NONDESTRUCTIVE DAMAGE EVALUATION INDICATOR BASED ON MODAL FLEXIBILITY CURVATURE

Due to the high sensitivity of the change in modal flexibility to structural damage, quite a few nondestructive damage evaluation indicators based on modal flexibility have been put forward. These indicators, such as the change in modal flexibility, modal flexibility index and the change in uniform load surface curvature, were used in some cases and proved to be valid to some extent. In this paper, a new indicator is constructed. Rather than using the change in modal flexibility, the change in curvature of modal flexibility is adopted and called the modal flexibility curvature (MFC). Although the change in uniform load surface curvature also uses curvature, it is different from MFC since it adds up the modal flexibility matrix rowwise and then calculates the change of curvature, while MFC computes the change of curvature columnwise in the modal flexibility matrix and chooses the maximum in each column. Two simulations, a simple beam and a four-span continuous beam, are utilized to verify the new indicator. Compared to the aforementioned indicators and modal curvature index, MFC is proved to be valid and efficient in various cases, and superior to the competitors.