In ultrasonic non-destructive testing (NDT) the use of a coupling liquid or solid between an emitter and the test structure is universal. These layers allow the energy to be transmitted into the structure as well as allowing reflected energy to be received. This project aims to build on recent advances in materials and 3D printing to develop novel coupling layers called metalayers containing small resonant elements. These metalayers can, in principle, be designed to perform almost any operation on the incoming wave. Hence, they are ideal candidates for coupling layers, where they can steer and focus the incident beam as required. The metalayers could replace and improve upon the commonly used coupling wedges in NDT. In this application they will increase coupling efficiency, save space and reduce materials costs. This case will also explore the use of metalayers to couple air-borne ultrasound into test structures. These metalayers will be developed in the project using a combination of numerical simulation, design and manufacture as well as testing and validation. 

I have reviewed lots of literature in acoustic metamaterials. I am working on the design principle of metamaterials and simulation analysis of existing metamaterial structures. I have also developed a finite element model of some metamaterials and a theoretical model of metamaterial lens. These could help me to design a lens to focus sound and ultrasound.