25.09.17
Form and function realised through advanced materials
Source: RTM Aug/Sep 17
Paul Gallen, sector manager at the National Composites Centre (NCC), outlines the benefits that composite materials bring to the production and operation of more lightweight trains.
Current rolling stock makes extensive use of fibre-reinforced composite materials in interior and exterior components, from interior panels and floors to aerodynamic vehicle cabs.
Where complexity of design within a single component is important, GRP (glass reinforced polymer composites) have long been the preferred solution.
However, composites can add much more value by combining the freedom of form benefits with structural optimisation. Composite components can incorporate complex changes of shape with high structural stiffness and strength, especially when carbon fibre-reinforced polymer composites are used. This approach facilitates significant weight and assembly complexity reduction through consolidation of multiple functions into fewer parts. Components and structures can be redesigned using composites to provide integral structural and functional support. Frameworks, brackets and ducts can be combined into consolidated single components, reducing the bill of materials.
This approach reduces part count, tooling, manufacturing and inventory costs, reduces assembly, as well as significantly reducing the vehicle weight – and light-weighting improves in service energy use. Reducing axle weight through right-weighting of the car body and other systems also reduces track wear and, when combined with the reduction of unsprung masses, improves the performance of high-speed rail vehicles. This approach also decreases track wear, and will result in reduced track access charges yielding long-term cost benefits to TOCs.
Composites are also extremely durable both in fatigue under vibratory and repetitive loads, and resistance to weather, corrosion and chemical attack is excellent, providing real opportunities for lower maintenance through the whole life of the vehicle. New rolling stock designs that utilise the form and function integration potential of composites could be radical and game-changing in their effects. The rolling stock manufacturer could create additional and larger doors and windows, novel intermediate vehicle ends through effective use of composites, all with enhanced crashworthiness in combination with integral noise and thermal insulation properties.
The use of composites in the automotive and aerospace sectors indicates that composite primary structures can reduce weight by up to 45% compared to an aluminium structure and 65% compared to steel. These composite structures are more effective at preserving passenger survival space than metal structures, even when combined with very large weight reductions.
In the near future, there will be an opportunity to integrate energy storage and sensing technologies into the composite components, producing smart materials. These materials will be able to ‘report’ issues, problems and wear, enabling the operator to streamline maintenance activities and reduce vehicle down times.
The NCC employs over 150 engineers and technicians, using design simulation and digital manufacturing tools to model and predict the performance of customers’ concepts, and are able to manufacture, test and develop prototypes. We can support the sector in its uptake of these materials. The use of state-of-the-art design, modelling and simulation techniques can significantly reduce risk and development time for innovative solutions utilising the form and function benefits of lightweight composites. They are here to help take the sector to the next level of innovation.
Now is the perfect time for accelerated innovation in the rail sector to develop increased understanding in the design and use of these materials for future generations of lightweight rolling stock. I see a future for rolling stock with reconfigurable interiors and door configurations, all using composites, for high-density Metro and high-pressure commuter routes. We are certain that seats made from composites can benefit from recent material and process innovations. I predict a potential 60% weight saving for each seat with the opportunity for at-seat luggage storage to give an improved experience for the rail traveller.
We have recently worked with partners in the rail industry to prototype a lightweight, durable train door made using recyclable composites that offers significant potential operational benefits and meets the integrity and fire retardancy standards that the sector demands. There is a significant opportunity to make a step change in the design of passenger rolling stock by transferring the composites and multi-materials knowledge, technology and supply chain capabilities from other industrial sectors. As part of the UK’s High Value Manufacturing Catapult network of industry-scale technology and innovation centres, we can help the rail sector make understanding and using this technology a shorter and easier journey.
FOR MORE INFORMATION
W: nccuk.com
W: hvm.catapult.org.uk