Effective Models for Prediction of Springback In Flanging

2000 ◽  
Vol 123 (4) ◽  
pp. 456-461 ◽  
Author(s):  
Nan Song ◽  
Dong Qian ◽  
Jian Cao ◽  
Wing Kam Liu ◽  
Shaofan Li
Keyword(s):  
Reproducing Kernel ◽  
Kinematic Hardening ◽  
Meshfree Method ◽  
Particle Methods ◽  
Isotropic Hardening ◽  
The Finite Element Method ◽  
Hardening Law ◽  
Reproducing Kernel Particle ◽  
Effective Models ◽  
Springback Angle

A study on the prediction of springback angle is presented, with focus on the straight flanging operation. The objective of this work is to evaluate the reliability of different methods of prediction. An experiment of straight flanging operation is conducted. Major prediction approaches such as analytical model, numerical simulation using the Finite Element Method (FEM) and the Meshfree Method using the Reproducing Kernel Particle Methods (RKPM) are discussed. A set of sample problems is computed and comparisons are made with the experiment. The numerical analysis shows that the prediction from the 3D meshfree contact code matches well with the data from the FEM 2D solid model. A material property described by the kinematic hardening law provides a better prediction of springback than the isotropic hardening law.

Effective Models for Prediction of Springback in Flanging

2000 ◽  
Author(s):  
Nan Song ◽  
Dong Qian ◽  
Jian Cao ◽  
Wing Kam Liu ◽  
Vikram Viswanathan ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Kinematic Hardening ◽  
Meshfree Method ◽  
Isotropic Hardening ◽  
Solid Model ◽  
Hardening Law ◽  
Effective Models ◽  
Springback Angle

Abstract A study on the prediction of springback angle is presented, with focus on the straight flanging operation. The objective is to evaluate the reliability of different ways of prediction. An experiment of straight flanging operation is conducted. Major prediction approaches such as analytical model, numerical simulation using Finite Element Method (FEM) and Meshfree Method are discussed. A set of sample problems is computed and comparisons are made with the experiment. The numerical analysis shows that the prediction from the 3D meshfree contact code matches well with the data from FEM 2d solid model. A material property described by the kinematic hardening law gives a better prediction of springback than the isotropic hardening law.

Investigation of Hardening Law on Welding Residual Stress Analysis for Nickel Based Alloy 82 Weld Metal

2020 ◽  
Author(s):  
Mitsuru Ejiri ◽  
Teppei Kubota ◽  
Yukihiro Soga ◽  
Nozomi Nishihara ◽  
Nobuyoshi Yanagida ◽  
...  
Keyword(s):  
Residual Stress ◽  
Kinematic Hardening ◽  
Residual Stress Distribution ◽  
Welding Residual Stress ◽  
Isotropic Hardening ◽  
The Finite Element Method ◽  
Hardening Law ◽  
Nickel Based Alloy ◽  
Combined Hardening ◽  
Residual Stress Analysis

Abstract There are three types of hardening laws for evaluating welding residual stress with the finite element method (FEM): kinematic hardening law, isotropic hardening law, and combined hardening law that combine these. The purpose of this paper is to investigate which hardening law is more appropriate for the evaluation of welding residual stress of alloy 82. We first performed two types of welding tests: welding both ends of a plate, and welding the periphery of a disc. We then compared the results of mock-up welding tests with the analysis results of welding residual stress with the kinematic hardening law and combined hardening law. Both the kinematic hardening law and the combined hardening law showed a welding residual stress distribution close to the results of the mock-up welding tests, but the combined hardening law tended to be closer to the mock-up results. Therefore when it is necessary to confirm the welding residual stress of alloy 82, it is considered appropriate to apply the combined hardening law.

Reproducing kernel particle methods for structural dynamics

1995 ◽  
Vol 38 (10) ◽  
pp. 1655-1679 ◽  
Author(s):  
Wing Kam Liu ◽  
Sukky Jun ◽  
Shaofan Li ◽  
Jonathan Adee ◽  
Ted Belytschko
Keyword(s):  
Structural Dynamics ◽  
Reproducing Kernel ◽  
Particle Methods ◽  
Reproducing Kernel Particle

On Simulation of Bend/Reverse Bend of Sheet Metals

1999 ◽  
Author(s):  
K. M. Zhao ◽  
J. K. Lee
Keyword(s):  
Bauschinger Effect ◽  
Kinematic Hardening ◽  
High Strength ◽  
Isotropic Hardening ◽  
Sheet Metals ◽  
Combined Model ◽  
Hardening Law ◽  
Three Point Bend Test ◽  
Point Bend ◽  
Plastic Shakedown

Abstract Bend/reverse bend tests are performed with a three-point bend test apparatus on two types of sheet metals, mild steel and high strength steel. The bend/reverse bend process tends to a steady cycle upon applying repeated cycles of displacements. Strain hardening and Bauschinger effects for both materials are detected. Three different hardening laws are used to simulate the bend process numerically. Isotropic hardening law overestimates the hardening component and by missing the Bauschinger effect and the plastic shakedown. Kinematic hardening rule underestimates the hardening component and exaggerates the Bauschinger effect. The combination of isotropic and nonlinear kinematic hardening predicts accurately both the Bauschinger effect and the plastic shakedown. The hardening parameters in the combined model are identified inversely by using micro genetic algorithm.

Generalized multiple scale reproducing kernel particle methods

1996 ◽  
Vol 139 (1-4) ◽  
pp. 91-157 ◽  
Author(s):  
Wing Kam Liu ◽  
Yijung Chen ◽  
R.Aziz Uras ◽  
Chin Tang Chang
Keyword(s):  
Reproducing Kernel ◽  
Multiple Scale ◽  
Particle Methods ◽  
Reproducing Kernel Particle

scholarly journals Enrichment of the Finite Element Method With the Reproducing Kernel Particle Method

1997 ◽  
Vol 64 (4) ◽  
pp. 861-870 ◽  
Author(s):  
Wing Kam Liu ◽  
R. A. Uras ◽  
Y. Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reproducing Kernel ◽  
Particle Method ◽  
Computational Procedure ◽  
Reproducing Kernel Particle Method ◽  
The Finite Element Method ◽  
Window Functions ◽  
Reproducing Kernel Particle ◽  
Element Method

The reproducing kernel particle method (RKPM) has attractive properties in handling high gradients, concentrated forces, and large deformations where other widely implemented methodologies fail. In the present work, a multiple field computational procedure is devised to enrich the finite element method with RKPM, and RKPM with analytical functions. The formulation includes an interaction term that accounts for any overlap between the fields, and increases the accuracy of the computational solutions in a coarse mesh or particle grid. By replacing finite element method shape Junctions at selected nodes with higher-order RKPM window functions, RKPM p-enrichment is obtained. Similarly, by adding RKPM window functions into a finite element method mesh, RKPM hp-enrichment is achieved analogous to adaptive refinement. The fundamental concepts of the multiresolution analysis are used to devise an adaptivity procedure.

Reproducing kernel particle methods

1995 ◽  
Vol 20 (8-9) ◽  
pp. 1081-1106 ◽  
Author(s):  
Wing Kam Liu ◽  
Sukky Jun ◽  
Yi Fei Zhang
Keyword(s):  
Reproducing Kernel ◽  
Particle Methods ◽  
Reproducing Kernel Particle

Multiresolution reproducing kernel particle methods

1997 ◽  
Vol 20 (4) ◽  
pp. 295-309 ◽  
Author(s):  
W. K. Liu ◽  
W. Hao ◽  
Y. Chen ◽  
S. Jun ◽  
J. Gosz
Keyword(s):  
Reproducing Kernel ◽  
Particle Methods ◽  
Reproducing Kernel Particle

scholarly journals Multiresolution Reproducing Kernel Particle Methods in Acoustic Problems

1995 ◽  
Author(s):  
W. K. Liu ◽  
C. T. Chang ◽  
Y. Chen ◽  
R. A. Uras
Keyword(s):  
Finite Elements ◽  
Reproducing Kernel ◽  
Particle Method ◽  
Particle Methods ◽  
Wave Number ◽  
Frequency Range ◽  
Frequency Wave ◽  
Realistic Representation ◽  
Reproducing Kernel Particle ◽  
Complex Phenomena

Abstract In the analysis of complex phenomena of acoustic systems, the computational modeling requires special attention for a realistic representation of the physics. As a powerful tool, the finite element method has been widely used in the study of complex systems. In order to capture the important physical phenomena, p-finite elements and/or hp-finite elements are employed. The reproducing kernel particle methods (RKPM) are emerging as an effective alternative due to the elimination of a mesh, and the ability to analyze a specific frequency range. Additionally, a wavelet particle method based on the multiresolution analysis encountered in signal processing has been developed. The interpolation functions consist of spline functions with built-in window. A variation in the size of the window implies a geometrical refinement, and allows the filtering of the desired frequency range. Preliminary analysis of the wave equation shows the effectiveness of this approach. The frequency/wave number relationship of the continuum case can be closely simulated by using the reproducing kernel particle methods. A similar methodology is also developed for the Timoshenko beam.

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