I-Corps: Development of Self-healing, Fiber-reinforced Composites

I-Corps项目更广泛的影响/商业潜力是开发自修复纤维增强复合材料（FRC）。该技术可用于在使用过程中自动修复分层损伤，从而提高现代结构的耐久性和寿命。在全球范围内，FRC是先进材料技术中规模最大、发展最快的领域之一。这种增长源于FRC在广泛行业的众多高性能应用，包括航空航天，国防，绿色能源，汽车，船舶，基础设施和电子产品。在高价值应用中使用的许多复合材料结构是多层层压板，在多年（长达30年）的服务中暴露在重复应力下。所提出的自修复复合材料是专门针对防止这些层压复合材料结构过早失效和延长使用寿命。此外，自修复FRC还提供了一种更可持续的途径，延长了使用寿命，增强了弹性和耐久性，使这种材料在复合材料行业中特别有吸引力，因为复合材料的维护和更换以及相关的停机时间成本很高。航空航天等行业也可能从增强的安全性中受益，在这些行业，最终用户报告了易分层部件的问题，包括旋翼机叶片和其他具有压降和紧固件孔的部件，这些部件会出现应力集中。I-Corps项目基于自修复纤维增强复合材料（FRC）平台的开发，该平台通过热修复实现原位自修复。所提出的方法依赖于可修复的热塑性塑料（TP），将其直接3d打印到编织纤维增强材料上，并与碳基电阻加热器共层压。在低于复合材料热固性基体玻璃化转变的温度下，图案化TP表现出高熔体流动和自加压的局限性微裂纹传递。快速（分钟级）原位热修复是通过电阻加热完成的。在增强材料上直接印刷TP会增加界面粘合，从而导致热塑性界面相的粘合失效。测试结果表明，与普通复合材料相比，i型断裂韧性提高了4倍，并且在持续循环次数（100+）的情况下，通过动态重粘，其自修复性能保持一致（高达100%）。与之前的技术相比，通过提出的原位热修复策略可以实现长时间的恢复，这代表了自修复可重复性的一个数量级飞跃。此外，用于自我修复的复合材料增强材料保留了机械性能，并与现有的制造工艺兼容，这两者对于最终的商业化都至关重要。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this I-Corps project is the development of self-healing fiber-reinforced composites (FRC). The proposed technology may be used to autonomously repair delamination damage during service, thereby enhancing the durability and longevity of modern structures. Globally, FRC represent one of the largest and fastest growing sectors of advanced materials technology. This growth stems from the numerous high-performance applications for FRC in a broad range of industries that include aerospace, defense, green energy, automotive, marine, infrastructure and electronics. Many of the composite structures used in the highest value applications are multi-layer laminates that are exposed to repeated stresses over multiple years (up to 30) of service. The proposed self-healing composite is specifically aimed at preventing premature failure in these laminated composite structures and extending service life. In addition, self-healing FRC also provide a more sustainable pathway that prolongs service life and enhances resilience and durability, making such materials particularly attractive in composite industries where maintenance and replacement and associated downtime are costly. Industries such as Aerospace also may benefit from enhanced safety, where end-users have reported issues with delamination-susceptible parts including rotorcraft blades and other components featuring ply-drops and fastener holes where stress concentrations arise.This I-Corps project is based on the development of a self-healing fiber-reinforced composites (FRC) platform that achieves in situ self-healing via thermal re-mending. The proposed approach relies on mendable thermoplastic (TP) that is 3D-printed directly onto woven fiber reinforcement and co-laminated with carbon-based resistive heaters. The patterned TP exhibits high melt-flow and self-pressurization for confined micro-crack delivery at temperatures below the glass-transition of the composite thermoset matrix. Rapid (minutes-scale) in situ thermal re-mending is accomplished via resistive heating. Printing TP directly on the reinforcement increases interfacial bonding, resulting in a cohesive failure through the thermoplastic interphase. Test results show a four-fold increase in mode-I fracture toughness over a plain composite, and a consistent self-healing performance (up to 100%) via dynamic re-bonding for sustained cycle counts (100+). The prolonged recovery made possible via this proposed in situ thermal re-mending strategy represents an order of magnitude leap in self-healing repeatability compared to prior technologies. In addition, the composite augmentations for self-healing preserve mechanical properties and are compatible with existing manufacturing processes, both of which are critical for eventual commercialization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.