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对Bodner Partom统一黏塑性本构理论 (B P模型 )进行了修正 ,改善了其对材料加载速率相关的黏塑性和循环硬化的模拟精度。改进模型包含两个各向同性硬化内变量 :一个用于描述小非弹性应变范围内快速的各向同性硬化 ,另一个以缓慢的演化速率来表述大的累积非弹性变形 ,如循环硬化过程中非弹性应变累积。利用ABAQUS的用户材料子程序将改进模型编成有限元计算代码 ,通过对镍基合金Udimet 72 0Li率相关黏塑性特征的本构模拟对其进行了验证 ,并与B P模型作了对比。结果表明改进模型能够以更高精度、更加灵活地对材料的非弹性力学行为进行建模。
The Bodner Partom unified visco-plastic constitutive theory (B P model) was modified to improve the simulation accuracy of the visco-plasticity and cyclic hardening related to the material loading rate. The improved model contains two isotropic hardening internal variables: one for rapid isotropic hardening in the small inelastic strain range and the other for large cumulative inelastic deformations at a slow evolution rate, such as during cyclic hardening Non-elastic strain accumulation. The ABAQUS user material subroutine is used to compile the improved model into the finite element code. The constitutive model of Ni-based alloy Udimet 72Li rate-dependent visco-plasticity is validated and compared with the B P model. The results show that the improved model can model the inelastic mechanical behavior of materials with higher accuracy and flexibility.