Thermal-wave nondestructive evaluation of a carbon-epoxy composite using mirage effect

Abstract

We report new results obtained for thermal-wave nondestructive evaluation applied to composite material using the mirage effect. We have thermally characterized a composite of woven carbon fibers and epoxy consisting of both opaque and transparent parts. We have measured the thermal diffusivity in the different regions of the composite. An anisotropy was found in the thermal diffusivity of the fibers and an effective diffusivity of the epoxy was calculated. From these experimental values we have been able to determine the thickness of the epoxy which coats, in many parts, the fibers. Subsurface cuts made perpendicular to the fibers were easily detected.