抄録
Considering the space environment, it is important to study the effects of thermal cycling on the damage progress behavior and mechanical properties of CFRP. In the present study, thermal cycling tests are performed on CFRP laminates first. After thermal cycling tests, tensile tests are conducted at room temperature. The purposes of the present study are to investigate damage progress behavior in CFRP laminates under thermal cycle loading experimentally and to discuss the effects of thermal cycles on the matrix cracking behavior under tension in CFRP
laminates. The specimens are (0/90/0), (0/90)s and (0/902)s for T 700 S/2500 and (0/90)s for T 800 H/3631. Thermal cycling tests are performed up to 1000 cycles. During the thermal cycling tests, the specimens are observed periodically by the replica technique and the X-ray to investigate matrix crack behavior. In all the laminates, matrix cracking is observed during thermal cycling. The matrix crack density is defined as the number of cracks per unit specimen length. It is found experimentally that the increasing rate of matrix crack density is higher in the laminates with thinner 90°ply. The crack growth rate is measured as a function of the matrix crack length. The thicker the thickness of 90°ply is, the larger the crack growth rate is. This matrix crack behavior is correlated to the energy release rate calculated by the finite element analysis. To discuss the effects of thermal cycles on matrix cracking under tension, tensile tests after thermal cycles are performed. In tensile tests, matrix crack density is measured as a function of the laminate strain. The effect of the number of thermal cycles on matrix cracking is investigated experimentally. It is found that the effect of thermal cycles on matrix crack behavior can be evaluated as a change in the critical values stress and energy release rate for matrix cracking.
