Potential of bragg grating sensors for aircraft health monitoring

The increased requirement to operate military platforms and aerospace structures beyond their designed life imposes heavy maintenance and inspection burden on aircraft operators and owners. In-service structural health monitoring is potentially a cost-effective approach by which service usage information can be obtained and knowledgeable decisions can be made. Advanced sensor technology, such as optical fibres, are expected to provide existing and future aircraft with added intelligence and functionality, reduced weight and cost, enhanced robustness and performance. This paper furthers the understanding of technical and practical issues related to full implementation of a fibre optic sensor based structural health monitoring system for aerospace and military platforms. It also reports experimental findings on the use of fibre Bragg grating sensors for measurement of parameters relevant to aircraft structural monitoring and smart structures; with an emphasis on the suitability of multifunctional fibre optic sensor system. Experimental evaluations revealed that Bragg grating sensors correlate well with conventional sensors technology for temperature, stain, crack growth and cure monitoring and were insensitive to pressures up to 300 psi. These sensors were determined to have minimum impact on the structural integrity when embedded parallel to host fibres into composite laminates. Recommendations on the implementation and integration of these sensors into a structural health monitoring system are also provided.