Features of dynamic response sensitivity and its application in damage detection

The sensitivity of general dynamic response of a structure with respect to a perturbation in a parameter of a dynamic system is addressed in this paper. The sensitivities of response of the structure when under sinusoidal, impulsive and random excitations is calculated, and their properties discussed. Local damage in the structure is represented by a perturbation of a system parameter, and a new sensitivity-based approach is presented for identifying the local damages in a structure directly from the measured dynamic responses. The solution is obtained with the penalty function method iteratively with regularization. Simulation studies on the effectiveness and accuracy of the proposed method are performed including measurement noise and initial model errors, and experiment work on steel beams with local damages has also been conducted. The proposed method is seen to give acceptable results even with the different types of model errors taking advantage of the plentiful amount of measured data from the responses.