AN EXPERIMENTAL INVESTIGATION OF DEFECT SIZING BY TRANSIENT THERMOGRAPHY

Details are presented of art experimental and theoretical investigatio n of the defect sizing capabilities of the transient thermography tech nique. Back-drilled hole artificial defects, of diameters from 2 to 10 mm and at depths between 0.5 and 1.7 mm, in bakelite plates, were the rmographically imaged. Full-width at half maximum (FWHM) of a defect i mage is shown to be accurately related to defect diameter These measur ements are also shown to be in excellent agreement with finite-differe nce simulations of the response of this type of defect. The temporal d ependences of the images are shown to provide an indication of defect depth.