Determination of thermal diffusivity distribution for three types of materials by transient thermography

Abstract

In many component applications knowledge of the two-dimensional distribution of material properties within the part is highly desirable as a quality assessment tool. The contour plotting of material properties allows identification of local regions of unacceptable variation for rejection, repair or further analysis. Transient thermography is a rapid, inexpensive, on-line, nondestructive technique that can be used to determine the two-dimensional distribution of material properties. In this paper the transient method of pulsed video thermography (PVT) is studied. Procedures for the parameter normalization and numerical method are combined with experimental data to accurately map the thermal diffusivity distribution over the entire surface of a specimen. Materials whose diffusivity ranged over three orders of magnitude were tested. The accuracy of the PVT results was evaluated by comparing local values with those obtained by standard laser flash diffusivity testing.