The quasi-static loading-unloading performance of thin ply carbon-epoxy ${[\pm {26}_5]}_{\text{s}}\text{,}{[\pm {27}_5]}_{\text{s}}$ and ${[\pm {26}_5/0]}_{\text{s}}$ laminates is presented. Consistent experimental results allow the reduction in laminate modulus to be evaluated using three different methods: secant modulus of each loading cycle; a secant modulus up to a constant stress, and the initial tangent modulus of reloading. It is shown, via all three methods, that these layups can undergo multiple cyclic loadings and display excellent retention of stiffness. The ${[\pm {26}_5/0]}_{\text{s}}$ layup displays a limited modulus reduction, despite the gradual failure of the $0°$ layers. The ${[\pm {\theta }_5]}_{\text{s}}$ specimens do not display any decrease in initial modulus and effectively suppress damage accumulation (shown via X-ray CT imaging), which both suggest that the stress–strain behaviour of these layups is ductile, rather than pseudo-ductile.

薄层碳环氧树脂的准静态装卸性能 ${[\pm {26}_5]}_{\text{s}}\text{，}{[\pm {27}_5]}_{\text{s}}$ 和 ${[\pm {26}_5/0]}_{\text{s}}$介绍了层压板。一致的实验结果允许使用三种不同的方法评估层压板模量的降低：每个加载周期的割线模量；直至恒定应力的割线模量，以及重新加载的初始切线模量。通过所有三种方法显示，这些叠层可以经受多次循环载荷，并表现出出色的刚度保持能力。这${[\pm {26}_5/0]}_{\text{s}}$ 铺层显示出有限的模量降低，尽管 $0°$层。这${[\pm {\theta }_5]}_{\text{s}}$ 样品没有显示出初始模量的任何下降，并有效地抑制了损伤积累（通过X射线CT成像显示），这都表明这些叠层的应力-应变行为是延性的，而不是假延性的。