Over the last few years, fiber optic sensors (FOS) have seen increased acceptance and widespread use in civil engineering, aerospace, marine, oil & gas, composites and smart structure applications. More and more, different research groups and blade manufacturers worldwide have started adopting fiber sensors and fiber Bragg gratings (FBGs) in particular, as practical sensing technology for wind blades. FOS are an attractive technology and reliable sensing solution due to the fact that are completely immune to electromagnetic interference, lightning and electric noise, unlike more conventional electronic sensors that are prone to failure given the harsh and exposed environmental conditions under which wind turbines normally operate.Typically, FBG sensor arrays-either surface-mounted or embedded-have been used to monitor the mechanical behavior of composite rotor blades during the design and qualification stages, as well as in service, to help monitor, on-line, the blades' condition under rotating, stationary and different wind load conditions. In this paper, will present test field results on the mechanical measurements from an experimental composite blade developed under Sandia Lab's S-Blade experimental wind turbine program, instrumented with FBG temperature and strain sensors. A discussion of the methodology, on-line monitoring electronic system, and results obtained will be presented.
The rehabilitation of damaged pipelines plays a critically-important role in maintaining the integrity management of pipeline systems. The repair techniques employed by pipeline operators typically include welded Type A and Type B sleeves, as well as composite repairs. Once repairs are made, operators must trust the integrity and soundness of the repairs based on various monitoring and inspection techniques; however, there are no current widely-accepted techniques for monitoring either the reinforcement or the pipe itself.
A research program was conducted that involved the embedding of fiber optics in a steel sleeve and E-glass / epoxy composite repair systems. Measurements from the fiber optic sensors included temperature, hoop strain, and axial strain, which allowed engineers to monitor conditions in both the repair and the pipe sample. The implications of embedded technologies in pipeline repairs are far-reaching, including the ability to monitor not only the reinforcement itself, but also serve as a resource for monitoring pipeline activities including third party damage and land movement. This paper presents results from the test program, but also concepts for continued use of pipeline repair embedded technologies and their impact on the generation of large-scale data and enhancement of integrity management efforts.
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