某乘用车白车身试验模态分析及动态特性评价

Experimental modal analysis and dynamic characteristic evaluation for body-in-white of a passenger car

首先介绍了多参考最小二乘复频域法(PolyMax)的基本原理,随后以某乘用车白车身为测试对象,分别采用PolyMax法和最小二乘复指数法(LSCE)对其进行模态试验得到系统前10阶模态参数。2种方法获取的稳态图和分析结果经过比较,表明PolyMax法比LSCE法特别适合密集模态参数识别,可去除虚假数学极点而保留真实物理极点,其分析精度及可靠性方面较后者优越。最后,利用模态振型图对白车身动态特性进行了分析与评价。

First, the paper introduced the theory of poly-refer- enee least-squares complex frequency-domain （PolyMax） method, and acquired the different top ten order modal parameters of a passenger car with PolyMax and least-squares complex experiment （LSCE） through a modal experiment. Then, with the comparative analysis of stabilization diagrams and experimental data that obtained in two different ways, the PolyMax method was especially used for intensive modal parameters identification and able to remove false mathematical poles as well as save true physical poles, compared with the method of LSCE. Therefore, the analysis accuracy and reliability of the former was advanced than that of the latter. Lastly, ac- cording to the modes vibration diagram, the dynamic characteristic evaluation for body-in-white and advices for structure design was carried out.