高周疲劳的损伤-硬化模型

两级循环加载条件下，材料的剩余寿命强烈地依赖于加载历史。究其原因，不同加载历史将引起材料的微结构发生不同的变化，使得材料的硬化效果和变形行为表现出明显的差异，从而影响了损伤的演化过程。本文引入硬化状态变量来表征加载历史对疲劳损伤演化过程的影响。通过对两级循环加载下损伤演化规律和剩余寿命的研究，认为在两级（或多级）加载条件下，材料的损伤演化和剩余寿命强烈地依赖于加载历史造成的损伤和硬 化状态。

Damage-Hardening Model of High Cyclic Fatigue

The remaining life of speciment is dependent upon loading history, under two level cyclic loading. The deformation behavior of material shows a great difference with different microstructure of material raised by different loading history. Consequently, the process of damage evolution is affected in present peper, hardening variable is introduced into the fatigue damage constitutive equation to express effect on damage evolution by loading history. By studying the rule of damage evolution and remaining life under conditions of two level cyclic loading, it is considered that damage evolution and remaining life of specimen are dependent strongly on damage and hardening state caused by loading history, under multi level cyclic loading.