Improvement on the iterated IRS method for structural eigensolutions

Iterated improved reduced system (IIRS) technique is a model reduction (or condensation) method by repeatedly updating a transformation matrix. An improvement on this dynamic condensation technique is proposed in this paper to modify the iterative transformation matrix and achieve faster convergence. Meanwhile, connection between the present algorithm and the subspace iteration method (SIM) is demonstrated. A proof of the convergence property is also presented. Applications of the method to two numerical examples have demonstrated that the proposed method can obtain the lowest eigensolutions of structures more accurately and efficiently, as compared with the current IIRS.