Damage localization in beam-like structures using changes in modal strain energy

Abstract

This paper investigates the application and reliability of using modal strain energy in damage localization estimation of beam-like structures. This is based on the fact that damage often cause a loss of stiffness that increase the modal displacement of two ends of beam element containing the damage, So the modal strain energy after damage will be increased and Modal Strain Energy Change Ratio (MSECR) in this element is larger than other elements and the location of damage is detected by finding the element with higher MSECR. To conduct this investigation, an experimental modal analysis program was carried out on a cantilever beam subjected to a controlled crack levels and the first seven mode shapes were extracted and used to calculate the modal strain energy change. The experimental MSECR was computed and the location of the damage was accurately identified especially for crack sizing as small as 10% of the beam height. Finally, finite elements models were built and validated, MSE change method was applied and the results demonstrate that the method is capable of localizing the damage for beam structure.