基于特征系统实现算法的夹具模态参数识别

Modal Parameter Identification for the Fixture by Using Eigensystem Realization Algorithm

针对振动试验中夹具的动力学设计和验证问题,探讨了仅根据响应输出进行模态参数识别的时域分析方法,即特征系统实现算法。以某夹具结构为研究对象,仅通过测试宽带随机激励下的加速度响应信号,对该夹具的模态参数进行了识别。在Matlab7.1上实现了一种基于相关函数的特征系统实现算法,利用加速度响应数据计算相关函数矩阵,并构造广义Hankel矩阵,得到了夹具的模态频率和阻尼比。奇异值分解和稳定图综合分析结果表明:特征系统实现算法能较好地对结构的动力学参数进行识别。

In order to solve the problem of dynamical design and verification for fixture in vibration test, a time domain analysis method of extract mode parameters from output-only data： Eigensystem Realization Algorithm is discussed. Taking a fixture structure as object, modal parameter identification of the fixture is performed with the real measured acceleration responses only under broadband random vibration exciting. On Matlab7. 1, a eigensystem realization algorithm association with correlation functions is implemented. According to the acceleration responses data, the correlation functions ma- trix is calculated and the Hankel matrix is formed. The modal frequencies and modal damping ratios of the fixture were obtained. With synthesis analysis of operation of singular value decomposition and sta- bilization diagram, the results show that the dynamic parameters can be identified using the Eigensys- tern Realization Algorithm.