Thermal methods for evaluating flaws in composite materials: A new approach to data analysis

Lock-in thermography represents a valid and consolidated techniques capable of detecting and quantifying defects in composite materials. This technique in industry is still not widespread especially for large structures, mainly because of the overall lengthy time required for testing due to the necessary scanning approach. In this work, the influence of the main setup parameters of the lock-in thermography technique is assessed, analysing simulated defects on a sample specimen made of GFRP. In particular, the attention was focused on the optimization of testing parameters for the improvement of signal quality and to reduce testing time. An analysis of the phase signal variations with the dimension and position of defect has been carried out and eventual implications about the quantitative evaluation of defects were discussed.