Abstract Delamination is a common failure mode observed in fiber reinforced polymeric composites subjected to thermo-mechanical loads. Reinforcements at the interlaminar regions or in the through-thickness direction have been previously shown to improve the damage resistance and durability of these composites. In particular additive manufacturing (AM), also called 3D printing, has been shown to increase the interlaminar shear strength when used for custom printing of polymer reinforcements over carbon fiber prepreg prior to the layup process of layered composites. In this paper, printing of interlaminar polymer reinforcements using fused deposition modeling (FDM) technique within AM is proposed for improving the interlaminar fracture toughness of carbon fiber laminates. The rationale behind this improvement in the interlaminar fracture toughness values due to printed polymer reinforcements (PPR) is investigated by elucidating the influence of varying the process parameters, such as print speed, spacing, and dimensions. An in-depth understanding of the bond quality between the prepregs and the printed polymers as well as the interlaminar fracture surfaces formed on the Mode-II fracture toughness values are established by developing an experimentally validated thermo-chemical finite element modeling framework.

中文翻译：

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通过增材制造提高聚合物基复合材料的 II 型层间断裂韧性

摘要 分层是在承受热机械载荷的纤维增强聚合物复合材料中观察到的常见失效模式。之前已经证明层间区域或厚度方向的增强材料可以提高这些复合材料的抗损伤性和耐久性。特别是增材制造 (AM)，也称为 3D 打印，已被证明在层状复合材料的叠层过程之前用于在碳纤维预浸料上定制打印聚合物增强材料时，可以提高层间剪切强度。在本文中，提出了在 AM 中使用熔融沉积建模 (FDM) 技术打印层间聚合物增强材料，以提高碳纤维层压板的层间断裂韧性。通过阐明不同工艺参数（例如印刷速度、间距和尺寸）的影响，研究了由于印刷聚合物增强材料 (PPR) 而导致层间断裂韧性值提高的基本原理。通过开发经过实验验证的热化学有限元建模框架，可以深入了解预浸料和印刷聚合物之间的粘合质量以及在模式 II 断裂韧性值上形成的层间断裂表面。