Fiber Optic Sensor Attachment Development and Performance Evaluations

摘要

Research conducted in the Flight Loads Laboratory (FLL) at the NASA Dryden Flight Research Center (DFRC) has subjected fiber optic (FO) sensors to hostile environments for in-flight applications and hot-structures ground testing (on hypersonic or reentry vehicles). Sensor attachment of both Fiber Bragg Gratings (FBG) and silica-based Extrinsic Fabry-Perot Interferometers (EFPI) have been accomplished on metallic and composite substrates. The FO sensors have been successfully demonstrated: 1) at room and elevated temperatures (to 1850 F); 2) with combined applied thermal and mechanical loads; and 3) and on both small laboratory coupons and large-scale structures for ground testing. Further development has been initiated to enhance the upper temperature limit for measuring strains. Current ceramic composite materials are to be used for structural load-bearing components and have applications in temperatures as high as 3000 F. A means for taking measurements on these materials at their maximum operating temperature is desired to validate models and ultimately minimize the size and mass of vehicle components.