Measurement of thermal strain inside motor specimens using optical fiber sensor

In early 1990, optical fiber sensor was focused on as the sensor of a monitoring system and it started to be applied to the measurement various physical value of an architectural and civil structures. But, thermal strain of structures has not been measured so much although the heat is important. The thermal strain of the mortar specimen was measured using fiber Bragg Grating sensor(FBG sensor). Strain gauge was used for verifying data measured by FBG sensor. Three different thermal strains were measured in one mortar specimen.