Dynamic condensation approach for response-based finite element model updating of large-scale structures

Abstract

This study develops the dynamic condensation approach to improve the computational efficiency of response-based finite element model updating of large-scale structures. Using the dynamic condensation approach, a small number of degrees of freedom (DOFs) are selected as master DOFs. A transformation matrix is then derived to relate the master DOFs to the total DOFs. The global vibration equation is reduced into a much smaller one by using the transformation matrix. The responses are calculated efficiently from the reduced vibration equation. The response sensitivities are derived directly from the reduced vibration equation to ensure that the response sensitivities with respect to design parameters are calculated simultaneously and efficiently. The response-based model updating is then performed using a few time history responses and response sensitivities only. The computational precision and efficiency of the proposed model updating method are verified using a steel frame and a large-scale suspension bridge.