Material Properties of Aluminum Alloy for Accurate Draw-Bend Simulation

2001 ◽  
Vol 123 (3) ◽  
pp. 287-292 ◽  
Author(s):  
K. M. Zhao ◽  
J. K. Lee
Keyword(s):  
Kinematic Hardening ◽  
Optimization Procedure ◽  
Model Material ◽  
Bending Test ◽  
Aluminum Sheet ◽  
Isotropic Hardening ◽  
Bending Moments ◽  
Hardening Model ◽  
Material Parameters ◽  
Normalized Error

The main objective of this paper is to simulate springback using a combined kinematic/isotropic hardening model. Material parameters in the hardening model are identified by an inverse method. A three-point bending test is conducted on 6022-T4 aluminum sheet. Punch stroke, punch load, bending strain, and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Material parameters are identified by minimizing the normalized error between two bending moments. A micro genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plasticity models. ABAQUS/Standard, which has the combined isotropic/kinematic hardening model, is used to simulate draw-bend of 6022-T4 aluminum sheet. Absolute springback angles are predicted very accurately.

Generation of Cyclic Stress-Strain Curves for Sheet Metals

2000 ◽  
Author(s):  
K. M. Zhao ◽  
J. K. Lee
Keyword(s):  
Constitutive Model ◽  
Kinematic Hardening ◽  
Optimization Procedure ◽  
High Strength ◽  
Cyclic Stress ◽  
Bending Moments ◽  
Sheet Metals ◽  
Stress Strain ◽  
Normal Anisotropy ◽  
Material Parameters

Abstract The main objective of this paper is to generate cyclic stress-strain curves for sheet metals so that the springback can be simulated accurately. Material parameters are identified by an inverse method within a selected constitutive model that represents the hardening behavior of materials subjected to a cyclic loading. Three-point bending tests are conducted on sheet steels (mild steel and high strength steel). Punch stroke, punch load, bending strain and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Normal anisotropy and nonlinear isotropic/kinematic hardening are considered. Material parameters are identified by minimizing the normalized error between two bending moments. Micro genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plastic models.

Generation of Cyclic Stress-Strain Curves for Sheet Metals

2000 ◽  
Vol 123 (4) ◽  
pp. 391-397 ◽  
Author(s):  
K. M. Zhao ◽  
J. K. Lee
Keyword(s):  
Constitutive Model ◽  
Kinematic Hardening ◽  
Optimization Procedure ◽  
High Strength ◽  
Cyclic Stress ◽  
Bending Moments ◽  
Sheet Metals ◽  
Stress Strain ◽  
Normal Anisotropy ◽  
Material Parameters

The main objective of this paper is to obtain the first few stress-strain loops of sheet metals from reverse loading so that the springback can be simulated accurately. Material parameters are identified by an inverse method within a selected constitutive model that represents the hardening behavior of materials subjected to a cyclic loading. Three-point bending tests are conducted on sheet steels (mild steel and high strength steel). Punch stroke, punch load, bending strain, and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Normal anisotropy and nonlinear isotropic/kinematic hardening are considered. Material parameters are identified by minimizing the normalized error between two bending moments. Micro-genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plastic models.

FEM Analysis on Pressure Vessel Components Containing LTAs Against Seismic Load Using Combined Non-Linear Isotropic/Kinematic Hardening Model

2013 ◽  
Author(s):  
Runze Zhou ◽  
Ikuo Kojima ◽  
Takuyo Kaida ◽  
Hirokazu Tsuji
Keyword(s):  
Carbon Steel ◽  
Kinematic Hardening ◽  
Equivalent Stress ◽  
Equivalent Plastic Strain ◽  
Fem Analysis ◽  
Steel Pipe ◽  
Isotropic Hardening ◽  
Seismic Load ◽  
Hardening Model ◽  
Material Parameters

Fitness-for-service (FFS) assessments are quantitative engineering evaluations that perform to demonstrate the integrity of an in-service component that may contain a flaw or damage [1]. It can be used to make run-repair-replace decisions to help determine if pressured equipment containing flaw that have been identified by inspection can continue to operate safety for some period of time. This paper provides a FFS assessment on carbon steel pipe which contained a LTA (Local Thin Area) against seismic load by FEM (Finite Element Method) analysis. ABAQUS Ver. 6.10, which has the combined isotropic / kinematic hardening model [2], is used to simulate the LTA contained carbon steel pipe against seismic load. Material parameters in the hardening model are identified by a symmetric strain cycle experiment based on ASTM E606. Isotropic hardening component is introduced by specifying the equivalent stress defining the size of the yield surface, as a tabular function of the equivalent plastic strain. Kinematic hardening component is obtained from the stabilized cycle of a specimen that is subjected to symmetric stain cycles. The authors introduced the way how to calibrate the material parameters of combined isotropic / kinematic hardening model. Then the authors calculated up to 100 cycles on carbon steel pipe which contained a Local Thin Area against seismic load at 300 degrees centigrade. The results comparison between FEM analysis and experiment shows that stress-strain hysteresis loop tendency and number of cycles to failure are predicted accurately.

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.

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.

Multilayer Kinematic Hardening Model for Carbon Steel and its Application to Inelastic Analyses of an Elbow Subjected to Cyclic In-Plane Bending

2015 ◽  
Author(s):  
Koji Iwata ◽  
Yasuhisa Karakida ◽  
Chuanrong Jin ◽  
Hitoshi Nakamura ◽  
Naoto Kasahara
Keyword(s):  
Carbon Steel ◽  
Kinematic Hardening ◽  
Isothermal Condition ◽  
Cyclic Hardening ◽  
Bending Test ◽  
Cyclic Plasticity ◽  
Repeated Loading ◽  
Stress Strain ◽  
Hardening Model ◽  
Plane Bending

Carbon steel STS410 (JIS Standard), which is widely used for high pressure piping components, exhibits cyclic hardening under repeated loading. Extreme seismic loading can cause repetitive large strains, eventually leading to the failure of components. For failure assessment of such components, inelastic analyses using cyclic plasticity constitutive models are needed. In this paper, a multilayer kinematic hardening model for cyclic plasticity, equipped with a set of standard stress-strain characteristics, is developed for STS410 under isothermal condition of various temperatures. This model can express not only the nonlinearity of stress-strain relations, but cyclic hardening of a material by introducing a generic stress-strain relation composed of a combination of monotonic and steady state cyclic stress-strain curves. Finite element large deformation elastic-plastic analyses with this model are conducted for a cyclic in-plane bending test of an elbow. The proposed constitutive model predicted well characteristic features of global deformation and local strain behaviors of the elbow.

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.

Simplified identification of material parameters for Yoshida-Uemori kinematic hardening model

2014 ◽  
Author(s):  
T. Phongsai ◽  
V. Uthaisangsuk ◽  
B. Chongthairungruang ◽  
S. Suranuntchai ◽  
S. Jirathearanat
Keyword(s):  
Kinematic Hardening ◽  
Hardening Model ◽  
Material Parameters
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