Application of strain rate potentials with multiple linear transformations to the description of polycrystal plasticity

作者：Rabahallah Meziane; Balan Tudor^*; Barlat Frederic

来源：International Journal of Solids and Structures, 2009, 46(9): 1966-1974.

DOI：10.1016/j.ijsolstr.2009.01.011

• Anisotropy
• Strain rate potentials
• Linear transformations
• Plasticity
• Sheet metal forming

This paper reviews a class of anisotropic plastic strain-rate potentials, based on linear transformations of the plastic strain-rate tensor. A new formulation is proposed, which includes former models as particular cases and allows for an arbitrary number of linear transformations, involving an increasing number of anisotropy parameters. The formulation is convex and fully three-dimensional, thus being suitable for computer implementation in finite element codes, The parameter identification procedure uses a micro-mechanical model to generate evenly distributed reference points in the full space of possible loading modes. Material parameters are determined for several anisotropic, fcc and bcc sheet metals, and the gain in accuracy of the new models is demonstrated. For the considered materials, increasing the number of linear transformations leads to a systematic improvement Of the accuracy, Lip to a number of five linear transformations. The proposed model fits very closely the predictions of the micromechanical model in the whole space of plastic strain-rate directions. The r-values, which are not directly used in the identification procedure, served for the validation of the models and to demonstrate their improved accuracy.

• 出版日期2009-5-1