The detection of first ply fracture and the analysis of failure mechanism of the CFRP have been carried out by acoustic emission(AE) measurements. X-ray, optical microscopy during tensile test of [0˚8]， [90˚8] and [0˚/90˚8/0˚] CFRP laminates. ln the case of [90˚8] ply, the failure of the CFRP laminate was found to initiate by intraply matrix cracking(mode I) of the 90˚ ply. ln the case of [0˚8] ply, the initial damage was confirmed by X-ray and 0˚ ply crack (mode II) propagating parallel to the fiber orientation. Much of modeⅡ crack and delamination were found to grow simultaneously, in the cross ply laminates. The amplitude of AE signal by modeⅠ crack is about 10 times lower than that by modeⅡ crack.

The detection of first ply fracture and the analysis of failure mechanism of the CFRP have been carried out by acoustic emission(AE) measurements. X-ray, optical microscopy during tensile test of [0˚8]， [90˚8] and [0˚/90˚8/0˚] CFRP laminates. ln the case of [90˚8] ply, the failure of the CFRP laminate was found to initiate by intraply matrix cracking(mode I) of the 90˚ ply. ln the case of [0˚8] ply, the initial damage was confirmed by X-ray and 0˚ ply crack (mode II) propagating parallel to the fiber orientation. Much of modeⅡ crack and delamination were found to grow simultaneously, in the cross ply laminates. The amplitude of AE signal by modeⅠ crack is about 10 times lower than that by modeⅡ crack.