Locating structural damage in real time using contrast maximization - Analysis and experiments

Abstract

A technique to identify structural damage in real time using limited instrumentation is presented. Contrast maximization is used to find the excitation forces that create maximum difference in the response of the damaged structure and the analytical response of the undamaged structure. The optimal excitations for the damaged structure are then matched against a database of optimal excitations to locate the damage. To increase the reliability of the approach under modeling errors and measurement errors, the contrast maximization approach is combined with an approach based on changes in frequency signature. A damage detectability measure which relates the effect of noise to the ability to detect damage is defined. The success in damage identification is quantitatively defined by a success factor. The technique is first tested numerically on a 36 degree of freedom space truss. A similar truss is then built and the FEM model of the structure is corrected using experimental data. The technique is applied to locate the damage in several members. The experimental results indicate that this technique can robustly identify the damaged member with limited measurements and real-time computation.