Abstract
Small-diameter fiber Bragg grating (FBG) sensors were embedded into the 90°ply on the border of the lower 0°ply of carbon fiber reinforced plastic (CFRP) cross-ply [0_4/(90)_4/0_4] laminates. When impact loading was applied to the specimens with a drop-weight impact tester, reflection spectrum from the sensors changed sensitively. In order to clarify these results, the spectrum was simulated theoretically. Furthermore, the intensity ratio of two peaks in the spectrum was found to be a good indicator for the quantitative evaluation of impact damage in real time.
