Finding Damage in Truss Structures Exploiting Modal Strains

The detection of potentially damaged elements in planar truss structures is a challenging task. Among the different methods proposed in literature, one promising procedure exploits the modal strains of the structure that are calculated from the flexibility matrix, which is, in turn, estimated from the lowest frequencies and corresponding modes of vibration. The benefit of this approach stems from the possibility of using a reduced number of mode shapes, usually available from the dynamic monitoring of the structure to perform the damage detection. In this work, a novel damage detection index based on modal strains is proposed, and its reliability in detecting stiffness reduction in elements of a planar truss is tested numerically.