Optimization of heating protocol in thermal NDT, short and long heating pulses: A discussion

Flash and continuous heating are widely used in transient thermal NDT. Choice of the most appropriate heating protocol leads to multiparametric optimization involving temperature resolution of an IR imager, injected energy, noise on the surface being tested, temperature signal, and contrast over defect as well as times when maximum signals occur. A theoretical analysis of the thermal inspection of glass fiber-steel and carbon epoxy plastic specimens is given. Experimental illustration is performed by testing Plexiglass specimens using both flash and continuous heating techniques. Decision-making rules and limits of the thermal NDT are discussed as well.