IDENTIFICATION AND DAMAGE DETECTION OF TRUSSES USING MODAL DATA

A method for identifying the element properties of a truss is developed in this paper. The measured natural frequencies and modal shapes of the truss are used in the identification process. The finite-element method is used to formulate the eigen-equation of the truss. The identification problem is then formulated as an optimization program in which the error norm of the eigen-equation is minimized. It is shown that given sufficient modal data, the element properties can be directly attained without iterations. Further, the solution is unique and global minimal. The identifiability of the inverse problem is then studied in depth. The perturbation method is adopted to investigate the influence of measurement errors on the identification results. A numerical example is presented to demonstrate the effectiveness of the proposed method in property identification and damage detection.