排气二分管罩的结构动态特性分析与改进

Structual Dynamic Characteristics Analysis and Improvement for Two-way Branch Exhaust Pipe Shield

针对某汽车发动机表面噪声辐射源之一的排气二分管罩,在ANSYS中建立了有限元模型并进行相应分析,分析结果与实验模态分析结果基本一致,这表明所建立的有限元模型可用于管罩的结构动态特性分析.并利用此模型,研究了管罩的结构参数、结构形式和相对应的管罩振动模态之间的关系,提出了最优的结构修改方案.改进后的分析结果表明排气二分管罩的自振频率明显提高,振动噪声得到有效抑制.

The two-way branch exhaust pipe shield is the main source of surface radiate noise of a vehicle＇s engine. Using the finite element analysis software ANSYS, a finite element model of the shield is established, and then the modal analysis is done theoretically with this model, the result is consistent with the experiment. The result shows that this finite element model can be used for the next structual dynamic characteristics analysis. With this model, the relationship of structural parameter, structural style of the shield and the corresponding vibrative modal is analyzed. The optimal improved measures are adopted which is based on the practical structure of the shield. The analysis of the improved structure shows that the increase of natural vibration frequency is visible, the vibration noise of the shield is suppressed distinctly.