约束阻尼结构油底壳的辐射噪声响度研究

建立含机油的约束阻尼结构油底壳的耦合模型及其辐射声场无限元模型,测取螺栓的振动加速度,将其加载于油底壳螺栓孔处计算油底壳辐射声场.提取距油底壳底面中心垂向10 cm处的声压仿真值,在500~3 000 Hz内的声压仿真值与测试值十分吻合,验证了油底壳声学计算的准确性.分别以油底壳辐射噪声A计权声压级总值及响度值为目标进行优化计算,对比分析可得:A计权声压级总值较低的噪声可能使人感觉噪声强度较大,以响度等声品质指标为目标才能最直接地改善部件的NVH性能.以辐射噪声响度为目标函数,采用自适应模拟退火算法对油底壳各层厚度进行优化,优化后响度值较原机降低40.0sone,降幅达27.3%,且改进后的总质量降低21.2%,NVH性能明显改善.

Research on Loudness of Radiation Noise of a Constrained-Layer Damping Oil Pan

The liquid-solid coupling model of a constrained-layer damping oil pan as well as the infinite model of the radiation acoustic field were established. The vibration accelerations of bolts， which were loaded in bolt holes for calculating the radiation acoustic field， were measured. The simulated value of sound pressure was acquired at the point which is vertically 10cm from the bottom center of the oil pan， and the value is extremely consistent with the measured value in the range of 500 to 3000Hz， proving preciseness of the acoustic calculation. Total value of A-weighted sound pressure level of radiation noise and the loudness value were respectively regarded as the objectives to optimize the oil pan. The results indicated that the noise with less sound pressure may make the noise sound louder， and only if the sound quality parameters are considered as optimization objectives， the NVH performance can be consequently improved effectively. Finally， the adaptive simulated annealing algorithm was adopted to optimize the thickness of the layers of the constrained-layer damping oil pan， with the loudness of radiation noise as the optimization objective. The result shows that the loudness value declined by 27.3%， reduced 40.0 sone and the mass can be reduced by 21.2%， and the NVH performance is promoted obviously.