Heat transfer modeling using analytical solutions for infrared thermography applications in multilayered buildings systems

There is growing interest in implementing predictive maintenance techniques to buildings and structures and consequently there is a pressing need for research in effective non-destructive testing (NDT) tools. Infrared thermography (IRT) is a popular NDT tool that has been used in various areas. However, since most known IRT testing techniques have been developed for evaluating materials such as metals, its use in buildings has been limited. In this study, we seek to further IRT applications in buildings by conducting experimental active IRT tests and comparing the results with heat transfer simulations. A simulation model based on analytical expressions is used to compute heat transfer by diffusion in multilayered media and active IRT tests are carried out in a controlled environment using a test specimen that imitates a defective building element. The test duration and frequency of acquisition are varied, as are the specimen characteristics (defect depth, thickness and thermal properties). A phase contrast approach is used to access features which could be useful in evaluating and characterizing defect depth, thickness and thermal properties. Additionally, the influence of noise on phase contrast results is analyzed by introducing random temperature variations in the time domain results that are generated by the simulation model.