Application of Acoustic Metamaterials in Pulse-Echo Ultrasonic Evaluation of Thick Hybrid Composite Laminates

Significant challenges exist in inspecting thick composite laminates for manufacturing defects and operational damage. This is due to acoustic attenuation and impedance mismatch at the interface between the different composite layers. An innovative concept for enhancing ultrasonic testing of such composite laminates is introduced in this study. The proposed solution exploits the ability of acoustic metamaterials to cloak virgin composite. Herein, we show that by incorporating carefully designed metamaterials in a pulse-echo ultrasonic testing setup, the position and size of a delamination in a thick hybrid composite laminate can be determined accurately.