Thermography detection of contact failures in double layered materials using the reciprocity functional approach

Abstract

Composite materials are found in many engineering applications such as aircrafts, pipes, nuclear reactors, electronic components and many others. The evaluation and detection of adhesion failures on the interface between the layers of these materials have great importance for these applications. This work deals with the quantitative detection of adhesion failures in a medium composed of two layers, by estimating the temperature difference, heat flux, and the thermal contact conductance at their interface. This has applications in the non-intrusive detection of delamination defects. The unknown functions are obtained by solving an inverse heat conduction problem with the Reciprocity Functional approach. Previous works conducted by the authors provided detailed theoretical and numerical analysis using simulated temperature measurements. This paper validates this methodology to a case where real measurements are used. An experimental set-up was built specifically for this task, where a FLIR sc660 thermographic camera was used. Such apparatus can also be used in the future to validate other techniques. The results show that it is possible to identify and quantify contact failures through the proposed methodology with actual measurements.