基于工作模态法的装载机后车架动态特性分析

Analysis of dynamic characteristics of a certain loader rear frame based on operational modal method

在介绍了工作模态法优点的基础上,采用LMS test.lab系统对某装载机后车架进行工作模态实验。首先测试各响应点怠速工况下振动信号,信号经预处理、计算互功率谱、集总和拟合振型后得到了其各阶模态参数。运用模态置信度指标及定置升速工况振动响应三维功率谱验证了模态参数的真实性。实验结果表明,在发动机常用工作转速范围内,后车架不存在突出共振问题。模态分析的结果为后车架动态设计中降低振动、噪声,提高可靠性提供了依据。

The merits of the operational modal method were introduced. A certain loader rear frame is tested by operational modal analysis system of LMS Test. Lab. The vibration signal of response points on idle are obtained firstly. Subsequently, modal parameters are extracted by steps of signal processing, computing cross power spectrum, summing,identifying nature frequencies and fitting vibration mode. Then, the spectral date of measured response and modal confidence index were applied in the modal validation. The experimental results show that there is basically no resonant problem with the rear frame. The modal analysis provide experimental basis for improving reliability and reducing vibration and noise in the dynamic design of the rear frame.