Thermal NDI of resistance welded composite structures

This paper presents a thermography-based approach for the non-destructive inspection (NDI) of thermoplastic composite welds. Termed HELTHY (Heat Emitting Layer for THermographY), the technique makes use of the heating element that is used in the welding process as the source of heat for thermographic inspection. Two techniques were utilised in observing surface signal variations: direct temperature measurement and lockin. An infrared camera was...