Vibration based structural damage detection in flexural members using multi-criteria approach

This paper uses dynamic computer simulation techniques to develop and apply a procedure using non-destructive methods for damage assessment in beams & plates, which are important flexural members in building and bridge structures. In addition to changes in natural frequencies, this multi-criteria procedure incorporates two methods, called the modal flexibility and the modal strain energy method, which are based on the vibration characteristics of the structure. Using the results from modal analysis, algorithms based on flexibility and strain energy changes before and after damage are obtained and used as the indices for the assessment of the status of the structural health. The objective is to evaluate the feasibility of the proposed multi-criteria method to identify and localise single and multiple damages in numerical models of flexural members having different boundary conditions. The application of the approach is demonstrated through two sets of numerical simulation studies on beam and plate structures with nine damage scenarios in each. Results show that the proposed multi-criteria method incorporating modal flexibility and modal strain energy method is effective in multiple damage assessment in beam and plate structures.