Abstract: An iterative method is presented for the modification of structural stiffness. The present method is a preconditioned conjugate gradient-based technique and is intended to utilize the existing stiffness matrix fac torization developed for the initial design. It can preserve the ease of impleme ntation and improve significantly the quality of the results. In particular, the method can adaptively monitor the accuracy of approximate solutions. The method is suitable for general finite element systems. The computational cost is significantly reduced. It has been validated by numerical examples that the proposed reanalysis method can achieve excellent approximate results for large changes in cross-sections and in structural geometry.

Key words: structural modifications, reanalysis, preconditioned conjugate gradient method