Optical fiber strain gauges for high-cycle fatigue monitoring of ceramic matrix composite materials

Abstract

Optical fiber sensing techniques are ideal for applications where high-temperature, electromagnetic interference, or vibration cause traditional electrical sensors to become unreliable. Gold-coated, silica-based optical fibers can withstand temperatures up to 900 degrees C and sapphire fibers can be employed for temperatures as high as 2000 degrees C. We present dynamic strain and temperature measurements of ceramic matrix composite specimens using extrinsic Fabry-Perot interferometric fiber optic strain and temperature sensors. The extremely low-mass and rugged construction of the sensors will allow them to survive high- cycle, high-temperature fatigue testing.