基于多目标优化技术的发动机罩加强筋布局设计研究

REINFORCEMENT LAYOUT DESIGN OF ENGINE HOOD BASED ON MULTI-OBJECTIVE OPTIMIZATION TECHNOLOGY

为了加强发动机罩壳的静态刚度特性和抑制振动能力,实现罩壳结构的轻量化,引入基于水平集法的拓扑优化技术和多目标理论,完成发动机罩加强筋布局的多目标优化设计。采用折衷规划法构建关于静刚度和一阶固有频率的多目标优化模型,运用水平集法求出罩壳加强筋的最佳分布形式。结果表明,该方法能大大地提高静动态结构性能,最大应力的下降说明罩壳应力集中现象得到有效的改善,缓解罩壳的疲劳现象。此外,基于层次分析法确定权重因子,避免了多目标优化模型构建中的主观能动性。采用平均频率法对动态目标函数的处理,有效地消除了动态优化过程中的收敛性。

In order to enhance the static stiffness characteristic and vibration suppression capability of the engine hood and realize the lightweight of hood structure,we introduce the topology optimization technology based on level-set method and the multi-objective theory,and complete the multi-objective optimization design for reinforcement layout of engine hood.The compromise programming approach were adopted to build the multi-objective optimization model on the static stiffness and first-order inherent frequency,and the level-set method was used to solve the optimal distribution of the reinforcement layout of the engine hood.The results show that our method can greatly improve the static and dynamic structural performance.The reduction of maximum stress indicates that the stress concentration of engine hood is improved,which relieves its fatigue.The weight factors are determined based on analytic hierarchy process so as to avoid the subjective initiative in the construction of multi-objective optimization model.The average frequency method is adopted to process the dynamic objective function so that the convergence is effectively eliminated during the process of dynamic optimization.