Study on pulsed thermography to detect water ingress in composite honeycomb panels

Abstract The pulsed thermography (PT) for water detection in aviation composite honeycomb panels was studied by finite element method and experiment. A 3-D heat conduction model of water detection in honeycomb panels was presented; the relationships between information parameters and water content were analyzed for three testing modes, i.e. the near water testing, far water testing and vertical testing. Some theoretical results were verified by experiment. The results indicate that, in the three testing modes, both the maximum differential temperature and maximum contrast are non-linear functions of water height, and increase with the water height. The detection sensitivity of the near water testing is the highest, the vertical testing takes the second place, and the far water testing is the lowest. The water content can be evaluated inversely by the curve of maximum contrast versus water height. The obtained results provide a technique support for water detection and evaluation of aviation honeycomb structures by PT