Scattering of Guided Waves by Interfacial Delamination in Aerospace Composite Laminates

Multi-layered composites have been increasingly used in the aerospace industry since they possess high durability while maintaining low weight to withstand harsh operating conditions. This article examines the utilization of ultrasonic guided waves within laminated composite plates with the aim of applying them in material characterization of composite structures. The investigation focuses on the theoretical analysis of wave motion generated by time-harmonic loads in composites, employing reciprocity theorems. We also explore the scattering of guided waves resulting from delamination at the laminate interface. By applying the reciprocity theorem, the expression for the scattering amplitude ratio of guided waves caused by the delamination defect can be derived explicitly. The results have been computed for the tri-layer aluminum-epoxy-aluminum plate and discussed in detail in terms of the dependence of the depth and width of the delamination defect.