钛合金燕尾榫高温低周微动疲劳寿命预测

Prediction of High-temperature Low Cycle Fretting Fatigue Life of Titanium Alloy Dovetail Tenon

针对钛合金燕尾榫的高温低周微动疲劳寿命预测问题,通过讨论试验载荷和温度对燕尾榫微动疲劳寿命的影响,发展了考虑温度影响的修正损伤参量,即拉伸型等效损伤参量 S和剪切型等效损伤参量 F,建立了能综合考虑温度和损伤参量影响的燕尾榫高温微动疲劳寿命模型,并拟合出某 TC11 钛合金燕尾榫连接结构的微动疲劳寿命模型中所需的材料常数。结果表明:拟合相关性系数最小为 0.9394,证实了该模型的适用性。通过计算拉伸型等效损伤参量 S和剪切型等效损伤参量 F在榫接触面上的最大值所在位置预测了微动裂纹的萌生位置,与微动疲劳试验件裂纹的萌生位置一致。利用高温微动疲劳寿命模型对不同试验载荷和温度下的燕尾榫连接结构的微动疲劳寿命进行预测,与试验结果相比,预测结果的误差在2倍分散带以内。

Aiming at the prediction model of high-temperature low cycle fretting fatigue life of titanium alloy dovetail tenon,by discussing the influence of test load and temperature on the fretting fatigue life of dovetail tenon,the modified damage parameters considering the influence of temperature,namely equivalent tensile damage parameter SWT damage parameter and equivalent shear damage parameter FS damage parameter,were developed. The high temperature fretting fatigue life model of dovetail tenon,which could comprehensively consider the effects of temperature and damage parameters was established,and the material constants required in the fretting fatigue life model of a TC11 titanium alloy dovetail tenon joint structure were fitted. The results show that the minimum fitting correlation coefficient is0.9394,which confirms the applicability of the model. By calculating the position of the maximum value of SWT and FS on the tenon contact surface,the initiating position of fretting crack is predicted,which is consistent with that of fretting fatigue test specimen. The fretting fatigue life of dovetail tenon joint structure under different test loads and temperatures is predicted by using the high-temperature fretting fatigue life model. Compared with the test results,the error of the prediction results is within 2 times of the dispersion band.