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 Elastic Module Degradation Measurement in Different Sizes of the Nonlinear Isotropic–Kinematic Yield Surface on Springback Prediction

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 511 ◽  
Author(s):  
Baara ◽  
Baharudin ◽  
Anuar ◽  
Ismail
Keyword(s):  
Residual Stress ◽  
Elastic Modulus ◽  
Kinematic Hardening ◽  
Strain Recovery ◽  
Final Shape ◽  
Hardening Model ◽  
New Model ◽  
Finite Element Software ◽  
Yield Surfaces ◽  
Springback Prediction

Commercial finite element software that uses default hardening model simulation is not able to predict the final shape of sheet metal that changes its dimensions after removing the punch due to residual stress (strain recovery or springback). We aimed to develop a constitutive hardening model to more accurately simulate this final shape. The strain recovery or balancing of residual stress can be determined using the isotropic hardening of the original elastic modulus and the hardening combined with varying degrees of elastic modulus degradation and the size of the yield surfaces. The Chord model was modified with one-yield surfaces. The model was combined with nonlinear isotropic–kinematic hardening models and implemented in Abaqus user-defined material subroutine for constitutive model (UMAT). The Numisheet 2011 benchmark for springback prediction for DP780 high-strength steel sheet was selected to verify the new model, the Chord model, the Quasi Plastic-Elastic (QPE) model, and the default hardening model using Abaqus software. The simulation of U-draw bending from the Numisheet 2011 benchmark was useful for comparing the proposed model with experimental measurements. The results from the simulation of the model showed that the new model more accurately predicts springback than the other models.

Springback Prediction Using the Split-Ring Test Based on a Combined Anisotropic Hardening Model

2012 ◽  
Vol 217-219 ◽  
pp. 1375-1380
Author(s):  
Chao Niu ◽  
Shun Lai Zang ◽  
Yang Zhang
Keyword(s):  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Current Model ◽  
Transient Behavior ◽  
Material Model ◽  
Yield Function ◽  
Ring Test ◽  
Split Ring ◽  
Hardening Law ◽  
Springback Prediction

Material model which could describe the Bauschinger effect is essential to accurately predict springback since strain path reverse is quite common in sheet metal forming. In this paper, a combined isotropic-kinematic hardening law which can capture the Bauschinger effect, transient behavior and permanent softening was used to model the hardening behavior. Also, the non-quadratic anisotropic yield function, Yld2000-2d, was chosen to describe the anisotropy. An inverse identificat- ion method was carried out to calibrate the material parameters by using uni-axial tension and Bauschinger simple shear tests. Experiments of cylindrical cup drawing and following split-ring tests were performed. Similar processes were carried out by numerical simulation, and springback predicted by present model was compared with experiments and that of vonMises model. The result shows that the current model significantly improves the accuracy of springback prediction.

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.

scholarly journals Effects of Hardening Model and Variation of Elastic Modulus on Springback Prediction in Roll Forming

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1005 ◽  
Author(s):  
Naofal ◽  
Naeini ◽  
Mazdak
Keyword(s):  
Elastic Modulus ◽  
Cyclic Loading ◽  
Kinematic Hardening ◽  
Roll Forming ◽  
Isotropic Hardening ◽  
Plastic Behavior ◽  
Forming Process ◽  
Hardening Models ◽  
Springback Prediction ◽  
Roll Forming Process

In this paper, the uniaxial loading–unloading–reloading (LUR) tensile test was conducted to determine the elastic modulus depending on the plastic pre-strain. To obtain the material parameters and parameter of Yoshida-Uemori’s kinematic hardening models, tension–compression experiments were carried out. The experimental results of the cyclic loading tests together with the numerically predicted response of the plastic behavior were utilized to determine the parameters using the Ls-opt optimization tool. The springback phenomenon is a critical issue in industrial sheet metal forming processes, which could affect the quality of the product. Therefore, it is necessary to represent a method to predict the springback. To achieve this aim, the calibrated plasticity models based on appropriate tests (cyclic loading) were implemented in commercial finite element (FE) code Ls-dyna to predict the springback in the roll forming process. Moreover, appropriate experimental tests were performed to validate the numerical results, which were obtained by the proposed model. The results showed that the hardening models and the variation of elastic modulus have significant impact on springback accuracy. The Yoshida-Uemori’s hardening represents more accurate prediction of the springback during the roll forming process when compared to isotropic hardening. Using the chord modulus to determine the reduction in elastic modulus gave more accurate results to predict springback when compared with the unloading and loading modulus to both hardening models.

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.

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.

Calculation of drawbead restraining forces with the Bauschinger effect

1998 ◽  
Vol 212 (7) ◽  
pp. 549-553 ◽  
Author(s):  
Y You
Keyword(s):  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
Material Model ◽  
Constitutive Law ◽  
Isotropic Hardening ◽  
Hardening Material ◽  
Cyclic Property ◽  
Restraining Force ◽  
Comparison With Experiments ◽  
Better Than

In this paper, a numerical model for the calculation of the drawbead restraining force is described. The model is formulated using an elastoplastic finite deformation, finite element method. Because of the bending, unbending and reverse bending deformation which occurs as the sheet metal passes through the drawbead, a kinematic hardening constitutive law associated with a description of the cyclic property and the Bauschinger effect is considered. In comparison with experiments, the results based on the kinematic hardening material model proved to be better than those based on the usual isotropic hardening material model.

Springback Prediction Using Finite Element Simulation Incorporated With Hardening Data Acquired From Cyclic Loading Tool

2019 ◽  
Vol 6 (1) ◽  
pp. 19-39
Author(s):  
Jasri Mohamad ◽  
Mohd Zaidi Sidek
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Bauschinger Effect ◽  
Fe Simulation ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Mixed Hardening ◽  
Element Simulation ◽  
Simulation Results ◽  
Springback Prediction

The aims of this article are to present the accuracy of springback prediction in U-bending sheet metal forming processes using finite element (FE) simulation incorporated with kinematics or mixed hardening parameters that are derived from cyclic data provided by the developed cyclic loading tool. The FE simulation results in the form of springback angles are compared with the experimental results for validation. It was found that the mixed hardening model provides better simulation results in predicting springback. This is due to the capability of the isotropic hardening part of this model to describe cyclic transient and the kinematic hardening part to improve description of the Bauschinger effect. Kinematic hardening however, on its own is capable of providing relatively good springback simulation illustrated by errors of less than 8 percent. Overall, the data provided by cyclic loading from the newly developed bending-unbending tool is considered valuable for simulating springback prediction.

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