Modal Analysis of Simplified Composite Combined Shell with Composite Flexible Skin in Thermal Environment

针对当前变体飞机变弯度柔性前缘较高的气动载荷和较大的变形需求的问题，本研究提出并设计了一种新型柔性蒙皮模型。首先，将柔性蒙皮模型设计为复合材料–粘弹性材料组合壳结构，基于瑞利–里兹法和有限元法分析得到系统的固有频率和模态振型，与理论值进行了对比。通过改变温度、耦合角度，在多个工况下进行结果分析，讨论了温度、耦合角度对组合壳结构的固有频率和振型的影响。研究发现，温度对固有频率的影响主要来自于温度导致的材料力学性能下降，小耦合角下对低阶频率影响较大，为提高柔性蒙皮性能提供了一种新思路。Aiming at the current problem of higher aerodynamic loads and larger deformation requirements of variable-angle flexible leading edge for morphing aircraft, a new flexible skin model is proposed and designed in this study. Firstly, the flexible skin model is designed as a composite-viscoelastic material combination shell structure, and the natural frequency and modal vibration pattern of the system are analyzed based on the Rayleigh-Ritz method and the finite element method, and compared with the theoretical values. The effects of temperature and coupling angle on the natural frequencies and vibration shapes of the combined shell structure are discussed by varying the temperature and coupling angle and analyzing the results under several working conditions. It is found that the effect of temperature on the natural frequency mainly comes from the temperature-induced degradation of the mechanical properties of the material; the small coupling angle has a greater effect on the low-order frequency, which provides a new way of thinking to improve the performance of the flexible skin.