基于模态分析及动刚度优化的低噪声正时罩设计

Low Noise Design of the Timing-cover Based on Modal Analysis and Dynamic Stiffness Optimization

正时罩盖属于薄壁件,其刚度小、面积大,很容易与其相连的发动机体发生共振,辐射噪声较大。利用有限元方法分析装配状态下正时罩盖的各阶振型,获得其噪声辐射的关键模态;并施加单位载荷于正时罩盖有限元模型,将其作为动态响应分析的激励,得到正时罩盖表面响应分布,并通过试验来验证其模型准确性。以动刚度作为优化目标,对其内部的加强筋进行了重新设计及布置,使正时罩盖的模态振型避开正时轮系啮合激励频段,进而降低辐射噪声。仿真和试验结果均验证该方法的有效性。

Because of the small rigidity and large area,the timing-cover is easy to resonate and the radiation noise is large. Finite Element Method was used to obtain modes of the timing-cover under assembly condition. The unit load was used as the excitation of the dynamic response analysis to obtain the response distribution of the timing cover surface,and the accuracy of the model was verified by experiments. In order to optimize the dynamic stiffness,the internal stiffener was redesigned and arranged. The modal vibration mode of timing cover was avoided from the meshing excitation frequency band of the timing gear system,so as to reduce the radiation noise. Simulation and experimental results verify the effectiveness of the method.