Measurements of Temperature and Residual Strain during Fatigue of a CFRP Composite Using FBG Sensors

摘要

Fatigue behaviour is a major point for structural materials. In this paper temperature and residual strain during fatigue of a carbon fiber reinforced polymer (CFRP) are measured. CFRP beam specimens, with fiber Bragg grating (FBG) sensors and thermocouples embedded at selected locations, are subjected to three-point bending cyclic loading at 0.1Hz, 1Hz, 10Hz and 20Hz. Thermocouples are used to measure the temperature while FBGs can sense the temperature and strain as welL From the experimental results, transient steep peaks of temperature increases (up to 2.3°C) are discovered at the beginning of loading. The temperature increments due to fatigue are around 1.0°C, which are not relevant to frequencies from 0.1Hz to 20Hz. The residual strains of 10με-20 με during fatigue are reported, independent of loading frequency and FBG location.