Combined approximation for reanalysis of complex eigenvalues

Based on the Kirsch combined approximation and the second order perturbations, a new reanalysis method for complex eigenvalues of modified structures is given. The accuracy of the results obtained by the proposed method is improved compared with those obtained only by the second order perturbations. Two numerical examples are presented to illustrate the validity and improvements of the proposed method and the results show that the new method is effective even if large modifications of structural parameters are made.