基于运行模态法的动力总成刚体模态试验研究

介绍两种基于运行模态法的动力总成刚体模态参数识别方法,即频域分解法与时域随机状态子空间辨识法。发动机怠速工况下,运行模态法可以识别出动力总成悬置系统在垂向跳动与绕侧向俯仰的刚体模态,并且可以识别出动力总成怠速激励下的谐波模态;而动力总成受到白噪声激励,运行模态法可以识别出动力总成悬置系统的全部六自由度刚体模态。从对比可知,运行模态法识别的模态参数与常规试验模态法结果基本一致,表明利用工况激励法进行模态参数识别是行之有效的。

Experimental Study on Powertrain Rigid-Body Modes Based on Operational Modal Analysis Method

Two methods of powertrain mounting system（PMS） rigid-body modes identification,frequency domain decomposition（FDD） method and stochastic subspace identification（SSI）,based on operational modal analysis（OMA） are introduced.It is found that in idle condition the bounce and pitch modes of PMS can be identified using FDD and SSI method,and the powertrain harmonic modes due to the idle excitation are also detected.While under the condition of white noise excitation,all the six rigid-body modes of PMS can be identified using FDD and SSI methods.The consistency and accuracy of extracted modal parameters are verified by comparing the results with those resulted from the OMA and EMA methods.The two methods can be used for PMS rigid-body modes identification and dynamic modification effectively.