耦合蠕变损伤的粘塑性模型用于疲劳-蠕变交互作用的研究

该文对550℃下30CrMoNiV5-11转子钢进行了轴向应力控制的带保持时间的疲劳实验.按照Le-maitre有效应力的概念,采用Kachanov损伤演化方程,推导了耦合损伤的粘塑性流动方程和随动硬化方程,使用返回映射和向后欧拉方法实现应力更新,并在有限元软件ANSYS的接口程序UMAT中嵌入用户程序.对试样疲劳-蠕变交互行为进行模拟,结果表明,耦合蠕变损伤变量后,模拟结果较不含损伤变量模型的模拟结果精度大为提高.

STUDY OF CREEP-FATIGUE INTERACTION USING A VISCOPLASTIC MODEL COUPLED WITH A CREEP DAMAGE

Experiments of steel rotor 30CrMoNiV5-ll under axial stress controlled with hold time were carried out in this paper. Based on the conception of Lemaitre' s effective stress, viscoplastic flow and hardening functions, both coupled with damage, were derived from the Kachanov' s equation of damage in this paper. The backward Euler method and the return mapping method were used for stress updating. The modified constitutive model coupled with creep damage was then included into the finite element program ANSYS, in which the interaction behavior of the model was simulated. Results show that the modified model coupled with damage can significantly increase the accuracy.