DETERMINATION OF THE NATURAL FREQUENCIES AND MODE SHAPES FOR LARGE STRUCTURES BY ACCELERATED NEWTON-RAPHSON METHOD

An efficient numerical method which can calculate the natural frequenc ies and mode shapes for very large structural systems is presented. Th is method applies the accelerated Newton-Raphson method to eigenproble ms. If eigenvalues are not multiple, this method can calculate the nat ural frequencies and mode shapes without any numerical instability whi ch may be encountered in the inverse iteration method with shift. The efficiency of this method is verified by comparing convergence and sol ution time for numerical examples with those of the well-known methods such as the subspace iteration method and the determinant search meth od. (C) 1997 Elsevier Science Ltd.