Experimental Validation and Noise Assessment of the Thermal-VFM

The virtual fields method is a well-known inverse technique used to identify the constitutive parameters of materials starting from full-field measurement. The method exploits the equilibrium equation, written in the form of the principle of virtual work, to extract the constitutive parameters directly from the measured data. Similar considerations can be done also in the thermal analysis using the law of conservation of thermal energy. In particular, thermography provides a full-field map of the temperature on a specimen surface. From the temperature map, the Thermal Virtual Fields Method (TVFM) is used to extract the thermal properties of the material, like, for instance, the conductivity matrix. Such method was already validated on simulated experiments and the results presented in a previous work. The aim of the present paper is to give a first experimental validation of the method. A suitable experimental set-up was developed using, as target, an aluminum sheet and heater mats to generate the heat flux. The temperature full-field map was detected using a IR camera and the TVFM was accordingly applied to extract the conductivity matrix and the convective heat transfer coefficient. The accuracy of the identification and the impact of the measurement noise is also discussed.