Stress and Strain Histories of Multiple Bending-Unbending Springback Process

2000 ◽  
Author(s):  
H.-M. Huang ◽  
S.-D. Liu ◽  
S. Jiang
Keyword(s):  
Deformation Process ◽  
Prediction Accuracy ◽  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Stress And Strain ◽  
Drawing Process ◽  
Hardening Models ◽  
Accuracy Stress ◽  
Modeling Code ◽  
Numerical Simulation Technique

Abstract A drawbead model with sheet metal passing through multiple bending-unbending processes was employed in this study to understand the springback phenomenon and to develop a numerical simulation technique for more accurate prediction of the springback process. The deformation process is simulated using an implicit Finite Element Modeling code. The predicted results were compared with the physically measured ones, including clamping and restraining forces, thickness strains and the curvatures of the deformed sheets. Consideration of the Bauschinger effect and employment of a combined isotropic and kinematic hardening models greatly improve the prediction accuracy. Stress and strain histories under various conditions during the drawing process are studied in detail in an attempt to provide a better basis for comparison for dynamic explicit solutions.

Stress and Strain Histories of Multiple Bending-Unbending Springback Process

2001 ◽  
Vol 123 (4) ◽  
pp. 384-390 ◽  
Author(s):  
H.-M. Huang ◽  
S.-D. Liu ◽  
S. Jiang
Keyword(s):  
Deformation Process ◽  
Prediction Accuracy ◽  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Stress And Strain ◽  
Drawing Process ◽  
Hardening Models ◽  
Accuracy Stress ◽  
Modeling Code ◽  
Numerical Simulation Technique

A drawbead model with sheet metal passing through multiple bending-unbending processes was employed in this study to understand the springback phenomenon and to develop a numerical simulation technique for more accurate prediction of the springback process. The deformation process is simulated using an implicit finite element modeling code. The predicted results were compared with the physically measured ones, including clamping and restraining forces, thickness strains, and the curvatures of the deformed sheets. Consideration of the Bauschinger effect and employment of a combined isotropic and kinematic hardening models greatly improve the prediction accuracy. Stress and strain histories under various conditions during the drawing process are studied in detail in an attempt to provide a better basis for comparison for dynamic explicit solutions.

A New Model for Springback Prediction for Aluminum Sheet Forming

2005 ◽  
Vol 127 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Jenn-Terng Gau ◽  
Gary L. Kinzel
Keyword(s):  
Experimental Data ◽  
Material Parameter ◽  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Low Cost ◽  
New Model ◽  
Hardening Models ◽  
Reverse Yielding ◽  
Springback Prediction ◽  
Better Than

A new model for springback, based on isotropic and kinematic hardening models, the Mroz multiple surfaces model, and observations from experimental data, is proposed in this paper. In this model, a material parameter (CM), which is significant after reverse yielding, is suggested to handle the Bauschinger effect. A simple, low-cost, multiple-bending experiment has been developed to determine CM for aluminum alloys AA6022-T4 and AA6111-T4. The new model fits available experimental results better than the isotropic and kinematic hardening models and the Mroz multiple surfaces model.

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.

scholarly journals Effect of Constitutive Equations on Prediction Accuracy for Springback in Cold Stamping of TRIP1180

2017 ◽  
Author(s):  
Ki-Young Seo ◽  
Jae-Hong Kim ◽  
Hyun-Seok Lee ◽  
Ji Hoon Kim ◽  
Byung-Min Kim
Keyword(s):  
Constitutive Equations ◽  
Prediction Accuracy ◽  
Fe Simulation ◽  
Kinematic Hardening ◽  
Hardening Models ◽  
Yield Functions ◽  
Hydraulic Bulging ◽  
Springback Prediction ◽  
Deformation Modes ◽  
Cold Stamping

The objective of this study is to evaluate the effect of constitutive equations on the prediction accuracy for springback in cold stamping with various deformation modes. In this study, two types of yield functions—Hill’48 and Yld2000-2d—were considered to describe yield behavior. Isotropic and kinematic hardening models based on the Yoshida–Uemori model were also adopted to describe hardening behavior. Various material tests (such as uniaxial tension, tension- compression, loading-unloading, and hydraulic bulging tests) were carried out to determine the material parameters of the models. The obtained parameters were implemented in the finite element (FE) simulation to predict springback, and the results were compared with experimental data. U-bending and T-shape drawing were employed to evaluate the springback prediction accuracy. Obviously, the springback prediction accuracy was greatly influenced by constitutive equations. Therefore, it is important to choose appropriate constitutive equations for accurate description of material behaviors in FE simulation.

Wechselverfestigung beim Fräsen von Stahl/Kinematic hardening in steel 42CrMo4

2021 ◽  
Vol 111 (09) ◽  
pp. 612-616
Author(s):  
Bernhard Karpuschewski ◽  
Jens Sölter ◽  
Andrey Vovk ◽  
Rainer Glüge
Keyword(s):  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Cyclic Loads ◽  
Wird Eine ◽  
Bending Tests ◽  
Cyclic Bending ◽  
Hardening Models ◽  
Jc Model ◽  
Cook Model

Bei der spanenden Endbearbeitung treten an der Oberfläche zyklische Belastungen in wechselnden Richtungen auf. Isotrope Verfestigungsmodelle wie das Johnson-Cook-Modell berücksichtigen dies nicht. In diesem Beitrag wird eine Erweiterung des JC-Modells um einen kinematischen Verfestigungsanteil untersucht, um genauere Vorhersagen zu ermöglichen. In zyklischen Biegetests wurden für 42CrMo4 die Parameter für einen Armstrong-Frederick-Ansatz ermittelt, der im FE-System „Abaqus“ implementiert wurde.   During the finishing of components, cyclic loads occur on the surface in alternating directions. Isotropic hardening models do not take this into account. Here, an addition of kinematic hardening to the Johnson-Cook model is investigated. In cyclic bending tests, a Bauschinger effect was observed on 42CrMo4. This can be simulated by supplementing the JC model with the Armstrong-Frederick approach with a Vumat in the FE-System „Abaqus“.

Predictions of microtorsional experiments by micropolar plasticity

2005 ◽  
Vol 461 (2053) ◽  
pp. 189-205 ◽  
Author(s):  
Paschalis Grammenoudis ◽  
Charalampos Tsakmakis
Keyword(s):  
Size Effects ◽  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Circular Cylinders ◽  
Isotropic Hardening ◽  
Gradient Plasticity ◽  
Material Response ◽  
Micropolar Plasticity ◽  
Classical Plasticity ◽  
Hardening Rules

Kinematic hardening rules are employed in classical plasticity to capture the so–called Bauschinger effect. They are important when describing the material response during reloading. In the framework of thermodynamically consistent gradient plasticity theories, kinematic hardening effects were first incorporated into a micropolar plasticity model by Grammenoudis and Tsakmakis. The aim of the present paper is to investigate this model by predicting size effects in torsional loading of circular cylinders. It is shown that kinematic hardening rules compared with isotropic hardening rules, as adopted in the paper, provide more possibilities for modelling size effects in the material response, even if only monotonous loading conditions are considered.

Elastic-Plastic Finite Element Simulation and Fatigue Life Prediction for Beam and Elbow Under Cyclic Loading

2007 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Brian N. Leis
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Cyclic Loading ◽  
Plastic Strain ◽  
Kinematic Hardening ◽  
Kinematic Model ◽  
Cyclic Plastic ◽  
Hardening Models ◽  
Critical Location ◽  
Cyclic Plastic Strain

Work hardening and Bauschinger effects on plastic deformation and fatigue life for a beam and an elbow under cyclic loading are examined using finite element analysis (FEA). Three typical material plastic hardening models, i.e. isotropic, kinematic and combined isotropic/kinematic hardening models are adopted in the FEA calculations. Based on the FEA results of cyclic stress and strain at a critical location and using an energy-based fatigue damage parameter, the fatigue lives are predicted for the beam and elbow. The results show that (1) the three material hardening models determine similar stress at the critical location with small differences during the cyclic loading, (2) the isotropic model underestimates the cyclic plastic strain and overestimates the fatigue life, (3) the kinematic model overestimates the cyclic plastic strain and underestimates the fatigue life, and (4) the combined model predicts the intermediate cyclic plastic strain and reasonable fatigue life.

Kinematic hardening and Bauschinger effect

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Khanh Chau Le
Keyword(s):  
Bauschinger Effect ◽  
Kinematic Hardening
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