The new composite material contains double the volume of glass fibres compared to common composites and thus is extremely stabile. The increased amount of glass fibres was enabled through an innovative process the engineers from EPL Composite Solutions developed within the EU funded research project CLEANMOULD.
Glass fibre mats impregnated with resin powder are placed into a mould. This mould is then packed in a plastic bag, the bag is sealed and the air extracted. With the help of the vacuum the mat keeps attached to the mould. In an oven heated up to 200°C, the powder resin melts. When molten, the thermoplastic resin provided from Cyclics Corporation in Germany, gets as runny as water and coats the glass fibres.
A cube made from the new plastic weighs only one quarter of the same cube made from steel. Through the reduction of weight five percent of fuel can be saved. But even more important is its improved shape.
The plastic frame consists of only one piece. This allows the designers to change its aerodynamic properties. Smooth surfaces underneath the trailer reduce the draft considerably. The design has an inherent drag reduction of 13 percent that can be further improved to 20 percent with optimisation of the design. At high speeds, such as motorway cruising, this aerodynamic drag is the dominant factor in determining heavy goods vehicle fuel consumption. With the new shape another 10 percent of fuel can be saved.
The prototypes have been tested thoroughly on a series of demanding test tracks at the Motor Research Industry Association (MIRA) in Warwickshire, the biggest test ground in the UK. They included a breaking test, speed bumps and cobblestone roads.
Deflections and accelerations through the trailer have been measured to see which parts in the trailer are under high stress or strain. The results so far are very promising and the engineers envisage already the next steps: “The composites are ready to roll out into the industry now”, says Matthew Turner, CLEANMOULD project coordinator and composite engineer at EPL.