发动机外部管路系统的卡箍布局多目标优化

Multi-objective Optimization of Clamps Layout for Engine External Pipeline System

针对航空发动机外部管路系统卡箍布局不合理而导致发动机发生共振或振动过大问题,对发动机复杂管路的卡箍布局进行优化设计。将卡箍简化为末端固定的线性约束弹簧单元,建立管路系统的整体有限元模型;进行卡箍在复杂3维管路上的位置参数化处理;通过相对灵敏度分析获得对固有频率以及随机振动响应影响较大的5个关键卡箍位置参数;确定2个优化目标分别为前4阶固有频率远离发动机工作频率和随机振动应力均方根响应最小化;采用多目标遗传算法对5个关键卡箍参数进行优化。结果表明:通过优化设计同时实现了多阶频率调节和随机振动应力均方值的减小;对不同优化方案的效果进行对比发现,不同的优化方法各有优劣,无法使2个优化目标同时达到最优结果。

In order to solve the problem of excessive resonance or vibration of the engine caused by unreasonable layout of clamps in the external pipeline system of aeroengine,the optimal design of clamp layout was carried out for complex pipeline of aeroengine.The clamp was simplified to a linear constrained spring element with fixed end,and the whole finite element model of pipeline system was established.The positions of the clamps on the complex 3 D pipeline were parameterized.Through the relative sensitivity analysis,five key clamp position parameters which had great influence on the natural frequency and random vibration response were obtained.Two optimization objectives were determined as follows:first four natural frequencies were far away from the engine operating frequency and the root mean square response of random vibration stress was minimized.Five key clamps parameters were optimized by multi-objective genetic algorithm.The results show that the multiple natural frequencies adjustment and the mean square value of random vibration stress are reduced simultaneously by optimization design.The results of different optimization schemes are compared,and it is found that different optimization methods have their own advantages and disadvantages,which can not make the two optimization objectives achieve the optimal results at the same time.