CIVA Modelling as an Effective Tool for Air-coupled Through-Transmission Ultrasonic Inspection

Air-coupled ultrasound has been used as a tool for surface profilometry and to inspect highly attenuative materials such as composite laminates and foams for voids or disbonded areas. Significant losses are experienced with air-coupled ultrasound applications due to the attenuation in air and high impedance mismatch. As a result, not many inspections use the traditional pulse-echo approach. Instead, through transmission is preferred. Considering how most air-coupled probes are driven using a tone-burst excitation, resulting in a very narrow bandwidth (ringy) pulse, through transmission is a practical option since it relies solely on amplitude response rather than temporal resolution. CIVA software features the ability to simulate an air-coupled ultrasonic through-transmission inspection by using imported 3D CAD files. This paper describes how such an inspection can be modelled in the simulation software.