基于全场等效损伤测试的累积损伤模型

A Damage Cumulative Model Based on Whole Equivalent Damage Field Testing

材料 LY1 2 CZ在固定的一组循环数下 ,对其中每一预定循环数进行不同应力水平的疲劳试验。并测出材料的韧性变化率 ,以此为损伤变量得到该组循环数下损伤量与交变应力水平关系的曲线族。该曲线族可以转换成相同损伤量下交变应力与循环数关系的等效损伤线族。通过对材料 LY1 2 CZ等效损伤线族测试和分析 ,给出损伤线族方程表达式。由此得到的损伤累积模型可以计算复杂加载下材料的剩余寿命。

Fatigue tests are performed on various alternative stress levels for a group of fixed cycle number. The material toughness change rate is selected as fatigue damage parameter and is measured after fatigue tests. A group of stress level versus damage quantity test data is obtained. By fixing the damage quantity, this group cure is then transformed into equivalent damage cure family. Different points in each cure have the same damage quantity. In this paper, material LY12CZ equivalent damage cure families are measured. And by mathematical analysis, this equivalent damage cure family function is mathematically expressed,the damage cumulative model induced from equivalent damage assumption can calculate material remaining life on complex loading. Theoretical prediction is in agreement with multi-stage loading test results for two materials.