Parametric Identification of Truss Structures Using Static Strains

Abstract

A method for identifying the element properties of a truss is developed in this paper. The axial strains of the truss elements measured in static tests are used in the identification process. The finite-element method is used to derive the equilibrium equation of the truss. The identification problem is then formulated as an optimization program in which the error norm of the equilibrium equation is minimized. It is shown that given sufficient test data the element properties can be directly attained without iterations. Furthermore, the solution is unique and globally minimal. The proposed method can be applied to total truss identification as well as substructure identification. 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 proposed method. Finally, a model test is performed to examine the effectiveness of the method in real applications.