基于工作变形的车体模态振型分解技术研究

The research of vehicle body modal shape decomposition technology based on operational deflection shape

为对车体的工作变形进行模态分解，首先对某型铝合金车体进行台架模态实验，然后通过稳态图中的极点找出车体在0～50Hz的工作变形，再利用模态置信判据（MAC）和模态比例因子（MSF）在车体工作变形中找出模态“基”群，通过车体工作变形公式将车体工作变形分解为在特定频率下模态“基”群的线性叠加。分解结果显示：工作变形分解理论分解车体工作变形效果较好；其中各“基”模态所占的比重不同，其中菱形、1阶垂弯和扭转在某些频率下所占比重较高。

In order to carry out the modal shape decomposition of the vehicle body, Firstly, modal experiments has been done for a certain type aluminum alloyvehicle body. Then locate the operational deflection shape through stable figure from 0 to 50Hz and use modal assurance criterion （MAC） and modal scale factor （MSF） to identify modal ＂base＂ group. Next decompose the operational deflection shape into a linear superposition of modal ＂base＂ group at a specific frequency through the deformation formula. The results show that： it get good effect to decompose the operational deflection shape of vehicle body through decomposition theory; Wherein the proportion of each of the ＂base＂ modal vary, whichthe rhombic, 1 step vertical bending and torsional have higher frequency of occurrence.