1995 年 44 巻 507 号 p. 1433-1438
This study dealt with the tensile strength and fracture mechanism of quasi-isotropic carbon/epoxy laminates with different stacking sequence. The stacking sequences employed in this study were [0/±45/90]s, [0/+45/90/-45]s, [0/90/±45]s, [±45/0/90]s, [±45/90/0]s, [90/0/±45]s and [90/±45/0]s. The maximum load of each quasi-isotropic laminate showed a higher value than that of  laminate.
Splitting failure in 0° layer, shear fracture in 45° layer and delamination initiated from the cracks in 90° layer were dominant fracture patterns in quasi-isotropic carbon/epoxy laminates, and their control was important to improve the laminate strength. Especially the suppression of the splitting failure in 0° layer was most important for the improvement of laminate strength because the load bearing capacity of 0° layer was the highest among all layers. The laminates with 0° layer placed at the inner layer showed higher strength because the splitting failure in 0° layer was suppressed sufficiently. The shear fracture in 45° layer initiated from the cracks in 90° layer also affected the laminate strength. The [90/±45/0]s laminate showed the highest strength among the laminates employed in this study, since the suppression of the fracture in 0° layer and of the fracture progress from the cracks in 90° layer is realized well. From the viewpoint of the suppression of fracture, it was verified that the application of interleaf was effective for the improvement of laminate strength of quasi-isotropic carbon/epoxy laminates.