"Repair of Thermoplastic Composites: Processing, Modelling and Characterization"

为了成功实现下一代公务和商用飞机的成本和重量降低，必须研究新的先进结构材料。热塑性复合材料有可能降低成本和重量，与热固性复合材料相比具有一些优势，例如更好的损伤容限。这一优势使它们成为可能受到冲击损坏的应用的理想选择，例如机翼前缘。开发了热固性复合材料的修复方法。在粘合修复的情况下，损坏的复合材料层从部件表面去除，并在表面上应用新的预浸渍层。然后通过施加热量和压力来实现材料的固化。就热塑性复合材料而言，目前正在更换损坏的部件而不是进行修复，这会带来相关的负面成本和环境影响。缺乏对热塑性复合材料修复的研究也限制了它们在小型部件上的使用，因为更换大型复杂的航空航天结构部件将变得非常昂贵。鉴于上述情况，该研究项目旨在通过建模、加工和表征来开发修复高性能热塑性复合材料结构的方法。将研究热塑性复合材料焊接接头的长期环境退化和老化，并开发创新的制造技术来修复热塑性复合材料，同时考虑到其独特的再加工或再焊接能力。这将包括修复因冲击而在焊缝中产生的分层或修复更严重的损坏，例如更换复合材料部件的多个层，始终以恢复部件的初始机械性能为目标。制造技术将与预测聚合物在重新加工或重新焊接时的固结、结晶度和降解的过程模型相关联。这项工作将为加拿大航空航天业提供高性能热塑性复合材料结构的修复方法，从而实现成本降低和积极的环境影响。

To successfully achieve cost and weight reduction in the next generations of business and commercial airplanes, new advanced structural materials must be investigated. Thermoplastic composite materials have the potential to lead to such cost and weight reductions with some advantages over thermosetting composites like their better damage tolerance. This advantage makes them ideal candidates for applications in which impact damage is likely, e.g., wing leading edges. Repair methods were developed for thermosetting composites. In the case of bonded repairs, the damaged composite plies are removed from the component's surface and new pre-impregnated plies are applied on the surface. Curing of the material is then achieved by applying heat and pressure. When it comes to thermoplastic composites, the damaged components are currently being replaced instead of being repaired, with associated negative cost and environmental impacts. The lack of research done on repair of thermoplastic composites also limits their use to small components as it would become very expensive to replace a large and complex aerospace structure component. In light of the above, this research program aims to develop methodologies for repairing high performance thermoplastic composite structures by means of modelling, processing and characterization. The long-term environmental degradation and ageing of thermoplastic composite welded joints will be investigated and innovative manufacturing techniques will be developed to repair thermoplastic composites, taking into account their unique ability to be re-processed or re-welded. This will include repair of delamination created in a weld line by impact or repair of more severe damage, e.g., replacement of several plies of a composite components, always with the goal of restoring the initial mechanical properties of the component. The manufacturing techniques will be linked to process models that predict the consolidation, crystallinity and degradation of the polymer as it is re-processed or re-welded. This work will provide Canadian aerospace industry with repairing methods for high performance thermoplastic composite structures, thus achieving cost reduction and positive environmental impact.