考虑加载历史影响的蠕变律

考虑到蠕变过程中,材料内部微观结构的变化,会使材料的变形行为发生改变,本文引入硬化状态变量表征加载历史对材料变形行为的影响,提出的蠕变律可以正确反映蠕变三个阶段的变形规律,由此导出的蠕变损伤演变方程与加载历史有关。其结果可以为分析多级蠕变加载时损伤演变过程和剩余寿命估算提供新的思路。

CREEP LAW WITH EFFECT OF LOADING HISTORY

The deformation behavior of materials would be affected by microstructure varying during creep. In present paper, a hardening variable is introduced into creep law to express an effect of loading history. The creep law proposed can describe creep behavior of all three stages correctly. Using the creep law proposed, damage constitutive equation is obtained. According to this equation, creep damage evolution depends not only on present loading condition and existing damage state but on hardening state caused by previous loading history. This damage constitutive equation takes into consideration the order effect of loading and can provide a new approach for prediction the remaining life under multi level creep loading.