Development of a Thermographic NDI System for Service Damage Identification in Inaccessible Areas

The periodic inspection and evaluation of components and systems is paramount to ensure they stay reliable throughout their service life. These tests which occur during the operation of the equipment serve as a means of performance assessment, failure analysis and prevention, monitoring, reliability analysis or could be applied to life cycle prediction. This paper documents the methodology and findings of an MSc group project involved in developing a portable non-destructive inspection system for inaccessible areas using pulsed thermography. In addition to being a fast and inexpensive inspection technique it also allows sub surface inspection in a wide range of materials. The resulting system is capable of identifying service damages in metals and composites and will lead to time and cost savings through in-service inspection. It proves the feasibility of adapting pulsed thermography for inspection of inaccessible areas by integrating a mirror based system. The use of this system has been demonstrated in the inspection of a train axle. Possible sources of error have been identified and recommendations for future improvements have been made.