中文摘要：

在分析多轴疲劳几种常用非比例度定义的基础上,提出了一种非比例度定义方法,进而以American Society of Mechanical Engineers（ASME）规范案例中非比例加载多轴疲劳设计准则采用的应变参量作为基本损伤参量,发展了一种新的多轴疲劳寿命预测模型.结果表明：1所提出的非比例度定义可以描述任意已知轮廓的、非周期的、变幅的非比例加载路径;2与两种常用的多轴非比例加载疲劳寿命模型的预测结果对比可知,新的寿命预测模型对14种比例和非比例加载路径下304不锈钢材料的寿命预测与试验吻合更好,预测结果基本位于2倍分散带以内.

英文摘要：

A non-proportionality description was proposed based on the analysis of several commonly used non-proportionalities in multiaxial fatigue.Furthermore,a new multiaxial low cycle fatigue life prediction model was developed by combining the newly defined nonproportionality with the strain parameter of the design criterion for non-proportional fatigue in the American Society of Mechanical Engineers（ASME）code case,which was considered as the basic damage parameter.On the basis of analytical study,conclusions can be drawn as follow：（1）the defined non-proportionality can accommodate arbitrary paths with the given contour under variable amplitude and non-periodic loadings;（2）compared with two commonly used models,the predicted multiaxial fatigue lives of 304 stainless steel under 14 strain paths using the proposed model agree better with the experimental results,which are almost within two-time scatter band of the test results.