Periodic Reporting for period 3 - SUSTAINair (SUSTAINablility increase of lightweight, multifunctional and intelligent airframe and engine parts)
Berichtszeitraum: 2024-01-01 bis 2024-06-30
SUSTAINair is dedicated to improving the environmental impacts caused by an aircraft throughout its entire life cycle and taking up the challenge to foster innovation on Circular Economy in the aviation industry by researching on application of recycled materials and optimized resource efficiency. Commercial aviation contributes 2-3% of the world’s manmade emissions of CO2 with transportation as a whole producing ~24% according to the UN Intergovernmental Panel on Climate Change (IPCC). SUSTAINair addresses the major challenge of GREENING OF AIRCRAFT – in a way, that environmental benefits are meeting economic viability and European competitiveness at once. A large scale of synergies allowed the consortium to focus on eight Key Enabling Technologies (KETs), each of which is targeting challenging Key Performance Indicators (KPIs). Validation of these KPIs was performed individually per KET, as well as in an integral manner by means of three demonstrators, showcasing and evaluating all investigated KETs.
SUSTAINair project efforts are organized in 5 technical workpackages (WP1-5), that directly reflect the S&T objectives. Additionally, there are Work Packages for DEC and Project Management Efforts (WP6 & 7).
The first period of the project was centred around progressing individual material technologies in combination with advancing processing routes to enable the projected recycling scenarios, based on a diligent definition of mechanical testing scenarios and general design requirements. Intensive work was carried out on developing future cast and wrought aluminium alloys with enhanced recyclability. Lab-scale and industrial scale casting was applied, with equivalent material properties. A first generation of performance-enhanced Al-Mg-Si alloys was produced and characterized. AM of Titanium powders was performed using virgin and recycled powder feedstock, first correlations between LPBF feedstock “age” and material performance could be obtained. CFRP upcycling development was performed for thermoset and thermoplastic secondary resources and a variety of recyclate grades from real production wastes were investigated for both material categories. First joining trials have been performed, for metal as well as thermoplastic and thermoset composites. Titanium samples with additively manufactured pins have been joined with thermoset composite sheets and single lap shear (SLS) tests have been performed. For the metal and thermoset composite parts, both 1st and 2nd life materials have been considered and a variety of process parameters screened. Next-gen SHM systems, damage modes and -propagation were analyzed, novel sensors and their structural integration progressed beyond state of the art. Potential SHM methods were reviewed, selected, further developed, and numerically and experimentally validated on component level. The original plan to provide beyond lab-scale proof of feasibility of the “automated rivet removal robot head” was re-defined relying on water jet cutting.
During P2 period, SUSTAINair partners completed most of the technical tasks and started to transfer their findings to designing and manufacturing of 3 different demonstrators. Further development of sustainable manufacturing, recycling and characterization of the processed materials was achieved. Rivet removal experiments have been carried out, including investigation in scanning techniques and cutting strategies for automated dismantling. Intensive studies were carried out on upcycling and the derived new recyclate materials were characterized and investigated, concluding in a LCA for the novel processes. SHM methods were successfully demonstrated and used in the final cyclic tests with promising findings regarding the further sensor development. Extensive joining tests were performed, for metal as well as thermoset and thermoplastic composites and hybrid combinations, considering both first and second life materials. The strength of the joints was tested to quantify the performance of 2nd life materials compared to their 1st life counterparts. With M19 of SUSTAINair, the realization of a total of 3 different demonstrators started, showcasing all of the 8 KETs investigated. Manufacturing activities were initiated, alongside preparation of individual test and assessment plans of all demonstrator variants.
The 3rd and final project period fully focused on the manufacturing and evaluation of all 3 demonstrators and enforced DEC efforts. Despite some delays to the original timeplan, all sought technical work could be completed successfully and in time with only minor deviations towards the DoA. DEC activities culminated in the organization of a conference on circular aviation, where all outcomes of the project were presented and discussed. Dialogue with stakeholders from the aviation industry was also continued in the EEAB with industry experts and cooperation with EASA on the potential standardization of SUSTAINair´s findings.
The first period of the project was centred around progressing individual material technologies in combination with advancing processing routes to enable the projected recycling scenarios, based on a diligent definition of mechanical testing scenarios and general design requirements. Intensive work was carried out on developing future cast and wrought aluminium alloys with enhanced recyclability. Lab-scale and industrial scale casting was applied, with equivalent material properties. A first generation of performance-enhanced Al-Mg-Si alloys was produced and characterized. AM of Titanium powders was performed using virgin and recycled powder feedstock, first correlations between LPBF feedstock “age” and material performance could be obtained. CFRP upcycling development was performed for thermoset and thermoplastic secondary resources and a variety of recyclate grades from real production wastes were investigated for both material categories. First joining trials have been performed, for metal as well as thermoplastic and thermoset composites. Titanium samples with additively manufactured pins have been joined with thermoset composite sheets and single lap shear (SLS) tests have been performed. For the metal and thermoset composite parts, both 1st and 2nd life materials have been considered and a variety of process parameters screened. Next-gen SHM systems, damage modes and -propagation were analyzed, novel sensors and their structural integration progressed beyond state of the art. Potential SHM methods were reviewed, selected, further developed, and numerically and experimentally validated on component level. The original plan to provide beyond lab-scale proof of feasibility of the “automated rivet removal robot head” was re-defined relying on water jet cutting.
During P2 period, SUSTAINair partners completed most of the technical tasks and started to transfer their findings to designing and manufacturing of 3 different demonstrators. Further development of sustainable manufacturing, recycling and characterization of the processed materials was achieved. Rivet removal experiments have been carried out, including investigation in scanning techniques and cutting strategies for automated dismantling. Intensive studies were carried out on upcycling and the derived new recyclate materials were characterized and investigated, concluding in a LCA for the novel processes. SHM methods were successfully demonstrated and used in the final cyclic tests with promising findings regarding the further sensor development. Extensive joining tests were performed, for metal as well as thermoset and thermoplastic composites and hybrid combinations, considering both first and second life materials. The strength of the joints was tested to quantify the performance of 2nd life materials compared to their 1st life counterparts. With M19 of SUSTAINair, the realization of a total of 3 different demonstrators started, showcasing all of the 8 KETs investigated. Manufacturing activities were initiated, alongside preparation of individual test and assessment plans of all demonstrator variants.
The 3rd and final project period fully focused on the manufacturing and evaluation of all 3 demonstrators and enforced DEC efforts. Despite some delays to the original timeplan, all sought technical work could be completed successfully and in time with only minor deviations towards the DoA. DEC activities culminated in the organization of a conference on circular aviation, where all outcomes of the project were presented and discussed. Dialogue with stakeholders from the aviation industry was also continued in the EEAB with industry experts and cooperation with EASA on the potential standardization of SUSTAINair´s findings.
For aluminium recycling alloys, the concept of nanoeutectics was expanded, linking the typical base system of automotive value streams, i.e. Al-Mg-Si with a significant share of the aviation EoL bandwith by actively utilizing large Zn-additions. Beyond, the method was also applied to incorporate Iron (Fe) as an active ingredient enhancing the alloys properties, thereby fitting the material composition to realistic EoL waste stream compositions. The resulting alloy, AlMg6Si2Zn3FeNi could meet the KPIs proposed. Further incorporation of Cu (and Mn) was outlined on basis of thermodynamic calculus. This completed the projects overarching goal of providing a material for high performance parts from universal aluminium waste streams. A broad range of such alloys can significantly reduce Europe’s dependency on non-domestic primary Al resources, next to offering a three to fivefold direct reduction in processing energy consumption. Failure modes in recycled, hence by definition short fibre CFRP-materials impose unprecedented challenges towards robust design of such structures. By simultaneously advancing production routes and applying advanced characterization of failure in this materials, robust processing windows become available, elucidating the performance limits of fully recycled fibre reinforced materials. To enable the integral design of subassemblies in line with circular economy concepts, the focus of SUSTAINair is on welding and bonding techniques, thus replacing rivets at maximum. As could be proven on microstructural scale, e.g. nanostructured eutectic aluminium alloys show no weakening of joining interfaces. Structural assemblies that are to date milled from large precursors at immense material losses can be designed and produced by combining near net-shape at equal performance. Choosing the same base of alloys (Al-Mg-Si) for both cast and wrought substructures puts omitting rivets overall within reach in future generation aircraft. Next to advancing SHM and MRO methodology for all material classes described, realizing novel sensor generations that can be integrated into assemblies without reducing cyclability of structures in EoL will allow to reduce safety margins (in particular with respect to secondary feedstock utilization) in product/structural design without compromising safety.