USE OF FREQUENCY RESPONSE FOR DAMAGE DETECTION: AN OPTIMIZATION APPROACH

This paper presents results from a study that investigates the use of frequency response for damage detection. A two stage optimization approach is proposed to identify the presence of damage in a structure, and to find the location and severity of damage. The proposed approach requires the measured frequency response to statistically quantify the presence and severity of damage. Multiple simulations are presented to demonstrate the capability of the proposed approach. For the simulations, damage is characterized as a local flexibility through the use of a model that is based on Linear Elastic Fracture Mechanics (LEFM). A simply supported beam is used to evaluate the effectiveness of the proposed damage detection algorithm by using the frequency response from the simulation model and incorporating different levels of noise. The optimization approach is found to be successful in determining the status of the beam, and in predicting the crack size and the crack location even in the presence of a high level of noise and with relative coarse sampling of the frequency response. It is also observed that the crack size predicted by the damage detection algorithm is relatively more sensitive to the random noise added to the frequency response as compared to the location of the crack.