Application of the VPSC Model to the Description of the Stress–Strain Response and Texture Evolution in AZ31 Mg for Various Strain Paths

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Nitin Chandola ◽  
Raja K. Mishra ◽  
Oana Cazacu
Keyword(s):  
Mechanical Response ◽  
Mechanical Test ◽  
Texture Evolution ◽  
Mean Field ◽  
Strain Curve ◽  
Temperature Deformation ◽  
Strain Response ◽  
Stress Strain ◽  
Self Consistent ◽  
Strain Paths

Accurate description of the mechanical response of AZ31 Mg requires consideration of its strong anisotropy both at the single crystal and polycrystal levels, and its evolution with accumulated plastic deformation. In this paper, a self-consistent mean field crystal plasticity model, viscoplastic self-consistent (VPSC), is used for modeling the room-temperature deformation of AZ31 Mg. A step-by-step procedure to calibrate the material parameters based on simple tensile and compressive mechanical test data is outlined. It is shown that the model predicts with great accuracy both the macroscopic stress–strain response and the evolving texture for these strain paths used for calibration. The stress–strain response and texture evolution for loading paths that were not used for calibration, including off-axis uniaxial loadings and simple shear, are also well described. In particular, VPSC model predicts that for uniaxial tension along the through-thickness direction, the stress–strain curve should have a sigmoidal shape.

Numerical Simulation of the Four-Roll Bending Process for 2.25Cr-1Mo-0.25V Thick-Plate at Elevated Temperature

2017 ◽  
Author(s):  
Yafei Wang ◽  
Guangxu Cheng ◽  
Zaoxiao Zhang ◽  
Yun Li ◽  
Jianxiao Zhang
Keyword(s):  
Numerical Simulation ◽  
Elevated Temperature ◽  
Plate Thickness ◽  
Strain Curve ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Plate Bending ◽  
Stress Strain ◽  
Explicit Finite Element ◽  
Bending Process

In this paper, the four-roll plate bending process of 2.25Cr-1Mo-0.25V steel at elevated temperature is investigated by numerical simulation. This 3-D simulation is finished by using the elastic-plastic dynamic explicit finite element method (FEM) under the ANSYS/LS-DYNA environment. The strain softening behavior of 2.25Cr-1Mo-0.25V steel at elevated temperature is presented and discussed. The stress-strain relationship of the steel plate is modeled using a piecewise linear material model, with the stress-strain curve obtained through tensile tests. The plate bending process with a plate thickness of 150 mm is investigated. The amount and position of maximum plastic deformation are analyzed. The present study provides an important basis for the optimization of bending parameters and further investigation of the effect of high-temperature deformation on the resistance to hydrogen attack of 2.25Cr-1Mo-0.25V steel.

Micromechanical Mean-Field Analysis for Stress-Strain Curve of Lotus-Type Porous Iron

2005 ◽  
Vol 486-487 ◽  
pp. 489-492
Author(s):  
Masakazu Tane ◽  
Soong Keun Hyun ◽  
T. Ichitsubo ◽  
Hideo Nakajima
Keyword(s):  
Mean Field Theory ◽  
Mean Field ◽  
Strain Curve ◽  
Longitudinal Axis ◽  
Field Analysis ◽  
Plastic Behavior ◽  
Porous Iron ◽  
Compression Tests ◽  
Stress Strain ◽  
Helium Atmosphere

We studied the plastic behavior of lotus-type porous iron with unidirectional long cylindrical pores. Lotus-type porous iron with different porosities was fabricated by the continuous zone melting method in a pressurized hydrogen and helium atmosphere. To calculate the stress-strain curves for lotus iron, we applied a modified Qiu-Weng’s micromechanical mean-field theory that has recently been proposed by the present authors [J. Mater. Res., in press], and compared the results with those of compression tests. We experimentally found that the deformation resistance and work hardening rate depend on the sample porosity and loading direction. They decrease with an increase in porosity, and their values in the loading along the direction perpendicular to the longitudinal axis of pores are smaller than those in the parallel-direction loading. Our micromechanical calculations reproduce well the stress-strain curves experimentally obtained and express the experimental trends successfully.

The Effects of Strain Rate and Thickness on the Response of Thin Layers of Solder Loaded in Pure Shear

1997 ◽  
Vol 119 (2) ◽  
pp. 81-84 ◽  
Author(s):  
A. Gilat ◽  
K. Krishna
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Strain Rate ◽  
Mechanical Response ◽  
Pure Shear ◽  
Strain Curve ◽  
Thin Layers ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Stress And Deformation

A new configuration for testing thin layers of solder is introduced and employed to study the effects of strain rate and thickness on the mechanical response of eutectic Sn-Pb solder. The solder in the test is loaded under a well defined state of pure shear stress. The stress and deformation in the solder are measured very accurately to produce a reliable stress-strain curve. The results show that both the stress needed for plastic deformation and ductility increase with increasing strain rate.

Evaluation of Anisotropic Pipe Steel Stress-Strain Relationships Influence on Strain Demand

2012 ◽  
Author(s):  
James D. Hart ◽  
Nasir Zulfiqar ◽  
Joe Zhou
Keyword(s):  
Strain Hardening ◽  
Pipe Steel ◽  
High Strain ◽  
Strain Curve ◽  
High Strength ◽  
Strain Response ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Hardening Modulus ◽  
Strain Relationship

Buried pipelines can be exposed to displacement-controlled environmental loadings (such as landslides, earthquake fault movements, etc.) which impose deformation demands on the pipeline. When analyzing pipelines for these load scenarios, the deformation demands are typically characterized based on the curvature and/or the longitudinal tension and compression strain response of the pipe. The term “strain demand” is used herein to characterize the calculated longitudinal strain response of a pipeline subject to environmentally-induced deformation demands. The shape of the pipe steel stress-strain relationship can have a significant effect on the pipe strain demands computed using pipeline deformation analyses for displacement-controlled loading conditions. In general, with sufficient levels of imposed deformation demand, a pipe steel stress-strain curve with a relatively abrupt or “sharp” elastic-to-plastic transition will tend to lead to larger strain demands than a stress-strain curve with a relatively rounded elastic-to-plastic transition. Similarly, a stress-strain curve with relatively low strain hardening modulus characteristics will tend to lead to larger strain demands than a stress-strain curve with relatively high strain hardening modulus characteristics. High strength UOE pipe can exhibit significant levels of anisotropy (i.e., the shapes of the stress-strain relationships in the longitudinal tension/compression and hoop tension/compression directions can be significantly different). To the extent that the stress-strain curves in the different directions can have unfavorable shape characteristics, it follows that anisotropy can also play an important role in pipeline strain demand evaluations. This paper summarizes a pipeline industry research project aimed at evaluation of the effects of anisotropy and the shape of pipe steel stress-strain relationships on pipeline strain demand for X80 and X100 UOE pipe. The research included: a review of pipeline industry literature on the subject matter; a discussion of pipe steel plasticity concepts for UOE pipe; characterization of the anisotropy and stress-strain curve shapes for both conventional and high strain pipe steels; development of representative analytical X80 and X100 stress-strain relationships; and evaluation of a large matrix of ground-movement induced pipeline deformation scenarios to evaluate key pipe stress-strain relationship shape and anisotropy parameters. The main conclusion from this work is that pipe steel specifications for high strength UOE pipe for strain-based design applications should be supplemented to consider shape-characterizing parameters such as the plastic complementary energy.

scholarly journals Effect of Wall Thickness on Stress–Strain Response and Buckling Behavior of Hollow-Cylinder Rubber Fenders

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1170 ◽  
Author(s):  
Ming-Yuan Shen ◽  
Yung-Chuan Chiou ◽  
Chung-Ming Tan ◽  
Chia-Chin Wu ◽  
Wei-Jen Chen
Keyword(s):  
Hollow Cylinder ◽  
Wall Thickness ◽  
Contact Area ◽  
Reaction Force ◽  
Strain Curve ◽  
Strain Response ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Fourth Degree ◽  
Bending Deformation

In this study, the effect of wall thickness (15–25 mm) on the stress–strain response of hollow-cylinder rubber fenders were investigated by conducting monotonic compression tests. It was found that a progressive increase in lateral bending deformation was observed during monotonic compression. Simultaneously, the extent of the lateral deflection decreased notably with an increasing wall thickness. From the experimental results, the fact is accepted that buckling occurred in the tested fender due to the fact that the ratio of the height to the wall thickness was higher than four in all of the considered cases. Moreover, an s-shape profile appeared in the stress–strain curves, which became clearer as the wall thickness was reduced from 25 to 15 mm. To assess the performance of fenders objectively, an energy-effectiveness index, C E R , was introduced to quantify the energy absorption capacity of the fender. From the experimental observations, it was inferred that the contact area of the folded inner surface of the fender produced under compression generated an additional reaction force and affected the shape of the stress–strain curve since the measured load consisted of two reaction forces: one caused by the self-contact area, and the other resulted from the compression-bending deformation that occurred in the side wall of the fender. To examine this assertion, a finite element analysis (FEA) was conducted and confirmed the effect of the reaction force on the sensitivity of the s-shape characteristic of the stress–strain curve. Finally, a polynomial regression was conducted and the calculated results based on the fourth-degree stress polynomial function correlated very well with the measured stress–strain curves.

Constitutive modelling of the mechanical response of a polycaprolactone based polyurethane elastomer: Finite element analysis and experimental validation through a bulge test

2020 ◽  
pp. 030932472095833
Author(s):  
Nahuel Rull ◽  
Asanka Basnayake ◽  
Michael Heitzmann ◽  
Patricia M. Frontini
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Response ◽  
Strain Curve ◽  
Image Correlation ◽  
Bulge Test ◽  
Polyurethane Elastomer ◽  
Stress Strain ◽  
Element Analysis ◽  
Nonlinear Stress

The mechanical behaviour of a high performance polycaprolactone based polyurethane elastomer (PCL) up to large strain levels, cyclic loading and equibiaxial stress has been assessed. The PCL can be categorised as a rubber-like material, thus, showing nonlinear stress-strain behaviour. The materials elastic network is based on a high molecular weight PCL polyol which gives the material its elastomeric behaviour similar to polyurethanes. In this work, mechanical testing capturing the major features of the stress-strain curve under different loading conditions is performed. Both, uni-axial loading-unloading curves and bulge test are thoroughly studied through the addition of digital image correlation (DIC) to measure the strain field. Results show the presence of hysteresis and loading configuration dependence. Then, two well-known hyperelastic constitutive models, the Arruda-Boyce eight-chain and Bergström-Boyce, were fitted to the uni-axial monotonic and cyclic test data and compared to the bulge test experimental results through finite element analysis (FEA) in Abaqus.

scholarly journals Influence of Yttrium Addition on Texture and Deformation Behavior in an Extruded ZM31 Alloy

2021 ◽  
Author(s):  
Nabila Tahreen
Keyword(s):  
Strain Hardening ◽  
Magnesium Alloys ◽  
Deformation Behavior ◽  
Business Models ◽  
Mechanical Response ◽  
Texture Evolution ◽  
Strain Curve ◽  
True Stress ◽  
Dislocation Slip ◽  
Microstructural Development

The current “storm” of lightweighting, a revolution in materials, processes, and business models, which is brewing on the horizon of the auto industry, inspires researchers and engineers to develop and apply new wrought magnesium alloys with improved properties. For wider applications in the automotive and aerospace industries, the enhancement of strength, thermal stability and formability of magnesium alloys is required. In recent years, Mg-Zn-Y series alloys have received a considerable attention from the research community due to their improved mechanical properties. The present study was aimed at evaluating the influence of Y addition to Mg-Zn-Mn system based on phase formation, mechanical response and texture development with special attention paid to recrystallization, hot characterization and relative activity. The dissertation evaluated the strain hardening and deformation behavior of as-extruded Mg-ZnMn (ZM31) magnesium alloy with varying Y contents via compression testing at room temperature, 200°C and 300°C. Alloy ZM31+0.3Y consisted I-phase (Mg3YZn6); alloy ZM31+3.2Y contained I-phase and W-phase (Mg3Y2Zn3); alloy ZM31+6Y had long-period stacking-ordered (LPSO) X-phase (Mg12YZn) and Mg24Y5 particles. With increasing Y content the basal texture became weakened significantly. While alloys ZM31+0.3Y and ZM31+3.2Y exhibited a skewed true stress-true stain curve with a three-stage strain hardening feature caused by the occurrence of {10 Ī 2} extension twinning, the true stress-true strain curve of alloy ZM31+6Y was normal due to the dislocation slip during compression. The evolution of flow stress, texture and microstructure during the compression tests has been studied under various conditions of temperature and strain rates. Optical metallography, EBSD techniques and X-ray diffraction were employed to study the microstructural development and texture evolution. The deformation activation energy was calculated and the processing maps were generated to determine the optimum hot working parameters. In addition, viscoplastic selfconsistent model was successfully used to predict the experimental textures. Lastly, the strengthening mechanisms in each Mg-Zn-Mn-Y material are established quantitatively for the first time to account for grain refinement, thermal mismatch, dislocation density, load bearing, and particle strengthening contributions. The present work laid the foundations for a better understanding the role of Y elements on deformation behavior in magnesium alloys.

Influence of Compression upon the Shear Properties of Bonded Rubber Blocks

1980 ◽  
Vol 53 (5) ◽  
pp. 1133-1144 ◽  
Author(s):  
L. S. Porter ◽  
E. A. Meinecke
Keyword(s):  
Shear Stress ◽  
Shear Modulus ◽  
Simple Shear ◽  
Compressive Force ◽  
Strain Curve ◽  
Shear Loading ◽  
Total Force ◽  
Strain Response ◽  
Stress Strain ◽  
Spring Rate

Abstract Rubber has a stress-strain response to compression-shear loadings that is the same as its stress-strain response to simple shear loadings. However, its load-deflection response to the compression-shear loading is not the same as its simple shear response. In determining the stress-strain relationship of the compression-shear loading from the load-deflection responses, three factors must be considered. First, the compression of the sample gives a lower rubber thickness. After calculating the strain, the lower thickness will give a higher strain than the original thickness at an equal deflection. Second, the compression gives a larger surface area due to bulging of the rubber. The higher area would result in a lower stress than the original area at an equal load. Third, the force that is necessary to compress the rubber block is stored in the rubber. When the rubber is sheared, the shear vector of the compressive force aides in deflecting the rubber. Therefore, the shear force vector would be added to the recorded load to determine the total force needed to shear the rubber. The resulting shear stress would be higher than the shear stress calculated by using the recorded load in calculating the shear stress. With all three factors accounted for, the shear stress-strain of the rubber is the same for the compressed part as it is for the uncompressed part. Therefore, the rubber's shear modulus, the slope of the shear stress-strain curve, has not been affected by the superimposed compression and remains an inherent property of the rubber. When designing a part to be used in a compression-shear application, one can use the shear and compression moduli normally obtained for shear and compression applications. The compression modulus would be used for determining the compressive spring rate and the amount of force used in lowering the shear spring rate. The shear modulus would be used to determine the shear rate by taking into account the geometry changes and the force due to compression.

Modeling Texture, Twinning and Hardening Evolution during Deformation of Hexagonal Materials

2005 ◽  
Vol 495-497 ◽  
pp. 1001-1006 ◽  
Author(s):  
Carlos Tomé ◽  
George C. Kaschner
Keyword(s):  
Strain Rate ◽  
Texture Evolution ◽  
Deformation Texture ◽  
Strain Response ◽  
Stress Strain ◽  
Critical Stresses ◽  
Loading Direction ◽  
Hexagonal Materials

Hexagonal materials deform plastically by activating diverse slip and twinning modes. The activation of such modes depends on their relative critical stresses, function of temperature and strain rate, and the orientation of the crystals with respect to the loading direction. For a constitutive description of these materials to be reliable, it has to account for texture evolution associated with twin reorientation, and for the effect of the twin barriers on dislocation propagation and on the stress-strain response. In this work we introduce a model for twinning which accounts explicitly for the composite character of the grain, formed by a matrix with embedded twin lamellae which evolve with deformation. Texture evolution takes place through reorientation due to slip and twinning. The role of the twins as barriers to dislocations is explicitly incorporated into the hardening description via a directional Hall-Petch mechanism. We apply this model to the interpretation of compression experiments both, monotonic and changing the loading direction, done in rolled Zr at 76K.

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