AN ACCURATE MODAL SUPERPOSITION METHOD FOR CALCULATING FREQUENCY RESPONSE FUNCTION OF VISCOELASTICALLY DAMPED STRUCTURES

An accurate modal superposition method for calculating frequency response function of viscoelastically damped structures is put forward. As shown in this paper, the errors of calculation are considerable, while only a few of low-frequency vibrating modes are used in modal superposition for calculating frequency response function of viscoelastically damped structures. The contribution of high- frequency vibrating modes and creeping modes to frequency response function of viscoelastically damped structures is expressed by the low- frequency vibrating modes and the system matrixes, and the errors of calculation are corrected. In this method, the calculation precision can be improved greatly with limited increase of computational effort. A numerical example is given, which demonstrates the correctness and efficiency of the present method.