scholarly journals A non-associated plasticity model with anisotropic and nonlinear kinematic hardening for simulation of sheet metal forming

2015 ◽  
Vol 69-70 ◽  
pp. 370-382 ◽  
Author(s):  
Aboozar Taherizadeh ◽  
Daniel E. Green ◽  
Jeong Whan Yoon
2002 ◽  
Vol 2002.15 (0) ◽  
pp. 197-198
Author(s):  
Noriyuki SUZUKI ◽  
Shunji HIWATASHI ◽  
Akihiro UENISHI ◽  
Xavier LEMOINE ◽  
Cristian TEODOSIU

Author(s):  
C. L. Chow ◽  
X. J. Yang

The paper presents a generalized mixed isotropic-kinematic hardening plastic model coupled with anisotropic damage for sheet metal forming. A nonlinear anisotropic kinematic hardening is developed. For the predication of limit strains at localized necking in stamping under complex strain history, the model and its associated damage criterion for localized necking are established and implemented into LS-DYNA3D by compiling it as a user subroutine. The finite element simulation of LS-DYNA3D based on the present model is carried out. The location of localized necking for sheet metal forming has been successfully identified.


2011 ◽  
Vol 473 ◽  
pp. 875-880 ◽  
Author(s):  
Yalin Kiliclar ◽  
Roman Laurischkat ◽  
Stefanie Reese ◽  
Horst Meier

The principle of robot based incremental sheet metal forming is based on flexible shaping by means of a freely programmable path-synchronous movement of two tools, which are operated by two industrial robots. The final shape is produced by the incremental infeed of the forming tool in depth direction and its movement along the geometry’s contour in lateral direction. The main problem during the forming process is the influence on the dimensional accuracy resulting from the compliance of the involved machine structures and the springback effects of the workpiece. The project aims to predict these deviations caused by resiliences and to carry out a compensative path planning based on this prediction. Therefore a planning tool is implemented which compensates the robot’s compliance and the springback effects of the sheet metal. Finite element analysis using a material model developed at the Institute of Applied Mechanics (IFAM) [1] has been used for the simulation of the forming process. The finite strain constitutive model combines nonlinear kinematic and isotropic hardening and is derived in a thermodynamical setting. It is based on the multiplicative split of the deformation gradient in the context of hyperelasticity. The kinematic hardening component represents a continuum extension of the classical rheological model of Armstrong–Frederick kinematic hardening which is widely adopted as capable of representing the above metal hardening effects. The major problem of low-order finite elements used to simulate thin sheet structures, such as used for the experiments, is locking, a non-physical stiffening effect. Recent research focuses on the large deformation version of a new eight-node solid-shell finite element based on reduced integration with hourglass stabilization. In the solid-shell formulation developed at IFAM ([2], [3]) the enhanced assumed strain (EAS) concept as well as the assumed natural strain (ANS) concept are implemented to circumvent locking. These tools are very important to obtain a good correlation between experiment and simulation.


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