基于相干分析的汽车轮心力对振动噪声贡献的对比研究

Comparative Study on the Contributions of Wheel Center Forces to the Vibration and Noise of Vehicle Based on Coherence Analysis

六自由度轮心力对汽车振动噪声贡献率的计算对汽车NVH性能分析具有重要的指导意义。本文中从理论上分析了采用多重相干法处理相干激励时存在的两个问题,即只适用于能将所有激励划分成彼此之间相关性很小的分组情况,且只能计算分组整体对响应的能量贡献率。阐明了无论激励是否相关,采用虚相干法均能直接计算六自由度轮心力的贡献率。实验结果表明,在激励分组(单个车轮上的所有激励为一组)之间存在较大的相干性时,采用多重相干法计算得到的各轮贡献率误差较大,而采用虚相干法能取得较好的结果。

The calculation of the contributions of 6-DOF wheel center forces to the vibration and noise of vehicle has important guiding significance for the analysis of vehicle NVH performance. In this paper,two major defects of multi-coherent method when dealing with coherent excitations are analyzed theoretically,that it can only be applied to the situations when there exist little coherences between different excitation divisions and it can only calculate the overall energy contribution ratio of excitation division. It is also expounded that virtual coherent method can directly calculate the contribution ratios of 6-DOF wheel center forces no matter excitations are coherent or not.The results of experiment show that when there exist obvious coherences between different excitation divisions( all excitations on a single wheel are in the same division),the contributions of wheels calculated using multi-coherent method have larger error,while virtual coherent method can get a better result.