GOALI: Inter-Laminar Toughening of Composite Structures: Bonding Mechanisms and Delamination Resistance

这个学术界与工业界联系的资助机会（GOALI）研究项目研究了聚合物基复合材料层间增韧的新工艺。 对增韧复合材料结构的需求来自于优先的平面纤维/基体脆性脱粘（分层）。 该方法旨在通过将韧性热塑性聚合物夹层紧密地结合到层片和热固性环氧树脂基质上，在每个现有应力集中部位附近的纤维织物层片之间局部地整合韧性热塑性聚合物夹层。 通过（1）热熔融粘合热塑性夹层与纤维以深度包封纤维，和（2）在随后的真空辅助树脂传递模塑固化中扩散粘合热塑性夹层与热固性基质，实现紧密粘合。 分析将产生显着的洞察力的耦合效应的纤维夹层和夹层基体粘结的断裂韧性和抗分层预制复合材料。研究界面的润湿和粘性流动行为以及热固性-热塑性相互扩散动力学将阐明这些结合机制的相互作用。 该项目的预期结果将为设计和制造具有更大抗分层性的更高效复合材料部件开辟新方向。 PI与主要工业合作伙伴的密切互动将通过特定应用的层压板制造和测试促进热塑性交织方法的快速发展，从而提高重要可再生能源的竞争力，从而产生更广泛的社会影响。 如果大型锥形层压复合材料（如风力涡轮机叶片）的韧性得到增强，则更长的叶片和更高的风力涡轮机将有助于降低成本、扩大风能使用并减少环境影响。 从这项工作中获得的工艺知识和建模发展可以扩展到广泛的材料制造技术，如不同材料的连接和密封：热固性热塑性基体复合材料粘合，热固性基体复合材料与金属粘合。

This Grant Opportunity for Academic Liaison with Industry (GOALI) research project investigates a novel process for the inter-laminar toughening of polymer matrix composites. The need to toughen composite structures arises from the preferential planar fiber/matrix brittle de-bonding (delamination). The method aims to locally integrate a tough thermoplastic polymer interleaf between fiber fabric plies near each existing stress concentration site by intimately bonding it to the plies and the thermoset epoxy matrix. The intimate bonding is achieved through (1) hot melt bonding the thermoplastic interleaf with fibers to deeply encapsulate the fibers, and (2) diffusively bonding it with the thermoset matrix in the subsequent vacuum assisted resin transfer molding curing. Analysis will yield significant insights into the coupled effects of fiber-interleaf and interleaf-matrix bonding on the fracture toughness and delamination resistance of preform composites. Investigation into the interface resolved wetting and viscous flow behaviors as well as thermoset-thermoplastic inter-diffusion kinetics will elucidate interactions underlying these bonding mechanisms. The expected results from this project will develop new directions for the design and fabrication of more efficient composite components with greater delamination resistance. The PI's close interaction with a key industrial partner will lead to the rapid development of the thermoplastic interleaving method through application-specific laminate fabrication and testing, leading to greater competitiveness of an important renewable energy source and thus broader societal impact. If the toughness of large, tapered laminate composites such as wind turbine blades is enhanced, longer blades and taller wind turbines will help reduce cost, spread wind energy usage, and reduce environmental impact. Process knowledge and modeling developments gained from this work may be extended to a wide range of material fabrication techniques such as dissimilar materials joining and sealing: thermoset-thermoplastic matrix composite bonding, and thermoset matrix composite to metals bonding.