利用互相关差分模型在环境激励下提取模态参数

 对于一些大型结构,难以采用人工激励进行模态识别,只能利用环境激励信息,单独从响应数据提取模态参数。针对这一实际情况,首先从经典差分模型入手,推导出了环境激励下的多参考点互相关差分模型,然后分别采用增广矩阵法和多项式特征值法求解模态参数。最后采用一飞机模型对多参考点互相关差分模型法进行了试验验证,并且将2种求解方法得到的结果进行了比较。结果表明,多参考点互相关差分模型能够有效地进行环境激励下的模态识别,并且多项式特征值法比增广矩阵法所得结果更好。

MODAL PARAMETER IDENTIFICATION USING THE DIFFERENCE MODEL WITH CROSS-CORRELATION FUNCTION FROM AMBIENT RESPONSE

It is necessary for some large scale structures to extract modal parameters using only ambient responses. A poly reference difference model with a cross correlation function is derived from the classical difference model in this paper. The augmented matrix method and polynomial eigenvalue method are used to get modal parameters respectively. Then an experiment on an aircraft model is done to verify the validity of the proposed method. And the results from both the augmented matrix and polynomial eigenvalue are compared. It shows that the presented method can be used to identify modal parameters effectively under ambient excitation and that the polynomial eigenvalue method is superior to the augmented matrix method.