Impact success story: Composites
When you combine fibres with a plastic, you get a material that remains very light and yet very hard and strong. Composite materials offer many benefits in terms of safety and the environment.
Energy savings through lower weight
Composites recently gained fame when they were used to make up the entire chassis of BMW’s electric model, the i3. “It’s so light that just two people can lift it.” In fact, the idea behind the use of composites when it comes to mobility is always the same: achieve a lower weight in order to use less fuel. “When you make electric cars, the batteries can add an enormous amount of mass, up to 100 kilograms, so people try to save mass elsewhere.”
And classic fuel cars? They also include composites, although the high cost remains a barrier. “That’s why you first see them popping up in more expensive sports cars. Parts manufacturers in particular have done a lot of research because they see composites as a possible means to reducing mass, through what has often been called ‘secondary weight savings’. If the chassis is lighter, the engine can also be lighter. This leads to a sort of cascade of weight reduction.”
Wim Van Paepegem speaks of a massive revolution: “If you board a recently built aircraft, more than half of it is made of composite material. Sometimes the entire wings and body of the aircraft are made of the material, but because they are painted white and lacquered, it goes unnoticed and therefore hardly anyone knows this.”
3D printing with medical applications
The second type of material that Wim Van Paepegem and his fellow scientists work on at Ghent University is 3D printing, where materials are melted locally with a laser to form complex geometries that are very difficult to produce by traditional machining. This field is already fairly well known in the hobby world, but what many people do not know is that the technology is also used, for example, in the production of orthotics for children with walking difficulties and the production of tailor-made external aids for people with muscle problems. Materials experts are currently also working on a new project to produce medical implants, for example for hips or pieces of the skull, jawbone and back implants used for very complex fractures.
The research involving 3D printing mainly concerns medical applications such as patient support aids in particular. The scientists work together with orthopaedic companies, hospitals and surgeons who design implants. Based on a CT scan showing the fracture and what the remaining bone looks like, a design is made for an implant that fits as closely as possible. The material that ultimately comes out of the printer must be able to withstand mechanical stress so that people with a prosthesis can still exercise, for example.
Composites to increase safety
“Safety is therefore an important factor,” Wim Van Paepegem emphasises. “For example, we have conducted a study of bicycle helmets. A bicycle helmet must absorb a certain amount of energy upon a fall. We do research and simulations for companies that make bicycle helmets. Better bumpers, building glazing with stronger explosion resistance, reinforcements in car doors, etc.: these topics are also among the focuses of our research.”