Carbon fiber-reinforced plastics (CFRP), which is expected to reduce the weight of transportation vehicle, was cut by laser irradiation with a CO_2 gas laser (0.8kW, 20kHz, 8μs, v=lm/min) and CW single-mode fiber lasers (0.3kW, CW, v=lm/min; 2kW, CW, 7m/min), and conventional machining with a diamond sawing (v=0.12m/min). The effect of cut process on the cutting quality, tensile/fatigue properties under high-temperature of 110℃ and moisture environments with relative humidity of 50% was investigated for cross-ply [0/90] CFRP. The static tensile and fatigue tests were conducted in moisture environments using a materials testing system developed for simulating severe environments. The laser-cut specimens identified a thermal damage with micro-crackings by a micro X-ray CT. The tensile and fatigue strjpnth decreased with introducing the temperature and the humidity.
