Abstract:

It’s very important to calculate the sound pressure in vehicle from the powertrain torque excitation for advanced vehicle development. In this paper, a detailed full vehicle structure model and a fluid cavity model was built with FE method, and the coupled fluid-structure equations was derived. The model was validated with the method of modal assurance criterion. Based on the models，the sensitivity of sound pressure over toque, which is called P/T, was calculated. In 30-100Hz, the simulation result had a good consistency with the test result, but not in 10-30Hz. The simulation and tests of mount isolation and powertrain rigid body modes were completed and the results were analyzed. The influence of mount dynamic-stiffness characteristics on P/T was proved. Finally, when the mount dynamic stiffness value was increased, the P/T simulation and tests had a good consistency in the whole band of 0-100Hz.

摘要：

准确预测车辆内部对发动机力矩输入的声学灵敏度（即P/T）对车辆前期NVH开发具有重要意义，建立详细的整车结构及声腔流体有限元模型，并推导流体—结构耦合有限元方程，进行P/T仿真计算，并在相同边界条件下进行试验。仿真结果与试验值在30 Hz～100 Hz有较好一致性，但在10 Hz～30 Hz低于试验值。通过对传递路径中的悬置隔振及动力总成刚体模态进行仿真与试验对比分析，发现悬置低频动刚度特性对P/T灵敏度有较大影响。根据悬置低频动刚度特性调整悬置动刚度，仿真计算与试验值在整个频带即0～100 Hz皆有较好的一致性。仿真与试验结果为车辆开发前期进行车内噪声水平控制提供一定参考。

关键词: 声学；有限元法；流体&mdash, 结构耦合；P/T灵敏度；悬置动刚度