Quantitative Dynamic and Distributed Fiber-Optic Sensing has Come of Age

Abstract

While the importance of static fiber-optic distributed quantitative sensing has been already recognized, appreciated and applied, adding full dynamic, real-time characteristics is of crucial importance, as it enables the use of distributed sensing in time-varying scenarios in multiple applications, such as: aerospace, civil engineering, transportation and more. For example, distributed load monitoring and damage detection in a flying platform must have dynamic capabilities due to the constant motion of the subsystems under investigation. Even 'static' applications, such as the distributed mapping of strain over a loaded long wing, require some dynamic performance. Otherwise, the accuracy of the supposedly 'static' measurements may be compromised by parasitic vibrations of the structure. Worse, testing personnel, losing their patience to wait until all vibrations die, will be reluctant to move to fiberoptic sensing. The paper outlines a few promising commercially available technologies for quantitative fiber-optic dynamic and distributed sensing of mainly strain but also temperature, suitable for general SHM applications. It also discusses relevant specifications, with emphasis on the required sampling rates for the temporal bandwidth of a given application and mention a wish-list for a more widespread use of the technology.