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L. Anand - One of the best experts on this subject based on the ideXlab platform.
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polycrystalline shape memory materials effect of Crystallographic Texture
Journal of The Mechanics and Physics of Solids, 2001Co-Authors: P. Thamburaja, L. AnandAbstract:Abstract A crystal-mechanics-based constitutive model for polycrystalline shape-memory materials has been developed. The model has been implemented in a finite-element program. In our finite-element model of a polycrystal, each element represents one crystal, and a set of crystal orientations which approximate the initial Crystallographic Texture of the shape-memory alloy are assigned to the elements. The macroscopic stress–strain responses are calculated as volume averages over the entire aggregate. Pseudoelasticity experiments in tension, compression, and shear have been performed on an initially Textured polycrystalline Ti–Ni alloy. In order to determine the material parameters for Ti–Ni, the stress–strain results from a finite-element calculation of a polycrystalline aggregate subjected to simple tension have been fit to corresponding results obtained from the physical experiment. Using the material parameters so determined, the predicted pseudoelastic stress–strain curves for simple compression and thin-walled tubular torsion of the initially Textured Ti–Ni are shown to be in good accord with the corresponding experiments. Our calculations also show that the Crystallographic Texture is the main cause for the observed tension–compression asymmetry in the pseudoelastic response of Ti–Ni. The predictive capability of the model for the variation of the pseudoelastic behavior with temperature is shown by comparing the calculated stress–strain response from the model against results from experiments of Shaw and Kyriakides (J. Mech. Phys. Solids 43 (1995) 1243) on Ti–Ni wires at a few different temperatures. By performing numerical experiments, we show that our model is able to qualitatively capture the shape-memory effect by transformation. We have also evaluated the applicability of a simple Taylor-type model for shape-memory materials. Our calculations show that the Taylor model predicts the macroscopic pseudoelastic stress–strain curves in simple tension, simple compression and tubular torsion fairly well. Therefore, it may be used as a relatively inexpensive computational tool for the design of components made from shape-memory materials.
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Polycrystalline shape-memory materials: Effect of Crystallographic Texture
Journal of the Mechanics and Physics of Solids, 2001Co-Authors: P. Thamburaja, L. AnandAbstract:A crystal-mechanics-based constitutive model for polycrystalline shape-memory materials has been developed. The model has been implemented in a finite-element program. In our finite-element model of a polycrystal, each element represents one crystal, and a set of crystal orientations which approximate the initial Crystallographic Texture of the shape-memory alloy are assigned to the elements. The macroscopic stress-strain responses are calculated as volume averages over the entire aggregate. Pseudoelasticity experiments in tension, compression, and shear have been performed on an initially Textured polycrystalline Ti-Ni alloy. In order to determine the material parameters for Ti-Ni, the stress-strain results from a finite-element calculation of a polycrystalline aggregate subjected to simple tension have been fit to corresponding results obtained from the physical experiment. Using the material parameters so determined, the predicted pseudoelastic stress-strain curves for simple compression and thin-walled tubular torsion of the initially Textured Ti-Ni are shown to be in good accord with the corresponding experiments. Our calculations also show that the Crystallographic Texture is the main cause for the observed tension-compression asymmetry in the pseudoelastic response of Ti-Ni. The predictive capability of the model for the variation of the pseudoelastic behavior with temperature is shown by comparing the calculated stress-strain response from the model against results from experiments of Shaw and Kyriakides (J. Mech. Phys. Solids 43 (1995) 1243) on Ti-Ni wires at a few different temperatures. By performing numerical experiments, we show that our model is able to qualitatively capture the shape-memory effect by transformation. We have also evaluated the applicability of a simple Taylor-type model for shape-memory materials. Our calculations show that the Taylor model predicts the macroscopic pseudoelastic stress-strain curves in simple tension, simple compression and tubular torsion fairly well. Therefore, it may be used as a relatively inexpensive computational tool for the design of components made from shape-memory materials. © 2001 Elsevier Science Ltd. All rights reserved.
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the process of shear band formation in plane strain compression of fcc metals effects of Crystallographic Texture
Mechanics of Materials, 1994Co-Authors: L. Anand, Surya R. KalidindiAbstract:Abstract The recent advances in the development of constitutive equations for large deformations of ductile single crystals and the development of robust finite element procedures for solving non-homogeneous boundary-value problems using these constitutive models, provide a foundation for understanding and predicting many features of the localization of deformation into shear bands. This paper presents the results of a numerical simulation of the effects of Crystallographic Texture evolution on the process of shear band formation in plane strain compression of initially isotropic OFHC polycrystalline copper. An aggregate of single crystals is used to represent a polycrystal. The calculations are two-dimensional plane strain at the macroscopic level, but they use the actual slip system structure for fee materials with twelve {111} 110 type slip systems. In the calculations an element of the finite element mesh represents either a single crystal or a part of a single crystal, and the constitutive response at an integration point is given by the single crystal constitutive model. The calculation procedures enforce equilibrium and compatibility throughout the polycrystalline aggregate in the weak finite element sense. No initial material or geometric imperfections are prescribed, but the initial lattice orientations are different from one grain to the next. The localization of deformation in the simulations is found to be a natural outcome of large deformation processes in ductile polycrystalline materials, and associated with the concurrent evolution of Crystallographic Texture. Comparison of results from the numerical simulations against experimental measurements shows that the resolution of grain-scale micro-shear bands requires very fine finite element meshes. The limitations of our computers are such that at present even very refined finite element meshes are too coarse to capture grain-scale shear bands. However, our simulations do capture the major features that are observed experimentally. In particular, the averaged global stress-strain behavior, the Crystallographic Texture, and the orientation of macroscale shear bands predicted by our simulations are close to those measured in our experiments.
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polycrystalline plasticity and the evolution of Crystallographic Texture in fcc metals
Philosophical transactions-Royal Society of London. Physical sciences and engineering, 1992Co-Authors: Curt A Bronkhorst, Surya R. Kalidindi, L. AnandAbstract:A Taylor-type model for large deformation polycrystalline plasticity is formulated and evaluated by comparing the predictions for the evolution of Crystallographic Texture and the stress-strain response in simple compression and tension, plane strain compression, and simple shear of initially ‘isotropic’ OFHC copper against ( a ) corresponding experiments, and ( b ) finite element simulations of these experiments using a multitude of single crystals with accounting for the satisfaction of both compatibility and equilibrium. Our experiments and calculations show that the Taylor-type model is in reasonable first-order agreement with the experiments for the evolution of Texture and the overall stress-strain response of single-phase copper. The results of the finite element calculations are in much better agreement with experiments, but at a substantially higher computational expense.
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Crystallographic Texture evolution in bulk deformation processing of FCC metals
Journal of the Mechanics and Physics of Solids, 1992Co-Authors: Surya R. Kalidindi, Curt A Bronkhorst, L. AnandAbstract:A Taylor-type polycrystalline model, together with a new fully-implicit time-integration scheme has been developed and implemented in a finite element program to simulate the evolution of Crystallographic Texture during bulk deformation processing of face centered cubic metals deforming by Crystallographic slip. The constitutive equations include a new equation for the evolution of slip system deformation resistance which leads to macroscopic strain hardening behavior that is in good accord with experiments performed on OFHC copper. The good predictive capabilities of the constitutive equations and the time-integration procedure for simulating the stress-strain behavior and the evolution of Texture under both homogeneous and non-homogeneous deformation conditions are demonstrated by comparing numerical simulations against experimental measurements in simple shear and a simple plane-strain forging experiment on copper. © 1992 Pergamon Press plc.
J. Gravier - One of the best experts on this subject based on the ideXlab platform.
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influence of residual stress surface roughness and Crystallographic Texture induced by machining on the corrosion behaviour of copper in salt fog atmosphere
Corrosion Science, 2012Co-Authors: J. Gravier, V Vignal, S BisseybretonAbstract:Abstract The influence of quadratic stress, Crystallographic Texture, lubrication and surface roughness generated by superfinish turning on the corrosion behaviour of pure copper was quantified in salt-fog atmosphere. This was done using statistical analysis (Pearson’s correlation matrix). Three compounds were found after corrosion tests: atacamite/paratacamite and a black layer (mixture of the lubricant and the salt atmosphere). Surface characteristics were classified according to their decreasing influence on the formation of atacamite/paratacamite as follows: surface roughness and quadratic stress. Lubrication and the Crystallographic Texture have the lowest influence on corrosion processes. Surface observations revealed that general dissolution occurred under atacamite/paratacamite.
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Influence of residual stress, surface roughness and Crystallographic Texture induced by machining on the corrosion behaviour of copper in salt-fog atmosphere
Corrosion Science, 2012Co-Authors: J. Gravier, V Vignal, S. Bissey-bretonAbstract:The influence of quadratic stress, Crystallographic Texture, lubrication and surface roughness generated by superfinish turning on the corrosion behaviour of pure copper was quantified in salt-fog atmosphere. This was done using statistical analysis (Pearson's correlation matrix). Three compounds were found after corrosion tests: atacamite/paratacamite and a black layer (mixture of the lubricant and the salt atmosphere). Surface characteristics were classified according to their decreasing influence on the formation of atacamite/paratacamite as follows: surface roughness and quadratic stress. Lubrication and the Crystallographic Texture have the lowest influence on corrosion processes. Surface observations revealed that general dissolution occurred under atacamite/paratacamite. © 2012 Elsevier Ltd.
S Bisseybreton - One of the best experts on this subject based on the ideXlab platform.
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influence of residual stress surface roughness and Crystallographic Texture induced by machining on the corrosion behaviour of copper in salt fog atmosphere
Corrosion Science, 2012Co-Authors: J. Gravier, V Vignal, S BisseybretonAbstract:Abstract The influence of quadratic stress, Crystallographic Texture, lubrication and surface roughness generated by superfinish turning on the corrosion behaviour of pure copper was quantified in salt-fog atmosphere. This was done using statistical analysis (Pearson’s correlation matrix). Three compounds were found after corrosion tests: atacamite/paratacamite and a black layer (mixture of the lubricant and the salt atmosphere). Surface characteristics were classified according to their decreasing influence on the formation of atacamite/paratacamite as follows: surface roughness and quadratic stress. Lubrication and the Crystallographic Texture have the lowest influence on corrosion processes. Surface observations revealed that general dissolution occurred under atacamite/paratacamite.
S. Bissey-breton - One of the best experts on this subject based on the ideXlab platform.
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Influence of residual stress, surface roughness and Crystallographic Texture induced by machining on the corrosion behaviour of copper in salt-fog atmosphere
Corrosion Science, 2012Co-Authors: J. Gravier, V Vignal, S. Bissey-bretonAbstract:The influence of quadratic stress, Crystallographic Texture, lubrication and surface roughness generated by superfinish turning on the corrosion behaviour of pure copper was quantified in salt-fog atmosphere. This was done using statistical analysis (Pearson's correlation matrix). Three compounds were found after corrosion tests: atacamite/paratacamite and a black layer (mixture of the lubricant and the salt atmosphere). Surface characteristics were classified according to their decreasing influence on the formation of atacamite/paratacamite as follows: surface roughness and quadratic stress. Lubrication and the Crystallographic Texture have the lowest influence on corrosion processes. Surface observations revealed that general dissolution occurred under atacamite/paratacamite. © 2012 Elsevier Ltd.
V Vignal - One of the best experts on this subject based on the ideXlab platform.
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influence of residual stress surface roughness and Crystallographic Texture induced by machining on the corrosion behaviour of copper in salt fog atmosphere
Corrosion Science, 2012Co-Authors: J. Gravier, V Vignal, S BisseybretonAbstract:Abstract The influence of quadratic stress, Crystallographic Texture, lubrication and surface roughness generated by superfinish turning on the corrosion behaviour of pure copper was quantified in salt-fog atmosphere. This was done using statistical analysis (Pearson’s correlation matrix). Three compounds were found after corrosion tests: atacamite/paratacamite and a black layer (mixture of the lubricant and the salt atmosphere). Surface characteristics were classified according to their decreasing influence on the formation of atacamite/paratacamite as follows: surface roughness and quadratic stress. Lubrication and the Crystallographic Texture have the lowest influence on corrosion processes. Surface observations revealed that general dissolution occurred under atacamite/paratacamite.
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Influence of residual stress, surface roughness and Crystallographic Texture induced by machining on the corrosion behaviour of copper in salt-fog atmosphere
Corrosion Science, 2012Co-Authors: J. Gravier, V Vignal, S. Bissey-bretonAbstract:The influence of quadratic stress, Crystallographic Texture, lubrication and surface roughness generated by superfinish turning on the corrosion behaviour of pure copper was quantified in salt-fog atmosphere. This was done using statistical analysis (Pearson's correlation matrix). Three compounds were found after corrosion tests: atacamite/paratacamite and a black layer (mixture of the lubricant and the salt atmosphere). Surface characteristics were classified according to their decreasing influence on the formation of atacamite/paratacamite as follows: surface roughness and quadratic stress. Lubrication and the Crystallographic Texture have the lowest influence on corrosion processes. Surface observations revealed that general dissolution occurred under atacamite/paratacamite. © 2012 Elsevier Ltd.