抄録
Considering the space environment, it is important to study the effects of thermal cycling on the mechanical properties of composite materials. It is known that composite laminates subjected to thermal cycling suffer from matrix cracking. In the present study, thermal cycling induced matrix cracking in CFRP laminates is investigated experimentally. A carbon/epoxy system, T300/2500, is used. Laminate configurations are (0/90)s, (90/0)s and (±45)s. The specimens are thermally cycled between -196℃ and 100℃ Thermal cycling tests are performed up to 1000 cycles. During the thermal cycling test, the polished edge surfaces of specimens are examined by the replica technique to detect microscopic damages. The matrix crack density is measured as a function of the number of thermal cycles. The number of thermal cycles at initial cracking in (0/90)s and (90/0)s are similar and smaller than that in (±45)s. The matrix crack density increases more rapidly in (0/90)s than in (90/0)s. The matrix crack density growth rate in (±45)s is smaller than those in (0/90)s and (90/0)s. Tensile tests are performed on the specimens subjected to the thermal cycling. To discuss the matrix cracking behavior under tension after thermal cycles, the critical energy release rate and the critical stress for matrix cracking are evaluated. The effect of thermal cycles on matrix cracking under tension can be evaluated by the change in the critical energy release rate and the critical stress.
