Recent developments in vibrothermography

Abstract

Due to the sensitivity of fluorescent penetrant inspection to surface roughness of the inspected material, researchers have been investigating alternative inspection methods. Vibrothermography is one of the contactless nondestructive testing methods in which vibration pulses with high frequencies (typically 20-40 kHz) are used in a part for a short period of time to produce thermal gradient at the defect. In this technique, thermographic or infra-red cameras are used for radiation detection due to thermal gradient in the range of 0.9-14 µm electromagnetic spectrum. This paper focuses on the recent developments in vibrothermography. It covers basics, history, equipments used, types, materials, probability of detection, principle of heat generation mechanism and factors that affect detectability in vibrothermography.

Defect detection by laser shear interferometry based on the thermal response of materials with vibratory loading

“…In this method, vibratory loading is used to generate heat in pieces at the defect area and detect the thermal changes of the part using IR camera. 19 In 1980, Reifsnider et al 20 examined the heat generated by a viscoelastic mechanism on a sample of a polymer composite including delamination defects. They have shown that even the heat generated by this mechanism, will be higher in the stress concentration areas.…”