排气歧管罩动态特性分析与结构改进设计

排气歧管罩是某6360汽车发动机的主要表面噪声辐射源,利用有限元分析技术建立了其有限元模型并进行解析模态分析,分析结果与实验基本一致.在此基础上进行了在发动机缸体振动激励下的瞬态响应分析,结果表明排气歧管罩自由边法向振动速度最大,是其噪声辐射的主要来源.对排气歧管罩进行了结构改进.其分析结果表明改进效果良好,排气歧管罩的辐射噪声得到明显降低.

Dynamic Characteristics Analysis and Structure Design of Improvement for Exhaust Manifold Cover

The exhaust manifold cover is the main source of surface radiate noise of a 6 360 vehicle's engine.By using the finite element analysis technology,a finite element model of the cover is established,and then the modal analysis is done theoretically with this model,the result is consistent with the experiment.On this basis,the transient response of the cover under the excitation of engine block's vibration is analyzed.The result show that the free edge is the main source of radiate noise,because its normal velocity is maximal.The improved measures are adopted which is based on the practical structure of the cover.The analysis of the improved structure shows that the measures are effective,the radiate noise of the cover is decreased distinctly.