ABSTRACT This paper investigates the effect of glass fibre orientation on the impact damage evolution and post-impact residual strength of glass/epoxy laminates, using mechanical and acoustic emission (AE) analysis. The glass fibre reinforced polymer (GFRP) composite laminates with stacking sequence such as 0°, 90°, [±45°] and [0°/90°] were tested. The indentation-induced damage behaviour was examined in GFRP composite laminates by conducting drop weight impact and quasi-static indentation (QSI) tests to induce barely visible impact damage (BVID). Both tests provided essentially the same results for damage modes, dent depth, back surface crack size and load-deflection history. Mechanical parameters such as peak force, incident energy, absorbed energy, rebound energy and linear stiffness were used for the quantification of the indentation response. The AE parameters, such as amplitude, rise time, counts and energy were considered for monitoring damage progression during QSI loading. Also, other parameters linked to AE monitoring, such as the rise angle (RA), Felicity ratio (FR) and sentry function (SF) were measured for evaluating damage progression in each cycle of indentation. These results showed the [±45°] laminates having higher indentation damage resistance compared to other fibre orientation, whereas residual compressive strength was high for 0° laminates.

中文翻译：

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基于AE监测的循环压痕载荷下玻璃纤维取向对抗冲击损伤影响的实验研究

摘要 本文研究了玻璃纤维取向对玻璃/环氧树脂层压板的冲击损伤演变和冲击后残余强度的影响，使用机械和声发射 (AE) 分析。对玻璃纤维增​​强聚合物（GFRP）复合材料层压板进行了0°、90°、[±45°]和[0°/90°]等堆叠顺序的测试。通过进行落锤冲击和准静态压痕 (QSI) 测试以诱导几乎不可见的冲击损坏 (BVID)，在 GFRP 复合层压板中检查压痕诱导的损坏行为。两种测试在损伤模式、凹痕深度、背面裂纹尺寸和载荷-挠度历史方面提供了基本相同的结果。机械参数如峰值力、入射能量、吸收能量、回弹能量和线性刚度用于量化压痕响应。AE 参数，如振幅、上升时间、计数和能量被考虑用于监测 QSI 加载期间的损坏进展。此外，还测量了与 AE 监测相关的其他参数，例如上升角 (RA)、Felicity 比 (FR) 和哨兵函数 (SF)，以评估每个压痕循环中的损坏进展。这些结果表明，[±45°] 层压板与其他纤维取向相比具有更高的抗压痕损伤能力，而 0° 层压板的残余压缩强度较高。测量幸福比 (FR) 和哨兵功能 (SF) 以评估每个压痕循环中的损伤进展。这些结果表明，[±45°] 层压板与其他纤维取向相比具有更高的抗压痕损伤能力，而 0° 层压板的残余压缩强度较高。测量幸福比 (FR) 和哨兵功能 (SF) 以评估每个压痕循环中的损伤进展。这些结果表明，[±45°] 层压板与其他纤维取向相比具有更高的抗压痕损伤能力，而 0° 层压板的残余压缩强度较高。