Free vibration analysis of locally modified regular structures using shifted inverse iteration method

In this paper a numerical method is proposed based on single vector iterations for finding a few natural frequencies and mode shapes of the modified regular systems. The proposed method utilizes the information obtained from a decomposable model, called the base model, to transform the eigenproblem associated with the free vibration of the modified system into a simpler problem which can be handled more efficiently through vector iterations such as shifted inverse iteration method. The efficiency of the proposed method is demonstrated through examples in terms of the number of iterations required, speed and storage requirements. Comparison is made with standard vector iteration method applied to the entire structural model.