiberreinforced
polymer (FRP), as a means of improving the punching behavior of
reinforced concrete flat slabs were numerically investigated. Finite element (FE)
model using ABAQUS computer program was developed to analyze eight half-scaled
slabs, in terms of load-carrying capacity, ductility, stiffness, and crack patterns. These
eight specimens were divided into two groups (G1 and G2) with four specimens for
each of them. Specimens of G1 was similar to that of G2 in all details but differ in the
eccentricity of the applied load. Specimens of G1 were tested with concentric load,
while these of G2 were tested with 150 mm eccentricity. For each group, one specimen
was built as control (unstrengthened), one was strengthened by FRP-sheet, and the
other two was strengthened by TRM-jacket with two different mesh opening (10 and
20 mm). The results obtained from FE analysis showed that the efficiency of TRM in
increasing the punching shear capacity of strengthened slabs was less than that of
FRP. In addition, the slabs strengthened by TRM showed stiffer behavior than that
strengthened by FRP, but lesser ductile. TRM effectiveness was sensitive to the mesh
size of the textile. When the mesh size decreased, stiffness was increased and ductility
was decreased.
Analysis of Economic Growth Quality to Improve Society Welfare in Southeast S...theijes
This study entitled "Analysis of Economic Growth Quality to Improve Society Welfare in Southeast Sulawesi". The research activities carried out as an effort to help the government of Southeast Sulawesi in solving economic problems is based on the economic growth achieved over the value of the national average but has not been able to provide overall welfare for the people. The aims to be achieved in this research is to investigate and analyze the impact economic growth quality to improve society welfare in Southeast Sulawesi. The research was conducted by taking samples at six districts and two cities in Southeast Sulawesi. The data used is quantitative data that is processed by the research model that had been developed by using statistical analysis econometric approach with panel data regression.The results showed that economic growth quality have significant impact with a positive direction to rate of society welfare in several districts / cities in Southeast Sulawesi. This means that economic growth quality that proxy with the pace of GDP growth, Gini Ratio Index , Williamson Index, the percentage decline in poverty and unemployment were able to improve society welfare in some districts / cities in Southeast Sulawesi which proxy with income per capita and Human Development Index during the period from 2006 until 2015
Non-woven fabric filters integrated with decentralized system for domestic wa...theijes
Pilot plant composed of fabric filters integrated with the decentralized treatment plant ZECUwas tested for its ability to remove the suspended solids and organic matters presented as TSS, CODt and CODs from wastewater. The filters were made from scrim polyester non-woven fabrics and were tested on gravity driven pressure. The investigation was executed on two phases. In the first phase; the flux rates were changed from 3.5-15 L/m2 /hr and the differential hydraulic head was 1.5 m, average TSS, CODt and CODs effluent concentrations 40 mg/l, 177 mg/l and 119 mg/l respectively. In the second phase the differential hydraulic head was changed to be 2.5 m, average TSS, CODt and CODs effluent concentrations were 43.6 mg/l, 133.7 mg/l and 105.3 mg/l respectively. The potential removal mechanism for the suspended solids by fabric filters is straining or sieving by filter pores. The potential removal mechanism for dissolved organic matters is dynamic membrane layer formed on the fabric filters surface and was able to remove soluble organic matters with CODs average removal efficiencies of 21.25% and 18.9%inphase (1) andphase (2) respectively.
A General-Purpose Architectural Approach to Energy Efficiency for Greendroid ...theijes
Mobile application processors are soon to replace desktop processors as the focus of innovation in microprocessor technology. Already, these processors have largely caught up to their more power hungry cousins, supporting out-of order execution and multicore processing. In the near future, the exponentially worsening problem of dark silicon is going to be the primary force that dictates the evolution of these designs. We have argued that the natural evolution of mobile application processors is to use this dark silicon to create hundreds of automatically generated energy-saving cores are called conservation cores, which can reduce energy consumption by an order of magnitude. Conservation cores(C-cores) try to solve utilization wall and consequently Dark Silicon issues.Greendroid is a development library for the android platform. It is intended to make UI developments easier and consistent through your applications. This paper describes Greendroid, a research prototype that demonstrates the use of such cores to save energy broadly across the hotspots in the android mobile phone software stack.
Availability of a Redundant System with Two Parallel Active Componentstheijes
This paper considers a redundant system which consists of two parallel active components. The time-to-failure
and the time-to-repair of the components follow an exponential and a general distribution, respectively. The
repairs of failed components are randomly interrupted. The time-to-interrupt is taken from an exponentially
distributed random variable and the interrupt times are generally distributed. We obtain the availability for the
system
Production of CH4 and C2 hydrocarbons by axial and radial pulse H2/CO2 discha...theijes
Production of methane CH4 from a mixture gas of carbon dioxide CO2 and hydrogen H2 has been established by two types of pulse discharges. One is an axial discharge with a use of thin pair Ni wire electrodes separated by a narrow gap, and the other is a coaxially radial discharge with a use of inner rod and outer tube electrodes made of stainless steel (SUS). The former provides an intense gap discharge, while the latter provides a gentle discharge in the annular region. Decomposition of CO2 is enhanced in the former case when Ni (nickel) mesh disc electrode is placed behind the gap. Ni is known as catalysis. When the radial discharge proceeds in a closed gas system, 2C hydrocarbons such as ethane and ethylene are generated in case that a cylindrical mesh electrode made of Ni is attached to the powered SUS tube electrode. Both of the CH4 production and the energy efficiency for CH4 production are enhanced in case of Ni mesh electrodes, without a use of additional heating for the Ni catalysis. Synergy effect of plasma and Ni catalyst is observed
Paleoenvironment and Provenance Studies of Ajali Sandstone in Igbere Area, Af...theijes
The stratigraphy and sedimentology of the Ajali Sandstone successions in Igbere area,Afikpo Basin were studied in order to determine plaeoenvironmental setting and sourcemodel of the deposits. The studied deposits consist of five lithofacies namely: pebblysandstone facies, cross-bedded, laminated, bioturbated sandstone facies and mudstonefacies. Paleoenvironmental interpretation based on facies associations and sedimentarystructures revealed tide-influenced fluvial deposits, while inferences from bivariate plotsof calculated univariate parameters indicated fluvial deposits. The granulometricanalyses of the sediments indicated a predominantly moderately sorted, medium-grainedsandstone with some poorly sorted populations. The kurtosis ranged from mesokurticthrough leptokurtic to extremely leptokurtic sand populations and generally with somesymmetrical, positive and negative skewness. This result is suggestive of a sandpopulation with different tails, especially for the facies representing the poorly sortedpopulations. The sandstone in the area is essentially quartz sandstone or quartz arenitebased on petrographic analysis. The relative abundance of the framework elements (Q96, F 0 and R 4) suggests super-mature sand with a maturity index 19.0. Themineralogical and textural maturity of the sandstone therefore, indicated a polycyclicdeposit. This together with the constituent heavy minerals and paleocurrent directionsinferred that sources of detritus were from both the uplifted continental pluton and old sedimentary domain, respectively. The Crystalline Basement rocks of both theCameroon and Adamawa Highlands, the Oban Massif and western Nigeria Ilesha Spuron the one hand and the Abakaliki Anticlinorium on the other hand both satisfied suchsource models for the post-Santonian Ajali quartz–sand deposit.
Analytical Execution of Dynamic Routing Protocols For Video Conferencing Appl...theijes
In modern network communications, Routing protocols are getting an important function for the user data path that are responsible for controlling the routers to communicate together and forward packets by routers over the best trip path from a base node to a destination one. Dynamic routing protocols represented by RIP, OSPF and EIGRP are explained here for addressing various networks with different traffic environments. In this paper, the performance of these protocols are estimating with many factors like convergence activity and duration, average throughput, network end-to-end delay, Point-to-Point Utilization over the simulation based on OPNET academic version. From Simulation results, EIGRP have a fastest time convergence compared with other topologies of networks are confirmed and the OSPF has the highest Point-to-Point Utilization in the network followed by EIGRP then RIP. So, there is an attempt for finding out which protocols are suitable for the networks and from analyses to understand the role of the routing protocols in different network scenarios
E-Governance and the ICT Legislative Frameworktheijes
This study assesses the effect of ICT policies and practices toward ensuring the governance supported by information sharing in Tanzania. Logically, the work is organized in four main categories. The first category introduces the study through providing the background, statement of the problem and objectives. This part is followed by a research method. The study was based on interpretive principles, and it used secondary data to arrive to its conclusions. The analysis is conducted through grouping elements, which responds to the same pattern of the study, under the same section. The last part of the study provides the conclusion and recommendations to the local legislative framework
Bituminous Pavement Recycling – Effective Utilization of Depleting Non-Renewa...theijes
Bituminous pavement recycling is an effective and worldwide proven technique of conserving Energy, Environment and Economy while ensuring maintenance and preservation of roadway network. In the pavement recycling process, the materials from deteriorated pavements known as Reclaimed Asphalt Pavement (RAP), is partially or fully reused in fresh construction. The concept of RAP lies in restoring the physico-chemical properties of the aged bitumen to its original and at the same time to enhance the mechanical properties and strength of the aged binder. This paper gives a brief overview of various recycling methods of bituminous pavement including (1) Hot mix recycling, (3) Hot-in-place recycling, (3) Cold central plant recycling, (4) Coldin-place recycling, and (5) Full depth reclamation, their advantages, selection considerations, review of mix design procedure, unresolved issues related to their use and future scope in Indian context.
Turbofan Engine Modelling and Control Design using Linear Quadratic Regulator...theijes
There are many applications in which gas turbine engine is used today, including aircraft propulsion for both commercial and military purposes, and power generation and in all these Control systems technology has played a fundamental role in enhancing performance. Modelling plays a significant role in the development of the entire engine system performance. This paper investigated Linear Quadratic Regulator (LQR) model-based control method to obtain estimates of performance parameters. The main control variable selected is the fuel flow to control the rotational speed of high-pressure spool speed of the turbofan engine. Firstly a suitable mathematical model of the engine is developed in MATLAB Simulink environment with both the intercomponent volume and the constant mass flow methods used. Equations of the mass flow rate and the torque balance are incorporated in the steady state and dynamic state of the thermodynamic engine model. This represents the engine model by a set of first-order differential and algebraic equations and a linearized model is extracted for the analysis and design of a controller by LQR. It is demonstrated that LQR based controllers can perform better than conventional PID controllers. The settling time, rise time and maximum overshoot for LQR based controller are all less than those for PID based controller. The input also changes more accurately for LQR than the PID controller compared.
The Effect of Arm Stiffness on the Elasto-Kinematic Properties of Single-Axle...theijes
The paper is focused on the stiffness analysis of the longitudinal arm of single-axle suspension on elastokinematic behaviour of the vehicle axle which is highly important when considering the handling characteristics related tovehicle safety.The elasto-kinematic behaviour of the axle determines the course of the geometrical parameters of wheel suspension, the toe angle and camber as the function of wheel movement during force loading. This paper presents the complex MBS (Multi-Body Simulation)model of the wheel suspension with nonlinear characteristics of rubber-metal bushings. The model also comprises force elements such as springs, shock absorbers, stops and the transverse stabilizer. The model of flexible arm is implemented in the MBS model using the Craig-Bampton method, which represents a flexible body based on the synthesis of its own modal shapes. Subsequently,elasto-kinematic simulations are performed with the help ofthe computational system Hyperwork. The computational part of the paper presents the results of the elasto-kinematic behaviour of wheel axle for the flexible arm with different sheet metal thicknesses (2, 3 and 4 mm) and different materials (steel and aluminium alloy AlSi7Mg). Individual calculation models are compared to each other and also to the model of suspension with therigidarm. Elasto-kinematic analyses are also validated by the measurement inthe testing stage.
Retrospective and Prospective Studies of Gastro-Intestinal Helminths of Human...theijes
A five-year retrospective and one-year prospective studies of gastrointestinal (GIT) helminths was carried out in humans and dogs in Makurdi, Nigeria. Data from 534 individuals presented at the Federal Medical Centre (FMC) and 103 faecal samples from dogs at the Veterinary Teaching Hospital (VTH), University of Agriculture, Makurdi from 2007 to 2014 were used. The overall prevalence of zoonotic GIT helminths in humans was 76.21% (407/534) and 56.31% (58/103) in dogs. The differences in the prevalences in humans based on sex,ethnicity and age were not statistically significant (χ2 , P< 0.05). However, the test of individual factor (coefficient) on GIT helminthes in humans showed that hookworms prevalence was dependent on age (P = 0.001), Ascaris lumbricoides was dependent on ethnicity and age (P = 0.000 and 0.005), Taenia spp. prevalence was dependent on age and sex (P = 0.007 and 0.005), and Strongyloides stercoralis prevalence was dependent on age (P = 0.04). The prevalence in dogs depended on age and breed (χ2 ,P < 0.05) but not on sex (χ2 ,P > 0.05). Hookworms, Taenia spp and Trichuris vulpisoccurred in humans and dogs. Hookworms were the most common helminth of both humans and dogs. Individual factor (coefficient) on the effect of risk factors on specific helminths is essential in understanding the epidemiology of each helminth. Attention should be paid to control measures in man anddogs.
A Study of the Root Causes of High Failure Rate of Distribution Transformer -...theijes
A distribution transformer is one of major electrical equipment that links the power utility and power consumers. It is what enables the power utility to supply electricity to consumers. In recent time, there has been an upsurge of distribution transformers premature failure before reaching the desired and designed service life. Consequently, the power utility has been incurring huge economical losses in replacing the faulty transformers or repairing them. On the other hand, failure of transformer inconveniencies power end users by interrupting the power supplies for prolonged period of time before the faulty transformer is replaced. In this paper, an effort is made to investigate the root causes of premature failure of distribution transformers. Research has revealed that line surges and switching transients are among the main causes of the transformers failures as this accelerates deterioration of insulation materials. This has been aggravated by lack of lightning arrestors and vandalism of low voltage and high voltage earthing systems. It is also noted that a transformer is usually ‘killed’ by unusual stresses that usually break down its weak insulation and hence leading to reduced transformer life. Use of concrete poles with earth wire appended is proposed to deter vandalism of earthing wire. In addition, proper fuse grading, installation of High Voltage (HV) expulsion fuses and regular Operational and Maintenance (O&M) has been recommended to reduce the premature failure of distribution transformers.
Initial and Boundary Value Problems Involving the Inhomogeneous Weber Equatio...theijes
Initial and boundary value problems of the inhomogeneous Weber differential equation are treated in this work. General solutions are expressed in terms of the parametric Nield-Kuznetsov functions of the first and second kinds, and are computed when the forcing function is a constant or a variable function of the independent variable
A Case Study of Teaching the Concept of Differential in Mathematics Teacher T...theijes
In high schools of Viet Nam, teaching calculus includes the knowledge of the real function with a real variable. A mathematics educator in France, Artigue (1996) has shown that the methods and approximate techniques are the centers of the major problems (including number approximation and function approximation...) in calculus. However, in teaching mathematics in Vietnam, the problems of approximation almost do not appear. With the task of training mathematics teachers in high schools under the new orientations, we present a part of our research with the goal of improving the contents and methods of teacher training
The Effect of Personality Traits on Social Identification, Transformational L...theijes
This study aims to establish the role model the effect of personality traits on social identification, transformational leadership and employees performance. To examine the patterns of the effect between the variables used inferential analysis tool that Software SPSS version 21.0. The results of this study indicate that, personality traits that can improve employees performance when incorporating the variables that come into play, namely social identification and transformational leadership in Provincial Government Southeast Sulawesi.
The Investigation of Primary School Students’ Ability to Identify Quadrilater...theijes
In Vietnamese mathematics curricula, primary school students explicitly learn the concept of quadrilaterals such as parallelogram, rhombus, rectangle, square and trapezoid in the Grades 3, 4 and 5. They are presented individually, and there is no comparison between their characteristics. Therefore, the students will be difficult to recognize the relationships among kinds of quadrilaterals. The results of an investigation of 186 primary school students revealed that most of them found it easy to identify squares and rectangles but many of them asserted that “a square is not a rectangle”
Effects of Self Compacting Concrete Using the Discrete Models as Binary & Ter...theijes
The effect of using nanosized[4],[5] pozzolanic materials [1], [12], 14] like Fly ash(FA) [3], Metakeolin (MK) [8],Silica fume(SF)[6],Rise husk ash(RHA)[14],Ground granulated blust furnace slag (GGBFS)[2] etc. as partial replacement with dry weight of Ordinary Portland Cement(OPC) to enhance the strength, durability, workability of concrete. The test results of fresh and the hardened properties of Self compacting concrete (SCC)[8],[19] incorporating pozzolanic materials at various percentage by fixing the Water to Binder (i.e. powder)ratio(w/b) of 0.45. The effects of pozzolanic materials properties of SCC were investigated by comparing the test results. Various tests [4],[5],[9] were conducted on fresh SCC like the slump flow, L-box passing ability of the SCC mixtures and T500mm slump flow time were also done. Compressive strength test [9] along with the Initial surface absorption test(ISAT) and the Capillary suction test(CST)[7] were also performed on the hardened SCC[8]
The Characteristics of Traffic Accidents Caused by Human Behavior on the Road...theijes
The number of motor vehicles increasing impact of the issue of congestion and increasing number of traffic accidents. Roads Maj.Sungkono Kedung Kandang District of Malang has a high accident rate from 2008to 2012 according to data from Malang Police Unit Laka. Results Analysis off act or saffecting the behavior ofthe trafficaccident rateinthe RoadMayjendSungkono Malang include professional act orsaccidents by 87% is private, thehome city ofthe perpetratorsof accidentsas much as53.07% came fromMalang,, the age ofthe perpetratoraccident46.296% isaged26-45years, agepedestriansinvolved35.484% age<17th and17-25th ..Based onthe rate of accidentsper yearin theevent of an accidentat maximumie38.89%.
Review of Waste Management Approach for Producing Biomass Energy in Indiatheijes
The high volatility in fuel prices in the recent past, resulting turbulence in energy markets and the increase of the GHG has compelled many countries to look for alternate sources of energy, for both economic and environmental reasons. With growing public awareness about sanitation, and with increasing pressure on the government and urban local bodies to manage waste more efficiently, the Indian waste to energy sector is poised to grow at a rapid pace in the years to come. The dual pressing needs of waste management and reliable renewable energy source are creating attractive opportunities for investors and project developers in the waste to energy sector.
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.
There are many parameters of concrete that
influence its strength gaining characteristics. This study is
an attempt to use the early compressive strength test result to
estimate compressive strength at different ages. Potential
utilization of the early day compressive strength result to
predict characteristic strength of normal weight concrete has
been investigated. A simple mathematical model capable of
predicting the compressive strength of concrete at any age is
proposed for both stone and local aggregate concrete. The
basic model consists of a rational polynomial equation having
only two coefficients. This study also proposes a simple reliable
relationship between the coefficient p (strength at infinite
time) with the strength values of concrete of a particular day.
This relation greatly simplifies the concrete strength
prediction model. The developed model is validated for
commonly used stone aggregate concrete and also for local
(brick) aggregate concrete. Data used in this study are collected
from some previous studies and recent experimental works.
The analysis carried with the model using different data
exhibit reliable prediction of concrete strength at different
ages (7, 14, 28 days etc.) with excellent efficiency.
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.
Experimental and numerical evaluation of plasticity model with ductile damage...IJERA Editor
This work aims to develop a methodology for numerical evaluation via finite elements applied to projects shields sheet metal. To validate the methodology physical test were conduct and were compare with the numerical simulation. In the simulation, a plasticity material modelit was used at high strain rates, besides the insertion of a damage model through forming limit diagram (FLD) to capture the initiation of damage and energy criteria for propagation of the fracture. The tested shielding design is for the II-A protection level using the type 9mm ammunition.
Experimental and numerical evaluation of plasticity model with ductile damage...IJERA Editor
This work aims to develop a methodology for numerical evaluation via finite elements applied to projects shields sheet metal. To validate the methodology physical test were conduct and were compare with the numerical simulation. In the simulation, a plasticity material modelit was used at high strain rates, besides the insertion of a damage model through forming limit diagram (FLD) to capture the initiation of damage and energy criteria for propagation of the fracture. The tested shielding design is for the II-A protection level using the type 9mm ammunition.
Performance Based Evaluation of Shear Walled RCC Building by Pushover AnalysisIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Ultimate strength of composite beam with web openings subjected to combined n...eSAT Publishing House
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
Comparative study of experimental and analytical results of frp strengthened ...eSAT Publishing House
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
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Gen AI Study Jams _ For the GDSC Leads in India.pdf
Experimental Determination of Fracture Energy by RILEM Method
1. The International Journal Of Engineering And Science (IJES)
|| Volume || 6 || Issue || 3 || Pages || PP 103-112 || 2017 ||
ISSN (e): 2319 – 1813 ISSN (p): 2319 – 1805
DOI: 10.9790/1813-060301103112 www.theijes.com Page 103
Experimental Determination of Fracture Energy by RILEM
Method
Naik Partha Uday
Department of Civil Engineering, MGM College of Engineering, Kamothe.
--------------------------------------------------------ABSTRACT-----------------------------------------------------------
This paper deals with investigation of fracture energy (GF) of concrete. The study involves experimental
determination of fracture energy (GF) by testing three point bend concrete beams of same size but varying notch
to depth ratios. RILEM fracture energy (GF) and Stress Intensity factor values is determined.
Keywords: Concrete, Fracture mechanics, RILEM fracture energy, fracture toughness, , three point bending,
stress intensity factor.
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Date of Submission: 14 March 2017 Date of Accepted: 25 March 2017
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I. INTRODUCTION
Concrete, due to its excellent shielding capability, fire rating, long service life under normal and accidental
conditions and ease in construction with relatively lower cost, is used extensively in building most of the civil
engineering structures. In-spite of such salient features, the concrete structures generally consist of numerous
micro-cracks that might result in fracture of the concrete structures under service loads, accidental load and/or
exposure to regular environmental conditions. Thus a micro-crack in concrete may become a potential source of
crack propagation leading to a probable catastrophic failure. In order to prevent such accidents, it is necessary to
predict the failure mechanisms of structures, so that the safety of concrete structures throughout the service life
can be assured. The failure mechanism can be studied by quantifying the energy consumed in crack propagation
and formation of new crack surfaces. In a concrete structure, the crack growth requires a certain amount of
energy that can only be studied through an energy based propagation criterion, which provides a fundamental
basis for understanding the phenomenon of concrete fracture mechanism.[10]
Concrete despite predominantly elastic material response, exhibits a stable non-linear fracture response in
tension loading, when tested under displacement control. The reason for the non-linearity is the development of
a fracture process zone (FPZ) ahead of the crack tip. In a quasi brittle material like concrete the energy
dissipated for the formation of FPZ ahead of the crack tip, is termed as fracture energy. The concrete fracture
energy characterizing the failure process is still under extensive research. The size-independent fracture energy
is the most useful parameter in the analysis of cracked concrete structure. The present study investigates an easy
and robust technique for the determination of the size independent fracture energy of concrete.
Following are the main objective of the present study:
1. To study Fracture mechanics, concrete behaviour, failure mechanism and load bearing capacity of concrete
structures.
2. To study concrete as a quasi-brittle material through load displacement curve.
3. To study crack propagation of pre-notched beams.
4. To calculate Fracture Energy and study variation of same with respect to varying notch to depth ratio.
Fracture mechanics is in developing stage thus there are many things to research. In this present study, Fracture
Energy which is one of the important parameter will be calculated using work energy method. The method used
is the best technique and approved by RILEM, thus the name RILEM method.
The present work is restricted considering the experimental testing to be done. Study involves experimental
testing of pre-notched beams under three point bending. Beams of same size but with varying notch to depth
ratio are used. Mathematical modelling of present work is out of scope.
II. LITERATURE SURVEY
There are many research carried on Fracture Mechanics now-a-days. Some of the papers which I found
important for my research are reviewed and discussed here. In first paper by S.Y. Alam, A. Loukili, F.
Grondin, E. Rozière, June 2015, "Use of the digital image correlation and acoustic emission technique to
study the effect of structural size on cracking of reinforced concrete"[12]
an experimental investigation is
performed by employing two experimental techniques simultaneously i.e. digital image correlation and acoustic
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emission to study the degradation of reinforced concrete beams. The first method gives precise measurement of
surface displacements, thus crack openings and crack spacing are determined. In order to complement this
method and to investigate damage mechanisms, acoustic emissions resulting from internal damage are also
analysed. To study the effect of structural size Beams of three different sizes but proportionally similar, were
tested. Experimental measurements were compared with Euro-code expressions.
Based on results, following things were concluded. Bending tests were performed on reinforced concrete beams.
In the first part of the study, under service loading, comparison of Euro-code expressions for crack openings and
cracks spacing and experimental measurements were done. At low strains and for the smallest beam size the
results show that the measured values more or less agree with the calculated values. However, as the strain
increases, the Euro-code expressions underestimate the crack openings and spacing. As the size of the beam
increases the discrepancy between Euro-code estimation and experimental measurements of crack openings and
crack spacing increases. It seems that difference in expressions is due to the shift in failure modes observed
when the size of the specimen increases, which is not taken in account in expressions.
Micro-cracking is studied through AE parametric analysis in the second part of the study,. AE hits and AE
energy are analysed in the top and bottom sensors. Larger the beam size, the number of hits and AE energy
released are low during the initial loading stages. The AE energy release is more abrupt in larger beam (D3) at
peak load, while in the smaller beams it is quasi-continuous. A grouping method (similar to K-means method) is
used to identify different classes of AE energy released. For these classes, when the size increases from small to
large beams, AE parameters are analysed to identify micro-cracking and macro-cracking phases. The
conclusions are based on the results obtained on 1:3 scale. As the fracture process is more complex in reinforced
concrete as compared to plain concrete, more conclusive results may be obtained on a wider scale.
In next paper by, A. Nazari, J.G. Sanjayan, June 2015, "Stress intensity factor against fracture toughness
in functionally graded geo-polymers"[13]
the benefits of producing functionally graded geo-polymer in terms
of their modified stress intensity factor and fracture toughness are discussed. Pre-notched functionally graded
geo-polymer beams were fabricated by two different fly ash-based geo-polymer mixtures. The load was applied
parallel to the functionally graded region; two different structures were evaluated by changing the position of
the notch. The obtained results indicated that the crack nucleation and growth depend on the interaction between
stress intensity factor and fracture toughness. A crack facing an upward fracture toughness region is arrested,
when the applied stress is equal to the weakest strength of the constituent materials. On the other hand, the
fracture toughness of a crack facing a downward fracture toughness gradient is more than that facing an upward
one, without any subsequent arresting. It was shown that the position of the notch, and experiencing of
downward or upward gradient in mechanical properties mainly determine the final flexural strength of the
specimens.
Following conclusions were made in this paper. A modification method was proposed to the variations of stress
intensity factor, K, in FGG specimen. At first, fracture toughness, Kc, of functionally graded region was
suggested to change exponentially. By intersecting the curves of K and Kc, fracture toughness of functionally
graded specimens was determined. However, to deliver a comprehensive formulation of K, a modification
procedure was carried on. In addition to the variations of K in functionally graded region, the post monolithic
region in FGG is affected by the variation of K in functionally graded region. A modification factor of elastic
modulus ratio was proposed to determine the effect of notch position on fracture toughness of specimens. While
both specimens consist of G1 and G2 monolithic specimens, the fracture energy strongly depends on the notch
tip position. Regardless of the content of constituent materials, upward and downward changes of mechanical
properties determine the crack initiating and propagating across the FGG specimens. This modification factor is
not observed in most theoretical models and only variation of properties in graded region is considered.
However, experimental observations in this paper show this important difference feature.
Paper by Xiufang Zhang, Shilang Xu, March 2011, "A comparative study on five approaches to evaluate
double-K fracture toughness parameters of concrete and size effect analysis"[11]
discussed here. Using
experimental method and four existing analytical methods, the current paper presents a comprehensive
comparison of double-K fracture toughness parameters of concrete evaluated. Fracture tests were carried out on
compact tension wedge splitting specimens with various depths varying from 200 mm up to 1000 mm. In the
analytical calculation, depending on the relationship between critical crack tip opening displacement and the
abscissa value of turning point on bilinear softening curve, two different distributions of cohesive stress are
considered along crack extension. Four available analytical calculations yield almost the same values of double-
K fracture toughness parameters and agree well with those obtained from the experiment, which confirms the
consistency of five approaches.
He concluded that, crack development process from initial cracking to stable propagation to unstable
propagation in concrete may be well described through double-K fracture model in which two fracture control
parameters, called double-K fracture toughness, i.e., initiation fracture toughness and unstable fracture
toughness are introduced. In this study, a comparison of double-K fracture toughness parameters determined
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from the experimental measurements and four existing analytical solutions, i.e., Gauss–Chebyshev integral
method, simplified equivalent cohesive force method, simplified Green’s function method and four terms weight
function method, was done on the compact tension wedge splitting specimens with various depths. It must be
stressed in the calculation of cohesive fracture toughness that when large specimens are considered, the value of
the critical crack tip opening displacement CTODc is usually higher than that of ws on the bilinear softening
curve. The assumption of the linear cohesive stress distribution along crack extension is inapplicable for large
specimens especially ones with depth of more than 600 mm , which was adopted in the previous studies for
smaller specimens. From size effect analysis, the following main conclusions can be made:
a) unstable fracture toughness and initiation fracture toughness are not much affected by the specimens depth,
with the average value of about 1.656 MPa-m1/2
and 0.806 MPa-m1/2
, respectively;
b) as the depth of specimen increases up to about 600–800 mm depth range, both the extending critical
fracture process zone (ac-ao) and critical crack tip opening displacement CTODc are shown to increase.
Beyond this range, they appear to alter little and may be considered as material properties.
Lastly, paper by N. Trivedi, R.K. Singh, J. Chattopadhyay, March 2015," A comparative study on three
approaches to investigate the size independent fracture energy of concrete"[10]
discussed here deals with
investigation of size-independent fracture energy (Gf) of concrete. The study involves numerical modelling of
three point bend concrete beams that are geometrically similar having constant length to depth ratio with
varying notch to depth ratios. Values evaluated numerically and experimentally for RILEM fracture energy (Gf)
are found to be in reasonable agreement. Gf is estimated from developed relationship of fracture energy release
rate and through bilinear model by Gf values. Gf values have been utilized t odevelop a simple methodology for
estimation of Gf. Comparative analysis
has been carried out for Gf from three different methodologies.
Based on results he concluded, the size-independent fracture energy of concrete is the most useful parameter in
the analysis of cracked concrete structure which is investigated in the present work. The finite element
simulations of the TPB specimens of different sizes with a/W= 0.05, 0.25 and 0.33 are performed by
incorporating the concrete properties based on fracture energy strain softening model. Following conclusions are
drawn from the above study:
The estimated RILEM fracture energy (Gf) values of concrete from the numerically predicted and
experimentally observed load–load line displacement curves are found to be in reasonably good agreement.
The present work develops an easy and robust technique for the determination of the size independent
fracture energy of concrete. The study also invokes a primary approach based on concrete fracture
mechanics that describes the nonlinear aspects of concrete behaviour through load–load line responses for a
range of a/W ratios and help to understand the failure mechanisms and load bearing capacity of concrete
structures.
A comparative analysis of 3 methods used to measure the size-independent fracture energy of concrete has
been carried out. The observed values of GF from the three methodologies are found to be in reasonable
agreement. It is, therefore, concluded that either method can be used to obtain a unique value of the size-
independent fracture energy of concrete due to consistent trend of fracture energy values evaluated by all
methods.
Literature presented above shows many research are going on the Fracture parameters like Fracture Energy "Gf"
and Stress Intensity Factor "KIC" due to their importance in Fracture Mechanics. Various methods are used to
determine this parameters, but most simple and best technique approved by RILEM is Work of Fracture Method
which is also known as RILEM method.
The fracture parameters "Gf" & "KIC" are size independent thus it does not vary with size of structure if they are
geometrically similar.
III. THEORITICAL BACKGROUND
The material fracture properties are characterised by only three parameters - Fracture Energy,
Uni-axial Strength Limit and Width of the Crack Band ( Fracture Process Zone), while strain softening modulus
is a function of theses parameters. The fracture energy of concrete is the most important parameter in the
fracture behaviour of concrete that describes the mechanism of cracking. The commonly used method for
measuring the fracture energy is the work-of-fracture method recommended by RILEM.
The total energy of fracture includes all the energy dissipated per unit propagation distance of the fracture
process zone as a whole. This is called the Fracture Energy "Gf". The fracture toughness "Gc" defined by LEFM
is equal to Fracture Energy "Gf".
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Work of Fracture Method: ( RILEM )
This method, which was originally developed for ceramics is the first method of testing for fracture properties of
concrete to be proposed as a standard (RILEM, 1985) . The basis for applying this method to concrete was
developed by Hillerborg and his co-workers. Their method uses the "fictitious crack" concept.
The method can be applied to a variety of test specimen geometries but the proposed standard uses a beam
specimen loaded in three point bending with a central edge notch. RILEM technical committee recommended
the guidelines for determination of fracture energy of cementitious materials by conducting TPB test on notched
beam as shown in fig. 1. In order to obtain a complete load and load point displacement curve, a closed loop
servo hydraulic testing machine is recommended.
The fracture behaviour of concrete characterized by the RILEM measures the averaged fracture energy over the
entire projected ligament area.
Fig. 1 Three Point Bend Geometry
According to RILEM recommendation, the fracture energy is evaluated by dividing the total applied energy
with the projected ligament area. Briefly, the test procedure consists of the following steps :
1. The beam proportions are selected in relation, to maximum aggregate size. The minimum depth d is
approximately six times the size of the aggregate.
2. The vertical load-point deflection of the beam is to be measured and plotted continuously along with the
applied load P.
3. The test is to be conducted in a manner to produce stable crack growth. If closed-loop testing is used then
strain control should be selected. If a closed-loop system is not available, then a stiff testing machine is
required.
Therefore, for a specimen with a depth "W" and an initial crack length "a" as shown in fig. 1, the "Gf " is given
as:
Gf ( α , W ) = ∫ P d∂
where, α = a / W i.e notch to depth ratio.
IV. EXPERIMENTAL WORK
Materials used:
Cement: Ordinary Portland cement 43 grade conforming to Indian standard specification (IS:269-1976) was
used.
Aggregate: Sand obtained from local river beds was used as fine aggregate. Aggregate of maximum size 20mm
was used as coarse aggregate.
Water: Ordinary potable water was used.
Mix Adopted:
A concrete mix of 1:1:2 by weight with a water cement ratio of 0.45 was used. Generally this proportion of mix
gives M25 grade concrete.
Casting and curing of specimens:
The notch is made by using a Plywood of 2-3mm thickness of required size. Concrete was poured in three layers
and vibrated. Plywood was removed after 3-4hrs when initial setting of concrete is passed. After 24 hours of the
casting of the beam the mould was removed. Specimens were cured in a curing tank for 28 days.
Test Specimens:
A total of 18 beams were cast for testing. All 18 beams were of same size having different notch to depth ratio.
In each beam notch was at the centre.
Beams are divided into 3 types P1, P2 & P3 depending on notch to depth ratio. Six number of beams are cast for
each type of beam. Following are the details:
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Table 1. Beam Specification
Beam Type Beam Size Notch to depth ratio
P1 700 * 150 * 150 0.15
P2 700 * 150 * 150 0.35
P3 700 * 150 * 150 0.50
Details of Experimental Set-up:
The general view of experimental set-up for three-point loading is shown in fig.2. Testing of the beam was
carried out on Universal Testing Machine. Using the mechanical dial gauge with 0.01 mm least count the
vertical deflection of the beam at centre was measured.
Test Procedure:
Load was applied in the downward direction at centre of the beam. At every load increment, deflection at centre
of the beam were noted, using which load Vs deflection curves were plotted. Load increment on UTM was
controlled so that the maximum load is reached in 10-15mins.
Experimental methods to obtain softening portion:
When the load was nearing the maximum, the pointer in the deflectometer on UTM showed a sudden jerk to the
backward direction. But the deflection suddenly increased. From that point the load decreases gradually as
deflection increases. At some point, the system becomes stable. In this way, with decreasing load, higher
deflection is recorded before complete fracture of the beam. The negative inclination of the curve load Vs.
deflection is called softening portion of the curve.
V. RESULTS & DISCUSSION
The Load Vs Deflection curve for all 18 beams are plotted using results given below in table.
Fig. 2. Experimental set-up for three point bend test.
Fig. 3. Casting and development of artificial notch using ply-wood.
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Table 2. Experimental results for Beam P1
Fig 4. Load displacement curve for beam of notch to depth ratio 0.15
Table 3. Experimental results for Beam P2
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Fig 5. Load displacement curve for beam of notch to depth ratio 0.35
Table 5. Experimental results for Beam P3
Fig 6. Load displacement curve for beam of notch to depth ratio 0.50
We can observe from all Load Vs Displacement curve for each beam that the curve is a straight line before it
reaches to max. displacement. When its nearing to max. displacement there is a non-linearity in the curve and a
sudden increase in displacement when we reach to max load. Beyond that, the load gradually decreases but
displacement keeps on increasing till it reaches to failure. A portion after max load attained is a softening
portion of a curve. Such strain hardening and strain softening shows concrete is a Quasi-brittle material.
Some of the equations used:
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1) Brown and Swarley's equation for (S / D) = 4 for Geometry Function 'Y',
Y (a / W) = 1.93 - [ 3.07 * (a / W)] + [ 14.53 * (a / W)2
] - [ 23.98 * (a / W)3
] +
[ 25.22 * (a / W)4
]
2) Fracture Energy, Gf = A / [( W - a) * B ]
3) Bending Moment, B.M = (P * S) / 4 + BM due to self wt. of beam
4) Stress Intensity Factor (Fracture Toughness),
KIC = ( 6 * Y * BM * √a ) / ( B2
* W )
Table 6. Values of Fracture Energy and Stress Intensity Factor
Beam Notch to
depth ratio
(a/W)
Notch
depth 'a'
(m)
Max.
load 'P'
(KN)
Area
under
Curve 'A'
Bending
Moment
'BM'
Gf
(N/m)
Y KIC
(MPa m1/2
)
Gc
(N/m)
P1,1 0.15 0.0225 7.0 4.01 1.067 209.67 1.728 491.7 9.673
P1,2 0.15 0.0225 6.8 3.443 1.037 180.03 1.728 477.9 9.136
P1,3 0.15 0.0225 6.6 3.678 1.01 192.31 1.728 465.5 8.667
P1,4 0.15 0.0225 7.2 3.854 1.097 201.52 1.728 505.6 10.22
P1,5 0.15 0.0225 6.5 3.568 0.992 186.56 1.728 457.2 8.361
P1,6 0.15 0.0225 7.3 4.11 1.11 214.91 1.728 511.6 10.47
P2,1 0.35 0.0525 3.4 1.388 0.527 94.91 1.986 426.2 7.964
P2,2 0.35 0.0525 3.6 1.349 0.557 92.24 1.986 450.5 9.624
P2,3 0.35 0.0525 3.2 1.324 0.497 90.53 1.986 401.9 7.461
P2,4 0.35 0.0525 3.6 1.365 0.557 93.33 1.986 450.5 9.235
P2,5 0.35 0.0525 3.5 1.366 0.527 93.40 1.986 426.2 8.694
P2,6 0.35 0.0525 3.6 1.398 0.557 95.59 1.986 450.5 8.118
P3,1 0.50 0.0750 2.2 0.838 0.347 74.49 2.606 440.4 7.757
P3,2 0.50 0.0750 2.6 0.834 0.407 74.13 2.606 516.5 9.389
P3,3 0.50 0.0750 2.5 0.816 0.392 72.53 2.606 497.5 8.892
P3,4 0.50 0.0750 2.4 0.825 0.377 73.33 2.606 478.4 8.776
P3,5 0.50 0.0750 2.3 0.812 0.362 72.18 2.606 459.4 8.442
P3,6 0.50 0.0750 2.0 0.791 0.317 70.31 2.606 402.3 6.474
From above obtained results we can take average and summarize as follows:
Table 7. Summary
Beam
Type
Max. Load
(KN)
Displacement at
max. load (mm)
Failure Load
(KN)
Max. Displacement
(mm)
Gf
(N/m)
KIC
(MPa m1/2
)
Gc
(N/m)
P1 6.90 0.31 1.40 0.91 197.5 484.92 9.42
P2 3.52 0.31 1.20 0.59 93.33 460.97 8.52
P3 2.33 0.40 1.17 0.46 72.83 454.42 8.29
From table 7, we can see that max. load for all type of beams differ from each other. As notch to depth ratio
increases max load carrying capacity decreases. Thus, type P1 beams takes more load than other two type. But
failure load of all three types of beams almost remains same. Displacement observed at max load also does not
have much of difference. Max displacement of all three types of beams vary. From load Vs displacement curve,
type P1 is more ductile than other two types. Ductility decreases as notch to depth ratio increases.
Fracture Energy or Fracture Toughness "Gf" calculated for type P2 & type P3 do not have much difference but
type P1 has some abrupt value. The reason is due to boundary effect. As notch created in type P1 was very close
to boundary of beam the width of Fracture Process Zone (FPZ) is enormous and thus the fracture energy
obtained is abrupt and thus boundary effect was observed in type P1 beam. Due to boundary effect we will
neglect Gf values of type P1 and therefore the range of fracture energy is 72-93 N/m.
Stress intensity factor "KIC" is calculated using Brown and swarley's equation. "KIC" is also called as Toughness.
Both fracture toughness "Gf" and toughness "KIC" are one and the same. They define the propagation of cracks
one in energy and other in stress respectively. The range of "KIC" is 454-484 MPa m1/2
.
Energy release rate Gc defined by Griffiths considering concrete as a brittle material is also calculated here.
Values determined experimentally for Gc & Gf should be equal but it is found they are not. Thus, we can confirm
concrete is not a brittle material. Also, Gc determines only the energy dissipated in front of notch to propagate
till failure whereas Gf gives the total energy dissipated in the beam i.e. to propagate notch, to create FPZ in front
of notch and micro cracks in beams therefore the difference in value. The range of Gc is found out to be 8 to 10
N/m.
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VI. CONCLUSION
Based on testing of 18 beams and evaluating the values of Fracture Energy, following conclusion can be drawn:
1) The study invokes a primary approach based on concrete fracture mechanics that describes the nonlinear
aspects of concrete behaviour through load–load line responses for a range of a/W ratios and help to
understand the failure mechanisms and load bearing capacity of concrete structures.
2) Strain hardening and strain softening was studied through load vs displacement curve.
3) Failure of all beams was through pre-notch which was expected.
4) Deflection of beams is linear in pre-peak curve and increases abruptly when reaches peak load.
5) Fracture Energy decreases as notch to depth ratio increases.
6) The range of Fracture Energy is from 72N/m to 93N/m.
7) Boundary effect was observed in type P1 beams i.e. beams with notch to depth ratio of 0.15.
VII. FUTURE SCOPE
The concept of Fracture mechanics is still in developing stages and so much to find before we apply in practical
world. Following are some future study which can be done to the present work:
1) Developing a FEM model for the present work and compare the experimental and numerical work.
2) Testing of various geometrically similar beams with different sizes having constant span to depth ratio and
varying notch to depth ratio.
3) Experimental work (2) can be extended by varying span to depth ratio.
REFERENCES
[1]. ACI Committee 446.1R (chaired by ZDENEK P. BAZANT), "Fracture Mechanics of Concrete: Concepts, Models' and
Determination of Material Properties", Fracture Mechanics.
[2]. ACI Committee446 (chaired by Vellore Gopalaratnam), "Finite Element Analysis of Fracture in Concrete Structures: State of The
Art", 446.3R-97.
[3]. BARENBLATT G. I. 1959," The formation of equilibrium cracks during brittle fracture. General ideas and hypothesis. Axially-
symmetric cracks", Prikladnaya Matematikai Mekhanika, Vol. 23, No.3, pp. 434-444.
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[9]. Materials and Structures/Materials et Constructions, Vol. 33, January-February 2000, pp 3-5 "RILEM TC 162-TDF : Test and
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[10]. N. Trivedi, R.K. Singh, J. Chattopadhyay, March 2015," A comparative study on three approaches to investigate the size
independent fracture energy of concrete", Elsevier, Engineering Fracture Mechanics 138 (2015) 49-62.
[11]. Xiufang Zhang, ShilangXu, March 2011, "A comparative study on five approaches to evaluate double-K fracture toughness
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[12]. S.Y. Alam, A. Loukili, F. Grondin, E. Rozière, June 2015, "Use of the digital image correlation and acoustic emissiontechnique to
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[14]. B.L. Karihaloo, H.M. Abdalla and T.Imjai, 2003, "A Simple method of determining the true specific fracture energy of concrete",
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[15]. Bhushan L. Karihaloo, 1995, "Fracture Mechanics & Structural concrete", Longman Scientific & Technical.