STRAIN AND DAMAGE MONITORING OF POLYMER MATRIX COMPOSITE MATERIALS AT ELEVATED TEMPERATURES USING FIBER OPTIC SENSORS

摘要

A study employing a unique experimental test protocol is conducted to investigate the capability of fiber-Bragg grating sensors to monitor strain and detect damage in polymer matrix composites at elevated temperatures. An advanced interrogation system and an optical spectrum analyzer are utilized to track the variation in the optical fiber wavelength and the wavelength spectrum for correlation with strain gage measurements and with observed damage. Static tension tests indicate that optical sensors accurately measure axial strain when compared to a conventional strain gage. Tension-tension fatigue testing suggests that these optical sensors are capable of continuously monitoring strain and tracking the stiffness loss of a specimen during cyclic loading. Their ability to detect mechanical damage at elevated temperatures is however limited at this stage. Results show that employing optical sensors for elevated temperature applications appears to be promising, but additional work is necessary to confirm this discovery.