不同气流偏角下的壁板热颤振分析及多目标优化设计

 研究了考虑热效应的不同气流偏角下的壁板颤振问题及其多目标优化设计。采用考虑气流偏角影响的一阶活塞气动力、Von-Karmon大变形理论和准定常热应力理论建立了复合材料壁板热颤振方程。利用模拟退火算法,对不同温度场下的偏航壁板颤振速度进行计算。以偏航壁板热颤振速度和壁板重量为多目标函数,在不发生热屈曲的条件下进行优化设计。结果显示：温升使偏航壁板颤振发生“跳跃”现象,对应的气流偏角发生变化;当壁板热颤振模态不变时,偏航壁板颤振速度随温升呈下降趋势,两者呈线性关系;而当热颤振模态发生变化,即偏航壁板颤振发生“跳跃”现象时,偏航壁板颤振速度随温升先升高而后降低,两者呈非线性关系;Pareto解对应的多目标函数之间呈线性关系。

Thermal Flutter Analysis of Panel and Multi-objective Optimization Design Considering Variations of Flow Yaw Angle

This article investigates problems of flutter analysis with thermal effect and multi-objective optimization design of a laminated composite panel that takes into consideration variations of flow yaw angle. A finite element formulation of the composite panel flutter, which can account for the effect of the flow yaw angle, is established using the Von-Karman large deflection plate theory, the quasi-steady theory of thermal stress and the first-order piston aerodynamics. The thermal flutter speeds of the panel under yawed flow are obtained by means of a simulated annealing optimization algorithm. A multi-objective optimization design subjected to the constraints on the critical buckling temperature is conducted, in which the maximum thermal flutter speed under yawed flow and minimum weight of panels are taken as the objective function. The results show that the thermal effect is able to produce a transition phenomenon in panel flutter under yawed flow, and that the corresponding flow yaw angle also changes. On condition that the thermal flutter modes are kept unchanged, the thermal flutter speed of the panel under yawed flow decreases approximately linearly as the temperature rises; whereas if the thermal flutter modes change, the flutter speed first increases and then decreases as the temperature rises, which exhibits a nonlinear relationship between flutter speed and temperature elevation. It is seen that the tradeoff between the multi-objective functions which are associated with the Pareto sets is linear.