A NOVEL TECHNIQUE FOR INVERSE IDENTIFICATION OF DISTRIBUTED STIFFNESS FACTOR IN STRUCTURES

A computational inverse technique for identifying stiffness distribution in structures is proposed in this paper using structural dynamics response in the frequency domain. In the present technique, element stiffness factors of the finite element model of a structure are taken to be the parameters, and explicitly expressed in a linear form in the system equation for forward analysis of the harmonic response of the structure. This offers great convenience in applying Newtonʹs method to search for the parameters of stiffness factor inversely, as the Jacobian matrix can be obtained simply by solving sets of linear algebraic equation derived from the system equation. Examples of identifying stiffness factor distribution which is often related to damage in the elements of the structure are presented to demonstrate the present technique. The advantages of the present technique for inverse parameter identification problem are (1) the number of the parameters can be very large; (2) the identification process is very fast and (3) the accuracy is very high. The efficiency of the proposed technique is compared with genetic algorithms.