Quantitative evaluation of thermal diffusivity and thickness of mortar cover using induction thermography

Abstract

This paper presents an inverse method used to determine the thermal diffusivity and the cover thickness of a reinforced beam. The steel reinforcement bar was heated with an induction heating device and surface temperatures were recorded with an infrared camera. Then, a numerical modelling was developed in order to simulate the surface temperature. An alternate difference implicit algorithm was used to solve the thermal transfer equation. The method was implemented in an inverse problem that leads to the identification of the thermal diffusivity and the cover thickness. A study of the sensitivity functions revealed that both parameters can be simultaneously estimated during the heating phase. The computational results are in good agreement with reference values. © RILEM 2013.