Towards Tailored Composite Bonded Repairs (BONDPAIR)

走向定制复合粘合修复 (BONDPAIR)

• 批准号: EP/N021975/1
• 负责人: Kali Babu Katnam
• 金额: $ 12.65万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FN021975%2F1
• 关键词: Towards; Tailored; Composite; Bonded; Repairs

Advanced composites are currently being used in aircraft structures (primary and secondary components) to a significant extent (e.g. 50% by weight in Boeing 787, Airbus A350 and Bombardier C-Series). For these new generation of aircraft structures with large composite components, the existing repair technology must be significantly improved to fabricate robust, reliable and certifiable repairs for restoring damaged (e.g. impact loads) primary structural components. It is important to note that primary aircraft structural components are critical to aircraft structural integrity and safety. The primary components are highly loaded and relatively thick (ranging from ~3 mm to ~25 mm) with several laminae having different fibre orientations, and thus require advanced repair design and fabrication techniques to restore the original structural/operational conditions. In this regard, current repair design and fabrication approaches need to be significantly improved for repairing primary composite aircraft structures. As mechanically fastened composite repairs are not ideal for polymer composite structures because of the stress concentrations induced by fasteners, bonded scarf repairs, which can provide high joint efficiency and aerodynamic surface finish, offer opportunity to improve composite repair methodology and thus have greater potential for aircraft repairs. The extent of material damage is often uncertain and depends on the source/nature of damage. The amount of material that needs to be removed from the parent component for a scarf repair not only depends on the amount of material damaged but also the geometrical parameters (e.g. patch shape, scarf angle) of the patch designed. A significant amount of undamaged material around the damaged region needs to be machined in order to achieve the designed patch geometry. In addition, the amount of undamaged material removed can have an adverse effect on a component that is designed to take high stresses. To minimize the removal of undamaged material from the component, the design of scarf repairs should be tailored for a given repair condition. On the other hand, novel fabrication techniques need to be developed to achieve complex patch geometries (e.g. accurate machining of parent laminate, curing of a mating patch).In this context, the proposed research is focused towards tailored composite bonded repairs to primary composite structures using non-conventional scarf patch geometries. The project aims to (a) develop a novel infusion-based repair methodology to fabricate scarf repairs using easy-to-store materials (carbon fibre fabric, thermoplastic veils) without pre-preg and film adhesives, (b) minimize the amount of undamaged material from the parent component by incorporating non-conventional patch geometries for enhancing parent-patch interface stress distribution, and (c) characterising failure behaviour of tailored scarf repairs and comparing with conventional scarf repairs. The ambition of this research project is to develop scientific pathways that will enable future repair technologies, especially tailored for primary composite components in aircraft structures.

先进复合材料目前在很大程度上(例如波音787、空中客车A350和庞巴迪C系列中50%的重量)被用于飞机结构(主要和次要部件)。对于这些具有大型复合材料部件的新一代飞机结构，必须显著改进现有的维修技术，以制造出坚固、可靠和可认证的维修来恢复受损(如冲击载荷)的主要结构部件。值得注意的是，飞机的主要结构部件对飞机的结构完整性和安全性至关重要。主要部件负荷高且相对较厚(从~3 mm到~25 mm)，有几个具有不同纤维取向的薄板，因此需要先进的修复设计和制造技术来恢复原始的结构/操作条件。在这方面，目前的修复设计和制造方法需要显著改进，以修复主要的复合材料飞机结构。由于紧固件引起的应力集中，机械紧固复合材料修复对于聚合物复合材料结构来说并不理想，因此粘结围巾修复可以提供高连接效率和气动表面光洁度，为改进复合材料修复方法提供了机会，因此在飞机修复方面具有更大的潜力。物质损害的程度往往是不确定的，取决于损害的来源/性质。围巾修复需要从母部件上移除的材料量不仅取决于损坏的材料量，还取决于所设计的补丁的几何参数(例如，补丁形状、围巾角度)。为了达到设计的贴片几何形状，需要对受损区域周围的大量未受损材料进行机械加工。此外，未损坏材料的去除量可能会对设计为承受高应力的零部件产生不利影响。为了最大限度地减少部件上未损坏的材料，围巾修复的设计应针对给定的修复条件量身定做。另一方面，需要开发新的制造技术来实现复杂的贴片几何形状(例如，母层压板的精确加工，匹配贴片的固化)。在这一背景下，拟议的研究集中在利用非传统的围巾贴片几何形状对主要复合材料结构进行定制的复合材料粘接修复。该项目旨在(A)开发一种新的基于输液的修复方法，使用易于储存的材料(碳纤维织物、热塑性面纱)制作围巾修复，而不使用预浸胶和薄膜粘合剂，(B)通过采用非传统贴片几何结构来增强母体-补片界面的应力分布，最大限度地减少母体组件未损坏的材料的量，以及(C)描述定制围巾修复的失效行为，并与传统围巾修复进行比较。该研究项目的雄心是开发科学途径，使未来的维修技术成为可能，特别是为飞机结构中的主要复合材料部件量身定做。

项目成果

Towards balancing in-plane mechanical properties and impact damage tolerance of composite laminates using quasi-UD woven fabrics with hybrid warp yarns

• DOI: 10.1016/j.compstruct.2019.111083
• 发表时间: 2019-10-01
• 期刊: COMPOSITE STRUCTURES
• 影响因子: 6.3
• 作者: Katnam, K. B.;Dalfi, H.;Potluri, P.
• 通讯作者: Potluri, P.

Intra-laminar toughening mechanisms to enhance impact damage tolerance of 2D woven composite laminates via yarn-level fiber hybridization and fiber architecture

• DOI: 10.1002/pc.25325
• 发表时间: 2019-12-01
• 期刊: POLYMER COMPOSITES
• 影响因子: 5.2
• 作者: Dalfi, Hussein;Katnam, Kali B.;Potluri, Prasad
• 通讯作者: Potluri, Prasad

Tailoring Bonded Scarf Repairs in Composite Structures

复合结构中粘合围巾的剪裁修复

• 发表时间: 2017
• 作者: Wu Z