高温升环境下热端部件薄壁连接结构声疲劳强度分析与试验验证

Acoustic Fatigue Strength Analysis and Experimental Verification of Thin-Walled Connection Structures with Hot Sections under High Temperature Rise Environment

关键词:  薄壁连接结构  高温声疲劳  强度分析  寿命预估  试验验证

Key words:  Thin-walled connection structure  High temperature acoustic fatigue  Strength analysis  Life expectancy  Test verification

摘要:

针对航空航天飞行器热端部件，探究其薄壁连接结构在高温升强噪声环境工况下的振动响应及疲劳寿命预估问题，通过对高温合金GH188材料的薄壁板施加根部螺栓连接的边界条件，运用接触有限元以及耦合的有限元和边界元法，研究薄壁板在变温度和变声压级载荷下的振动响应，讨论应力、应变响应值随温度和声压级变化的规律，并运用雨流计数法绘制其损伤矩阵，结合Miner损伤累计理论对其在不同热声载荷下的疲劳寿命进行预估。分析表明，结构响应值普遍随温度和声压级的上升而增大且声载荷对响应值影响较大，疲劳寿命相应减小。针对预估的响应及寿命结果开展试验，试验结果印证了仿真计算中结构危险位置处的轴向应力和寿命预估结果的准确性，为航空航天飞行器薄壁连接结构在热声载荷下的疲劳寿命预估提供了一种合理方法。

Abstract:

Aiming at the hot end components of aerospace vehicles， the vibration response and fatigue life prediction of its thin-walled connection structure under high temperature and strong noise environment are studied. By applying the boundary conditions of the root bolt connection to the thin-walled plate made by superalloy GH188， the contact finite element and the coupled finite element and boundary element methods are used to study the vibration response of the thin-walled plate under variable temperature and variable sound pressure level loads. The law of the stress and strain response value change with temperature and sound pressure level is discussed and the rainflow counting method is used to draw the damage matrix， combined with the Miner damage accumulation theory to predict its fatigue life under different thermoacoustic loads. The analysis shows that the response value of the structure generally increases with the rise of temperature and sound pressure level， and the acoustic load has a greater influence on the response value， and the fatigue life is correspondingly reduced. Tests on the predicted response and life results are carried out and the test results confirm the accuracy of the axial stress and life prediction results at the dangerous position of the structure in the simulation calculation. It provides a reasonable method for predicting the fatigue life of thin-walled connecting structures of aerospace vehicles under thermoacoustic loads.