基于相关函数的振动结构工作模态参数识别方法

把工作模态参数识别方法中的NEXT法发展为直接利用振动结构的加速度响应信号即可进行结构参数辨识的方法，理论上推导了振动结构相对于速度、加速度信号的脉冲响应函数，以及振动结构加速度响应信号间的相关函数，证明振动结构加速度响应信号间的相关函数与加速度信号的脉冲响应函数具有相同形式的表达式．另外以无约束等截面梁为例，利用梁振动的加速度响应信号间的相关函数作为梁的加速度信号的脉冲响应函数，采用特征系统实现法进行梁的工作模态参数识别，其结果与梁的理论参数值及频域法和利用脉动响应函数的特征系统实现法的识别结果进行了比较，结果表明工作模态识别方法在识别振动结构固有频率方面具有较高的精度．

Operating Modal Parameter Identification of Vibrating Structure Based on Correlation Function

NEXT,one of the operating modal parameter identification approaches,was developed to identify vibrating structure modal parameters by using acceleration response signal directly.The impulse response functions of vibrating structure described by velocity and acceleration signal were deduced,and the correlation functions of acceleration response signal were derived in theory,which verified that the correlation functions of acceleration response signal have the same form as impulse response functions described by acceleration signal.In addition,taking a free beam of which section is equal as an example,the modal parameters of the beam were calculated using eigensystem realization algorithm(ERA) of correlation functions instead of impulse response functions.The results were compared with the theoretical values and results by frequency analysis techniques and ERA using impulse response function.It is shown that the results from operating modal parameter identification possess higher accuracy in identifing modal frequency of vibrating structure.