Additive manufacturing (AM) of continuous yarn-reinforced biobased composites presents multi-functional properties and low environmental impact of this technology. Few studies focused on the mechanical damage mechanisms of continuous biobased composites obtained by AM processes, while it is a topic of high interest for the mastery of mechanical behaviors and optimization of the materials for high requirement applications. This study aims to assess the damage and fracture modes of continuous flax yarn-reinforced PLA manufactured by AM, with different yarn orientations. The additively manufactured biobased composites were characterized by tensile test, 3D microscopy and micro-tomography to link the process-structure-properties relationships regarding the damage and fracture modes. The results showed that the 0° manufactured composite had a significant enhancement of tensile properties compared to other configurations. The damage mechanism presented fiber rupture with polymer transverse cracks at 0°, while the 45° and 90°-oriented composites showed premature fiber/matrix interface debonding. This study aims to find the relationship between damage mechanisms, deposition strategy, and anisotropy of the additively manufactured long vegetal fibers-reinforced biobased composite materials. The results bring a new understanding of the anisotropy and defects in printed composite materials regarding their mechanical behaviors during damage.

中文翻译：

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通过喷嘴内浸渍增材制造 3D 打印连续亚麻纤维增强复合材料的损伤和断裂研究


连续纱线增强生物基复合材料的增材制造（AM）呈现出该技术的多功能特性和低环境影响。很少有研究关注通过增材制造工艺获得的连续生物基复合材料的机械损伤机制，而对于掌握机械行为和优化高要求应用的材料来说，这是一个备受关注的话题。本研究旨在评估采用增材制造技术制造的不同纱线取向的连续亚麻纱线增强 PLA 的损伤和断裂模式。通过拉伸测试、3D 显微镜和显微断层扫描对增材制造的生物基复合材料进行表征，以将损伤和断裂模式的工艺-结构-性能关系联系起来。结果表明，与其他配置相比，0° 制造的复合材料的拉伸性能显着增强。损伤机制表现为纤维断裂并在0°处出现聚合物横向裂纹，而45°和90°取向的复合材料则表现出纤维/基体界面过早脱粘。本研究旨在寻找增材制造的长植物纤维增强生物基复合材料的损伤机制、沉积策略和各向异性之间的关系。这些结果使人们对印刷复合材料在损坏期间的机械行为的各向异性和缺陷有了新的认识。