A composite aero-structure with self-repair capabilities would offer durability, extend its service life and amend maintenance protocols, potentially leading to lower aircraft operational costs. Despite the extensive research activities in the area of self-healing resins applied to composite materials, the research for aeronautical applications is currently very limited. To this end, the main objective of Hipocrates is the development of self-repair composite materials by transforming widely used resins within aeronautical industry to self-healing materials.
On 20 November 2013 delegates from Fundacion Tecnalia Research & Innovation (ES), TNO Eindhoven (NL), Applied Mechanics Laboratory/University of Patras (GR), GMI Aero (FR), SupraPolix (NL), Inasco Hellas (GR), Centro Tecnológico L'Urederra (ES), Aarnnova Aerospace (ES), University of Ioannina (GR), ACCIS/University of Bristol (UK) and Element Materials Technology Hitchin (UK), gathered in San Sebastian, Spain, to officially kick-off the research work of a European project.
The activity, funded under the EU Framework Program 7 (contract no.605412), is titled Self-healing polymers for concepts on self-repaired aeronautical composites (named Hipocrates in honour of the father of healing). It is a 36-month activity, targeting the development of self-healing strategies and material developments, from chemistry to final composite processing, for delivering aeronautical composite parts with self-repair. It is expected that the developments shall have a high potential for spill-out effects to other application industries where composites find use.
Given the current technological level of maturity of self-repair, secondary structural composites will be targeted, focussing on epoxy enrichment with appropriate chemical agents, and following three main strategies:
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Nano-encapsulation (incorporation of nano-encapsulated healing agents and a dispersed catalyst within a polymer matrix)
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Reversible polymers strategy where remediable polymer matrices render damage repairable through triggered reversible cross-linking (Diels-Alder chemical reactions)
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Combinations of these technologies will be tried for the first time.
Manufacturing challenges that arise from incorporating such self-healing thermosetting systems into fibrous composites (prepreg, infusion/RTM) will be closely investigated to ensure effective transfer of desired properties to the large scale needed by industrial processes.
Element’s role within the 11-strong consortium will be to design and develop impact, fracture and fatigue mechanical tests to assess the efficiency of the self-healing process.
Rick Sluiters, Element’s VP of Europe Operations, says: “This research will also benefit all Element aerospace testing teams, as the knowledge gained and new test methodologies innovated will be shared across our global network of experts and laboratories."
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