基于位错密度的体心立方晶体塑性本构模型
Crystal plasticity constitutive model for BCC based on the dislocation density

晶体塑性理论是将晶体微观尺度的位错运动与宏观尺度的塑性形变相结合的重要理论，提供了在细观尺度内研究材料力学行为的有效方法。位错的密度变化对金属晶体的硬化行为有着重要的影响。该文在晶体塑性理论的基础上引入位错运动理论，建立基于位错密度的体心立方晶体（body center cubic，BCC）塑性本构模型，研究BCC的力学行为；并借助ABAQUS有限元软件，编写UMAT子程序，实现对BCC结构的铁单晶及多晶单轴拉伸试验的数值模拟。结果表明：该本构模型能有效地模拟铁单晶及多晶单轴拉伸的力学行为。
Abstract：Crystal plasticity theory is a fundamental theory that combines the crystal microscopic slip mechanism with macroscopic plastic deformation to predict meso-scale plastic deformation. The dislocation density has an important influence on the hardening behavior of metal crystals. This paper presents a constitutive model based on crystal plasticity theory and dislocation motion theory for the BCC crystal structure. The model is used to study the mechanical behavior of a BCC lattice. Using the UMAT subroutine in ABAQUS for numerical simulations of a uniaxial tensile tests of single crystal and polycrystal iron. The results show that the constitutive model effectively simulates the mechanical behavior of the uniaxial tensile test for single crystal and polycrystal iron.