A gradient crystal plasticity theory for large deformations with a discontinuous accumulated plastic slip

作者：Erdle Hannes; Bohlke Thomas^*

来源：Computational Mechanics, 2017, 60(6): 923-942.

DOI：10.1007/s00466-017-1447-7

• Size effects
• Gradient plasticity
• Grain boundary yield condition
• Finite crystal plasticity
• Discontinuous finite elements

The implementation of novel material models in the microscale gives a deeper understanding of inner and intercrystalline effects of crystalline materials. For future works, this allows more precise predictions of macroscale models. Here, we present a finite gradient crystal plasticity theory which preserves the single crystal slip kinematics. However, the model is restricted to one gradient-stress, associated with the gradient of the accumulated plastic slip, in order to account for long range dislocation interactions in a physically simplified, numerically efficient approach. In order to model the interaction of dislocations with and their transfer through grain boundaries, a grain boundary yield condition is introduced. The grain boundary flow rule is evaluated at sharp interfaces using discontinuous trial functions in the finite element implementation, thereby allowing for a discontinuous distribution of the accumulated plastic slip. Simulations of crystal aggregates are performed under different loading conditions which reproduce well the size dependence of the yield strength. An analytical solution for a one-dimensional single slip supports the numerical results.

• 出版日期2017-12
• 单位中国地震局工程力学研究所