|About this Abstract
||NUMIFORM 2019: The 13th International Conference on Numerical Methods in Industrial Forming Processes
||S-01: Modeling of the Anisotropic Behavior in Plasticity
||A Comparative Study between Elasto-plastic Self-consistent Crystal Plasticity and Anisotropic Yield Function with Distortional Hardening Formulations for Sheet Metal Forming
||Marko Knezevic, Zhangxi Feng , Seong-Yong Yoon, Jaehyun Choi , Milovan Zecevic, Frederic Barlat
|On-Site Speaker (Planned)
A comparative study between micro- and macro-mechanical constitutive models is carried out while predicting mechanical behavior of the alloy AA6022-T4 during several loading scenarios of increasing complexity including monotonic tension, large strain cyclic deformation, and drawing of a cup. The micro model is a recently developed implicit formulation of elasto-plastic self-consistent (EPSC) crystal plasticity, which is coupled with the implicit finite element method through the use of a user material subroutine in Abaqus. In the coupled formulation, every finite element integration point embeds the implicit EPSC constitutive law taking into account microstructure evolution and the directionality of deformation mechanisms acting at the single crystal level. The crystallography based EPSC model integrates a dislocation-based hardening law and accounts for inter-granular stresses and slip system level back-stresses, which make it capable of capturing non-linear unloading and the Bauschinger effect. The macro model is a recently developed anisotropic yield function incorporating distortional hardening using the homogeneous anisotropic hardening (HAH) approach. Parameters pertaining to the micro and macro models are identified using a set of monotonic and cyclic tests performed for AA6022-T4. Simulation results in terms of flow stress behavior and anisotropic yield surface evolution are used to verify the models. The predicted earing profile and the springback profile based on the cup drawing simulation carried out using the two constitutive formulations in Abaqus are used to evaluate the predictive characteristics of the models. Finally, the simulation results obtained using the two formulations are discussed in terms of accuracy and computational efficiency.