This study experimentally investigates geometrically necessary dislocations (GNDs) and local mechanical property variations in the ferrite phase of dual phase steels. Electron backscatter diffraction measurements show GND densities are an order of magnitude higher near ferrite-martensite interfaces than in ferrite grains. Nanoindentation tests reveal local hardening of ferrite near interfaces. Detailed testing specifies the hardened interface region is typically 1.5 μm thick. A finite element model is developed considering graded hardness properties in the ferrite near interfaces, aiming to model macroscopic mechanical behavior based on microstructural properties.
Axial Capacity Enhancement of CFRP Confined Columns Made of Steel Fiber Reinf...IOSRJMCE
Results of the experimental study on the axial compressive behavior of steel fiber reinforced concrete (SFRC) wrapped with fiber reinforced polymer (FRP) have been presented in this paper. A total of 18 concrete cylinders were tested under axial compression. The effects of steel fiber parameters were investigated which includes fiber aspect ratio (AR) and fiber volume fraction (VF). The concrete cylinders were divided into groups of confined and unconfined ones. In accordance with previous study, it was found that, FRP confined cylinders showed greater axial stress than that of unconfined specimens. Although the presence of steel fiber increases the peak axial stresses for both confined and unconfined group of specimens, but no significant change of peak axial stress (and peak strain) has been observed in both confined and unconfined group due to increase of fiber volume ratio. But with the increase of fiber aspect ratio, the peak axial stresses of both unconfined and FRPconfined cylinders were found to slightly decrease. It was also observed that, concrete specimens reinforced with internal steel fiber absorbed much higher energy than that of unreinforced ones.
Experimental Investigation of Axial Capacity and Energy Absorption of SFRC Co...IJMERJOURNAL
ABSTRACT: This paper presents the results of the experimental study on the axial compressive behavior of steel fiber reinforced concrete (SFRC) wrapped with fiber reinforced polymer (FRP). A total of 18 concrete cylinders were tested under axial compression. The effects of steel fiber parameters were investigated which includes fiber aspect ratio (AR) and fiber volume fraction (VF). The concrete cylinders were divided into groups of confined and unconfined ones. In accordance with previous study, it was found that, FRP confined cylinders showed greater axial stress than that of unconfined specimens. Although the presence of steel fiber increases the peak axial stresses for both confined and unconfined group of specimens, but no significant change of peak axial stress (and peak strain) has been observed in both confined and unconfined group due to increase of fiber volume ratio. But with the increase of fiber aspect ratio, the peak axial stresses of both unconfined and FRP-confined cylinders were found to slightly decrease. It was also observed that, concrete specimens reinforced with internal steel fiber absorbed much higher energy than that of unreinforced ones.
Improving Mechanical Properties of AL 7075 alloy by Equal Channel Angular Ext...IJMER
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.
Experimental study on Torsion behavior of Flange beam with GFRPIJSRD
The Study deals with experimental study using glass fiber polymers in civil science. Repairing represents an important aspect of the construction industry and its importance is increasing due to surrounding conditions or geoenvironmental degradations, increased service loads, reduced ability (to hold or do something) due to (old/allowing to get old/getting older), worsening because of poor construction materials and work quality’s and need for seismic-related have demanded the need for repair and rehabilitation of existing structures. Fiber reinforced polymers has been utilized effectively as a part of numerous applications such as low weight, high quality and capacity to last. Numerous past examination chips away at torsion strengthening were centered on strong rectangular RC Beams with distinctive strip designs and diverse sorts of fiber. Distinctive models were produced to torsion test for strengthening of RC beams and effectively utilized for approval of the test works.In the present work test study was done with a specific end goal to have a superior comprehension the conduct of torsion reinforcing of strong RC flanged T-Beam. A RC T-beam is deliberately examined and intended for torsion like a RC rectangular beam; the impact of cement on flange is disregarded by codes. In the present study impact of width in changing so as to oppose torsion is concentrated on flange width of controlled bars. Alternate specification considered is reinforcing and fiber orientations.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Deformation behavior of consecutive workpieces and Stable -Unstable Flow in Materials Processed in equal channel angular pressing and grain refinement.
This document summarizes an article that discusses the behavior of hollow circular steel tubes under axial and eccentric compression loading, both with and without glass fiber reinforced polymer (GFRP) jacketing. Twelve steel tube specimens were tested under different loading conditions. Finite element analysis was also conducted using ANSYS software. The results showed that GFRP jacketing effectively arrested elephant foot buckling in steel tubes under both loading conditions. It also enhanced the stiffness, ultimate load capacity, and ductility of unwrapped tubes. However, more than two layers of GFRP wrapping led to undesirable inward buckling of the tubes.
This document presents an experimental and analytical study comparing the structural behavior of composite concrete slabs with profiled steel decking. 18 full-scale slab specimens were tested under different shear span lengths to evaluate the longitudinal shear bond strength between the concrete and steel deck. The experimental results were compared to analytical calculations using the m-k method and partial shear connection method from Eurocode 4. The m-k method was found to provide a more conservative estimate of load-carrying capacity than the partial shear connection method, with generally good agreement between experimental and analytical values.
Axial Capacity Enhancement of CFRP Confined Columns Made of Steel Fiber Reinf...IOSRJMCE
Results of the experimental study on the axial compressive behavior of steel fiber reinforced concrete (SFRC) wrapped with fiber reinforced polymer (FRP) have been presented in this paper. A total of 18 concrete cylinders were tested under axial compression. The effects of steel fiber parameters were investigated which includes fiber aspect ratio (AR) and fiber volume fraction (VF). The concrete cylinders were divided into groups of confined and unconfined ones. In accordance with previous study, it was found that, FRP confined cylinders showed greater axial stress than that of unconfined specimens. Although the presence of steel fiber increases the peak axial stresses for both confined and unconfined group of specimens, but no significant change of peak axial stress (and peak strain) has been observed in both confined and unconfined group due to increase of fiber volume ratio. But with the increase of fiber aspect ratio, the peak axial stresses of both unconfined and FRPconfined cylinders were found to slightly decrease. It was also observed that, concrete specimens reinforced with internal steel fiber absorbed much higher energy than that of unreinforced ones.
Experimental Investigation of Axial Capacity and Energy Absorption of SFRC Co...IJMERJOURNAL
ABSTRACT: This paper presents the results of the experimental study on the axial compressive behavior of steel fiber reinforced concrete (SFRC) wrapped with fiber reinforced polymer (FRP). A total of 18 concrete cylinders were tested under axial compression. The effects of steel fiber parameters were investigated which includes fiber aspect ratio (AR) and fiber volume fraction (VF). The concrete cylinders were divided into groups of confined and unconfined ones. In accordance with previous study, it was found that, FRP confined cylinders showed greater axial stress than that of unconfined specimens. Although the presence of steel fiber increases the peak axial stresses for both confined and unconfined group of specimens, but no significant change of peak axial stress (and peak strain) has been observed in both confined and unconfined group due to increase of fiber volume ratio. But with the increase of fiber aspect ratio, the peak axial stresses of both unconfined and FRP-confined cylinders were found to slightly decrease. It was also observed that, concrete specimens reinforced with internal steel fiber absorbed much higher energy than that of unreinforced ones.
Improving Mechanical Properties of AL 7075 alloy by Equal Channel Angular Ext...IJMER
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.
Experimental study on Torsion behavior of Flange beam with GFRPIJSRD
The Study deals with experimental study using glass fiber polymers in civil science. Repairing represents an important aspect of the construction industry and its importance is increasing due to surrounding conditions or geoenvironmental degradations, increased service loads, reduced ability (to hold or do something) due to (old/allowing to get old/getting older), worsening because of poor construction materials and work quality’s and need for seismic-related have demanded the need for repair and rehabilitation of existing structures. Fiber reinforced polymers has been utilized effectively as a part of numerous applications such as low weight, high quality and capacity to last. Numerous past examination chips away at torsion strengthening were centered on strong rectangular RC Beams with distinctive strip designs and diverse sorts of fiber. Distinctive models were produced to torsion test for strengthening of RC beams and effectively utilized for approval of the test works.In the present work test study was done with a specific end goal to have a superior comprehension the conduct of torsion reinforcing of strong RC flanged T-Beam. A RC T-beam is deliberately examined and intended for torsion like a RC rectangular beam; the impact of cement on flange is disregarded by codes. In the present study impact of width in changing so as to oppose torsion is concentrated on flange width of controlled bars. Alternate specification considered is reinforcing and fiber orientations.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Deformation behavior of consecutive workpieces and Stable -Unstable Flow in Materials Processed in equal channel angular pressing and grain refinement.
This document summarizes an article that discusses the behavior of hollow circular steel tubes under axial and eccentric compression loading, both with and without glass fiber reinforced polymer (GFRP) jacketing. Twelve steel tube specimens were tested under different loading conditions. Finite element analysis was also conducted using ANSYS software. The results showed that GFRP jacketing effectively arrested elephant foot buckling in steel tubes under both loading conditions. It also enhanced the stiffness, ultimate load capacity, and ductility of unwrapped tubes. However, more than two layers of GFRP wrapping led to undesirable inward buckling of the tubes.
This document presents an experimental and analytical study comparing the structural behavior of composite concrete slabs with profiled steel decking. 18 full-scale slab specimens were tested under different shear span lengths to evaluate the longitudinal shear bond strength between the concrete and steel deck. The experimental results were compared to analytical calculations using the m-k method and partial shear connection method from Eurocode 4. The m-k method was found to provide a more conservative estimate of load-carrying capacity than the partial shear connection method, with generally good agreement between experimental and analytical values.
Dynamic Analysis of Double-Skin Composite Steel PlatesIOSR Journals
1) The document analyzes dynamic finite element models of double-skin composite steel plates subjected to impact loading. A rigid penetrator impacts composite panels made of steel skins separated by a concrete core with shear stud connectors.
2) Results show that the panels have good energy absorption capacity due to the ductility of the lower steel plate and stiffness provided by lower shear studs. Increasing the upper or lower plate thickness, or concentrating more studs in the center, increases the energy absorbed before perforation.
3) The failure patterns are investigated. Under impact, the upper plate initially perforates and moves upward due to inertia effects. The upper studs increase plate stiffness. Concrete failure is more localized than under static
A Study on Effect of Sizes of aggregates on Steel Fiber Reinforced ConcreteIJERD Editor
Plain, unreinforced concrete is a brittle material, with a low tensile strength, limited ductility and
little resistance to cracking. In order to improve the inherent tensile strength of concrete there is a need of
multidirectional and closely spaced reinforcement, which can be provided in the form of randomly distributed
fibers. Steel fiber is one of the most commonly used fibers The present experimental study considers the effect
of aggregate size and steel fibers on the modulus of elasticity of concrete. Crimped steel fibers at volume
fraction of 0%.0.5%, 1.0% and 1.5% were used. Study on effect of volume fraction of fibers and change of
aggregate size on the modulus of elasticity of concrete was also deemed as an important part of present
experimental investigation. This work aims in studying the mechanical behavior of concrete in terms of modulus
of elasticity with the change of aggregate size reinforced with steel fibers of different series for M30 and M50
grade concretes. The results obtained show that the addition of steel fiber improves the modulus of elasticity of
concrete. It was also analyzed that by increasing the fiber volume fraction from 0%, to 1.5% there was a healthy
effect on modulus of elasticity of Steel Fiber Reinforced concrete.
Experimental Behavior of RC Beams Strengthened by Externally Bonded CFRP with...IJERDJOURNAL
Abstract:- Carbon fiber-reinforced polymers (CFRP) laminates, or plates, offer very high-strength potential; however, handling of long pieces of these flexible plates can present challenges under field conditions. The development of methods for splicing CFRP plates will enhance the versatility and Practicality of using these materials in field applications. This paper studies the efficiency of CFRP lap splice in externally bonded CFRP flexural strengthened reinforced concrete beams. Seven half-scale beams with different conditions were tested in two-point bending until failure. Two groups were tested; the first one includes control specimens: the first without CFRP strengthening, the second strengthened with full length and without splice, and the third with cutoff at middle of the beam. All specimens in the second group having cut-off at the middle and with lap splice lengths equal 300, 450, 600, 900 mm. respectively on each side of the cut-off. The study illustrates the effect of confinement on the first crack load, failure load, mid-span deflection, and strain in both reinforcement and CFRP. The failure load was also predicted analytically by CEB-FIP (1993), adopting the traditional sectional analysis for strain compatibility. Instead of strain measuring, three accurate bond-slip models are used to provide accurate prediction for the contribution of CFRP in the flexural capacity of the strengthened beam since all strengthened beams are failed by interfacial debonding of CFRP.
Mechanical property assessment of austempered and conventionally hardened aisiIAEME Publication
The document summarizes a study that assessed the mechanical properties of AISI 4340 steel that underwent austempering heat treatment versus conventional hardening. Specimens were subjected to tensile, torsion, hardness, impact, and microstructure tests in the as-bought, austempered, and conventionally hardened conditions. Austempering improved tensile, torsional, and impact strength compared to conventional hardening, though it showed a slight decrease in hardness. Lower bainitic and martensitic microstructures were observed after austempering and conventional hardening, respectively.
Strengthening of reinforced concrete beam using steel fiber at different dept...eSAT Journals
Abstract
This paper presents the results of an experimental investigation for enhancing the shear and ultimate strength capacities of reinforced concrete (RC) beams using steel fiber at different depths. Ultimate loads, load-deflection curves, cracking and crushing patterns have been compared with those of the RC beams without steel fiber henceforth noted as controlled beam. A total of four sets of experiments each having three concrete beams, one set control beam and three sets with randomly distributed discrete steel fiber at different depths henceforth noted as fiber reinforced concrete (FRC) beam, were performed to determine the most economical structure in the perspective of ultimate strength and shear capacity. From the test results, it was found that incorporation of steel fiber in RC beams have shown to be effective in enhancing the shear strength capacity. It has also been observed that the strength increases with the use of varying depth of steel fiber. Beam strengthened using this scheme has shown 20% increase in shear strength and ultimate load in comparison to controlled beam.
Key Words: Reinforced Concrete Beams, High Strength Concrete, Steel fibers, strengthening
This study investigated the compressive strength of reinforced concrete columns wrapped with different hybrid fiber reinforced polymer (FRP) configurations. Four 150x380mm concrete columns were tested: one unconfined control column and three wrapped with different combinations of glass, basalt, and jute FRP. The column wrapped with two layers each of basalt, glass, and jute FRP (CBGJ) achieved the highest compressive strength, reaching 1000kN and exceeding the unconfined column's strength by 25%. Analysis of the load-displacement and load-strain behaviors showed that the CBGJ wrapping configuration resulted in higher displacement and strain values compared to the other specimens. The results indicate that hybrid FRP wrapping can significantly
This document discusses the importance of grain size in materials and methods for producing ultrafine grain and nanomaterials. Decreasing grain size improves mechanical properties through increasing dislocations and grain boundaries. Severe plastic deformation techniques like equal channel angular pressing and high pressure torsion are used to refine grains down to the nanoscale in a top-down process. These nanomaterials exhibit high strength, ductility, and thermal stability due to their small, uniformly distributed grains.
1) The document describes an experimental investigation of glass fibre reinforced plastic (GFRP) bridge deck panels subjected to static and fatigue loading.
2) Testing of prototype GFRP composite bridge deck panels was conducted under simulated wheel loads, with two rectangular patch loads applied symmetrically.
3) The results showed that under buckling criteria, panels failed at 123.6 kN with a deflection of 7.538mm, and under local shear criteria panels failed at 113.8 kN with a deflection of 4.057mm. Panels also resisted up to 5 million fatigue cycles.
Fatigue behaviour of reinforced concrete beams with corrodedkmpmanoj
The document summarizes a study on the fatigue behavior of reinforced concrete beams with corroded steel reinforcement. Several beams were constructed with varying levels of corrosion induced in the steel reinforcement. The beams were subjected to high-cycle fatigue loading. The corrosion reduced the fatigue life of the beams and decreased the flexural stiffness. Testing of the corroded steel bars after fatigue loading found that corrosion and fatigue reduced the yield strength of the steel but did not significantly change the tensile strength. The critical region for failure was found to be at the location of most severe corrosion pits in the steel.
An Analytical Study on Static and Fatigue Analysis of High Strength Concrete ...Stephen Raj
In recent years FRP stands as a better alternative to restore and upgrade deficient structures. The deficiency may be due to change in design standards, improper construction practices (or) adverse environmental conditions. Under such circumstances, adoption of appropriate technique for restoring the structure becoming challenging task. The objective of this thesis work is to evaluate the static and fatigue response of HSC beams with externally bonded FRP laminates using ANSYS software. The modeling and analysis is done using the software for HSC beam. The beams were strengthened with FRP laminates. The models are provided with carbon types of Fiber Reinforced Polymer (FRP) laminates. The available experimental data of HSC beam in flexure behavior is the source material of this analysis work. All the relevant data are taken from that source material. The static and fatigue load cases are applied and the results are discussed. The comparison is made between the available experimental results of HSC beam with analytical based results of HSC beam.
Knowledge and Experience of Menopause - A Rural Based Study in Aligarhjournal ijrtem
ABSTRACT: The menopause is a transitional phase in women’s life.The level of oestrogen is decreased ,because of which a variety of symptoms such as hot flushes, mucosal dryness, excessive sweating, emotional fluctuations, psychoses, decr-eased strength and calcification of bones occurs. Attitudes, perception and expectations are part of the psychosocial phenomenon surrounding menopause. Natural menopause is diagnosed after 12 months of amenorrhoea not associated with a pathological cause. Menopause is a gradual process that lasts for about 2 years, called climacteric. It is normal and should not be taken as a disease or syndrome. The aim of this study was to find out the knowledge and experience of menopausal symptoms among women who had attained menopause
The document summarizes research testing the effect of steel fiber volume fraction on the flexural strength of high-strength concrete beams. 25 beams were tested with steel fiber volumes from 0.5-4%. Testing showed flexural strength increased with higher fiber volumes. As fiber content increased, the failure mode transitioned from shear to flexure. Load-deflection curves showed higher maximum loads and deflections for beams with more fibers. In conclusion, adding steel fibers increases flexural strength of beams, especially at lower fiber volumes.
IRJET-Experimental behavior of Concrete under Compression Load with Steel Fib...IRJET Journal
This document summarizes research on the experimental behavior of concrete under compression load when partially replacing cement with steel fiber and ferrocement. The research involved casting and testing cylinders and cubes of M25 grade concrete with different mixes - some with steel fiber and ferrocement additions and others without. The results showed that concrete with a 0.5% addition of steel fiber and no ferrocement layers had the highest ultimate strain and a 16% increase in compressive strength compared to plain concrete cubes. The research concluded that steel fiber and ferrocement additions can improve the performance and properties of concrete under compression loads.
IRJET- Experimental Study of Structural Behaviour of Double Skin Hollow –...IRJET Journal
This document summarizes an experimental study on the structural behavior of double skin hollow concrete filled steel tubular (DSH-CFST) columns under axial compressive loading. 36 specimens were tested with varying hollowness ratios. Test results showed that DSH-CFST columns can provide higher strength and ductility than solid CFST columns. Stress-strain curves and load-deformation curves were compared for different specimen types. The study found that DSH-CFST columns exhibited up to 77% higher compressive stresses than solid CFST columns. DSH-CFST columns also demonstrated improved ductility compared to solid CFST columns. The results provide information on optimizing the strength and structural performance of DSH-CFST columns
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.
IRJET - Performance of SFRC Beams under Combined State of Flexure, Direct...IRJET Journal
This document summarizes research on the performance of steel fiber reinforced concrete (SFRC) beams under combined states of flexure, direct compression, and shear. It describes an experimental study that tested SFRC beams with various fiber volume fractions (0%, 0.5%, 0.75%, 1.0%) under different compression loads (0, 50, 100, 125 kN). The study found that adding steel fibers increased the compressive strength, flexural strength, and shear strength of the concrete beams. Beams with higher fiber content performed better under the combined loading conditions compared to beams with lower or no fiber content. The document provides details on the materials, beam specimens, mixing, casting, curing, and testing methods used
Study on flexural strengthening of RC beams using ferrocement laminates with ...IRJET Journal
This document reviews 17 articles on strengthening reinforced concrete beams with ferrocement laminates containing Recron-3S fibers. The articles studied parameters like the type and number of wire meshes in the laminates, mortar mix ratios, and fiber usage. Several studies found that adding 2-3 layers of wire mesh laminates containing 2.35% mesh reinforcement and 30% steel slag increased the load capacity and ductility of strengthened beams compared to control beams. Other studies concluded that bottom layers of ferrocement provided better strengthening than side layers alone. Overall, the document evaluates research on using ferrocement laminates containing fibers to flexurally strengthen reinforced concrete beams.
The document summarizes an experimental study that investigated the flexural behavior of reinforced concrete beams strengthened with various materials and techniques. Eight beams were tested with different strengthening approaches, including carbon fiber reinforced polymer sheets, glass fiber reinforced polymer sheets, steel plates, or combinations of these materials. Beams were preloaded to induce cracking before strengthening. The strengthened beams were then reloaded to failure. The study aimed to evaluate the flexural properties, failure loads, stiffness, and ductility of beams strengthened with different materials and techniques. In general, strengthening increased yield and ultimate loads but reduced beam ductility compared to the unstrengthened control beam.
Cyclic Response of Reinforced Concrete Moment Resisting Beams Repaired with E...IJERA Editor
This paper presents the results of a quasi-static cyclic test carried out on a reinforced concrete special moment resisting beam to study the efficiency of traditional repair techniques in restoring the strength and stiffness capacity of damaged RC beams. The beam was tested in a cantilever mode and was subjected to a standard loading protocol with increasing amplitude of displacement cycles. The final damage state of the beam consisted of severe cracking and spalling of the cover concrete. The cracks were repaired with low-viscosity injection epoxy and the spalled concrete was repaired with early-strength grout. The repaired specimen was subjected to the same loading protocol as the original specimen to study the efficiency of the repair technique employed. It was observed that epoxy injection is not effective in restoring the strength and stiffness of beams with bar slip of longitudinal bars at the support end.
A Study of Electrical and Magnetic Properties of La+3 Substituted Ni-Zn Ferritesiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Preparation and Structural Properties of Aluminium Substituted Lithium Nano F...IOSR Journals
This document describes the preparation and structural properties of aluminum-substituted lithium nanoferrites synthesized using the citrate gel auto combustion method. Nanoferrites with the general formula Li0.5AlxFe2.5-xO4 (where x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared at low temperature (1800C). X-ray diffraction analysis confirmed the formation of a single-phase cubic spinel structure with particle sizes ranging from 13 to 27 nm. Lattice parameter, density, and porosity were calculated from the XRD data and showed decreases with increasing aluminum content. Scanning electron microscopy revealed the formation of
Dynamic Analysis of Double-Skin Composite Steel PlatesIOSR Journals
1) The document analyzes dynamic finite element models of double-skin composite steel plates subjected to impact loading. A rigid penetrator impacts composite panels made of steel skins separated by a concrete core with shear stud connectors.
2) Results show that the panels have good energy absorption capacity due to the ductility of the lower steel plate and stiffness provided by lower shear studs. Increasing the upper or lower plate thickness, or concentrating more studs in the center, increases the energy absorbed before perforation.
3) The failure patterns are investigated. Under impact, the upper plate initially perforates and moves upward due to inertia effects. The upper studs increase plate stiffness. Concrete failure is more localized than under static
A Study on Effect of Sizes of aggregates on Steel Fiber Reinforced ConcreteIJERD Editor
Plain, unreinforced concrete is a brittle material, with a low tensile strength, limited ductility and
little resistance to cracking. In order to improve the inherent tensile strength of concrete there is a need of
multidirectional and closely spaced reinforcement, which can be provided in the form of randomly distributed
fibers. Steel fiber is one of the most commonly used fibers The present experimental study considers the effect
of aggregate size and steel fibers on the modulus of elasticity of concrete. Crimped steel fibers at volume
fraction of 0%.0.5%, 1.0% and 1.5% were used. Study on effect of volume fraction of fibers and change of
aggregate size on the modulus of elasticity of concrete was also deemed as an important part of present
experimental investigation. This work aims in studying the mechanical behavior of concrete in terms of modulus
of elasticity with the change of aggregate size reinforced with steel fibers of different series for M30 and M50
grade concretes. The results obtained show that the addition of steel fiber improves the modulus of elasticity of
concrete. It was also analyzed that by increasing the fiber volume fraction from 0%, to 1.5% there was a healthy
effect on modulus of elasticity of Steel Fiber Reinforced concrete.
Experimental Behavior of RC Beams Strengthened by Externally Bonded CFRP with...IJERDJOURNAL
Abstract:- Carbon fiber-reinforced polymers (CFRP) laminates, or plates, offer very high-strength potential; however, handling of long pieces of these flexible plates can present challenges under field conditions. The development of methods for splicing CFRP plates will enhance the versatility and Practicality of using these materials in field applications. This paper studies the efficiency of CFRP lap splice in externally bonded CFRP flexural strengthened reinforced concrete beams. Seven half-scale beams with different conditions were tested in two-point bending until failure. Two groups were tested; the first one includes control specimens: the first without CFRP strengthening, the second strengthened with full length and without splice, and the third with cutoff at middle of the beam. All specimens in the second group having cut-off at the middle and with lap splice lengths equal 300, 450, 600, 900 mm. respectively on each side of the cut-off. The study illustrates the effect of confinement on the first crack load, failure load, mid-span deflection, and strain in both reinforcement and CFRP. The failure load was also predicted analytically by CEB-FIP (1993), adopting the traditional sectional analysis for strain compatibility. Instead of strain measuring, three accurate bond-slip models are used to provide accurate prediction for the contribution of CFRP in the flexural capacity of the strengthened beam since all strengthened beams are failed by interfacial debonding of CFRP.
Mechanical property assessment of austempered and conventionally hardened aisiIAEME Publication
The document summarizes a study that assessed the mechanical properties of AISI 4340 steel that underwent austempering heat treatment versus conventional hardening. Specimens were subjected to tensile, torsion, hardness, impact, and microstructure tests in the as-bought, austempered, and conventionally hardened conditions. Austempering improved tensile, torsional, and impact strength compared to conventional hardening, though it showed a slight decrease in hardness. Lower bainitic and martensitic microstructures were observed after austempering and conventional hardening, respectively.
Strengthening of reinforced concrete beam using steel fiber at different dept...eSAT Journals
Abstract
This paper presents the results of an experimental investigation for enhancing the shear and ultimate strength capacities of reinforced concrete (RC) beams using steel fiber at different depths. Ultimate loads, load-deflection curves, cracking and crushing patterns have been compared with those of the RC beams without steel fiber henceforth noted as controlled beam. A total of four sets of experiments each having three concrete beams, one set control beam and three sets with randomly distributed discrete steel fiber at different depths henceforth noted as fiber reinforced concrete (FRC) beam, were performed to determine the most economical structure in the perspective of ultimate strength and shear capacity. From the test results, it was found that incorporation of steel fiber in RC beams have shown to be effective in enhancing the shear strength capacity. It has also been observed that the strength increases with the use of varying depth of steel fiber. Beam strengthened using this scheme has shown 20% increase in shear strength and ultimate load in comparison to controlled beam.
Key Words: Reinforced Concrete Beams, High Strength Concrete, Steel fibers, strengthening
This study investigated the compressive strength of reinforced concrete columns wrapped with different hybrid fiber reinforced polymer (FRP) configurations. Four 150x380mm concrete columns were tested: one unconfined control column and three wrapped with different combinations of glass, basalt, and jute FRP. The column wrapped with two layers each of basalt, glass, and jute FRP (CBGJ) achieved the highest compressive strength, reaching 1000kN and exceeding the unconfined column's strength by 25%. Analysis of the load-displacement and load-strain behaviors showed that the CBGJ wrapping configuration resulted in higher displacement and strain values compared to the other specimens. The results indicate that hybrid FRP wrapping can significantly
This document discusses the importance of grain size in materials and methods for producing ultrafine grain and nanomaterials. Decreasing grain size improves mechanical properties through increasing dislocations and grain boundaries. Severe plastic deformation techniques like equal channel angular pressing and high pressure torsion are used to refine grains down to the nanoscale in a top-down process. These nanomaterials exhibit high strength, ductility, and thermal stability due to their small, uniformly distributed grains.
1) The document describes an experimental investigation of glass fibre reinforced plastic (GFRP) bridge deck panels subjected to static and fatigue loading.
2) Testing of prototype GFRP composite bridge deck panels was conducted under simulated wheel loads, with two rectangular patch loads applied symmetrically.
3) The results showed that under buckling criteria, panels failed at 123.6 kN with a deflection of 7.538mm, and under local shear criteria panels failed at 113.8 kN with a deflection of 4.057mm. Panels also resisted up to 5 million fatigue cycles.
Fatigue behaviour of reinforced concrete beams with corrodedkmpmanoj
The document summarizes a study on the fatigue behavior of reinforced concrete beams with corroded steel reinforcement. Several beams were constructed with varying levels of corrosion induced in the steel reinforcement. The beams were subjected to high-cycle fatigue loading. The corrosion reduced the fatigue life of the beams and decreased the flexural stiffness. Testing of the corroded steel bars after fatigue loading found that corrosion and fatigue reduced the yield strength of the steel but did not significantly change the tensile strength. The critical region for failure was found to be at the location of most severe corrosion pits in the steel.
An Analytical Study on Static and Fatigue Analysis of High Strength Concrete ...Stephen Raj
In recent years FRP stands as a better alternative to restore and upgrade deficient structures. The deficiency may be due to change in design standards, improper construction practices (or) adverse environmental conditions. Under such circumstances, adoption of appropriate technique for restoring the structure becoming challenging task. The objective of this thesis work is to evaluate the static and fatigue response of HSC beams with externally bonded FRP laminates using ANSYS software. The modeling and analysis is done using the software for HSC beam. The beams were strengthened with FRP laminates. The models are provided with carbon types of Fiber Reinforced Polymer (FRP) laminates. The available experimental data of HSC beam in flexure behavior is the source material of this analysis work. All the relevant data are taken from that source material. The static and fatigue load cases are applied and the results are discussed. The comparison is made between the available experimental results of HSC beam with analytical based results of HSC beam.
Knowledge and Experience of Menopause - A Rural Based Study in Aligarhjournal ijrtem
ABSTRACT: The menopause is a transitional phase in women’s life.The level of oestrogen is decreased ,because of which a variety of symptoms such as hot flushes, mucosal dryness, excessive sweating, emotional fluctuations, psychoses, decr-eased strength and calcification of bones occurs. Attitudes, perception and expectations are part of the psychosocial phenomenon surrounding menopause. Natural menopause is diagnosed after 12 months of amenorrhoea not associated with a pathological cause. Menopause is a gradual process that lasts for about 2 years, called climacteric. It is normal and should not be taken as a disease or syndrome. The aim of this study was to find out the knowledge and experience of menopausal symptoms among women who had attained menopause
The document summarizes research testing the effect of steel fiber volume fraction on the flexural strength of high-strength concrete beams. 25 beams were tested with steel fiber volumes from 0.5-4%. Testing showed flexural strength increased with higher fiber volumes. As fiber content increased, the failure mode transitioned from shear to flexure. Load-deflection curves showed higher maximum loads and deflections for beams with more fibers. In conclusion, adding steel fibers increases flexural strength of beams, especially at lower fiber volumes.
IRJET-Experimental behavior of Concrete under Compression Load with Steel Fib...IRJET Journal
This document summarizes research on the experimental behavior of concrete under compression load when partially replacing cement with steel fiber and ferrocement. The research involved casting and testing cylinders and cubes of M25 grade concrete with different mixes - some with steel fiber and ferrocement additions and others without. The results showed that concrete with a 0.5% addition of steel fiber and no ferrocement layers had the highest ultimate strain and a 16% increase in compressive strength compared to plain concrete cubes. The research concluded that steel fiber and ferrocement additions can improve the performance and properties of concrete under compression loads.
IRJET- Experimental Study of Structural Behaviour of Double Skin Hollow –...IRJET Journal
This document summarizes an experimental study on the structural behavior of double skin hollow concrete filled steel tubular (DSH-CFST) columns under axial compressive loading. 36 specimens were tested with varying hollowness ratios. Test results showed that DSH-CFST columns can provide higher strength and ductility than solid CFST columns. Stress-strain curves and load-deformation curves were compared for different specimen types. The study found that DSH-CFST columns exhibited up to 77% higher compressive stresses than solid CFST columns. DSH-CFST columns also demonstrated improved ductility compared to solid CFST columns. The results provide information on optimizing the strength and structural performance of DSH-CFST columns
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.
IRJET - Performance of SFRC Beams under Combined State of Flexure, Direct...IRJET Journal
This document summarizes research on the performance of steel fiber reinforced concrete (SFRC) beams under combined states of flexure, direct compression, and shear. It describes an experimental study that tested SFRC beams with various fiber volume fractions (0%, 0.5%, 0.75%, 1.0%) under different compression loads (0, 50, 100, 125 kN). The study found that adding steel fibers increased the compressive strength, flexural strength, and shear strength of the concrete beams. Beams with higher fiber content performed better under the combined loading conditions compared to beams with lower or no fiber content. The document provides details on the materials, beam specimens, mixing, casting, curing, and testing methods used
Study on flexural strengthening of RC beams using ferrocement laminates with ...IRJET Journal
This document reviews 17 articles on strengthening reinforced concrete beams with ferrocement laminates containing Recron-3S fibers. The articles studied parameters like the type and number of wire meshes in the laminates, mortar mix ratios, and fiber usage. Several studies found that adding 2-3 layers of wire mesh laminates containing 2.35% mesh reinforcement and 30% steel slag increased the load capacity and ductility of strengthened beams compared to control beams. Other studies concluded that bottom layers of ferrocement provided better strengthening than side layers alone. Overall, the document evaluates research on using ferrocement laminates containing fibers to flexurally strengthen reinforced concrete beams.
The document summarizes an experimental study that investigated the flexural behavior of reinforced concrete beams strengthened with various materials and techniques. Eight beams were tested with different strengthening approaches, including carbon fiber reinforced polymer sheets, glass fiber reinforced polymer sheets, steel plates, or combinations of these materials. Beams were preloaded to induce cracking before strengthening. The strengthened beams were then reloaded to failure. The study aimed to evaluate the flexural properties, failure loads, stiffness, and ductility of beams strengthened with different materials and techniques. In general, strengthening increased yield and ultimate loads but reduced beam ductility compared to the unstrengthened control beam.
Cyclic Response of Reinforced Concrete Moment Resisting Beams Repaired with E...IJERA Editor
This paper presents the results of a quasi-static cyclic test carried out on a reinforced concrete special moment resisting beam to study the efficiency of traditional repair techniques in restoring the strength and stiffness capacity of damaged RC beams. The beam was tested in a cantilever mode and was subjected to a standard loading protocol with increasing amplitude of displacement cycles. The final damage state of the beam consisted of severe cracking and spalling of the cover concrete. The cracks were repaired with low-viscosity injection epoxy and the spalled concrete was repaired with early-strength grout. The repaired specimen was subjected to the same loading protocol as the original specimen to study the efficiency of the repair technique employed. It was observed that epoxy injection is not effective in restoring the strength and stiffness of beams with bar slip of longitudinal bars at the support end.
A Study of Electrical and Magnetic Properties of La+3 Substituted Ni-Zn Ferritesiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Preparation and Structural Properties of Aluminium Substituted Lithium Nano F...IOSR Journals
This document describes the preparation and structural properties of aluminum-substituted lithium nanoferrites synthesized using the citrate gel auto combustion method. Nanoferrites with the general formula Li0.5AlxFe2.5-xO4 (where x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared at low temperature (1800C). X-ray diffraction analysis confirmed the formation of a single-phase cubic spinel structure with particle sizes ranging from 13 to 27 nm. Lattice parameter, density, and porosity were calculated from the XRD data and showed decreases with increasing aluminum content. Scanning electron microscopy revealed the formation of
Spin coating is a process that uses centrifugal force to spread a liquid solution evenly and produce a thin film of uniform thickness on a surface. It has various applications in industries like microelectronics. A simple model of spin coating was developed based on assumptions of laminar, axisymmetric flow. This model derived an equation showing film thickness decreases over time according to fluid properties like viscosity and spin speed. Further work aims to model non-Newtonian fluid spin coating and experimentally validate the models.
Spin coating is a process that uses centrifugal force to spread a liquid solution evenly and create a thin film on a surface, such as a semiconductor wafer. It involves depositing fluid onto a substrate that is then spun to evenly distribute the fluid via centrifugal force. The spinning causes the coating to thin at a rate dependent on viscosity and spinning velocity until the solvent evaporates, leaving a uniform thin film of specific thickness. Spin coating is widely used in microelectronics manufacturing to apply coatings like photoresist and insulating layers. Common defects include bubbles, swirling patterns, and streaks caused by issues with deposition uniformity or process parameters.
This document discusses magnetic properties of ferrites and their applications. It begins by explaining how ferrites exhibit quantum size effects and changes in magnetic behavior at the nanoscale due to increased surface area. It then describes the crystal structure of ferrites and the different types of magnetic ordering they can exhibit. Applications discussed include use of ferrites in transformers, sensors, data storage, and biomedical technologies. Magnesium ferrite is highlighted as a potential humidity sensor due to its porous structure and semiconducting properties.
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This document summarizes an article that studied orientation gradients and geometrically necessary dislocations (GNDs) in two ultrafine grained dual-phase steels with different martensite particle size and volume fraction. High-resolution electron backscatter diffraction (EBSD) was used to quantify orientation gradients, pattern quality, and GND density variations at ferrite-ferrite and ferrite-martensite interfaces. Two methods were demonstrated to calculate GND density from the EBSD data based on kernel average misorientation and dislocation density tensor. The overall GND density was shown to increase with increasing total martensite fraction, decreasing grain volume, and increasing martensite fraction in the vicinity of ferrite.
Effects of Continuous Cooling On Impact and Micro Structural Properties of Lo...IJMER
Some mechanical properties and microstructural analysis were conducted on shielded
metal arc weldments of low carbon steels in some simulated environments. Specimens were prepared
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for impact strength using Charpy impact testing machine showed that impact strength of water cooled
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martensitic structure and finer pearlite grains. The microstructure of the samples was studied using
photographic visual metallurgical microscope. For low cooling rate as in the air cooled sample, the
austenite was observed to transform into ferrite and pearlite. Ferrite is a body-centred cubic crystal
structure of iron alloys. For higher cooling rates of water and salt water cooled samples, low
temperature transformation products like bainite (an acicular microstructure which is not a phase) or
martensite (a very hard form of steel crystalline structure) were formed. The salt water cooled samples
had more martensite regions because of the increased cooling rate
IRJET- Study on Fibre Reinforced Polymer Beams with BFRP WrappingIRJET Journal
This document discusses a study on rehabilitating corroded steel beams using Basalt Fibre Reinforced Polymer (BFRP) fabric wrapping. The objectives are to determine the change in load-carrying capacity and ductility of corroded beams after rehabilitation, model the behavior using finite element analysis, and determine the optimum BFRP thickness for different corrosion levels. Experimental tests were conducted on concrete beams with BFRP wrapping to study their failure modes, crack patterns, and load capacities compared to unrepaired beams. Finite element models were also developed to simulate beam behavior and optimize BFRP thickness based on corrosion level. The results indicate that the yield and ultimate load capacities of corroded beams can be restored through BFR
Reuse of Lathe Waste Steel Scrap in Concrete PavementsIJERA Editor
These project works assess on the study of the workability and mechanical strength properties of the concrete reinforced with industrialized waste fibers or the recycled fibers. In each lathe industries wastes are available in form of steel scraps are yield by the lathe machines in process of finishing of different machines parts and dumping of these wastes in the barren soil contaminating the soil and ground water that builds an unhealthy environment. Now a day’s these steel scraps as a waste products used by innovative construction industry and also in transportation and highway industry. In addition to get sustainable progress and environmental remuneration, lathe scrap as worn-recycle fibers with concrete are likely to be used. When the steel scrap reinforced in concrete it acquire a term; fiber reinforced concrete and steel fibers in concrete defined as steel fiber reinforced concrete (SFRC).Different experimental studies are done to identify about fresh and hardened concrete properties of steel scrap fiber reinforced concrete (SSFRC) and their mechanical properties are found to be increase due to the addition of steel scrap in concrete i.e. compressive strength, flexural strength, impact strength, fatigue strength and split tensile strength were increased but up to 0.5-2% scrap content . When compared with usual concrete to SSFRC, flexural strength increases by 40% and considerable increases in tensile and compressive strength. These steel scrap also aid to improve the shrinkage reduction, cracking resistance i.e. preventing crack propagation and modulus of elasticity. The workability of fresh SSFRC are carried out by using slump test but it restricted to less scrap contents. This work focuses on the enhancement of structural strength and improvement in fatigue life of concrete pavements by reuse of scrap steel in concrete. These concrete roads with SSFRC promises an appreciably eminent design life, offer superior serviceability and minimize crack growth and corrosion. The pioneer idea of this work is the reuse of waste lathe scrap as recycled steel fibers, which provides more cost-effective and eco-friendly sustainable SFRC PAVEMENTS.
Historical analysis of metal cutting shows that metal removal rates have been increasing in the course of the century, predicated by the advancement in tool materials but the steel design has lagged behind. This paper examines the mechanisms of chip formation and tool wear as a function of cutting speed in metal cutting. Chemical wear is identified as the dominant mechanism of tool wear at high cutting speeds caused by temperature rise due to shear localisation in the primary and secondary shear zones of chip. Shear localisation in the primary shear zone is shown to be influenced by both microstructural parameters, i.e. matrix hardening and second phase particles, and metal cutting variables, i.e. cutting speed (strain rate) and feed (pressure).
Microstructural characterization and elastoplastic behaviour of high strengtIAEME Publication
This document discusses microstructural characterization and elastoplastic behavior of high strength low alloy steel. It describes how the steel was thermomechanically processed by controlled rolling just above the A3 temperature and then water quenched. Electron backscatter diffraction and nanoindentation were used to characterize the microstructure and mechanical properties. The ferrite grain size was refined to 1-3 microns through dynamic strain induced transformation of austenite during processing. The ferrite formed via different mechanisms exhibited varying elastoplastic behavior related to their carbon content and formation temperature.
The document analyzes the formability, fracture behavior, void coalescence, and texture of batch annealed (BA), continuous annealed (CA), and cold rolled (CR) 430 grade stainless steel sheets through tensile testing, forming limit diagrams, fractography, and texture analysis. Microstructural observations found elongated grains in the rolling direction, with average grain size decreasing in the order of CA, BA, and CR sheets. CA and BA sheets exhibited better formability than CR sheets based on forming limit diagrams and texture analysis, though CR sheets still showed satisfactory performance for certain applications.
MECHANICAL PROPERTY ASSESSMENT OF AUSTEMPERED AND CONVENTIONALLY HARDENED AIS...IAEME Publication
The chemical composition and mechanical properties of steel decide its applicability for manufacturing various components in different areas of engineering interests. Heat treatment processes are commonly used to enhance the required properties of steel with or without change in chemical composition. The present work aims to perform conventional hardening and Austempering treatment with experimental investigation of the effect of austempering and conventional hardening (quenching) on AISI 4340 steel. Different tests like tensile, torsion, hardness, impact and microstructure analysis are carried out in as bought and heat treated conditions
IRJET- Investigate Curing Behavior of Fly Ash based Polymeric Ferrocement Con...IRJET Journal
This document summarizes an investigation into the curing behavior of fly ash-based polymeric ferrocement concrete. Fly ash-based geopolymer mortar was used instead of cement mortar, and was activated using sodium hydroxide and sodium silicate alkaline activators. The investigation studied the effects of different curing conditions (oven, steam, membrane, accelerated, and natural sunlight) on flexural behavior. It also analyzed the effect of adding chicken wire mesh layers on flexural strength. Testing was performed on 500mm x 500mm x 50mm samples containing fly ash-geopolymer mix and chicken wire mesh.
This document reviews the friction stir welding (FSW) process. FSW is a solid-state welding technique invented in 1991 that uses a rotating tool to generate heat and plasticize materials being joined, allowing them to bond without melting. It can weld materials like aluminum alloys that are difficult to weld using conventional fusion welding. The document discusses the principles of FSW, factors that affect weld microstructure and properties like tool parameters and heat flow, and summarizes several studies that examined the effects of FSW parameters and post-weld treatments on mechanical properties and microstructure of welded aluminum alloys.
A refined energy-based model for friction stir processing of Al- Zn-Mg alloyIJERA Editor
Friction stir processing (FSP) is a promising solid state surface modification technique. Also, considered as an
innovative technique that the FSPwas employed to modify the surface layer of aluminium alloy. The FSP passes
of only two passes were applied on aluminium alloy samples. A rotating tool with a pin and shoulder is inserted
into a single piece of material and results in significant microstructural changes in the processed zone, due to
intense plastic deformation. It has been proved to be an effective way to refine the microstructure of aluminium
alloys, and thereby improve the mechanical properties. In procedural phenomenon there are different parameters
adjustment have been worked out to refine microstructure and several properties characterised to TEM, SEM,
FESEM and mechanical properties. In this study, a refined energy based model that estimates the energy
generated due to friction and plastic deformation is presented with the help ofexperimental and theoretical
results available in many literatures. The model is applied to 7xxx series of aluminium alloys.
A refined energy-based model for friction stir processing of AlZn-Mg alloy IJERA Editor
Friction stir processing (FSP) is a promising solid state surface modification technique. Also, considered as an
innovative technique that the FSPwas employed to modify the surface layer of aluminium alloy. The FSP passes
of only two passes were applied on aluminium alloy samples. A rotating tool with a pin and shoulder is inserted
into a single piece of material and results in significant microstructural changes in the processed zone, due to
intense plastic deformation. It has been proved to be an effective way to refine the microstructure of aluminium
alloys, and thereby improve the mechanical properties. In procedural phenomenon there are different parameters
adjustment have been worked out to refine microstructure and several properties characterised to TEM, SEM,
FESEM and mechanical properties. In this study, a refined energy based model that estimates the energy
generated due to friction and plastic deformation is presented with the help ofexperimental and theoretical
results available in many literatures. The model is applied to 7xxx series of aluminium alloys.
An Analysis of Mechanical Properties and Flexural Behavior of Concrete Slabs ...YogeshIJTSRD
In the era of concrete, concrete is exposed to chemical, such as carbonation and chloride adulteration break down the alkaline barrier in the cement. Subsequently, steel in the concrete becomes corrosive. Such phenomena lead to erosion of concrete at the reinforcement level, cracking and spelling of concrete due to volume increase of steel reinforcement. Different methods were investigated to overcome corrosion by numerous researchers.According to A.S.T.M D792 13 standards the density of H.F.R.P bars have been evaluated the experimental value with 0.1mg precision. As per the standards, the H.F.R.P bars are weighed. Then, the H.F.R.P bar is immersed in distilled water at 230C and the wet weight of the bar is noted. The weight of the Sinker in immersed condition is also noted.The laboratory tests carried out to evaluate the physical and mechanical properties of the newly developed H.F.R.P bars and are compared with that of conventional bars. The bond properties of H.F.R.P bars with concrete is also determined. Finally, it explains the experimental investigations on the flexural behavior of concrete one way slabs reinforced with H.F.R.P reinforcements under static loading and are compared with conventional ones. The stress strain performance of the sand coated H.F.R.P bar is linear, lacking yield point up to the failure transverse shear strength is 3 times lesser than the tensile strength of the H.F.R.P bars. Thermal properties of fibers are substantially different in the longitudinal and transverse direction. Therefore the thermal characteristics vary between products according to the fiber, matrix and the fiber volume ratio. In this study the longitudinal Coefficient of linear thermal expansion is 7.5 x 10 6 oC to 9x 10 6 oC. Whereas the transverse Coefficient of linear thermal expansion is between 15 x 10 6 oC to 20 x 10 6 oC. Load deflection graphs drawn exhibits the accordance between experimental and FEM ANSYS observations. The reduced deflection of FEM is due to the rigidness of meshing. The results also confer about the effect of tension stiffening and the bond slip. From the comparison it has been observed that experimental deflections vary from 1.03 to 1.37 times higher than the FEM deflections. Prerna Vaidya | Prof. Nitesh Kushwaha | Prof. Afzal Khan "An Analysis of Mechanical Properties and Flexural Behavior of Concrete Slabs Reinforced with H.F.R.P Reinforcements" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-3 , April 2021, URL: https://www.ijtsrd.com/papers/ijtsrd38691.pdf Paper URL: https://www.ijtsrd.com/engineering/civil-engineering/38691/an-analysis-of-mechanical-properties-and-flexural-behavior-of-concrete-slabs-reinforced-with-hfrp-reinforcements/prerna-vaidya
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.
IRJET- Effects of Electropulsing on SteelsIRJET Journal
This document summarizes research on the effects of electropulsing (also called electric pulse treatment), a modern technique, on various steels. Electropulsing uses electric pulses and shows effects like strengthening, grain refinement, and property improvements. It discusses how electropulsing affects properties of different steels, including strengthening dual-phase steel at high temperatures by promoting phase transformations, accelerating diffusion and dissolving precipitates in stainless steel, increasing the nucleation rate and forming nanostructures in pearlite steel, removing inclusions from molten steel, and partially healing cracks in medium carbon steel. The document concludes that electropulsing provides benefits like strengthening steels and inclusion/precipitate control and that further research is needed to
This document summarizes a study on the effect of chromium content on the microstructure and wear resistance of Fe-Cr-C hard facing layers. Hard facing layers containing various amounts of chromium were deposited on mild steel using shielded metal arc welding. Testing found that microstructure consisted of primary (Cr, Fe)7C3 carbides and eutectic phases. Higher chromium content refined the carbides. Wear resistance testing found that higher chromium, carbon, and silicon content resulted in higher hardness and less wear. Electrode I, with higher amounts of these elements, exhibited less wear than Electrode II. In conclusion, chromium content significantly affects microstructure and wear resistance, with higher chromium improving hardness and wear performance of Fe
Flexural and Torsional Behavior of Concrete Filled Tubular Flange GirderIRJET Journal
This document summarizes research on concrete filled tubular flange girders (CFTFGs). CFTFGs have a steel tube filled with concrete as the upper flange, which increases stiffness and allows the section to carry more load compared to a standard steel beam. The document reviews several studies that analyzed the flexural and torsional behavior of CFTFGs using finite element analysis and experiments. The studies found that filling the flange with concrete improves strength and stability. However, the moment capacity is reduced under axial tensile forces in the steel. The concrete filling also limits the axial tensile resistance to the plastic capacity of the steel alone.
Similar to Acta materialia 59 (2011) 4387 4394 dual phase steel gnd simulation and experiment homogenization (20)
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This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Generative AI Use cases applications solutions and implementation.pdfmahaffeycheryld
Generative AI solutions encompass a range of capabilities from content creation to complex problem-solving across industries. Implementing generative AI involves identifying specific business needs, developing tailored AI models using techniques like GANs and VAEs, and integrating these models into existing workflows. Data quality and continuous model refinement are crucial for effective implementation. Businesses must also consider ethical implications and ensure transparency in AI decision-making. Generative AI's implementation aims to enhance efficiency, creativity, and innovation by leveraging autonomous generation and sophisticated learning algorithms to meet diverse business challenges.
https://www.leewayhertz.com/generative-ai-use-cases-and-applications/
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Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
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Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
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1. Experimental and numerical study on geometrically
necessary dislocations and non-homogeneous mechanical properties
of the ferrite phase in dual phase steels
J. Kadkhodapour a,b,⇑
, S. Schmauder b
, D. Raabe c
, S. Ziaei-Rad a
, U. Weber b
,
M. Calcagnotto c
a
Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran
b
Institute for Materials Testing, Materials Science and Strength of Materials, University of Stuttgart, Stuttgart, Germany
c
Max-Planck-Institut fu¨r Eisenforschung, Du¨sseldorf, Germany
Received 21 January 2011; received in revised form 19 March 2011; accepted 22 March 2011
Available online 12 April 2011
Abstract
The microstructure of dual phase steels can be compared with a composite composed of a matrix of ferrite reinforced by small islands
of martensite. This assumption has been used in several attempts to model the mechanical properties of dual phase steels. However,
recent measurements show that the properties of the ferrite phase change with distance from the martensite grains. These measurements
showed that the grains of the ferrite phase are harder in the vicinity of martensite grains. As a consequence of this local hardening effect,
the ferrite phase has to be considered as an inhomogeneous matrix in modeling dual phase steels. This experiment inspired the idea that
local hardening is caused by geometrically necessary dislocations. The idea is investigated experimentally and numerically in the present
analysis, which for the first time leads to good agreement with experimental observations of the mechanical stress–strain behavior.
Ó 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Keywords: Dual phase steels; Nano hardness test; Geometrically necessary dislocations; Local hardening; Micromechanical model
1. Introduction
1.1. Motivation for dual phase steels
Present day industrial applications of sheet metal form-
ing require materials with high plastic deformation poten-
tial and high strength. This goal is not easy to achieve,
because usually an increase in the mechanical characteris-
tics of the sheet involves a reduction in its workability, in
terms of ductility, drawability, and formability. Despite
these considerations, dual phase steels have good formabil-
ity with relatively high strength; in particular they have
shown good ductility, continuous yielding followed by
rapid work hardening, a low yield to tensile strain ratio
and non-aging behavior at ambient temperature.
Dual phase steels are low carbon micro-alloyed steels,
characterized by a ferritic multiphase structure in which
martensite is dispersed. They have a purely ferrite matrix
and about 5–30% martensite dispersed in patches as a
second phase. They behave like composite materials in
which the ferrite matrix ensures good cold formability,
while the martensite is the strengthening element. The
correct proportions of the two phases allows a low yielding
stress, a high elongation value and a smooth flow–stress
curve with a high strain hardening coefficient [1,2].
1.2. Tensile properties of dual phase steels
Tremendous efforts have been expended on exploring
various aspects of dual phase steels. The effect of the
volume fraction (Vm), for example, of the harder phase
(martensite) has been investigated by different authors [3–
7]. Increasing the volume fraction of the harder phase
1359-6454/$36.00 Ó 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.actamat.2011.03.062
⇑ Corresponding author at: Department of Mechanical Engineering,
Isfahan University of Technology, Isfahan 84156-83111, Iran.
E-mail address: kadkhodapour@me.iut.ac.ir (J. Kadkhodapour).
www.elsevier.com/locate/actamat
Available online at www.sciencedirect.com
Acta Materialia 59 (2011) 4387–4394
2. was found to increase the yield and ultimate strengths of
the aggregate. Shen et al. [8] have shown, using a scanning
electron microscope equipped with a tensile straining stage,
that the distribution of strain between the ferrite and mar-
tensite phases, as well as among the different grains of each
phase, was observed to be inhomogeneous.
Various studies aimed at a better understanding of the
excellent mechanical properties of dual phase steels [9–
16]. There is broad consensus that the low elastic limit
(defined as the first deviation from Hooke’s law in the
stress–strain curve), the continuous yielding and the high
strain hardening rate are a consequence of the austenite–
martensite transformation, which involves volume expan-
sion. In our materials the volume expansion is approxi-
mately 2.9–4% at the martensite start temperature [9].
The strains produced by transformation result in residual
stresses in the surrounding ferrite [9]. These internal stres-
ses are assumed to facilitate plastic flow and, hence, reduce
the elastic limit. Furthermore, the volume change induces
plastic deformation of adjacent ferrite grains and, there-
fore, creates a high density of unpinned dislocations in
the vicinity of martensite [10–12], as was qualitatively stud-
ied by transmission electron microscopy (TEM) [13–15].
These dislocations are assumed to be (at least partly)
mobile during the early stages of deformation and contrib-
ute to work hardening. The heterogeneous distribution of
dislocations is supposed to control continuous yielding in
dual phase steels. It is assumed that the deformation starts
in ferrite areas with low dislocation densities and spreads
with increasing plastic strain into regions with higher dislo-
cation densities [16].
At least some of the adjacent ferrite grains have to
deform plastically owing to volume expansion during aus-
tenite–martensite transformation. During this deformation,
geometrically necessary dislocations (GNDs) are required
to maintain lattice continuity [17–19] and statistically
stored dislocations (SSDs) evolve from random trapping
processes [18]. After such transformation-induced deforma-
tion residual stresses remain due to inhomogenity of the
plastic deformation throughout the grains. However, it is
still not understood to what extent GNDs, SSDs, and the
associated residual stresses contribute to the yielding
behavior of dual phase steels. It is well known that GNDs
cause local hardening of the microstructure. But, to the best
of the author’s knowledge, no experimental observations of
this phenomenon have been reported in dual phase steels.
Various homogenization techniques are used in predict-
ing and quantifying the tensile mechanical properties and
initial work hardening behavior of various materials of
composite microstructure such as dual phase steels [20–
23]. None of these models consider local hardening inside
the microstructure.
1.3. Grain refinement in dual phase steel
In ultrafine single phase alloys it has been shown that
the increase in yield stress is accompanied by a decrease
in the work hardening rate, which is responsible for poor
ductility. This effect has been shown for Al- and Ti-con-
taining ultra-low carbon steel produced by accumulative
roll bonding (ARB) [24], in pure titanium [25] and in low
carbon steels [26] produced by equal channel angular press-
ing (ECAP), and in ferritic steels produced by ECAP or
ARB [27].
Ultrafine grain (UFG) dual phase steels with a ferrite
grain size of around 1 lm have been produced by applying
a two-step processing route consisting of (1) a deformation
treatment to produce UFG ferrite and finely dispersed
cementite or pearlite and (2) a short intercritical annealing
in the ferrite/austenite two-phase field followed by quench-
ing to transform all austenite to martensite. Grain refine-
ment in step (1) was achieved by ECAP [28], cold rolling
[29] and cold swaging [21]. A single pass processing route
based on deformation-induced ferrite transformation
(DIFT) was proposed by Mukherjee et al. [30].
It was consistently found that yield strength and tensile
strength increased on grain refinement, whereas uniform
and total elongation were less affected. The strain harden-
ing rate was found to increase with decreasing grain size
[28], which is in contrast to the observation of a very
restricted strain hardening rate in UFG low carbon fer-
rite/cementite steels [31,32]. As the number of investiga-
tions on this topic is very limited, a better understanding
of the mechanical response of dual phase steels to ferrite
grain sizes close to or below 1 lm is required.
In contrast to other methods to increase the strength of
steels, grain refinement simultaneously improves the tough-
ness of the material, i.e. its capability to absorb energy
under impact conditions [33,34]. Also, The Hall–Petch
coefficient of the yield strength is lower than in ferrite/
cementite steels that are refined to 1 lm and below [33,34].
CG ferrite exhibits wavy and strongly intersecting slip
bands without a preferred orientation, while UFG ferrite
basically shows two sets of nearly planar slip bands which
are oriented $40° to the tensile direction [33,34].
In the case of CG steel the failure process is mainly brit-
tle, which is documented by well-defined facets and cleav-
age steps on these facets, and only some small areas
consist of dimples. The dominant fracture mode of FG
steel is ductile, although smaller parts of the specimen have
undergone brittle fracture. The UFG steel shows dimples
throughout the specimens. This suggests a failure process
of void nucleation and growth and, hence, entirely ductile
fracture [33,34].
1.4. Present study
It has been mentioned that all the investigations on
grain size effects in dual phase steels were on laboratory
produced dual phase steel. The current work mainly
focuses on commercial fine grain dual phase steel (2 lm
grain size) produced by Thyssen-Krupp Steel AG. In this
sense, the result may be interesting. The results of detailed
investigations of this material are reported in this paper.
4388 J. Kadkhodapour et al. / Acta Materialia 59 (2011) 4387–4394
3. The analysis of tensile properties in the material began
from observations of additional hardening in the
microstructure when it is compared with the mixture of
properties in constituent phases. It was observed that
dislocation density pattern pile-up in grain boundaries
causes local hardening in the phase boundary and harden-
ing in the microstructure.
In this paper a review will first be carried out of
experimental investigations which have been carried out
to measure GNDs in the matrix near ferrite–martensite
phase boundaries [35]. The measured data indicate that
GNDs close to the ferrite–martensite phase boundaries
are around one order of magnitude higher that GNDs
inside the ferrite grains. Also, the hardness at different loca-
tions inside ferrite grains was measured. Finally, a finite
element model is developed which considers hardness var-
iation in the ferrite grains of the dual phase steels investi-
gated. In the last part of paper the effects of hardness
variation inside the ferrite grains on the macroscopic
behavior of the tensile model will be investigated through
simulation.
2. Experimental study of GND and local hardening in the
ferrite phase
To investigate GND distribution inside the microstruc-
ture two-dimensional EBSD measurements were carried
out on dual phase steel specimens. Electron backscattered
diffraction (EBSD) maps were taken in a JEOL JSM
6500F electron microscope equipped with a field emission
gun. The small beam diameter and its high brightness yield
high contrast Kikuchi patterns so that information about
small orientation deviations, even in areas with high dislo-
cation densities like phase or grain boundaries, were
obtained. A high speed DigiView CCD camera was used
for pattern acquisition. Data were recorded at a 50 nm step
size and analyzed using TSL software [35].
The kernel average misorientation (KAM) method was
then used to calculate the GND densities from EBSD data.
As a first order approach KAM, which is retrieved directly
from the EBSD data, was chosen as a measure of the local
misorientations. KAM quantifies the average misorienta-
tion around a measurement point with respect to a defined
set of nearest or nearest plus second nearest neighbor
points. It has been shown elsewhere [35] that this method
is appropriate for the calculation of GND densities.
Fig. 1 shows GND densities in a microstructural sample.
It can be observed that the GND densities are one order
higher close to the ferrite–martensite interface than away
from the interface.
To investigate the effect of GND densities on hardening
of the material, nanohardness testing was carried out on
the same microstructure. The nanohardness value (H) is
defined as the applied load divided by the projected area
of contact between the indenter and the sample. H (GPa)
is calculated in terms of P (nN) and A (nm2
). Fig. 2 shows
the results of this test. Local hardening in the ferrite phase
near the ferrite–martensite interface can be observed. The
extent and rate of hardening are different in different
grains, but the general trend is the same within ferrite
grains. In all cases near interface hardening can be
observed.
To micromechanically model the impact of GND on
macroscopic mechanical behavior the size and mechanical
properties of the interface region have to be specified.
For this purpose a more detailed test was carried out on
a typical sample area from the experiments in order to
specify the size and mechanical properties of the interface
region. The nanohardness test was carried out at 60 differ-
ent points on a commercial dual phase steel microstructure.
The results can be seen in Fig. 3. From the results of this
test the size of the interface region (in which the hardness
varies) can be assumed to typically be of a thickness of
1.5 lm and the mechanical properties were specified rela-
tive to the basic ferrite phase.
3. Modeling of the microstructure
Within the framework of the unit cell approach, the
behavior of materials with complex microstructures is
Fig. 1. GND in the microstructure [24].
J. Kadkhodapour et al. / Acta Materialia 59 (2011) 4387–4394 4389
4. studied by carrying out numerical or analytical studies of
the behavior of some part of the microstructure. The main
assumption, which must be justified, is that the microstruc-
ture of the material can be considered as a periodic repeat
of the area under study, and that the sample is therefore
representative of the microstructure of the material.
A computer unit cell model for dual phase steel was set
up in which the region between ferrite and martensite is
considered to be a phase boundary layer. The thickness
of this layer, derived from detailed experimental tests, is
given in Fig. 3. An elasto-plastic material model was used
for both the ferrite and martensite phases, based on the
experimental data presented in Fig. 6. The flow curves of
bulk ferrite and martensite were determined by uniaxial
tensile testing of the individual phases, performed in the
laboratories of Thyssen-Krupp Steel AG. For this purpose
test specimens of pure ferrite and pure martensite were pre-
pared. Due to the fact that in the heterogeneous dual phase
steel martensite has a much higher carbon content than in
the artificially produced pure martensite steel, a special
martensite melt was prepared having nearly the same car-
bon content as the dual phase steel. For the boundary layer
material data were assigned with respect to the ferrite
matrix according to Fig. 3. It can be observed in Fig. 3 that
the ferrite matrix gradually hardens as it comes nearer to
the martensite. The gradual hardening was approximated
by different layers in the model. Fig. 4 gives the model
and mesh for two layer and ten layer models. Elasto-plastic
material behavior is considered for the ferrite and martens-
ite phases and the interphase layers. An isotropic harden-
ing law is assigned for the plastic state. The yield stress is
given as a tabular function of plastic strain from the exper-
imental results.
The unit cell was then put under tensile loading and the
results were homogenized for comparison with the experi-
mental data. The homogenization scheme can be described
as follows. Macroscopic stress is defined as integration:
X
ij
¼
R
8
rijd8
8
ð1Þ
Fig. 2. Nanohardness tests on the microstructure of dual phase steel. (a and c) The nanohardness value at different locations in the microstructure; (b) the
nanohardness value according to distance from the grain boundary in case (a); (d) the nanohardness value according to distance from the grain boundary
in case (c).
4390 J. Kadkhodapour et al. / Acta Materialia 59 (2011) 4387–4394
5. For a discrete field emission volume the above equation
can be rewritten as:
X
ij
¼
Pn
1rij8n
8
ð2Þ
where n is the number of finite elements and 8n is the vol-
ume of the nth element. Analogously, the strains are calcu-
lated as:
Eij ¼
Pn
1eij8n
8
ð3Þ
The plot is for equivalent stress on the basis of equiva-
lent strain. The equivalent stress is calculated as:
X
eqv
¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
3
2
X0
ij
X0
ij
v
u
u
t ð4Þ
in which:
X0
ij
¼
X
ij
À
1
3
X
kk
ð5Þ
The equivalent strain can also be calculated as:
Eeqv ¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffi
2
3
EijEij
r
ð6Þ
in which:
Eij ¼ Eij À
1
3
Ekk ð7Þ
4. Simulation results and discussions
Using these results a unit cell model was built in which
the phase boundary was considered according to the exper-
Fig. 3. Detailed nanohardness tests on dual phase steel microstructure.
Fig. 4. Modeling of dual phase steel using (a) two layer and (b) 10 layer phase boundary models.
J. Kadkhodapour et al. / Acta Materialia 59 (2011) 4387–4394 4391
6. imental data (Fig. 5). For the phase boundary different
numbers of layers are considered in order to examine the
accuracy of the model with respect to the macroscopic
mechanical stress–strain behavior. The results are then
compared with the experimental data (Fig. 6). The results
show good agreement and it seems that the assumptions
in this model are realistic. It is also apparent that by
accurate parameter selection a one layer model provides
good accuracy using this material model. Therefore, the
one layer model will be used in this study for grain size
influence investigations.
In the next step, the grain size effect was modeled. Grain
size refers to the average size of the ferrite and martensite
grains in the microstructure. The effect of grain size was
Fig. 6. Simulation vs. experimental results of tensile tests for dual phase steel.
Ten interface
(e)
(j)
(o)
Five interface
(d)
(i)
(n)
Two interface
(c)
(h)
(m)
One interface
(b)
(g)
(l)
No interface
(a)
(f)
(k)
Initial
model
Von mises
equivalent
stress
Plastic
strain
layerlayer layer layer layer
Fig. 5. Results of the simulation for the layered model. (a–e) Initial model with different numbers of interface layers; (f–j) von Mises stress for tensile
loading; (k–o) equivalent plastic strain for tensile loading.
4392 J. Kadkhodapour et al. / Acta Materialia 59 (2011) 4387–4394
7. considered in the following way: as the grain size decreases
the grain boundary layer occupies a greater volume fraction
of the material. On the other hand, the strength of the grain
boundary is unknown. The effect of GND on material
hardening will be simulated in this part. Three different grain
sizes were considered and different volume fractions of the
Fig. 7. Model for dual phase steels of different grain size (the average size of the ferrite and martensite phases is taken as the grain size). Grain size: (a)
10 lm; (b) 5 lm; (c) 2 lm.
Fig. 8. Simulation vs. experimental results for different grain sizes for ry(GB): (a) 1.75 Â ry(ferrite); (b) 1.35 Â ry(ferrite).
J. Kadkhodapour et al. / Acta Materialia 59 (2011) 4387–4394 4393
8. phase boundary were assigned for each grain size (Fig. 7). It
was assumed that the thickness of the boundary phase is con-
stant and, therefore, the volume fraction will increase as a
result of grain size reduction. The macroscopic behavior of
the material is derived by homogenization of the behavior
in the microscopic model. The results are plotted for two dif-
ferent strengths of phase boundary layers in Fig. 8. The
strength of the boundary layer is the study parameter.
According to Fig. 3 it seems that the strength of the bound-
ary phase is 75% higher than that of the ferrite matrix. There-
fore, ry(GB) = 1.75 Â ry(ferrite) was considered in the first
simulation. The macroscopic behavior does not match the
experimental results perfectly, because the grain size of the
specimen was reported to be 2 lm and the simulation value
is much higher than the experimental value for a 2 lm grain
size. At this time no experimental database for the strength
of the grain boundary layer for different grain sizes is avail-
able. In this study, in order to simulate the macroscopic
behavior observed, for an average grain size reported to be
2 lm, the strength of the grain boundary layer is considered
to be 35% higher than for the ferrite matrix. The macro-
scopic tensile behavior, which is reported in Fig. 8b, matches
the experiments well.
According to the simulation results and previous
observations [33] the deformation pattern in fine grained
dual phase steel can be explained as follows. Grain
refinement causes an increase in yield strength and the
strain hardening rate of the ferrite matrix. It results in
rapid stress transfer to martensite grains. Therefore, the
macroscopic behavior increases.
5. Conclusions
Previous experimental investigations measuring GND
dislocations at the ferrite–martensite boundary have been
reviewed. The hardness at different locations inside ferrite
grains was also measured. Finally, a finite element model
was developed which considers the hardness variation in
ferrite grains of dual phase steels. The effects of hardness
variation inside ferrite grains on the macroscopic behavior
of the dual phase material were investigated. Changing the
grain size causes macroscopic hardening of dual phase
steels. In this study the effect of GND and hardening due
to GND in the material have been considered and the
mechanism of hardening analyzed.
Acknowledgements
We gratefully acknowledge financial support for J.K. by
the Deutscher Akademischer Austauschdienst (German
Academic Exchange Service, www.daad.org).
References
[1] Furukawa T, Tanino M, Morikawa H. Endo M Trans ISIJ
1984;24:113–21.
[2] Verein Deutscher Eisenhuttenleute. Steel handbook for materials
research and engineering, vols. 1 and 2. Berlin: Springer-Verlag;
1992–1993.
[3] Jiang Z, Guan Z, Lian J. J Mater Sci 1993;28:1814–8.
[4] Bag A, Ray KK, Dwarakadasa ES. Metall Mater Trans A
1999;30:1193–202.
[5] Tomita Y. J Mater Sci 1990;25:5179–84.
[6] Byun TS, Kim IS. J Mater Sci 1993;28:2923–32.
[7] Tomota Y. Mater Sci Technol 1987;3:415–21.
[8] Shen HP, Lei TC, Liu JZ. Mater Sci Technol 1986;2:28–33.
[9] Sakaki T, Sugimoto K, Fukuzato T. Acta Metall 1983;31:1737–46.
[10] Davies RG. Metall Trans A 1979;10:1549–55.
[11] Rashid MS. In: Davenport AT, editor. Formable HSLA and dual-
phase steels. New York: Metallurgical Society of AIME; 1979. p. 1–
24.
[12] Rigsbee JM, Abraham JK, Davenport AT, Franklin JE, Pickens JW.
In: Kot RA, Morris JW, editors. Structure and properties of dual-
phase steels. New York: Metallurgical Society of AIME; 1979. p.
304–29.
[13] Matlock DK, Krauss G, Ramos LF, Huppi GS. In: Kot RA, Morris
JW, editors. Structure and properties of dual-phase steels. New
York: Metallurgical Society of AIME; 1979. p. 62–90.
[14] Sherman AM, Davies RG, Donlon WT. In: Kot RA, Bramfitt BL,
editors. Fundamentals of dual-phase steels. New York: Metallurgical
Society of AIME; 1981. p. 85–94.
[15] Korzekwa DA, Matlock DK, Krauss G. Metall Trans A
1984;15:1221–8.
[16] Sarosiek AM, Owen WS. Mater Sci Eng 1984;66:13–34.
[17] Nye JF. Acta Metall 1953;1:153–62.
[18] Ashby MF. Philos Mag 1970;21:399–424.
[19] Kro¨ner E. Int J Eng Sci 1963;1:261–78.
[20] Al-Abbasi FM, Nemes JA. Int J Mech Sci 2003;45:1449–65.
[21] Delince M, Brechet Y, Embury JD, Geers MGD, Jacques PJ,
Pardoen T. Acta Mater 2007;55:2337–50.
[22] Wilkinson DS, Pompe W, Oeschner M. Prog Mater Sci
2001;46:379–405.
[23] Ishikawa N, Parks DM, Socrate S, Kurihara M. ISIJ Int
2000;40:1170–9.
[24] Tsuji N, Ito Y, Saito Y, Minamino Y. Scr Mater 2002;47:893–9.
[25] Ko YG, Shin DH, Park KT, Lee CS. Scr Mater 2006;54:1785–9.
[26] Park KT, Shin DH. Metall Mater Trans A 2002;33:705–7.
[27] Han BQ, Yue S. J Mater Proc Technol 2003;136:100–4.
[28] Son YI, Lee YK, Park KT, Lee CS, Shin DH. Acta Mater
2005;53:3125–34.
[29] Tsipouridis P, Werner E, Krempaszky C, Tragl E. Steel Res Int
2006;77:654–67.
[30] Mukherjee K, Hazra S, Petkov P, Militzer M. Mater Manuf Process
2007;22:511–5.
[31] Park KT, Kim YS, Lee JG, Shin DH. Mater Sci Eng A
2000;293:165–72.
[32] Tsuji N, Kamikawa N, Ueji R, Takata N, Koyama H, Terada D. ISIJ
Int 2008;48:1114–21.
[33] Calcagnotto M, Adachi Y, Ponge D, Raabe D. Acta Mater
2011;59:658–70.
[34] Calcagnotto M, Ponge D, Raabe D. Mater Sci Eng, A
2010;527:7832–40.
[35] Calcagnotto M, Ponge D, Demir E, Raabe D. Mater Sci Eng, A
2010;527:2738–46.
4394 J. Kadkhodapour et al. / Acta Materialia 59 (2011) 4387–4394