Additive Manufacturing of Bonded Joints by Continous Fibre Deposition for the Aerospace Industry

PECRE Award Holder: Dr Francisca Martinez-Hergueta, University of Edinburgh

Exchange Host: IMDEA Materials Institute, Spain

Composite materials for aeronautic applications is a growing market which is expected to reach £1250 million in 2030 (Composites Leadership Forum, 2016). Composites are lightweight materials which contribute towards greener energy generation and transportation, a key feature of EU environmental policies (Clean Sky, 2017). Furthermore, the emerging additive manufacturing techniques have strong potential to reduce the weight of the current aircraft (Aerospace Technology Institute, 2017). They offer boundless possibilities to tailor structural components and it could transform manufacturing, assembling and repair operations as known today. Identified applications include manufacturing of panels with geometric discontinuities, 3D printed bonded joints or in-situ patch repairs.

My aim is to use additive manufacturing to improve the mechanical performance of structural components and help the composites industry to overcome the current limitations to fulfill certification requirements. This research focuses on a particular application: replacement of riveted panels by 3D printed adhesively bonded joints. Bonded joints are an efficient method to produce large components. They allow the assembly of dissimilar materials and maintain the integrity of panels as there are no holes to weaken the structure. However, they also present stress concentrations near the ends of the bondline, resulting in a premature failure of the joint. Continuous fibre deposition additive manufacturing can produce stiffness-tailored joints and ensure redistribution of shear stresses, improving fracture toughness with respect to commercial structural adhesives.

The overarching objective of the project is to analyse the performance of bonded joints manufactured by additive continuous fibre deposition. Manfacturing techniques for single lap shear specimens will be developed and stifness-tailored sequences will be investigated to improve the fracture toughness and determine the configuration which optimises the strength of the joint. Industrial applications will be finally evaluated with IMDEA Materials Institute.