System Matrices Identification of Structure: An Insensitive Procedure for Data Point Configurations

A frequency-domain method for estimating the mass, stiffness and damping matrices of a structure is presented. The method is developed based on the normal frequency response functions extracted from the complex ones. In this method, a transformation matrix is obtained first from the complex frequency response functions of a structure. The damping matrix is calculated independently from this transformation matrix, while the mass and stiffness matrices are identified from the extracted normal frequency response functions by using the least squares method. Furthermore, in this paper, it is emphasized that the accuracy of identified system matrices for different data point configurations are addressed. The simulated and experimental results indicate that a more accurate damping matrix can be identified and the present method is insensitive to the data point configurations used in the identification procedure even for cases with only few data points.