Comparison between coupled local minimizers method and differential evolution algorithm in dynamic damage detections

In the present paper, performances of the Coupled Local Minimizers (CLM) method and the Differential Evolution (DE) algorithm for damage assessment of a cracked beam by FE model updating are compared. The presence of cracks in a structural member introduces local flexibilities modifying its dynamic behaviour. Changes in dynamic characteristics (frequencies and mode shapes) can be measured and subsequently used for damage detection. Comparison is performed by considering one crack first and two cracks in a second benchmark problem. The challenge is to find, by FE model updating, the crack location and the spring stiffness (related to the crack width). The effectiveness of two algorithms to find the set of optimization parameters has been compared by performing a statistical analysis of the optimization results.