CIRCULAR MANUFACTURING
Main objective is to research the differences in joining techniques and resulting overall quality of the different joints, applied to the material combinations under research. The aspects include joining for production of assemblies as well as improving conditions and economics for repair and EOL (End of Life), disassembly and recycling.
This will be achieved by applying circular concept design aspects:
- Casting process development for near-net shape metal test elements (additive manufacturing)
- Joining of metal test elements
- Joining of composite with metal test elements
- Joining of thermoplastic 1st and 2nd life composite test elements
- Joining of morphing elastomeric materials
The outcomes should advance circular economy concepts and solutions in aircraft manufacturing, tackling problems of waste and resource efficiency to minimise demand for materials and energy.
A database with test results for the several joining techniques, material combinations and sensors, both for new and recycled material will be created to allow for comparison of the techniques and quick referencing for individual joint properties.
SUSTAINair incorporates three key enabling technologies for manufacturing:
Online process monitoring of induction and conduction welding of thermoplastic composite structures
This key enabling technology focusses on alternative temperature measurement techniques and approaches which do not affect final weld properties and can therefore also be implemented during welding of final parts.
The driving forces behind the increased use of thermoplastic composite materials in fixed-wing and other aircraft, lie in their superior impact toughness, excellent thermal stability and – for most thermoplastic materials – their chemical resistance. The aim is to advance welding of different consolidated thermoplastic subcomponents into a single unit using an induction welding process reducing the need for fasteners or adhesives to reduce the overall assembly weight and improve material re-cyclability.
Advanced near-net shape manufacturing (additive manufacturing) of nano-eutectic aluminium alloys providing repairable, laser-welded structural assemblies
SUSTAINair joining technology includes combining novel alloy classes with advanced processing (light metal die-casting) and conventional joining technologies. As casting omits almost all material losses, the buy-to-fly ratio of structural assemblies can be greatly reduced compared to the state of art. Replacing steel-/titanium-based rivets by weld seams can further increase the specific performance of these sections, the ultimate vision of the project being a structurally and chemically fully integral fuselage of wing assembly.
Design combined nano- and macro-structures for joint interfaces of dissimilar materials
Taking into account the 1st and 2nd life composite and metal materials, SUSTAINair performs research on adhesive bonding technologies exploiting surface engineering and pre-treatment of the joint interfaces. Laser pre-treatments with pin-structured joints will be combined to produce reliable, high performance bonds.
In particular, the focus is on the mechanical and degradation behaviour (e.g. hydro-thermal aging and influence of media such as salt solutions or fuels). Both are strongly linked to the surface properties generated by the interface pre-treatments. Characterization methodologies including laser and electron scanning microscopies, as well as mechanical testing facilities (e.g. lap- shear testing) will be used to develop the long-term, stable adhesive joints.
NLR will be developing the online process for the monitoring of welding thermoplastic composite structures in collaboration with DTC.
AIT-LKR will work on advanced near-net shape manufacturing (additive manufacturing) of nano-eutectic aluminium alloys providing repairable, laser-welded structural assemblies in collaboration with JOANNEUM and DLR.
DLR will carry out research on adhesive bonding technologies focusing on surface design of the metallic parts with inputs by AIT-LKR, and TU Delft.
INVENT will work on joining of metal to thermoset composites, manufacturing of flexible joints, and technology demonstrator in collaboration with all partners.
TU Delft, AIT-LKR and DLR will test the joints for the different material combinations.