考虑尺寸效应的多晶金属循环塑性分析

本文采用多晶塑性分析方法，设材料点包含一定数量的各向异性单晶晶粒并考虑晶粒尺寸的影响，计算材料点的应力和应变时利用了Taylor假设。模型引入考虑尺寸效应的晶体滑移硬化函数，同时针对晶体滑移引入背应力及其方向性硬化的描述，以反映不同晶粒尺寸材料在循环加载条件下的力学行为。利用该模型，本文第一作者采用显式格式编制了与ABAQUS商用有限元软件接口的用户材料子程序（VUMAT），实例计算证实该模型可以反映和描述多晶金属材料在材料反复加载条件下的循环塑性行为与尺寸效应。

ANALYSIS OF CYCLIC PLASTICITY USING A POLYCRYSTALLINE MODEL TAKING ACCOUNT OF SIZE EFFECT

In this contribution,a representative volume element(RVE)containing some anisotropic crystalline grains is modeled in order to analyze the plasticity behavior of polycrystal.All crystalline grains consisting of the poly-crystal are assumed to follow the Taylor’s hypothesis.To take the grain size effect into account,a hardening function which includes both the grain size and the material characteristic length was proposed;also,a back stress model was introduced to capture the directional hardening of crystals.An explicit algorithm for the present constitutive model is developed,and then implemented into the VUMAT subroutine of ABAQUS.Finite element analyses of a pure polycrystalline copper applied to the symmetric strain cycle show that the present model can reasonably capture the grain size dependent cyclic plasticity behavior.