热振环境下钛合金薄壁结构疲劳寿命

由于钛合金薄壁结构长时间在飞行热振环境下结构内部产生不断变化的应力，可能引起结构疲劳失效，因此借助振动试验台搭建了高温振动疲劳测试系统，测定了20、150℃和300℃温度条件下钛合金悬臂薄板结构的随机振动S-N疲劳曲线，并建立了上述温度条件下钛合金悬臂薄板结构的疲劳寿命预测表达式，根据其计算得到的预测寿命与试验件的实际寿命相比误差较小，300℃、45.36 MPa应力水平下误差仅为3.76%。该方法可用于高温随机振动载荷作用下结构的疲劳性能和寿命预测研究。

Fatigue life of titanium alloy thin-walled structure under thermal vibration environment

Titanium alloy thin-walled structures are in the thermal vibration environment for a long time. The constantly changing stress produced in the thermal vibration environment may cause structural fatigue failure. A high temperature vibration fatigue testing system was built with the help of vibration test bench, and the random vibration S-N fatigue curves of titanium alloy cantilever thin plate structure were obtained at 20, 150 ℃ and 300 ℃. The fatigue life prediction expression of titanium alloy cantilever thin plate structure at the above temperature was established, and the error between the predicted life and the actual life of the test piece was small, which was only 3.76% at the condition of 300 ℃, 45.36 MPa stress level. The method can be used to study the fatigue performance and life prediction of structures under high temperature random vibration loads.