This work examines the crack-arresting capability of PEI and PVDF thermoplastic interlayers in short-glass fiber modified and core–shell rubber toughened epoxy materials under mode-I fracture loading. Experimental results show that the initial crack can be effectively arrested by the thermoplastic-epoxy interface and reinitiation of this crack at the thermoplastic layer requires up to 2.5 times higher load than the crack initiation load of the pristine epoxies. The interlayered designs also exhibit a significant increase in energy absorption by up to 43 times more than their pristine counterparts. Competing damage mechanisms and failure events are captured by microscopy images, digital image correlation and high-speed photography observations. Additionally, elasto-plastic fracture mechanics models based on configurational material forces theory are developed for a preliminary crack-arresting material selection and to elucidate the material inhomogeneity effects.

中文翻译：

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具有薄 PEI 和 PVDF 夹层的结构环氧树脂的耐损伤行为

这项工作研究了短玻璃纤维改性和核壳橡胶增韧环氧材料中 PEI 和 PVDF 热塑性夹层在 I 型断裂载荷下的止裂能力。实验结果表明，热塑性塑料-环氧树脂界面可以有效地阻止初始裂纹，并且在热塑性层上重新引发该裂纹需要比原始环氧树脂的裂纹萌生载荷高出 2.5 倍的载荷。夹层设计的能量吸收能力也显着提高，比原始设计高出 43 倍。通过显微图像、数字图像相关和高速摄影观察来捕获竞争性损坏机制和故障事件。此外，还开发了基于构型材料力理论的弹塑性断裂力学模型，用于初步止裂材料选择并阐明材料不均匀性影响。