Decentralized damage detection under ambient excitations with random decrement functions

All rights re served. In this paper, a decentralized damage detection method is proposed for civil structures under ambient excitations. This method do not have the limitations that the number of sensors should be larger than the number of unknown forces and the sensors must be available at the external forces as required by conventional methods. The random decrement (RD) functions are used for damage detection. The unknown structural parameters and RD functions are divided into a number of subsets according to its finite element configuration. Each subset of parameters can be updated with RD functions in the same region. The RD function consists of two parts: one is a nonlinear function that depends on structural parameters, the other is the initial value of the RD functions. The initial values of the RD functions and the physical structural parameters are improved in further iterations by model updating. A numerical example is employed to demonstrate the effectiveness of the proposed method.