基于多目标形貌优化的缸盖罩低噪声设计

为降低柴油机缸盖罩结构辐射噪声,运用有限元边界元法对其进行了噪声虚拟预测,得到噪声贡献量突出的关键模态.将缸盖罩结构的静态整体刚度和动态多阶关键频率统一为Euclidean 距离的多目标函数,采用带权重的折衷规划法对缸盖罩进行多目标形貌优化,并考虑装配、加工工艺性等因素重新设计了缸盖罩CAD模型.在保持边界条件一致的情况下,对重新设计后的缸盖罩进行噪声分析,结果表明:改进后的缸盖罩整体刚度得到加强,关键频率避开了主要辐射噪声共振频率区域,总声功率级下降3.5 dB(A). 

Low Noise Design of Cylinder Head Cover Based on Multi-objective Topography Optimization

In order to reduce the structural radiation noise of a diesel engine cylinder head cover, the finite element method (FEM) and boundary element method (BEM) were used for its virtual prediction and obtained the critical modal with dominant contribution to the structural radiation noise. Considering the static stiffness and several critical dynamic frequencies as Euclidean distance's multi-objective function, weighted compromise programming approach was applied to multi-objective topography optimization of the cylinder head cover. With the optimization result, the CAD model of the cover was redesigned taking manufacturing and assembling process into account. Finally, the radiation noise of the optimized cylinder head cover was analyzed under the same boundary conditions. The results show that the integral stiffness is improved, the critical frequencies avoid the original resonance frequency range that radiates noise most and the total acoustic power level has dropped by 3.5 dB (A).