Identification of Structural Damage Severity Using an Inverse Wave Analysis

The problem of non-destructively identifying the damage severity in a known damage region of a structure is considered. The damage is modeled as a reduction in Young’s modulus of the material in a local region. In the proposed model-based identification technique, wave sources are activated on the boundary of the structure, which generate traveling elastic waves. These waves travel from the sources to the damage region, and from there reach sensors, also located on the structure’s boundary. The sensors measure the time-dependent response of the structure, by recording certain displacement components at many discrete times. In the current work, all the data are generated synthetically, with an added artificial measurement noise. Based on these data, the damage severity in the various damage regions is estimated by solving an inverse minimization problem, involving a non-convex misfit functional. The minimization is performed using the Method of Moving Asymptotes. It is demonstrated, via several numerical examples, that it is possible to achieve accurate identification using this technique, sometimes even with a single sensor which is remote from the damage region and measures a single displacement component. Of course, to prove the practicality of the proposed method, laboratory experimentation is required, which is beyond the scope of this paper.