ABSTRACT
Measurement Data ............................................................. 144 5.4 Concluding Remarks and Future Prospects.................................................. 148 References .............................................................................................................. 150
Among the advantages of intrinsic fiber-optic sensors, distributed sensing is often cited as one of the principal potential benefits [1]. Distributed sensing is the ability to return the value of a measurand as a function of the linear position along an optical fiber. Fiber-optic sensors with such ability are called distributed fiberoptic sensors or fiber-optic distributed sensors. They inherit useful characteristics for structural health monitoring (SHM) from fiber-optic sensors, such as immunity to electromagnetic interference, durability, and the capability to be embedded into composite materials. They are still being actively developed into a unique form of sensor for which, in general, there may be no counterpart based on conventional sensor technologies [2]. This also means there is something unique and unfamiliar that characterizes the sensing technique. This introduction provides a brief overview of distributed fiber-optic sensors to outline their fascinating characteristics. Their sensing techniques and their application to the SHM of composite materials, as well as some issues to be considered for practical implementation, are also described briefly in this section and will be described in depth in Sections 5.2 and 5.3. This chapter focuses on the sensing process in SHM rather than the diagnosis and prognosis processes.
