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Full scale innovative composite windows frames for Regional Aircraft fuselage barrel on-ground demonstrators

Periodic Reporting for period 2 - WINFRAME 4.0 (Full scale innovative composite windows frames for Regional Aircraft fuselage barrel on-ground demonstrators)

Reporting period: 2020-03-01 to 2021-02-28

The WINFRAME 4.0 project was part of the CleanSky 2 initiative and dealed with the manufacturing of composite frames made in thermoplastics.
Regarding composite materials, the main current focus of the industry is on thermoset based composites, for many reasons, among it:
• Thermoset composites have been used in the aerospace industry since the 1960s, and the design and processing knowledge to exploit the materials has developed substantially.
• Major investments have been made in material property databases for thermoset composite man-rated aerospace applications.
• In many cases these databases are treated as company proprietary intellectual property, which makes it difficult to justify investment in alternate materials and processes.
• Industries associated with reinforcement that utilizes thermoset-compatible sizing is mature, including weaving and conversion into prepreg.
• Capital equipment and support services, such as tooling and semi-automation methodologies, are well established.
As expected with a maturing technology, major thermoset composite technology innovations and cost reduction opportunities are less frequent, with some notable exceptions.
Aircraft designers are using more lightweight composite structures to reduce fuel consumption, however, the application of composites in aerospace is not being driven by reductions in costs for composite materials or processing. Today, the most considered cost reductions are coming in the form of fuel savings and not part costs.
One projected breakthrough in the composites industry cost equation is expected to involve the large-scale manufacture of continuous fiber thermoplastic composites.
Potentially thermoplastics can offer improved raw materials and processing costs, as well as improved functional performance, but needs to be developed the processes in which autoclave is not needed, in theory, all processes but in practice, today in some cases, such as AFP with in-situ consolidation are still under development and so some autoclave cycle is needed to finish the part.
Press molding, as well called compression molding, as well sometimes named thermoforming is a process, which is among the quick processes for thermoplastic composite processing, being the part cycle time in the range of 10 min.
The aerospace sector is not away from this to make significant improvements in the process knowledge to be able to use the compression molding process to produce thermoplastic composite parts faster, with complex shapes, and at a reasonable cost that makes possible the use of it in commercial programs, even for smaller aircrafts such as regional ones.
Among components that can be transformed from metal fabrication to thermoplastic composite fabrication by compression molding, there are the windows frames of a regional aircraft, which need to be cost-effective.
Into the introduced context, the objective of the WINFRAME 4.0 project was:
The fabrication of regional aircraft thermoplastic composite windows frames using advanced and innovative industrial manufacturing processes Out of Autoclave in composite, such as compression molding, that allow a significant reduction of part weight (with a consequent reduction of operating costs for airlines) with at least the same overall production costs, compared to traditional metallic solutions.
The main approach carried out was to focus on innovative concepts of manufacturing technologies such as the thermoplastics compression molding process and, for this, WINFRAME 4.0 have carried out:
• Process set up and validation at the full-size level
• Parts fabrication for on-ground fuselage demonstrators
• Industrial cost evaluation
The WINFRAME 4.0 achieved a TRL5-6 at the end of the project which represents:
• Manufacturing process for windows frame is under control in terms of process parameters vs quality of part for instance in terms of void content, providing the geometry was not 1005 feasible without wrinkles
• Assembly process is set, windows frames are equipped, and all quality reports are done and frames were finally delivered for integration into demonstrators.
The project was divided into several stages.
In a first stage Process, Set-Up and Validation at full size of composite frames took place. During the stage, the manufactured parts were characterized in order to understand process capabilities and parts quality vs challenging geometry. Following a reasonable part quality achievement, the next stage was parts fabrication for on-ground fuselage demonstrators. In this sense, not only composite frames were manufactured, but also all the needed components to assembly the windows frames for structural tests, as well as for comfort tests.
The windows frames for the structural test were assembled and the ones for comfort assessment were kitted to further deliver it to the assembly site of the topic manager for the integration in the fuselage demonstrator.
As part of future feasibility, an industrial cost evaluation took place which is an estimation of what could be the future production in an industrial environment, even if many of the cost is yet to be optimized.
To complement the technical work a plan for Project Dissemination and Communication was deployed which counts for two technical articles a several press release news on the partner's website. As well project management was duñy carried out to get the utmost results.
The main results are the delivery of 24 windows frame, 12 of them assembled for structural evaluation of the demonstrator, and 12 of them kitted to be assembled by the topic Manager when assembling the overall demonstrator.
The planned exploitation are specially linked to future implementation of this type of components by Topic Manager in new regional aircraft programs.
Project results have been the delivery of 24 windows frames to be installed at the integrated composite fuselage demonstrators of a regional aircraft in the respective IADP.

Project Impact is the huge help to achieve efficient transport that respects the environment by the use of thermoplastic materials which project to save 75% energy; a reduction of waste and scrap by 10% by working directly at the defects root cause with a multidisciplinary approach through sensors for inline monitoring. As well the new aircraft that would come in the future helped by the findings of WINFRAME 4.0 will ensure safe and seamless mobility by a minimum of 15% weight reduction on structural components with the use of thermoplastic materials. Added to previous statements, WINFRAME 4.0 will help in building industrial leadership in Europe, which will increase competitiveness through mature out-of-autoclave technologies and manufacturing processes. In relation to impact on partners, it is especially remarkable for SOFITEC as an opportunity to develop additional knowledge in a field that is essential of its future competitiveness as it is the use of thermoplastics. As well for Eurecat, it helps to position the center in the field of high TRL thermoplastic composites.
Manufactred trial composite frame