随机谱下疲劳裂纹扩展的等损伤模型

本文对预测随机谱下疲劳裂纹扩展寿命的等损伤模型进行了较为系统的研讨，在损伤等价原则下导出5种不同形式的等损伤模型，并利用两种材料在两种谱型和两种应力水平下的疲劳裂纹扩展试验数据对其评估。结果表明：对于一般过载效应不强的随机型载荷，等损伤模型的预测精度足以满足工程要求；等损伤模型形式上的不同不会明显影响预测结果。本文还研究了经跑道计数法浓缩处理的简化谱对寿命预测结果的影响。

Equivalent Damage Model for Predicting FCG Life Under Random Spectrum Loading

This paper studies systematically the equivalent damage model for predicting fatigue crack growth life under random spectrum loading ,and five different forms of EDM are found through the equivalent damage principle By examining the correlation between the models and the FCG experimental data of LY12-CZ and 30CrMnSiNi2A under two random spectrum types and two limit stresses, it will be seen that for the random spectrum Loadings without the strong overload effect the predicting accuracy of EDM is able to satisfy the engineering need and the different forms of EDM do not produce the obvious influence on the results of prediction The effect of the predictions using the load spectrum condensed by the racetrack counting method is also discussed.