This paper presents the results of drop-weight impact testing (5 J to 30 J) on curved ±55° E-glass-epoxy laminates of varying radii and wall thickness. Three radii (75 mm, 100 mm, and 125 mm) on laminates with an effective wall thickness of 2.5 mm, and three wall thicknesses (2.5 mm, 4.1 mm, and 6.6 mm) with a radius of 100 mm were investigated. The damage pattern remained consistent, with the exception of the damage area, across the tested energies and was dominated by internal matrix cracking and multiple delaminations. However, no damage was recorded following a 5 J impact on the 2.5 mm thick laminates with 100 mm and 125 mm radii, all energy was absorbed elastically, while the laminate with a 75 mm radius of curvature developed a damage area of over 80 mm². The thicker laminates showed a reduced overall damage area but a greater number of delaminations. The relationship between laminate thickness and delamination threshold load was found to be in line with impact testing of flat plates, varying with the laminate thickness to the 3/2 power. However, the simplified beam theory and a fracture mechanics model developed for the prediction of delamination threshold of flat plates was found to underestimate the delamination threshold load (DTL) of the curved laminates studied by about 40%. An increase in the laminate’s flexural modulus of a factor of two is required to bring the model’s predictions in line with the DTL values measured experimentally, highlighting how curvature can enhance bending stiffness and alter damage evolution. Finally, a significant finding is that the DTL of the curved plates is around 15% lower than the value measured for the whole cylindrical pipe of same specifications. Testing curved sections rather than a whole pipe could reduce effort, but further work is required to confirm this statement.

本文介绍了在不同半径和壁厚的±55°弯曲E-玻璃-环氧层压板上进行落锤冲击试验（5 J至30 J）的结果。研究了有效壁厚为2.5毫米的层压板上的三个半径（75毫米，100毫米和125毫米）和半径为100毫米的三个壁厚（2.5毫米，4.1毫米和6.6毫米）。在整个测试能量范围内，除损坏区域外，损坏模式均保持一致，并且主要由内部基体裂纹和多次分层引起。但是，在半径为100 mm和125 mm的2.5 mm厚层压板受到5 J冲击后，没有记录到损坏，所有能量都被弹性吸收，而曲率半径为75 mm的层压板的损坏面积超过80 mm ²。较厚的层压板显示出减小的总损坏面积，但分层数量较多。发现层压板厚度和分层阈值载荷之间的关系与平板的冲击测试一致，其随层压板厚度变化至3/2次方。然而，发现用于预测平板的脱层阈值的简化梁理论和断裂力学模型低估了所研究的弯曲层压板的脱层阈值载荷（DTL）40％。为了使模型的预测值与实验测得的DTL值保持一致，需要将层压板的弯曲模量增加两倍，以强调曲率如何增强弯曲刚度并改变损伤演变。最后，一个重要的发现是，弯曲板的DTL比相同规格的整个圆柱形管的测量值低15％左右。测试弯曲部分而不是整个管道可以减少工作量，但是需要进一步的工作来确认这一说法。