Interaction of the primary anti-symmetric Lamb mode (AO) with symmetric delaminations: numerical and experimental studies

摘要

The interaction of an ultrasonic guided Lamb wave mode with delamination type defects in aquasi-isotropic laminated composite plate has been studied, using both simulations andexperiments. In a laminated composite plate with a symmetric delamination, when the primaryanti-symmetric mode, Ao, is incident at the entrance and exit of a delamination, it generates anew mode, So, that is confined only to sub-laminates and undergoes multiple reflections in thedelaminated region. It was observed that only the incident and mode-converted Ao modespropagate in the main laminate. The two modes reverberate between the two ends of thedelaminations while undergoing multiple mode conversions, leading to a trail of signals that iscaptured by the finite element model. The numerical observations were validated usingexperiments conducted using air coupled ultrasonic transducers.