Carbon fibre; new nano-technologies, new opportunities

Lighter, more resistant and self-repairing. The automotive world is looking at using increasingly advanced and hi-tech components on future vehicles. And it accomplishes all this using composite, multifunctional and hybrid materials. Thus producing entire car bodies, body parts, bumpers and engine parts that prove to be stiffer and stronger in comparison to traditional materials – even stronger than steel - though much lighter. Nevertheless, if this represents the present, the technological thrust we are all witnessing is producing a flurry of hi-tech initiatives in this field. A team of researchers from the University of Bologna is working at creating "intelligent" materials whose practical application may soon meet the interest of many auto components manufacturers. "We are developing composite materials with integrated sensors capable of sending warning signals on possible anomalies as well as being able to self-repair these damages", explains Andrea Zucchelli, professor of the industrial engineering department.
 
Among the various composite materials currently in use – Glass-fibre, Kevlar, Thermoplastics, particle enriched Aluminium  - the one attracting particular interest, both in research and practical applications, is Carbon-fibre. And here is where several companies and multinationals, among others, are focusing their attention, aiming at making it profitable in economic terms besides ensuring the best possible performance. According to the "Global Carbon-fibre in the automotive composites market 2017-2021" study, carried out by Technavio - a specialized market research company – the use of Carbon-fibre in the automotive industry is destined to grow, and reach by 2021 a 10% Cagr (compound annual growth rate). With the Asia-Pacific market taking the lion’s share, followed close behind by North America and Europe. In the future the use of carbon-fibre will be favoured by the growing demand for fuel efficient vehicles: simply put, lighter cars make more efficient vehicles. And it doesn’t end there, the inherent characteristics of this material will make cars even more resistant to collisions and therefore safer. The only limitation, preventing a large scale distribution of Carbon-fibre - as far as the automotive field is concerned – is represented by costs, still far too high. So much so that car manufacturers have, so far, limited its use to motor racing, high-end production vehicles and electric cars.
 
"All cars boasting a high number of components made of carbon-fibre - explains Zucchelli -. The reason is that this material is able to maximise the stiffness, strength and weight ratio." In fact, when compared to steel or aluminium, whose density amounts to 8 thousand and 2,700 kilograms per cubic metre respectively, this material is much lighter (1,600 / 1,800 kg per cubic meter). Carbon-fibre components, therefore, have a decidedly lower weight despite a stiffness and resistance comparable to steel. The down side? While steel is a highly ductile material, and therefore it deforms before breaking, composites are more fragile and lack pliancy. "Basically, Carbon-fibre is more sensitive to accidental loads - continues Zucchelli – and this involves a certain amount of risks. Tiny cracks inside the material, which could occurred as a result of mechanical stress or an accident, could spread without us noticing it, with the result that the part could break quite suddenly.” A critical issue that researchers have decided to solve by inserting sensors into the material. "In this way - Zucchelli explains - when micro-fractures appear in the material these are detected immediately and a warning is immediately sent to a control unit. This will allow to have the entire Carbon-fibre structure monitored at all times."
However, the research team hasn’t stopped to just embedding a bunch of sensors in the material. The next step was to insert a liquid, containing chemical compounds, capable of repairing the damage and increasing the safety and reliability of Carbon-fibre components. "Micro-pores make it possible for the liquid to move within the structure - says Zucchelli-, replicating, in a sense, what happens in the human body: we are creating a non-invasive yet very pervasive structure. Consequently, when a damage occurs, and the fibre breaks, the liquid starts pouring out and triggers a self-repairing process, stopping a small fractures from spreading to the rest of the structure and allows the material to regain its full efficiency again.” This innovation though, contrary to what one might expect, will not put plunge the whole assistance and repair business in a crisis, assures the professor. "The component has still suffered a “trauma”. So to understand how this damage, restrained thanks to auto-repair qualities, may impact the rest of the vehicle, especially if the component is particularly critical, we still have to rely on specialized assistance." This technology is still being tested, and it will take quite some time before making its way into our vehicles. It goes without saying, however, that the scenario, in terms of future business and business opportunities is broad indeed, so much so that component manufacturers, not to mention the aftermarket supply chain as a whole will have to re-think their strategies, looking at offering tomorrow’s drivers increasingly specialized tools and advanced skills in the care and maintenance of their vehicles.