Effect of Yield Surface Curvature on Local Necking in Biaxially Stretched Sheets in Porous Materials

1992 ◽  
Vol 114 (2) ◽  
pp. 196-200 ◽  
Author(s):  
Xiangqiao Yan
Keyword(s):  
Porous Materials ◽  
Yield Surface ◽  
Kinematic Hardening ◽  
Material Model ◽  
Isotropic Hardening ◽  
Material Models ◽  
Hardening Model ◽  
Local Necking ◽  
Highly Sensitive ◽  
Isotropic Expansion

In this paper, a recently proposed material model (Sun model) that is based on the lower bound approach of plasticity is extended by introducing a family of dilatant plasticity theories. The yield surfaces change by a combination of isotropic expansion and kinematic translation. The sensitivity of the local necking predictions in biaxially stretched sheets to the curvature of the yield surface in porous materials is addressed. The results of the present analysis obtained by using four material models, the isotropic hardening version of Sun, the kinematic hardening version suggested in this paper, the Gurson model, and the Mear and Hutchinson model, indicate that the local necking predictions are highly sensitive to the curvature of the yield surface, and the predictions given by the kinematic hardening model are more reasonable for local necking analysis than those by the isotropic hardening model.

Modeling the Deformation Response of High Strength Steel Pipelines—Part II: Effects of Material Characterization on the Deformation Response of Pipes

2012 ◽  
Vol 79 (5) ◽  
Author(s):  
Sunil Neupane ◽  
Samer Adeeb ◽  
Roger Cheng ◽  
James Ferguson ◽  
Michael Martens
Keyword(s):  
High Strength Steel ◽  
Material Characterization ◽  
Kinematic Hardening ◽  
High Strength ◽  
Longitudinal Direction ◽  
Material Model ◽  
Isotropic Hardening ◽  
Material Models ◽  
Hardening Material ◽  
Deformation Response

The material model proposed in Part I (Neupane et al., 2012, “Modeling the Deformation Response of High Strength Steel Pipelines—Part I: Material Characterization to Model the Plastic Anisotropy,” ASME J. Appl. Mech., 79, p. 051002) is used to study the deformation response of high strength steel. The response of pipes subjected to frost upheaval at a particular point is studied using an assembly of pipe elements, while buckling of pipes is examined using shell elements. The deformation response is obtained using two different material models. The two different material models used were the isotropic hardening material model and the combined kinematic hardening material model. Two sets of material stress-strain data were used for the isotropic hardening material model; data obtained from the longitudinal direction tests and data obtained from the circumferential direction tests. The combined kinematic hardening material model was calibrated to provide an accurate prediction of the stress-strain behavior in both the longitudinal direction and the circumferential direction. The deformation response of a pipe model using the three different material data sets was studied. The sensitivity of the response of pipelines to the choice of a material model and the material data set is studied for the frost upheaval and local buckling.

3-D Elastic-Plastic Constitutive Relationship of Mixed Hardening

2012 ◽  
Vol 249-250 ◽  
pp. 927-930
Author(s):  
Ze Yu Wu ◽  
Xin Li Bai ◽  
Bing Ma
Keyword(s):  
Finite Element ◽  
Constitutive Relation ◽  
Kinematic Hardening ◽  
Constitutive Relationship ◽  
Isotropic Hardening ◽  
Element Analysis ◽  
Hardening Model ◽  
Elastic Plastic ◽  
Mixed Hardening ◽  
Advantages And Disadvantages

In finite element calculation of plastic mechanics, isotropic hardening model, kinematic hardening model and mixed hardening model have their advantages and disadvantages as well as applicability area. In this paper, by use of the tensor analysis method and mixed hardening theory in plastic mechanics, the constitutive relation of 3-D mixed hardening problem is derived in detail based on the plane mixed hardening. Numerical results show that, the proposed 3-D mixed hardening constitutive relation agrees well with the test results in existing references, and can be used in the 3-D elastic-plastic finite element analysis.

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.

Influence of the Hardening Model on the Predicted Welding Distortion of DP600 Lap Joints

2010 ◽  
Vol 638-642 ◽  
pp. 3710-3715
Author(s):  
T. Schenk ◽  
I.M. Richardson ◽  
G. Eßer ◽  
M. Kraska
Keyword(s):  
Kinematic Hardening ◽  
Tensile Tests ◽  
Lap Joints ◽  
Welding Distortion ◽  
Isotropic Hardening ◽  
Hardening Model ◽  
Mixed Hardening ◽  
Overlap Joint ◽  
Definition Of ◽  
Robust Process

The accurate prediction of welding distortion is an important requirement for the industry in order to allow the definition of robust process parameters without the need to perform expensive experiments. Many models have been developed in the past decades in order to improve prediction. Assumptions are made to make the models tractable; however, the consequences are rarely discussed. One example for such an assumption is the strain hardening model, which is often a choice between either kinematic or isotropic hardening. This paper presents the results of tensile tests for DP600 performed from room temperature up to one thousand degrees and for different strain-rates. In order to employ a mixed isotropic-kinematic hardening model, the fractions of each hardening contribution have been determined by means of bend testing. The welding distortion of a DP600 overlap joint has been simulated and it is shown that such a mixed-hardening model results in more accurate and reliable results.

Three-dimensional plasticity with kinematic and isotropic hardening

2020 ◽  
pp. 421-428
Author(s):  
Lallit Anand ◽  
Sanjay Govindjee
Keyword(s):  
Plastic Strain ◽  
Kinematic Hardening ◽  
Three Dimensional ◽  
Small Strain ◽  
Back Stress ◽  
Isotropic Hardening ◽  
Evolution Law ◽  
Hardening Model ◽  
Rate Dependent ◽  
Viscoplastic Models

This chapter provides an introduction to combined isotropic-kinematic hardening plasticity models in the three-dimensional small strain setting. The additive decomposition of the strain is introduced along with the concepts of plastic strain, equivalent tensile plastic strain, and back stress for three-dimensional problems. Plastic flow is discussed and defined, and a complete model of plasticity is formulated with Kuhn-Tucker loading/unloading conditions. The kinematic hardening model is based upon the Armstrong-Fredrick evolution law. Both rate-independent and rate-dependent (viscoplastic) models are discussed.

A New Constitutive Model in the Theory of Plasticity—Part I: Theory

1995 ◽  
Vol 117 (4) ◽  
pp. 365-370 ◽  
Author(s):  
W. Jiang
Keyword(s):  
General Solution ◽  
Constitutive Model ◽  
Closed Form ◽  
Yield Surface ◽  
Kinematic Hardening ◽  
Material Response ◽  
Hardening Model ◽  
Theory Of Plasticity

By proposing two rules to regulate the movement of the yield surface, this paper develops a new kinematic hardening model in the theory of plasticity. A closed-form general solution is obtained in the case of linear stress paths, material response under cyclic loadings is discussed, and various tube problems are solved to demonstrate the model.

Ratcheting Simulation of Z2CN18.10 Austenitic Stainless Steel under Pre-Strain Conditions

2016 ◽  
Vol 853 ◽  
pp. 112-116
Author(s):  
Yong Wang ◽  
You Gang Peng ◽  
Xu Chen
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Good Prediction ◽  
Strain Accumulation ◽  
Modified Model ◽  
Hardening Model ◽  
Ratcheting Strain ◽  
Independent Model

Uniaxial ratcheting behaviors of Z2CN18.10 austenitic stainless steel under both tensile pre-strain (TP) and compressive pre-strain (CP) were experimentally studied at room temperature. The experimental results show that: TP restrains ratcheting strain accumulation of subsequent cycling with positive mean stress; lower level of CP is found to accelerate ratcheting strain accumulation while higher level of CP retards the accumulation. Based on the Ohno-Wang II kinematic hardening rule, rate-independent model, viscoplastic model, isotropic hardening model and a modified model were constructed to describe the ratcheting behaviors under various pre-strain conditions. All the four models gave fairly good prediction on ratcheting strains for various TP. The isotropic hardening model and modified model predicted acceptable ratcheting strain though still showed slight tendency of over prediction.

Effects of Hardening Models on CUO Forming and Springback Simulation of High Strength Line Pipes

2015 ◽  
Vol 817 ◽  
pp. 8-13 ◽  
Author(s):  
Qiang Ren ◽  
Tian Xia Zou ◽  
Da Yong Li
Keyword(s):  
Bauschinger Effect ◽  
Oil And Gas ◽  
Kinematic Hardening ◽  
High Strength ◽  
Isotropic Hardening ◽  
Forming Process ◽  
Hardening Model ◽  
Hardening Models ◽  
Combined Hardening ◽  
Springback Prediction

The UOE process is an effective approach for manufacturing the line pipes used in oil and gas transportation. During the UOE process, a steel plate is crimped along its edges, pressed into a circular pipe with an open-seam by the successively U-O forming stages. Subsequently, the open-seam is closed and welded. Finally, the welded pipe is expanded to obtain a perfectly round shape. In particular, during the O-forming stage the plate is suffered from distinct strain reversal which leads to the Bauschinger effect, i.e., a reduced yield stress at the start of reverse loading following forward strain. In the finite element simulation of plate forming, the material hardening model plays an important role in the springback prediction. In this study, the mechanical properties of API X90 grade steel are obtained by a tension-compression test. Three popular hardening models (isotropic hardening, kinematic hardening and combined hardening) are employed to simulate the CUO forming process. A deep analysis on the deformation and springback behaviors of the plate in each forming stage is implemented. The formed configurations from C-forming to U-forming are almost identical with three hardening models due to the similar forward hardening behaviors. Since the isotropic hardening model cannot represent the Bauschinger effect, it evaluates the higher reverse stress and springback in the O-forming stage which leads to a failure prediction of a zero open-seam pipe. On the contrary, the kinematic hardening model overestimates the Bauschinger effect so that predicts the larger open-seam value. Specifically, the simulation results using the combined hardening model show good agreement in geometric configurations with the practical measurements.

Constitutive Modelling of Anisotropy, Hardening and Failure of Sheet Metals

2011 ◽  
Vol 473 ◽  
pp. 631-636 ◽  
Author(s):  
Ivaylo N. Vladimirov ◽  
Yalin Kiliclar ◽  
Vivian Tini ◽  
Stefanie Reese
Keyword(s):  
Kinematic Hardening ◽  
Plastic Anisotropy ◽  
Forming Limit Diagram ◽  
Material Model ◽  
Constitutive Modelling ◽  
Forming Limit ◽  
Isotropic Hardening ◽  
Continuum Damage ◽  
Aluminium Sheets ◽  
Good Agreement

The paper discusses the application of a newly developed coupled material model of finite anisotropic multiplicative plasticity and continuum damage to the numerical prediction of the forming limit diagram at fracture (FLDF). The model incorporates Hill-type plastic anisotropy, nonlinear Armstrong-Frederick kinematic hardening and nonlinear isotropic hardening. The numerical examples investigate the simulation of forming limit diagrams at fracture by means of the so-called Nakajima stretching test. Comparisons with test data for aluminium sheets display a good agreement between the finite element results and the experimental data.

scholarly journals Towards an holistic account on residual stresses in full-forward extruded rods

2021 ◽  
Author(s):  
Dimosthenis Floros ◽  
Andreas Jobst ◽  
Andreas Kergaßner ◽  
Marion Merklein ◽  
Paul Steinmann
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Kinematic Hardening ◽  
Element Model ◽  
Elastic Response ◽  
Isotropic Hardening ◽  
Holistic View ◽  
Hardening Model ◽  
Forward Extrusion

AbstractAn holistic view is attempted towards prediction of the effect of residual stresses induced by full-forward extrusion on fatigue life of workpieces during operation. To study the effect of constitutive model on the accuracy of forming simulations, a combined nonlinear isotropic/kinematic hardening model as well as the isotropic hardening part of the same model are calibrated based on five compression-tension-compression uniaxial stress experiments. A full-forward extrusion finite element model is developed adapting both the aforementioned hardening plasticity models and the predicted residual stress states at the surface of the workpiece are compared against that of a corresponding forming experiment. Results show residual stress predictions of remarkable accuracy by the FE-models with the isotropic hardening model. The effect of residual stresses on fatigue life of the workpiece is qualitatively studied by uncoupled multiscale simulations featuring gradient crystal plasticity at the microscale. While the effective (homogenized) macroscale response indicates elastic response during a macroscopically cyclic loading, plasticity accompanying reduction of residual stresses is still present at the microscale within, e.g. grain boundaries.

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