Element-by-element model updating of large-scale structures based on component mode synthesis method

Component mode synthesis (CMS) method is developed and applied to the element-by-element model updating of large-scale structures in this study. Several lowest frequencies and mode shapes of the global structure are obtained with the free interface CMS method by employing the several lowest frequencies and mode shapes of each substructure individually. In this process, the removal of higher modes is compensated by the residual modes. The eigensensitivity of the global structure is then assembled from the eigensensitivities of each substructure to the updating element parameters. Subsequently, the global model is updated using the sensitivity-based optimization technique. The application of the present method to an 11-floor frame structure and to a large-scale structure demonstrates its accuracy and efficiency. The computational time required by the substructuring method to calculate the eigensensitivity matrices is significantly reduced, as compared with that consumed by the conventional global-based approach. Selection of the number of master modes is also proposed.