Induction Melt Incremental Thermoforming of Advanced Thermoplastic Composites

先进热塑性复合材料的感应熔融增量热成型

• 批准号: EP/X02766X/1
• 负责人: Philip Harrison
• 金额: $ 85.39万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX02766X%2F1
• 关键词: Induction; Melt; Incremental; Thermoforming; Advanced

Transport is responsible for around a quarter of the UK's total greenhouse gas emissions. Light-weight recyclable materials, such as thermoplastic composites, are recognised as a sustainable solution to reducing transport emissions via "light-weighting". Thermoplastic composites have several advantages over their thermosetting polymer composite cousins, including faster processing, improved recyclability and increased toughness, though they are more challenging to process which partly explains their smaller market share (~1/3rd that of thermosets). Consequently, there is an urgent need to address the manufacturing issues to realise their full weight and fuel saving potential. However, forming advanced thermoplastic composites into complex geometries is not always straightforward and production defects such as wrinkling, bridging and tearing of the forming sheet are commonplace.The main idea of the project is to develop a novel sheet forming process for advanced thermoplastic composites designed to mitigate manufacturing defects when thermoforming multi-axial laminates into complex geometries. This will be achieved through the creation of wrinkle-resistant 'lubricated-blanks' using a combination of induction heating and a novel incremental forming process. Typically, to achieve optimum mechanical properties in composites structures, placement of fibres in multiple directions is required to accommodate complex loading conditions. However, despite the development of sheet forming processes for advanced composites dating back over 30 years, questions regarding production defects have yet to be satisfactorily answered, namely: 'How to form complex components from pre-consolidated multi-axial thermoplastic laminates without inducing wrinkles?' and 'How to form highly complex geometries involving multiple recesses, without bridging or tearing of the forming laminate?' The proposed research combines two distinct new ideas. The first is to create a 'lubricated blank', using induction heating and melting of metallic inter-layers placed within the forming composite sheet to facilitate ultra-low inter-ply sliding friction and consequently, wrinkle-free forming of multi-axial pre-consolidated advanced thermoplastic composites. The electromagnetic properties of certain metals coupled with their high surface tension and low viscosity when molten mean they can be used as a medium with which to both inductively heat and lubricate the forming composite blank, thereby preventing wrinkles. The second idea is to use a multi-step forming tool designed to create an automatic sequential and incremental forming process in a single press-forming down stroke, beginning at the centre and subsequently moving outwards towards the perimeter of the sheet. The multi-step forming tool serves to both mitigate bridging and tearing and crucially, squeezes the molten metal out of the composite layup (like squeezing toothpaste from a tube!) and into the surrounding rubber diaphragm during the thermoforming process, leaving the final consolidated composite part almost completely free of embedded metallic inclusions.

交通运输占英国温室气体排放总量的四分之一左右。轻质可回收材料，如热塑性复合材料，被认为是通过“轻量化”减少运输排放的可持续解决方案。与热固性聚合物复合材料相比，热塑性复合材料具有几个优势，包括更快的加工速度，更好的可回收性和更高的韧性，尽管它们的加工更具挑战性，这部分解释了它们较小的市场份额（约为热固性材料的1/3）。因此，迫切需要解决制造问题，以实现其全部重量和节省燃料的潜力。然而，将先进热塑性复合材料成形为复杂的几何形状并不总是那么简单，并且成形片材的起皱、桥接和撕裂等生产缺陷是常见的。该项目的主要思想是开发一种用于先进热塑性复合材料的新型片材成形工艺，旨在减少将多轴向层压板热成形为复杂几何形状时的制造缺陷。这将通过使用感应加热和一种新的增量成形工艺相结合的耐磨损的“润滑坯料”的创造来实现。通常，为了在复合材料结构中实现最佳的机械性能，需要在多个方向上放置纤维以适应复杂的载荷条件。然而，尽管先进复合材料的片材成型工艺的发展可以追溯到30多年前，但关于生产缺陷的问题尚未得到令人满意的回答，即：“如何从预固结的多轴向热塑性层压材料形成复杂的部件而不引起褶皱？如何形成高度复杂的几何形状，包括多个凹槽，而不桥接或撕裂成形层压板？“这项研究结合了两个不同的新想法。第一种是制造“润滑坯料”，使用感应加热和熔化放置在成形复合材料片材内的金属夹层，以促进超低的层间滑动摩擦，从而无摩擦地成形多轴预固结的先进热塑性复合材料。某些金属的电磁特性与其熔融时的高表面张力和低粘度相结合，意味着它们可以用作介质，利用该介质感应加热和润滑成形复合材料坯件，从而防止起皱。第二个想法是使用多步成形工具，该多步成形工具被设计成在单个压制成形向下冲程中创建自动顺序和增量成形过程，从中心开始，随后向外朝向片材的周边移动。多步成型工具既可以减轻桥接和撕裂，也可以将熔融金属从复合材料层压中挤出（就像从管中挤出牙膏一样！）并在热成型过程中进入周围的橡胶隔膜，使得最终的固结复合部件几乎完全没有嵌入的金属夹杂物。