Abstract
The modal truncation problem of non-classically damped systems is constantly encountered in the dynamic analysis of engineering. The present study is designed to calculate the frequency response functions of the non- classically damping systems accurately on account of the Neumann expansion theory and the frequency shifting technique. Considering the first and the second term influence of the Neumann expansion equations in the frequency response analysis of the viscoelastic systems, we could correct the modal truncation problem of model displacement method. The property given in the study shows that this correcting method can reduce the high-order modes that can’t be calculated to the lower-order modes that are easier to be computed. And the proposed method can also solve the problem causing by the singularity of stiffness matrix. The result of case given in the article shows that it can improve the accuracy of harmonic response effectively compared model displacement.