Periodic Reporting for period 3 - RIB-AM (Research of Innovative and Breakthrough Additive Manufactured leading-edge concept)
Periodo di rendicontazione: 2021-11-01 al 2022-10-31
RIB-AM project contributes to the CS2 objectives with development of novel manufacturing technologies applied to large size components belonging to the primary structure of aircrafts. The final goal is to design and manufacture a leading typical edge structure. Within set of manufacturing techniques stand out the AFP using thermoplastic resins that will be used for skin manufacturing. At present, AFP in situ component manufacturing process was discarded, as the associated WP lead partner failed to develop the technology to required maturity. Oven consolidation technology has been chosen as leading-edge manufacturing process.
Main Objectives
Objective 1 (O1): Manufacturing of Leading Edge skin with long fibre reinforced thermoplastic by AFP. Objective has been affected: will be obtained by oven
Objective 2 (O2): Material development and FDM processing of short fibre reinforced high temperature and high performance polymers
Objective 3 (O3): Topology optimization of leading edge ribs
Objective 4 (O4): Inductive welding for reinforced thermoplastic
Objective 5 (O5): Hybrid structure integration
Objective 6 (O6): Development of inspection methodology of hybrid and complex geometries based on fast Non-Destructive Techniques
Objective 7 (O7): Development of novel Leading Edge concept based on advanced manufacturing and integration techniques
Main Objectives
Objective 1 (O1): Manufacturing of Leading Edge skin with long fibre reinforced thermoplastic by AFP. Objective has been affected: will be obtained by oven
Objective 2 (O2): Material development and FDM processing of short fibre reinforced high temperature and high performance polymers
Objective 3 (O3): Topology optimization of leading edge ribs
Objective 4 (O4): Inductive welding for reinforced thermoplastic
Objective 5 (O5): Hybrid structure integration
Objective 6 (O6): Development of inspection methodology of hybrid and complex geometries based on fast Non-Destructive Techniques
Objective 7 (O7): Development of novel Leading Edge concept based on advanced manufacturing and integration techniques
RIBAM proposes the development of novel in-situ technologies for manufacturing complex aeronautic composite parts, by out of autoclave approaches, and join them with induction and adhesives processes.
The project is challenging because of the technologies involved, the aeronautic requirements imposed, and the involved materials and processes development level. The targeted component has been a leading edge structure, kept as a goal from the beginning of the project until the end. It is composed of the skin and the ribs, to be joined by induction welding process.
For the skin of the part, a high performance reinforced thermoplastic was selected, for its consolidation by Automated Fibre Placement with in situ consolidation. This first approach had to be dismissed due to the low TRL of the proposed technology. The final solution for panels and leading edge skin fabrication was oven consolidation.
Even when considering a conventional technology, the high curvature of the surface brought strong difficulties to deliver the part without defects. The material involved, and the processes investigated in this project present a medium level of industrialization for highly curved surfaces with aeronautic requirements.
On the other hand, ribs were obtained by the additive manufacturing technology proposed, after deep research on the material and an optimization of the process. A research field of investigation is now open for increase the TRL, including post-processes and support strategies during fabrication.
The main limitation related to the ribs came from the mechanical properties of the material proposed and the behavior against bird-strikes events. It does not reach the desirable performance and therefore, the use of the ribs for flying purposes was dismissed for primary structures. However, it can be considered for secondary or auxiliary structures. The manufacturing process was proved to be robust enough to manufacture full scale components through additive manufacturing, several parts with enough repeatability.
RIBAM project has allowed the investigation of the induction welding process for dissimilar composites, obtained by different manufacturing technologies. It can be concluded that, even when the joints present an acceptable performance (compared to co-curing processes), repeatability is still far from an industrialization step. The spot size of the welding area must be improved in terms of the affected zone and the control of its dimension.
As a conclusion, RIBAM has allowed to investigate, maturate and propose solutions at demonstrator level for the application of novel manufacturing and assembly technologies with the main goal of in-situ manufacture dissimilar thermoplastic materials, joint them in a quick and flexible way, avoiding mechanical joints, and apply the developments to complex geometries such a Leading Edge with high level of curvature.
Examples of dissmination activities are the publication by DMRC of a scientific paper entitled “Investigation of specific FDM process parameters to optimize the polymer discharge of carbon fibre reinforced PEEK", published in "Macromolecular Symposia”; and the participation of CATEC in the national conference of composites materials, hold on the 21-23 of June 2022 at Seville. CATEC shared the results obtained by the characterization of the material developed in RIBAM for additive manufacturing purposes.
The project is challenging because of the technologies involved, the aeronautic requirements imposed, and the involved materials and processes development level. The targeted component has been a leading edge structure, kept as a goal from the beginning of the project until the end. It is composed of the skin and the ribs, to be joined by induction welding process.
For the skin of the part, a high performance reinforced thermoplastic was selected, for its consolidation by Automated Fibre Placement with in situ consolidation. This first approach had to be dismissed due to the low TRL of the proposed technology. The final solution for panels and leading edge skin fabrication was oven consolidation.
Even when considering a conventional technology, the high curvature of the surface brought strong difficulties to deliver the part without defects. The material involved, and the processes investigated in this project present a medium level of industrialization for highly curved surfaces with aeronautic requirements.
On the other hand, ribs were obtained by the additive manufacturing technology proposed, after deep research on the material and an optimization of the process. A research field of investigation is now open for increase the TRL, including post-processes and support strategies during fabrication.
The main limitation related to the ribs came from the mechanical properties of the material proposed and the behavior against bird-strikes events. It does not reach the desirable performance and therefore, the use of the ribs for flying purposes was dismissed for primary structures. However, it can be considered for secondary or auxiliary structures. The manufacturing process was proved to be robust enough to manufacture full scale components through additive manufacturing, several parts with enough repeatability.
RIBAM project has allowed the investigation of the induction welding process for dissimilar composites, obtained by different manufacturing technologies. It can be concluded that, even when the joints present an acceptable performance (compared to co-curing processes), repeatability is still far from an industrialization step. The spot size of the welding area must be improved in terms of the affected zone and the control of its dimension.
As a conclusion, RIBAM has allowed to investigate, maturate and propose solutions at demonstrator level for the application of novel manufacturing and assembly technologies with the main goal of in-situ manufacture dissimilar thermoplastic materials, joint them in a quick and flexible way, avoiding mechanical joints, and apply the developments to complex geometries such a Leading Edge with high level of curvature.
Examples of dissmination activities are the publication by DMRC of a scientific paper entitled “Investigation of specific FDM process parameters to optimize the polymer discharge of carbon fibre reinforced PEEK", published in "Macromolecular Symposia”; and the participation of CATEC in the national conference of composites materials, hold on the 21-23 of June 2022 at Seville. CATEC shared the results obtained by the characterization of the material developed in RIBAM for additive manufacturing purposes.
RIB-AM project is driving the establishment of additive methods in the aeronautical industry. On one hand, the AM technology applied to primary and large structures with thermoplastic resins reinforced with short-fibres. It will allow the manufacture of complex shape parts belonging to major structural elements. RIBAM has been proven that the mechanical performance of the material is not high enough to be used in primary structures, however it is a promising alternative for secondary structures, brackets, spacers, etc. Where the use of 3D printing, and the possibility of welding will bring flexibility to the assembly process in aeronautic.
On the other hand, AFP for the long fibre reinforced thermoplastic material with in situ consolidation. The use of this kind of resins with high temperature consolidation is not fully developed due to manufacturing difficulties. The implementation of thermoplastic composites improves the mechanical and impact performance, enabling the optimization of these structures. By the in-situ consolidation (out of autoclave) it could be expected a reduction of electricity and consumable costs, as well as the lead time associated to this activity. However, as it has been proved in RIBAM, AFP with in-situ consolidation using such materials is not fully ready for its implementation in complex geometries such as leading edge.
Currently, the welding process proposed in RIBAM, together with the investigations of hybrid joints between metallic and thermoplastics, are being studied at sample level. The results will allow to evaluate these novel materials and technologies in future industrial applications.
The technologies developed within RIB-AM project will take Europe to the cutting edge of the materials technology for additive methods with high performance resins.
According to the proposal, the expected impact of RIBAM are focused on:
-Structural weight reduction: currently, a reduction of 45% of the original FDM rib design has been obtained. Apart of that additional reduction is expected by removing mechanical joints, that will be evaluated by the end of the project.
-Reduction of non-recurrent costs (NRC): In RIBAM, NRC saving comes from the manufacturing of the rib, where no tooling is necessary because of the FDM process, therefore a 100% of reduction can be obtained at this regard.
-Minimization and simplification of inspection protocols: by avoiding drilling of the structure, removing specific inspections on drills. Only skin material, and Ribs will be evaluated through NDI.
-Parts delivery time reduction: by using in situ consolidation processes such as FDM process (3D printing). 70% quicker than a conventional LE rib.
On the other hand, AFP for the long fibre reinforced thermoplastic material with in situ consolidation. The use of this kind of resins with high temperature consolidation is not fully developed due to manufacturing difficulties. The implementation of thermoplastic composites improves the mechanical and impact performance, enabling the optimization of these structures. By the in-situ consolidation (out of autoclave) it could be expected a reduction of electricity and consumable costs, as well as the lead time associated to this activity. However, as it has been proved in RIBAM, AFP with in-situ consolidation using such materials is not fully ready for its implementation in complex geometries such as leading edge.
Currently, the welding process proposed in RIBAM, together with the investigations of hybrid joints between metallic and thermoplastics, are being studied at sample level. The results will allow to evaluate these novel materials and technologies in future industrial applications.
The technologies developed within RIB-AM project will take Europe to the cutting edge of the materials technology for additive methods with high performance resins.
According to the proposal, the expected impact of RIBAM are focused on:
-Structural weight reduction: currently, a reduction of 45% of the original FDM rib design has been obtained. Apart of that additional reduction is expected by removing mechanical joints, that will be evaluated by the end of the project.
-Reduction of non-recurrent costs (NRC): In RIBAM, NRC saving comes from the manufacturing of the rib, where no tooling is necessary because of the FDM process, therefore a 100% of reduction can be obtained at this regard.
-Minimization and simplification of inspection protocols: by avoiding drilling of the structure, removing specific inspections on drills. Only skin material, and Ribs will be evaluated through NDI.
-Parts delivery time reduction: by using in situ consolidation processes such as FDM process (3D printing). 70% quicker than a conventional LE rib.