热声载荷作用下薄壁结构非线性响应分析和试验验证

Nonlinear response analysis and test verification for thin-walled structures to thermal-acoustic loads

针对热声载荷作用下薄壁结构大挠度非线性响应问题,开展了固支约束金属薄壁板结构热声激励试验及数值模拟分析。通过计算结果与试验结果对比,表明两者结果存在一致性,进而验证了薄壁板在热声载荷作用下动态响应计算方法和数值模型的有效性。在此基础上,针对加筋板结构完成了多种热声载荷组合作用下的动力学响应计算,获得了时域位移响应。重点对该结构在后屈曲状态下的3种典型振动形式进行分析,总结出热载荷与声载荷之间的相对强度决定了板的不同跳变形式。采用统计分析方法建立了位移响应的概率谱密度函数(PDF)并绘图,清楚地显示了后屈曲板的PDF表现出双峰现象。使用功率谱密度(PSD)函数分析了响应频率和峰值随着温度升高的变化,并确定了板的软化和硬化区域。总结了屈曲前/后结构特定区域拉应力和压应力的变化规律,并阐述了造成这种变化的原因。本文工作可对热声载荷作用下薄壁结构响应分析和动强度设计提供参考依据。

To address the nonlinear response to thin-walled structure with large deflection under thermal-acoustic load,a thermal-acoustic excitation test and its corresponding simulation analysis for clamped metallic thin-walled plates have been implemented.The calculated results and the test results are consistent,verifying the effectiveness of the calculation method and the numerical model for thin-walled plate subjected to thermal-acoustic loadings.Based on these findings,the dynamic response calculation for a stiffen-reinforced plate structure under different thermal-acoustic load combinations is completed.Based on the obtained time-domain displacement response,analyses on structure vibration behaviors are mainly focused on three typical motions of the post-buckled plate,indicating that the relative strength between the thermal load and the acoustic load determines the Snap-through forms of the plate.The Probability Density Functions(PDF)of the displacement response are drawn by employing statistical analysis showing that the PDF of post-buckled plate exhibits double peak phenomena.Then the Power Spectral Density(PSD)functions are used to analyze the variations of response frequencies and their corresponding peaks with the increase of temperatures,as well as the determination of softening and hardening areas of the plate.At last,this paper discusses the variation of tensile stress with compressive stress in pre/post buckling areas,and gives the reasons for this kind of change.The work represented in this paper can provide some reference for dynamic response analysis and dynamic strength design of thin-walled structures subjected to thermal acoustic loadings.