AN ASSESSMENT OF SOME PRECONDITIONING TECHNIQUES IN SHELL PROBLEMS

Preconditioned Krylov subspace methods have proved to be efficient in solving large, sparse linear systems, in many areas of scientific comp uting. The success of these methods in many cases is due to the existe nce of good preconditioning techniques. In problems of structural mech anics, like the analysis of heat transfer and deformation of solid bod ies, iterative solution of the linear equation system can result in a significant reduction of computing time. Also many preconditioning tec hniques can be applied to these problems,thus facilitating the choice of an optimal preconditioning on the particular computer architecture available. However, in the analysis of thin shells the situation is no t so transparent. It is well known that the stiffness matrices generat ed by the FE discretization of thin shells are very ill-conditioned. T hus, many preconditioning techniques fail to converge or they converge too slowly to be competitive with direct solvers. In this study, the performance of some general preconditioning techniques on shell proble ms is examined. (C) 1998 John Wiley & Sons, Ltd.