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Substructure location and size effects on decentralized model updating

To improve the simulation accuracy of the finite-element (FE) model of an as-built structure, measurement data from the actual structure can be utilized for updating the model parameters, which is termed as FE model updating. During the past few decades, most efforts on FE model updating intend to update the entire structure model altogether, while using measurement data from the entire structure. When applied on large and complex structural models, the typical approaches may fail due to computational challenges and convergence issues. In order to reduce the computational difficulty, this paper studies a decentralized FE model updating approach that intends to update a substructure at a time. The approach divides the entire structure into a substructure (currently being instrumented and updated) and the residual structure. The Craig-Bampton transform is adopted to condense the structural model. The optimization objective is formulated to minimize the modal dynamic residuals from the eigenvalue equations in structural dynamics involving natural frequencies and mode shapes. This paper investigates the effects of different substructure locations and sizes on updating performance. A space frame example, which is based on an actual pedestrian bridge on Georgia Tech campus, is used to study the substructure location and size effects.

Author(s):

Xinjun Dong    
Georgia Institute of Technology
United States

Dapeng Zhu    
Georgia Institute of Technology
United States

Yang Wang    
Georgia Institute of Technology
United States