The COMBUSS Project
Developing of a new generation of greener aircrafts is currently a top priority for many aircraft manufacturers. Green aircrafts are expected to be more cost-efficient and in alignment with the global effort to slow down climate change, while providing fliers with greater comfort, thus making them more competitive globally.
In order to achieve such goals, a number of new technologies are being developed for the aerospace industry. In particular, lighter materials are being developed in order to progressively replace heavy metallic parts, in an effort to reduce fuel consumption. These materials include fibre-reinforced composites (e.g., high performance thermosets and thermoplastics). Other solutions include the development of airframe components with carefully designed geometries and shapes to optimise airflow and reduce drag.
A combination of these two approaches, which match specific focus areas of the Clean Sky 2 Innovative Aircraft Demonstrator Platforms (IADPs), would contribute towards significant reductions in fuel consumption and emissions. The European aerospace industry already possesses mature manufacturing production processes for composite parts. However, the production lags behind in the following areas: reliability, cost efficiency and green processing. The main challenges identified in the manufacture of high quality integrated composite parts using liquid composite molding processes are the following:
- Large parts require considerable tool mass to counteract the internal resin pressure
- Heating inhomogeneity is typically observed for large tools, especially when they have thickness variations
- In-autoclave processes are costly and time-consuming
- Distortion of the manufactured parts can occur when there is a mismatch between the thermal expansion between part and tool
- Large tools form expensive and critical infrastructure of manufacturing companies, making the extension of their service life of paramount importance; as such, they should be repairable and able to adapt to minor changes in design
Several niche technologies (e.g., out-of-autoclave composite manufacturing, on-line quality control) have thus been developed with the view to address the above challenges and provide solutions for manufacturing integrated and complex composite structures in a cost-effective and timely fashion.
As a way to drive innovation forward in the composite manufacturing domain, the COMBUSS project proposes to combine cutting edge technologies including out-of-autoclave processing (e.g., self-heating, modularity, multi-zone, durability) and materials and process monitoring techniques (e.g., in-process durable sensors, material-state driven control, automated heat transfer models).
The aim of the COMBUSS project is to develop, design, manufacture and deliver to the Topic Manager the prototype subcomponent manufacturing tooling needed to manufacture the stiffeners and panel of a lower wing part. This project will design the tooling system which will incorporate self-heated capability with multiple heating zones and advanced thermal management.
The COMBUSS project is centered around developing and implementing a cost-effective manufacturing process for integrated airframe composite structures for the next generation aircraft. As such, it will contribute to the following high-level goals set by the European Aviation and Flightpath 2050:
Lower environmental impact of aviation and reduced fuel consumption through the increased use of integrated low weight composite structures as well as aircraft drag reduction, to be enabled by innovative and complex part design
Introduction of more competitive aircraft to the market with increased flight performance (e.g., reliability, flight range, fuel consumption) and reduced time-to-market due to the elimination of time-consuming design review iterations required to develop and produce structures with acceptable degree of integration
More competitive and resource-efficient production through “first-time-right” production strategies of composite structures, thereby eliminating the cost associated with rework or recycling of material waste (e.g., faulty parts)
Enhanced mobility of EU citizens as a result of cheaper flight tickets, achieved by reduction of aircraft fuel consumption and other operation costs
Within the last fifteen years, the performance of modern aircraft airframes has increased thanks to technologies that reduce weight and increase aerodynamic efficiency. Key enabling technologies are the use of composite materials and the development of means to control airflow. To this end, Clean Sky 2 (CS2) Joint Technology Initiative (JTI) has devised a dedicated Innovative Aircraft Demonstrator Platform (IADP) in order to answer the societal needs and streamline the stakeholder's efforts. The Airframe IADP (AIR-IADP) offers a roadmap with concerted activities that will ensure technical excellence in the field and are expected to enhance the EU leadership in regional aircraft businesses, improve industrial competitiveness, create jobs and deliver innovative, more efficient, greener and safer aeroplanes.
To this end, the COMBUSS project will provide technological solutions for the development of a lightweight stiffened panel for a business jet lower wing, featuring an integrated and robust composite structure. In particular, COMBUSS will offer a unique system that combines robust thermal management of the curing process together with a continuous and in-situ monitoring of all process steps.
COMBUSS will promote the use of a self-heated fully controlled processing tool that will minimize the required energy budget and offer unparalleled quality assurance. In terms of energy savings, the return on investment period is expected to be much shorter when compared with conventional oven or autoclave. The innovations planned within COMBUSS will contribute towards the development of lightweight wingtip parts that can meet the AIR ITD schedule for system flight test. In the long term, it is expected that new breakthrough design approaches for the next generation of composite aircraft fleets will take place. Novel light-weight designs of CFRP structural components will lead to weight savings of up to 15%. Additionally, the development of new reliable integrated composite structures will improve the safety and operational capability of the aircraft, leading to an increase in operational life.
The overall cost reduction in composite part manufacture, that COMBUSS is expected to achieve, will lead to an increased interest in fibre-reinforced composites and improved product quality, along with more job opportunities in the relevant industry sectors. As such, COMBUSS will support the competitiveness of Europe’s aircraft industry and European aircraft operators. This is in line with the European Union (EU)’s focus on innovation as a basis for societal growth, prosperity, and job creation.
A major environmental impact of COMBUSS is the reduction of negative environmental impacts of new technologies, which is in line with forward-looking climate change policies as well as EU regulations. The technologies developed in COMBUSS will support the adoption of composite solutions as lightweight alternative to metals, which will help reduce vehicle’s weight and fuel consumption resulting in reduced CO2 emissions.
The ecological impact of COMBUSS will be twofold as:
It will develop the technical basis for the realisation of stiffened panels, which, in turn, is expected to offer significantly reduced fuel consumption
It will promote an energy efficient composite manufacturing process (resin infusion)
In order to maximise the aforementioned impacts, the COMBUSS consortium will implement a dedicated dissemination and exploitation strategy, predominantly aimed at ensuring:
The effective and sustainable dissemination of the project foreground within the European Aeronautics Community, through suitable dissemination and communication activities for each of the project’s identified target groups and end users (e.g., EASN (https://easn.net/))
The exploitation of the project’s results (i.e., the advanced tooling demonstrator) by the European Aeronautics Industry so as to maintain and reinforce technological advantage over the competition from outside Europe
The conveyance of new knowledge into the engineering education base, through publications to peer reviewed journals and specialized magazines, such as JEC Composites and Eureka!
The possible exploitation of the COMBUSS results and foregrounds by other sectors of the transport industry (e.g., road transport, rail transport)