Defect Recognition for Honeycomb Sandwich Composites Using Pulsed Thermography

Abstract:

Typical defects such as delamination and water/oil ingression existed in honeycomb composites during manufacturing and in-service period. The defects can reduce the performance of the composites significantly. The paper presented a nondestructive defect recognition method for honeycomb composites using pulsed thermography. In this study, based on analysis of the heat transfer in the object with two different medias, the relationship between the surface temperature and the thermal property of subsurface defects has been deduced; the surface temperature expression is put forward to consider the interaction of subsurface defects. In order to simulate the defects, CFRP sandwiched sample with different subsurface defects (debonding, water in the honeycomb core and oil in the honeycomb core) of the same volume inserted in the machined flat-bottom holes, the sample is heated with a short pulse of light, and the sample surface temperature is captured by infrared camera, and the data is processed to measure thermal diffusivity for the subsurface defects. The order of the measured thermal diffusivity is according with the theoretical value. The experiment results provide the feasibility of different defects recognition, and the influence factors are discussed.

• Periodical: Advanced Materials Research (Volume 773)
• Pages: 542-548
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.773.542
• Online since: September 2013
• Authors: Huo Yan, Hui Juan Li
• Keywords: Defect Recognition, Flat-Bottom Holes, Honeycomb Sandwich Composites, Pulsed Thermography

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