A Plasticity Model for Metals With Dependency on All the Stress Invariants

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
George Z. Voyiadjis ◽  
S. H. Hoseini ◽  
G. H. Farrahi
Keyword(s):  
Yield Criterion ◽  
High Strength ◽  
Experimental Tests ◽  
Deviatoric Stress ◽  
Cyclic Behavior ◽  
Isotropic Hardening ◽  
Plasticity Model ◽  
Mapping Algorithm ◽  
The Third ◽  
Stress Invariant

Recent experiments on metals have shown that all of the stress invariants should be involved in the constitutive description of the material in plasticity. In this paper, a plasticity model for metals is defined for isotropic materials, which is a function of the first stress invariant in addition to the second and the third invariants of the deviatoric stress tensor. For this purpose, the Drucker–Prager yield criterion is extended by addition of a new term containing the second and the third deviatoric stress invariants. Furthermore for estimating the cyclic behavior, new terms are incorporated into the Chaboche's hardening evolution equation. These modifications are applied by adding new terms that include the effect of pervious plastic history of deformation on the current hardening evaluation equation. Also modified is the isotropic hardening rule with incorporating the effect of the first stress invariant. For calibration and evaluation of this plasticity model, a series of experimental tests are conducted on high strength steel, DIN 1.6959. In addition, finite element simulations are carried out including integration of the constitutive equations using the modified return mapping algorithm. The modeling results are in good agreement with experiments.

Thermoviscoplasticity Theory Incorporating the Third Deviatoric Stress Invariant

2015 ◽  
Vol 51 (1) ◽  
pp. 85-91 ◽  
Author(s):  
M. E. Babeshko ◽  
Yu. N. Shevchenko ◽  
N. N. Tormakhov
Keyword(s):  
Deviatoric Stress ◽  
The Third ◽  
Stress Invariant

Advanced High Strength Steel Sheet Forming and Springback Simulation

2010 ◽  
Vol 97-101 ◽  
pp. 200-203 ◽  
Author(s):  
Ke Chen ◽  
Jian Ping Lin ◽  
Mao Kang Lv ◽  
Li Ying Wang
Keyword(s):  
High Strength Steel ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Sheet Material ◽  
High Strength ◽  
Material Model ◽  
Sheet Forming ◽  
Isotropic Hardening ◽  
Advanced High Strength Steel ◽  
Springback Prediction

With the increasing use of finite element analysis method in sheet forming simulations, springback predictions of advanced high strength steel (AHSS) sheet are still far from satisfactory precision. The main purpose of this paper was to provide a method for accurate springback prediction of AHSS sheet. Material model with Hill’48 anisotropic yield criterion and nonlinear isotropic/kinematic hardening rule were applied to take account the anisotropic yield behavior and the Bauschinger effect during forming processes. U-channel forming and springback simulation was performed using ABAQUS software. High strength DP600 sheet was investigated in this work. The simulation results obtained with the proposed material model agree well with the experimental results, which show a remarkable improvement of springback prediction compared with the commonly used isotropic hardening model.

scholarly journals NUMERICAL INVESTIGATION ON CYCLIC BEHAVIOR OF RING-BEAM CONNECTION TO GANGUE CONCRETE FILLED STEEL TUBULAR COLUMNS

2021 ◽  
Keyword(s):  
Cyclic Loading ◽  
Failure Modes ◽  
High Capacity ◽  
High Strength ◽  
Experimental Tests ◽  
Load Level ◽  
Cyclic Behavior ◽  
Tubular Columns ◽  
Earthquake Resistant ◽  
Parametric Studies

As a promising composite structure, gangue concrete filled steel tubular (GCFST) column exhibites favarable characteristics including high strength and economic efficiency. This paper conducted numerical investiagations on structural behavior of a ring-beam connection to GCFST column with concrete beam under cyclic loading. Furthermore, finite element models of column-beam connections were developed using ABAQUS and validated against full-scale experimental tests to identify accuracy of selected modeling approaches. Using these validated models, stress distribution of each component was examined to study the force-transferring mechanism among the components and failure modes of the ring-beam connection. Research study indicated that the ring-beam connection showed a reasonable force-transferring mechanism under cyclic loading and the remarkable earthquake-resistant performance with high capacity and acceptable ductility. Finally, parametric studies were performed to assess the influences of beam-to-column stiffness ratio,steel ratio, axial load level, and concrete compressive strength on connection cyclic behaviors. Parametric studies provided some suggestions and references for the application of the ring-beam connection in various engineering projects.

scholarly journals Towards better finite element modelling of elastic recovery in sheet metal forming of advanced high strength steel

2011 ◽  
Vol 2 (2) ◽  
pp. 217-227
Author(s):  
M. Safaei ◽  
W. De Waele
Keyword(s):  
Finite Element ◽  
Elastic Recovery ◽  
Yield Criterion ◽  
Rolling Direction ◽  
High Strength ◽  
Isotropic Hardening ◽  
Contact Models ◽  
Element Type ◽  
The Hill ◽  
Optimal Implementation

The first part of this study discusses the influence of element type on parameters such asaccuracy of the FE simulation, simulation time and convergence. Guidelines on optimal implementation ofelement types are proposed. It is shown that an inappropriate choice of element type results in difficulties inconvergence of the simulation or gives rise to problems such as shear locking in elements. In the secondpart of this study a series of finite element simulations using the Hill’48 planar anisotropic yield criterion anda standard U-shape forming test based on the NUMISHEET’93 benchmark was performed. Theeffectiveness of different isotropic hardening laws and different contact models is investigated. The mostappropriate hardening and contact definitions are defined from the viewpoint of optimal springbackprediction. Finally, the influence of the orientation of sheet strips relative to the rolling direction onspringback angles is evaluated.

Residual Stress Analysis of the Autofrettaged Thick-Walled Tube Using Nonlinear Kinematic Hardening

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
G. H. Farrahi ◽  
George Z. Voyiadjis ◽  
S. H. Hoseini ◽  
E. Hosseinian
Keyword(s):  
Plastic Deformation ◽  
Residual Stresses ◽  
Stress Tensor ◽  
Kinematic Hardening ◽  
Deviatoric Stress ◽  
Material Behavior ◽  
Behavior Modeling ◽  
The Third ◽  
Deviatoric Stress Tensor ◽  
Stress Invariant

Recent research indicates that accurate material behavior modeling plays an important role in the estimation of residual stresses in the bore of autofrettaged tubes. In this paper, the material behavior under plastic deformation is considered to be a function of the first stress invariant in addition to the second and the third invariants of the deviatoric stress tensor. The yield surface is assumed to depend on the first stress invariant and the Lode angle parameter which is defined as a function of the second and the third invariants of the deviatoric stress tensor. Furthermore for estimating the unloading behavior, the Chaboche's hardening evolution equation is modified. These modifications are implemented by adding new terms that include the effect of the first stress invariant and pervious plastic deformation history. For evaluation of this unloading behavior model a series of loading-unloading tests are conducted on four types of test specimens which are made of the high-strength steel, DIN 1.6959. In addition finite element simulations are implemented and the residual stresses in the bore of a simulated thick-walled tube are estimated under the autofrettage process. In estimating the residual stresses the effect of the tube end condition is also considered.

scholarly journals A GTN-like Model for Plastic Porous Materials

2014 ◽  
Vol 4 (6) ◽  
pp. 734-738
Author(s):  
L. Siad ◽  
S. C. Gangloff
Keyword(s):  
Constitutive Model ◽  
Yield Function ◽  
Isotropic Hardening ◽  
Extended Version ◽  
Gtn Model ◽  
Hardening Model ◽  
The Third ◽  
Third Stress Invariant ◽  
Stress Invariant ◽  
Good Agreement

An extended version of the well-known Gurson-Tvergaard-Needleman (GTN) isotropic hardening model is presented in this paper. The yield function of the proposed constitutive model possesses the distinctiveness to explicitly depend upon the third stress invariant. The presented constitutive model is used to analyze the necking of a round tensile bar. As long as softening initiation of specimen is not reached, the obtained numerical results highlight similarities and good agreement with those provided by the use of the GTN model. However, discrepancy shows up as soon as specimen failure starts.

Geometric and Material Nonlinear Analyses of a Heated Zigzag Pipeline: Case Study to Look for High Stress Situations

2006 ◽  
Author(s):  
Adilson Carvalho Benjamin ◽  
Rita de Ca´ssia Carvalho Silva ◽  
Joa˜o Nisan Correia Guerreiro ◽  
Abimael Fernando Dourado Loula
Keyword(s):  
Yield Criterion ◽  
High Stress ◽  
General Purpose ◽  
Isotropic Hardening ◽  
Plasticity Model ◽  
Nonlinear Analyses ◽  
Hardening Rule ◽  
Von Mises ◽  
Material Nonlinear

This paper describes the case study performed to look for high stress situations that may occur along the life span of a heated zigzag pipeline. The main results of several finite element (FE) analyses are presented. These analyses were performed using the general purpose FE program ABAQUS considering geometric and material nonlinearities. A rate-independent plasticity model using the von Mises yield criterion and isotropic hardening rule were adopted.

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