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Autonomous vehicles need lightweight materials

In a world of autonomous vehicles, composite materials may replace heavy metals as crash safety requirements fall, and surface durability needs rise. By Freddie Holmes

The debate is open as to when and where autonomous cars will roam city streets, but suppliers are eyeing new opportunities to shake up the way in which these vehicles are made. Tier 1 polymers expert Covestro believes that as the risk of a crash occurring falls, so too will the requirement for metal structures that are designed to protect occupants during high velocity collisions.

Speaking in Shanghai at Covestro’s Chinese R&D headquarters, a number of experts shared their views on how material selection is likely to diverge from the norm as vehicle automation increases.

Indeed, Bill Russo, an ex-Vice President at Chrysler and current Chief Executive of business advisory firm Automobility, believes that OEMs may no longer need to meet the crash requirements of a 200kph (125mph) crash on an Autobahn when designing cars for inner city travel. “For urban mobility, cars are over engineered,” he remarked at the event.

Kevin Shen, President of CHJ Automotive – a Chinese start-up that aims to build its own ride-share cars and operate as an ‘EV mobility provider’ – agreed, suggesting that “you don’t need large high speed cars in urban areas, you need the right tool for the use case.”

Having just one autonomous vehicle on the road is not sufficient in order to transition away from today’s high strength materials. But if every vehicle is autonomous, then it is possible

That being said, experts recognise that substituting today’s high strength metals with lightweight composite panels would not be viable where both autonomous and non-autonomous vehicles share the road, with the potential for high-speed collisions still rife. As Holly Lei, Senior Vice President of Commercial Operations, PCS (Polycarbonate Plastics), APAC China at Covestro, pointed out: “Having just one autonomous vehicle on the road is not sufficient in order to transition away from today’s high strength materials. But if every vehicle is autonomous, then it is possible, and I believe this trend will eventually come.”

Asian markets have become a popular test bed for autonomous driving systems. In August 2016, Boston-based start-up NuTonomy became the first company to operate a driverless taxi fleet as part of a pilot programme in Singapore. Japan’s Prime Minister has stated intentions for autonomous fleets to operate during the country’s Summer Olympics in 2020. CHJ Automotive’s Shen predicts that an autonomous shared car fleet will be operating on city streets in China as early as 2025. Volvo Cars plans to test autonomous driving cars on Chinese public roads as part of its Drive Me initiative – which began in December 2017 in Sweden – with members of the public behind the wheel.

Covestro’s Lei is confident that autonomous vehicles in some form will hit the road “soon”, and notes growing interest in composite substitutes for body panels, windows and interiors for this specific reason. “Our customers believe this will be a future trend, and will begin looking at how to invest in these solutions. Because in three years’ time, this may be a reality,” she said. “If that is the case, I do not think it will be necessary for body parts to have as much strength. As such, composites could be the solution.”

A clear solution to the blind spot

But what about the interim period, with road safety not yet perfected and human drivers still struggling to spot cars and pedestrians? The use of plastic windows and pillars could remove blind spots, commonly linked to the cause of pedestrian collisions.

If strength requirements are lower due to these sensors and software, you can integrate many things within the panels themselves

Covestro has worked with designers from the Umeå Institute of Design in Sweden to develop an autonomous electric vehicle (EV) concept – codenamed K2016 EV – which uses ‘bold’ material solutions both for the interior and exterior. As part of this concept, polycarbonate wrap-around glazing is used to replace the various windows that would feature on a traditional vehicle. This enabled Covestro’s designers to create a transparent A-pillar, which “improves passenger and driver vision,” according to Lei. What’s more, the overall solution is around 50% lighter than a traditional glass window approach.

All-plastic cars have been investigated before – the Bayer K67 was developed in the 1960s with high-strength plastics and foams, for example. High-performance polyurethane materials are already used widely within new vehicles, accounting for around 18% of the weight of an average mid-size car.

Replacing glass

High-performance plastics will replace traditional metals as well as glass inside the vehicle. Polycarbonates are not only shatterproof, but can also block harmful UV radiation – important in a car that will feature wrap-around windows and thus greater exposure to sunlight. Lei believes that more displays will be integrated within the car in future, and potentially take up entire panels.

“With autonomous vehicles and all of these new electronics entering the car, we don’t see boundaries any more from an application perspective,” said Lei. “If strength requirements are lower due to these sensors and software, you can integrate many things within the panels themselves. It’s not too difficult to imagine the use of displays as whole body panels, potentially allowing occupants to watch TV directly from the car door.”

It’s not too difficult to imagine the use of displays as whole body panels, potentially allowing occupants to watch TV directly from the car door

Lei also envisions a seamless, glass-like display that sweeps around the interior of the car, as opposed to the ‘stuck-on’ infotainment screen found in many cars today. Future cockpit concepts from interior suppliers such as Yanfeng Automotive Interiors and OEMs including Volvo Cars already depict the use of several screens within the car, both for the driver and passengers. But Lei believes these screens are likely to merge into a single panel thanks to cost-effective and dent-resistant polycarbonate materials.

As can be seen with existing displays used daily by consumers, such as smartphones, tablets and laptops, these surfaces need to be highly durable and scratch resistant. This is of particular importance in a ride-share application where the potential for damage is high. Users do not own the equipment, and are less likely to take care when entering or exiting the vehicle, or in using the applications.

Recent reports from French media have already highlighted that ride-share vehicles as part of the Autolib scheme have been subject to vandalism and misuse. However, Covestro’s Lei believes that existing polycarbonate materials will be able to stand up to the test, based on the fact that they are already used for exterior applications such as headlamps and windows, for example. Hard coatings can also be applied to further strengthen these materials, for additional chip and wear resistance. “All of those difficulties have already been overcome,” affirmed Lei.

This article appeared in the Q1 2018 issue of Automotive Megatrends Magazine. Follow this link to download the full issue