Identification of the Damping Matrix

Only experiments can provide the data necessary to obtain the damping matrix of a dynamic structural system. In the method proposed here the damping matrix can be separated from the mass and stiffness matrices and obtained in an independent of them way. Two methods are presented. In the first method it is assumed that all the degrees of freedom can be loaded and measured. Several methods for calculation of the damping, mass and stiffness matrices, using the experimental data are presented. In the second method the load is employed only in some chosen points. However, it is assumed again that all the degrees of freedom are measured. In order to identify the damping, stiffness and mass matrices of the structure the measured quantities are forced to comply with the general laws for a linear structure. The structure is idealized to be a linear dynamic structure with viscous damping. The measured quantities are measured during the tests at discrete points of the Frequency Response Function.