scholarly journals Plastic anisotropy and failure in thin metal: Material characterization and fracture prediction with an advanced constitutive model and polar EPS (effective plastic strain) fracture diagram for AA 3014-H19

2018 ◽  
Vol 151 ◽  
pp. 195-213 ◽  
Author(s):  
Robert E. Dick ◽  
Jeong Whan Yoon
Keyword(s):  
Plastic Strain ◽  
Constitutive Model ◽  
Material Characterization ◽  
Plastic Anisotropy ◽  
Fracture Prediction ◽  
Thin Metal ◽  
Effective Plastic Strain ◽  
Metal Material ◽  
Strain Fracture ◽  
Fracture Diagram

A Finite Element Model of Orthogonal Metal Cutting

1985 ◽  
Vol 107 (4) ◽  
pp. 349-354 ◽  
Author(s):  
J. S. Strenkowski ◽  
J. T. Carroll
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Metal Cutting ◽  
Element Model ◽  
Effective Plastic Strain ◽  
Orthogonal Metal Cutting ◽  
Chip Separation ◽  
Chip Geometry

A finite element model of orthogonal metal cutting is described. The paper introduces a new chip separation criterion based on the effective plastic strain in the workpiece. Several cutting parameters that are often neglected in simplified metal-cutting models are included, such as elastic-plastic material properties of both the workpiece and tool, friction along the tool rake face, and geometry of the cutting edge and workpiece. The model predicts chip geometry, residual stresses in the workpiece, and tool stresses and forces, without any reliance on empirical metal cutting data. The paper demonstrates that use of a chip separation criterion based on effective plastic strain is essential in predicting chip geometry and residual stresses with the finite element method.

scholarly journals Elasto-plastic analysis of the contact region between a rigid ellipsoid and a semi-flat surface

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879739 ◽  
Author(s):  
Pengyang Li ◽  
Lingxia Zhou ◽  
Fangyuan Cui ◽  
Quandai Wang ◽  
Meiling Guo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Contact Pressure ◽  
Contact Region ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Effective Plastic Strain ◽  
Normal Forces ◽  
Von Mises

When the load acting on a mechanical structure is greater than the yield strength of the material, the contact surface will undergo plastic deformation. Cumulative plastic deformation has an important influence on the lifespan of mechanical parts. This article presents a three-dimensional semi-analytical model based on the conjugate gradient method and fast Fourier transform algorithm, with the aim of studying the characteristic parameters of the contact region between a rigid ellipsoid and elasto-plastic half-space. Moreover, normal forces and tangential traction were considered, as well as the contact pressure resulting from various sliding speeds and friction coefficients. The contact pressure, effective plastic strain, von Mises stress, and residual stress were measured and shown to increase with increasing sliding velocity. Finally, when the friction coefficient, contact pressure, and effective plastic strain are increased, the von Mises stress is also shown to increase, whereas the residual stress decreases.

A Characteristic and a Precisely Constitutive Model for Undrained Clay

2020 ◽  
Vol 975 ◽  
pp. 203-207
Author(s):  
Shih Tsung Hsu ◽  
Wen Chi Hu ◽  
Yu Heng Lin ◽  
Zhuo Ling
Keyword(s):  
Shear Strength ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Strain Hardening ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Proposed Model ◽  
Taipei Basin ◽  
Undrained Shear

Constitutive models for soils are usually adopted in numerical method to analyze the behavior of geotechnical structures. This study performs a series of consolidated-undrained triaxial tests to establish the stress-strain curve of clay. A constitutive model that considers continuous strain hardening-softening is proposed based on the results of triaxial tests. Triaxial test results reveal that undrained shear strength linearly increases with an increase in consolidated pressure , the normalized undrained shear strength is about 0.52 not only for this study but also for the other two cases around Taipei Basin. Due to undrained condition, an associated flow rule between plastic strain increment and stress tensor is adopted. As accumulative plastic strain or/and consolidated pressure change, the mobilized undrained shear strength also changes. All parameters needed for the proposed model can be expressed as a function of undrained shear strength Su, The mobilized undrained shear strength for the proposed model during strain hardening-softening can be in term of accumulative plastic strain. This model can calculate the stress-strain curves of clayed soils accurately.

Studies about the Drained Creep Characteristic of Silt Soil on k0 Consolidation

2014 ◽  
Vol 941-944 ◽  
pp. 2631-2635 ◽  
Author(s):  
Yan Fang Wang ◽  
Zhi Gang Zhou ◽  
Zheng Yin Cai
Keyword(s):  
Plastic Strain ◽  
Constitutive Model ◽  
Creep Strain ◽  
Creep Test ◽  
Empirical Formula ◽  
Axial Loading ◽  
Soil Creep ◽  
Time Extension ◽  
Creep Characteristic ◽  
Creep Constitutive Model

The creep characteristic of saturated silt soil was studied by k0 consolidation creep test through two stress paths of axial loading and lateral lightening. According to test datas, some conclusions were submitted. First, the axial creep laws between the two stress paths were consistent on drainage conditions. Volume strains were much smaller than Axial strains. Volume strains presented alternation characteristic between shear shrinkage and shear dilatancy along with time extension. The silt soil creep constitutive model was presented. The results suggested combining the NHRI model describing the transient elastic-plastic strain with the creep empirical formula describing creep strain to establish the creep constitutive model.

The Forging Penetration Efficiency of C45 Steel Stepped Shaft Radial Forging with GFM Forging Machine

2010 ◽  
Vol 154-155 ◽  
pp. 593-596 ◽  
Author(s):  
Xiang Ru Liu ◽  
Xu Dong Zhou
Keyword(s):  
Plastic Strain ◽  
Compressive Strain ◽  
Three Dimensional ◽  
Mean Stress ◽  
Radial Forging ◽  
Effective Plastic Strain ◽  
Forging Process ◽  
Stepped Shaft ◽  
Radial Forging Process ◽  
Strain Layer

The numerical thermal mechanical simulation of radial forging process of C45 steel stepped shaft with GFM forging machine was carried out by three dimensional finite element method DEFORM 3D. According to effective plastic strain, mean stress and mean plastic strain distribution of the radial forging process, the forging penetration efficiency (FPE) was studied throughout. The results show that: effective plastic strain in the center of the forging is never be zero; The mean stress in the center of the workpiece is proposed to describe hydrostatic pressure in this paper. There is compressive strain layer beneath the surface of the workpiece, while there is tensile strain layer in the center of the forging. These studied results could be a valuable reference for designing the similar forging operations.

Visco-Elastic-Plastic Constitutive Model for A7N01-T6 Alloy Welding and Analytical Solutions with Finite Element Codes

2013 ◽  
Vol 446-447 ◽  
pp. 284-287
Author(s):  
K.J. Song ◽  
Y.H. Wei ◽  
Z.B. Dong ◽  
K. Fang ◽  
W.J. Zheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Constitutive Model ◽  
Strain Hardening ◽  
Strain Softening ◽  
Great Influence ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Creep Equation ◽  
Maximum Deformation

This paper has established a viscoelasticplastic constitutive model for A7N01T6 alloy welding, which is temperature and deformation history dependent. The model uses elasticmixed hardening plastic and creep equation to describe the strain hardening at low temperatures and strain softening at high temperatures, respectively. Then it is applied for finite element numerical simulation of the welding process. By comparison with the conventional temperature dependent elasticperfectly plastic model, the overall longitudinal residual compressive plastic strain and the maximum deformation of welding sheet are larger. This is because that the plastic strain is mostly produced in high temperature range. Strain softening has great influence on the evolution of plastic strain. The compressive plastic strain during heating is larger than the tensile plastic strain during cooling. Strain hardening effect on welding residual strain and stress is almost negligible. Using the established constitutive model, welding residual stress and strain are in good agreement with the theoretical results.

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