Restricted Pade scheme in computational structural dynamics

Restricted Pade schemes R-mp where the denominator is a complete power p of a linear function have been examined analytically by Norsett. Here this method is evaluated with paying special attention to numerical aspects when solving typical finite-element systems in structural dynamics with n degrees of freedom and with essential properties like sparsety and symmetry, This paper presents an efficient implicit restricted time-stepping scheme R-22 with a final coefficient matrix of order n and a leading error term proportional to h(4). This is a significant improvement compared with the most popular Pade- P-11-Newmark scheme with matrix order n, too, but error term h(3) on the one hand and the well established Pade-P-12-discontinuous Hamiltonian approach with error term h(4) but matrix order 2 x n on the other hand. The classical P-11-scheme and the new restricted R-22-scheme are compared in a modal manner and by assessing the correlation between local error estimator and global error. (C) 2001 Published by Elsevier Science Ltd.