基于状态变量的时域参数识别方法的某SUV白车身模态试验分析

Experimental modal analysis of a SUV BIW based on the state variable time domain parameter identification method

状态变量模态参数识别方法作为一种时域参数识别方法,适用范围很广。通过建立白车身模态试验系统,将此方法应用到某SUV白车身模态试验分析中,得到白车身的模态参数,并与频域的P-P法和时域的ITD方法识别的结果比较,固有频率最大偏差均在0.5%以内。试验表明,此车身在低频域内多为组合振型,局部模态并不理想,但整体振型具有较好的低频动态特性。试验结果分析对此SUV白车身后期的性能改进具有重要的指导意义。

The state variable modal parameter identification as a time domain parameter identification method,it＇ s widely used in the modal parameter identification. Here, the Body In White （BIW） modal test system is established, and the State Variable Method （SVM） is applied to analyze that of a SUV in order to get the modal parameters, which are then compared with those identified by the Peak-Peak （P-P） frequency domain method and the Ibrahim Time Domain （ITD） method, the maximum deviation of the natural frequenciesisless than 0. 5%. The result shows that the modal modes of car body are most combination modes in low frequency,and local modes are not ideal. But,the low-frequency dynamic of overall modal shape is better. The test results are of great guiding significance for the later improvement of the properties of SUV body-in-white.