飞机座舱有机玻璃结构疲劳寿命估算的局部应力法

基于飞机座舱有机玻璃为脆性材料的特性，提出估算飞机座舱有机玻璃结构件疲劳寿命的局部应力法。它以缺口件韧带上距离缺口根部d处的局部应力为参数，对照光滑试验件的S-N曲线，利用线性累积损伤理论，可以较好地预测结构件的疲劳寿命。对飞机座舱有机玻璃YB3的三种结构件进行了疲劳试验和寿命分析，结果表明：寿命估算结果与试验结果吻合较好。

Local Stress Approach for Fatigue Life Prediction of Polymethyl Methacrylate Members

The failure of polymethyl methacrylate members of aircraft cabins is mainly caused by cyclic loading. A local stress approach for the fatigue life prediction of polymethyl methacrylate members is proposed based on the linear elastics characteristics of polymethyl methacrylate members under the cyclic loading in service. In this approach the local stress from the notch root d is taken as a parameter for the fatigue life estimation, and the S-N curves of polymethyl methacrylate material and miner fatigue damage cumulative ruler are employed. d is assumed as a material characteristic constant and can be determined through the tests of standard smooth and notched specimens. For the polymethyl methacrylate YB3, d =0 27 mm. Three polymethyl methacrylate members are analyzed and tested under constant and variable amplitude cyclic loading. Results show that the fatigue life predicted by the approach is good coincided with the experiments.