Guided waves for damage characterization in curved beams

Curved beams are often found as connections of straight elements in structural networks, therefore there is an interest in assessing their integrity. The use of guided waves for damage characterization in structures is well established for straight elements but still requires a full understanding of the phenomena occurring when waves interact with discontinuities of different kinds, such as junctions between straight and curved elements and defects located in curved parts. In this paper, the semi analytical finite element method is used to describe wave propagation in curved beams. Firstly, the dispersion curves in toroidal beams are determined, then, the interaction of a longitudinal guided wave with a change of curvature and a defect is described. The effect of the curvature and damage parameters, that is position, extension and intensity on the propagation is studied using a one-dimensional model for the damaged structure. Notwithstanding its simplicity, this model can provide qualitative guidelines in view of the formulation of a damage characterization procedure.