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Increasing resource efficiency of aviation through implementation of ALM technology and bionic design in all stages of an aircraft life cycle

Periodic Reporting for period 2 - Bionic Aircraft (Increasing resource efficiency of aviation through implementation of ALM technology and bionic design in all stages of an aircraft life cycle)

Reporting period: 2018-03-01 to 2019-08-31

To reduce the impact of the growing aviation industry on European citizens, there is the need to reduce emissions in all successive phases of an aircraft lifecycle. This demanding task can only be achieved by implementing innovative (green) technologies and corresponding methodologies and concepts. Additive Layer Manufacturing (ALM) enables new design methodologies for lightweight structures, flexible and resource-efficient production of highly complex and low volume parts, innovative and resource-efficient supply chains and logistic concepts for manufacturing, repair, spare-part production as well as recycling and disposal. In addition, ALM technologies enable great weight saving potential for structural components and significant reduction of material waste during production. With the introduction of high strength aluminium alloys even greater weight saving becomes possible. The weight and waste reduction through the introduction of ALM will significantly reduce CO2 and NOx emissions.
One major challenge of ALM is the time consuming and expensive design process for bionic optimized parts. In many cases the high costs for development and manufacturing of bionic optimized parts prevent the application of ALM, limiting the energy- and resource-efficiency of the aircraft. The overall project goal of BionicAircraft is therefore to contribute to resource efficiency of aviation throughout the whole aircraft life cycle, based on Additive Layer Manufacturing (ALM). Three specifically designed demonstrators are used in the project to verify the achievement of the project objectives.
An automated and simplified design process has been determined for biomimetic lightweight structures. A toolset for a commercial 3D-CAD software has been developed, which allows a seamless workflow from the part design to the ALM pre-processing and post processing steps. It enables an automated bionic feature recognition based on a catalogue of parameterized structures, which was also developed in the frame of the project. A business plan has been developed for transfer to industrial applications.

The ICP atomization method was successfully transferred from standard Al alloys to high strength Al alloys. The high-strength AlSiSc alloy processed in the end of the first reporting period delivered superior mechanical properties and processability.The share of powder usable for ALM process was increased from 63% at the project start to 74%. In parallel small particle size fractions which are waste material, could be reduced by 10 %.

The ALM test rig has been developed and used to verify simulation models and optimize the laser beam profiles towards enhanced process stability and productivity. Overall it was possible to demonstrate that a productivity increase of 35% was achieved for the new high-strength AlSiSc material using innovative beam shaping optics.The successsful developments will increase the applicability of the process in the aviation industry, leading to more resource efficiency in aviation. An action plan has been developed in order to develop ALM parameter sets for highly productive and resource efficient ALM processes that can be commercialized in the future.

An in-line integrity system was developed to validate the quality of complex ALM parts directly after manufacturing. This allows to detect defects below the surface and to measure the outer geometry of the workpiece simultaneously. A business plan for the in-line ultrasonic detection of complex shaped components has been developed.

To be able to already check the integrity of an ALM part during the building process, an in-process integrity system based on the Strucutred Light 3D technology was developed. In the course of the project multiple technical solutions for in-service NDT methods have been evaluated. The most promising solutions are advanced ultrasonic testing as well as diffuse dome light inspection.

The overall applicability of ALM to the after sales supply chain has been explored, and new business models to reduce inventory, increase competiveness and increase market offering have been elaborated. The most promising ones were combined to a new concept, the Additive Manufacturing Marketplace. Based on this a new end-to-end process was developed, which unwraps a new way of handling the supply chain by introducing ALM as a niche in the current supply chain operations without replacing the existing end-to-end process.

Thermal Spraying has been found most promising for resource efficient and cost competitive repair of the new Al-based parts. Properties are only slightly below of those of the original material. Major advantages might be linked to the possible increase of the fracture properties of the repaired component.

The ICP spheroidization process has proven the capability to refurbish used ALM powder and enhancing its physical properties, thereby reducing the waste of powders following ALM production. It was shown that powders could be reused up to 18 times with only marginal effects on the porosity, hardness and tensile properties of the resulting ALM parts. An action plan has been developed to further investigate the ICP spheroidization technique with the ultimate goal to qualify the recycling method for the aerospace industry.
A bionic feature catalogue and an automated bionic design toolset were developed, allowing seamless integration of bionic features in the part design inside the the CATIA environment. The design of the demonstrator parts for ALM including topology optimization and introduction of bionic design features showed weight savings of up to 28% compared to the standard parts.

The ICP powder manufacturing process developed lead to an increase in the range of powder usable for ALM from 63% (state of the art at the project beginning) to 75%. This increease in productivity and resource efficiency will lead to cost savings in powder manufacturing of up to 15%.

The as-built mechanical properties of the newly developed high-strength Al powder processed by ALM were in the range of 550-598 MPa UTS and 3-5% elongation. Heat treatment was successfully developed to increase elongation to up to 7%. The mechanical properties correspond to an increase in UTS for AlSiSc of 20% compared to the industrial standard Al alloy.

Due to the development of beam shaping optics, the productivity of the ALM process for the Al-Si-Sc alloy was increased by 30%. Furthermore the energy efficiency increased by 35% due to the reduction in spatter in the process. Together with the increase in productivity and stability, a significant broadening of the processing window was achieved by using the innovative beam shaping optics.

The thermal spraying process has emerged as a new way of repairing damaged components. Measured toughness values were up to 50% higher than the one of the reference material used nowadays for the construction of structural aircraft parts.

Based on the weight savings achieved on the Bionic Aircraft demonstrators (27.5%), an overall weight reduction potential of 625 kg per aircraft can be derived ig ALM is implemented widely in the production of structural aerospace parts. This corresponds to a potential decrease in CO2 consumption of 886.000 tons per aircraft and year. Assuming an aircraft life cycle of 30 years the CO2 pollution of a fleet of 300 aircrafts representing a major airline could be reduced by 266 million tons or 27,1 %.
The BionicAircraft Resource Efficiency Cycle