基于FEM/BEM方法的缝纫机油盘低噪声设计研究

Low noise design of sewing oil pan based on finite element and boundary element method

针对某型缝纫机,建立了油盘的实体模型和有限元模型,利用HyperWorks-Optistruct进行模态分析,获得结构的固有频率和振型特性参数。在此基础上,利用MSC.Patran/Nastran进行频响分析,并将仿真结果与实验结果对比,验证了模型的有效性。通过拓扑优化和形貌优化对模型进行优化后,提高了油盘前5阶固有频率,避免了共振,且减小表面振动速度,降低了辐射声功率。通过利用SYSNOISE对油盘进行边界元噪声辐射仿真分析,结果表明油盘辐射噪声值降低。最后,经整机振动噪声测试试验,证明减振降噪效果明显。该研究成果能有效提高油盘的结构刚度和降低振动幅度,最终改善缝纫机整机的结构辐射噪声。

For a certain type of sewing machine, a solid model and a finite element model for its oilpan were built. Modal analysis was conducted with finite element method and the structure＇s natural frequencies and modal shapes were obtained with HyperWorks-Optistruct software. Then, with MSC Patran/Nastran software, frequency response analysis was performed. The results of simulation and test were compared to verify the validity of the model. The oil pan was improved with topology optimization and morphology optimization. After optimal design, the first five natural frequencies of the oil pan increased. Resonances were avoided and surface vibration velocity was reduced, so the radiated sound power was reduced. Using SYSNOISE, the results of noise radiation simulation based on boundary element analysis showed that the radiated noise of the oil pan decreases. Finally, the vibration and noise reductions increased obviously in vibration and noise tests for the improved sewing machine. It was shown that the study can effectively improve its oil pan＇s structural stiffness and reduce the vibration amplitude, and ultimately reduce the structural radiated noise of the whole sewing machine.