中文摘要：

基于材料裂纹扩展阻力曲线（R曲线）及裂纹扩展能量释放率理论,定义疲劳载荷下的有效能量释放率（Geff）为疲劳裂纹完全张开后用于裂纹扩展的能量,与同一载荷循环中由裂纹扩展阻力曲线表征的消耗能相等,提出了一种能够反映裂纹扩展物理本质的疲劳裂纹扩展寿命预测模型.该模型可以计算每一载荷循环中的裂纹扩展量,进而预测疲劳裂纹扩展寿命.通过试验测定了7050-T7451铝合金板材的R曲线,采用最小二乘法拟合获得到了R曲线表达式.运用本模型对同种材料耳片结构的裂纹扩展寿命进行了预测,与试验结果吻合较好,优于传统Paris模型的预测结果.

英文摘要：

Based on the R-curve and crack propagation energy release rate theory,the effective energy release rate Geff was narrated as the energy that makes the opened crack grow and is equal to the dissipated energy represented by R-curve in the same load cycle.The fatigue life prediction model which can reflect the physical essence of crack propagation was proposed.The fatigue crack propagation life can be predicted by adding up the length of crack grows in each load cycle using the model.The R-curve of 7050-T7451 aluminum alloy plate was determined and the expression was obtained by using the least square method.The crack growth test of attachment lugs with the same material was carried out.The fatigue crack propagation life of the test pieces was predicted by using the present model and compared with the test data.The results show that the model based on material＇s R-curve can predict fatigue crack growth life more accurately than Paris Model.