Fiber reinforced polymeric composite materials are becoming increasingly popular due to their high specific strength and stiffness. Other advantages are low thermal expansion, resistance to corrosion and fatigue and most importantly the ability to tailor their mechanical properties for the desired application. However, this versatility brings with it problems in respect of the strength design and failure modes, thus necessitating over design and frequent inspections. In general damage sites occur internally and inspection and assessment of damage requires the part to be taken out of service resulting in down time losses. Furthermore skilled technicians are required for evaluating the response from conventional damage assessment techniques. Thus the need to develop and use a built-in health monitoring system which constantly monitors the structural integrity of the structure is required. This was one of the motivations for the current research on development of a Fiber Optic Polarimetric Sensor (FOPS). The basis of the FOPS sensor is to monitor the change in birefringence of single mode and/or polarization maintaining fibers when subject to external stress and to correlate this to damage in the structure. Initial studies are directed at investigating the response and performance of different sets of fiber for load monitoring and damage detection. Among the initial problems which need to be resolved are:
Choice of fiber
Impregnation of fiber during processing
Input and output signal generation and analysis.
These aspects will be discussed with some examples in this paper.
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 3, pages 1507 - 1510 Publisher:Ashgate Publishing Company
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