高温强噪声作用直接影响复合材料薄壁结构的动态特性, 热载荷引起的热应力使结构发生热屈曲, 强噪声载荷使结构具有复杂的振动响应形式。针对热声载荷作用下薄壁结构的非线性响应问题, 以四边简支矩形复合材料薄壁板为研究对象, 计算不同温度和声压级组合下的典型热声响应。通过功率谱密度随温度和声压级的变化, 以及不同声压级下位移响应均方根值(RMS)的比较, 对复合材料热声响应的非线性特性进行分析。结果表明:热声载荷作用下复合材料薄壁结构的非线性响应特性显著, 可以从PSD图中看出屈曲前后的基频都有明显的变化, 跳变前后结构刚度是先降低后升高, 结构有硬化现象出现。
The dynamic characteristics of composite thin-walled structures are affected directly by high-intensity acoustic loadings in an elevated temperature.The thermal stresses caused by the thermal loadings can result in the thermal buckling, while the acoustic loadings can make structures vibrate in complicated motion forms.To get the nonlinear response of thin-walled structures to thermal-acoustic loadings, the simply supported rectangular composite plate model with different combinations of temperatures and SPLs is utilized.Then the PSD characteristics with temperatures and SPLs are analyzed and the RMS under different SPLs are compared to obtain the nonlinear characteristics of composite materials with thermal-acoustic loadings.The results show that the responses of composite thin-walled structures to the thermo-acoustic loadings are obviously nonlinear, and the nature frequencies in both pre-/post bucklings are apparently different in the PSD.The structural stiffness reduced, then increased before and after the snap-through motion, resulting in the hardening phenomenon.
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