基于模态分解的下位玻璃关门异响试验分析

Abnormal Sound Test Analysis in Door Closing Case with Fully Dropped Glass Based on Modal Decomposition

针对某车型的车门在下位玻璃状态下存在的关门异响问题,以工作变形分析为基础,提出了一种基于工作变形模态分解的关门异响振动噪声源识别方法。首先,对关门声信号进行短时傅里叶变换时频分析,判定出关门声存在二次冲击现象,且噪声能量主要分布在低频辐射噪声部分;其次,采用工作变形试验识别出车门工作变形主要频率及振型,通过车门半约束模态试验获取车门模态频率及振型;最后,依据车门模态特性对工作变形进行模态分解,判定出异响振动噪声源。利用此方法对某车门进行试验分析,成功识别出该车型关门过程中的异响振动噪声源。试验结果显示,改进后关门二次冲击现象消失,关门异响得到有效改善,验证了该异响识别方法的有效性。

In th light of the door closing abnormal sound appears at the glass of the vehicle door in the full drop state,a method based on modal decomposition of operational deflection shape for identifying vibration sources of abnormal sound is proposed.First,time-frequency analysis of the noise signal is carried out through the short time Fourier transfer method.The result shows that the abnormal sound has secondary impacts.The energy of noise is mainly distributed in the low-frequency radiated section.Then,the test of operational deflection shape is used to identify door deformation.The modal frequencies and vibration shapes are obtained by modal test.Finally,the vibration source of the abnormal sound is diagnosed through the result of modal decomposition.According to this method,the main vibration source of the abnormal sound is identified successfully,and some suggestions for improvement are put forward.The improved test result shows that after the optimization,the secondary impacts and abnormal noise disappeared.The experimental result shows that the method is feasible and valid.