This paper will describe and compare the capabilities of various non-destructive thermographic procedures for evaluating defects in aircraft composite materials. The information is derived from joint projects between RSAF and NTU. Lockin thermography is used by RSAF and other aircraft companies. It involves actively applying sinusoidal thermographic waves to the specimen and observing phase and amplitude changes at the specimen surface in order to evaluate structural information below the surface. Experiments were performed to evaluate defect characteristics such as depth, size and shape. The specimen contained very wide range of delamination defect sizes and depths. Finite Element and theoretical models, which included convection current considerations, were developed and will be presented. These showed good correlation with the experimental results. These models enable optimum frequencies and avoidance of blind frequencies to be predicted. Also experimental results will be presented using laser thermography which involves controlled heating of the structure surface using a laser and analysis using a thermographic camera. Finally experimental results will be presented comparing the capabilities of lockin, pulse reflection thermography, though transmission thermography, laser thermography and ultrasonic C scan will be presented.
Thermographic evaluation of aircraft composite materials
Thermographische Bewertung von Luftfahrt-Verbundwerkstoff
2008
20 Seiten, 13 Bilder, 5 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
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