A direct identification procedure for assessment of stiffness distribution

An identification procedure is presented for assessment of the stiffness distribution in structures with the aid of an inverse-problem algorithm, based on an FE model of the structure with an unknown stiffness distribution and a subset of measured vibration frequencies and vibration modes. Two independent stiffness indicators–axial and flexural–are used, determined by means of the axial strain and the curvature mode shapes, respectively. The procedure permits simultaneous location of damaged elements, with accurate quantification of damage severity. Furthermore, it is applicable to a variety of structure types, including frames, beams and trusses. The effects of random measurement noise and of realistic joints are taken into consideration. The effectiveness, reliability, and range of application of the procedure are demonstrated in a numerical study.