Model Updating Methods Using Complex Eigenvalues: Sensitivity-Based versus Cross-Model Cross-Mode

Abstract

This study proposes iterative methods for updating damping and stiffness matrices of a finite-element model based on measured complex eigenvalues, i.e., poles, which could have been obtained accurately by using various experimental modal analysis (EMA) or operational modal analysis (OMA) techniques. In each iteration of the proposed methods, updating the stiffness and damping parameters requires solving a set of simultaneous linear equations, which can be generated by following a traditional sensitivity-based (SB) method or a less-known cross-model cross-mode (CMCM) approach. Whereas the SB method uses the difference between the target and baseline models to generate equations, the CMCM-based approach utilizes the product between these two models. Analytically, the similarities and differences between them are fully explained. Through the numerical studies, it reveals that the CMCM-based approach might significantly outperform the SB method.