Nondestructive testing of 3D-hybrid components using air-coupled ultrasound

Abstract

The increasing use of hybrid lightweight structures in the automotive industry results in new challenges in the area of multi-material interfaces. Insufficient bonding quality between two different materials, especially in highly loaded structures, affects the component’s performance. Hence, it is very important to monitor the bonding quality during the multi-material component fabrication process obtaining a reliable save-lifedesign. Flat specimens, consisting of sheet steel and organic sheet layers were examined using air-coupled ultrasound transducers in reflection setup. By slanted incidence of the ultrasound on the profile’s surface, guided waves were excited in the specimen and delaminated areas could be visualized due to changed phase values in the received signal. Furthermore, a 3D-hybrid cap profile consisting of sheet steel, organic sheet layers and injection molded reinforcing ribs was examined using a special transducer setup. The received air-coupled guided wave signal reveals different signatures of bonded and delaminated organic sheets. Simulations of the guided wave propagation agree with the findings.