Structural modal reanalysis for topological modifications of finite element systems

In this paper, a procedure for modal reanalysis of structures subjected to topological modifications is presented. The procedure is based on results of initial modal analysis of the original structure. The topological modifications include addition of joints, where the number of degrees of freedom (DOF) is increased. The method deals with the stiffness and mass matrices of structures directly, so it can be used with a general finite element system. It is shown that the proposed method is very effective, highly accurate and easy to implement on a computer.