针对航空薄壁结构在热声载荷作用下的大挠度非线性动态响应问题,开展了矩形薄壁结构在热环境下的声激振试验与仿真计算;并将试验值与计算值进行对比.结果表明模态频率具有一致性,应变响应结果数量级相同,验证了薄壁结构热声响应计算方法的有效性.基于耦合的有限云/边界元法计算了加筋壁板在不同热声载荷组合下的动力学响应.重点研究了结构的热模态频率随温度的变化规律,结合功率谱密度(power spectral density)分析了应力响应在屈曲前后随温度与声压级的变化规律.采用雨流循环矩阵(MRFM)与雨流损伤矩阵(MRFD)讨论了应力循环块的分布与结构的损伤程度.最后结合改进雨流计数法、Morrow平均应力模型和Miner线性累积损伤理论计算并分析了疲劳寿命随屈曲系数与声压级的变化特征.%For nonlinear vibration response problems of large deflection of aerospace thin-walled structures to thermal-acoustic loads,the acoustic excitation test of rectangle thin-walled structures in thermal environment was conducted,and made the comparison between test values and simulation values.The results indicated that the thermal modal frequencies showed the consistent and the magnitude of strain responses kept be same,validating the effectiveness of thermal-acoustic calculation method for thin-walled structures.Further,the coupled FEM/BEM method was used to calculate dynamic responses of reinforced panels under different thermal-acoustic combinations.Researches were mainly focused on change law of thermal modal frequencies with the increase of temperatures.Power spectral density was applied to analyze stress response variation with temperatures and sound pressure level in pre/post buckling.Distribution of stress cycle blocks and damage degree of structures were discussed by using rain flow cycle matrix and rain flow damage matrix.Finally,combined with improved rain flow count method,morrow average stress model and miner linear cumulative damage theory,fatigue life of structures were calculated,and the change characteristics in different buckling coefficient and SPL were respectively analyzed.
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