Abstract: The present paper is presented a new method for problem s of structural dynamic reanalysis with very large changes in design variable. T his method is based on combining the power-series expansion of eigenvalue proble ms with the rational approximation of a vector-value function. The use of the ra tional approximation and the Rayleigh quotient leads to that the quality of powe r-series expansion is significantly improved and the range of approximation is extended with a few of additional operation counts. The method is simple in oper ation and easy in implement. Two numerical examples were used to show that the p roposed method can provide high quality approximations of the structural behavio r for large changes in design variable. For large modification in design variabl e, the rational approximation of a vector-value function is an efficient method for structural dynamic reanalysis.

Key words: structural dynamic reanalysis, matrix perturbation met hod, vector-valued rational approximation, Rayleigh quotient