损伤力学在塑性加工中的应用

The Application of Damage Mechanics to Plastic Working

损伤力学是一门新兴的固体力学分支。它目前主要用于机件安全评定与寿命估算。笔者根据损伤力学的概念、原理和方法，在空洞型塑性损伤特征和热力学的基础上导出新的塑性损伤演变方程。理论分析与实验结果表明，损伤变量与相当应变呈线性关系，并且其值受应力三轴变的显著影响。该方程不但能反映应力三轴度为正时的影响，而且能反映应力三轴度为负时的影响，从而使损伤力学可以与塑性加工学科结合起来，扩大了损伤力学的应用范围。

Damage mechanics is a new and developing branch of solids mechanics. UP to now, it is mainly applied to the evaluation of safety and life for parts. In accordance with the concept,principle and method of continuous damage mechanics,a kinetic equation for ductile damage,based on the feature of void--type plastic damage and on thermodynamics,has been derived by the present author. The theoretical and experimental results show that the Damage variable is linear with equivalent strain and it is affected remarkably by the triaxiality stress ratio. The kinetic equation of the damage variable in this paper may reflect not only the influence of a positive triaxality ratio but also the influence of a negative triaxiality ratio. Therefore, the branch-intersection of damage mechanics and plastic working may been realized, and the applying range of damage mechanics is extended.