Face it: we drive sheet metal origamis. And that is a good thing

The aunt of an ex-wife only drove big cars. And she was a lousy driver. Both things were related: she drove large vehicles because she was awful at the wheel. When I asked her about the glue that bonded these things together, she told me it was her belief that a bigger car would make her safer. She is long dead, now. Not due to a car crash, but to cancer. Even if she was still alive, I would never be able to show her the video below. She was the aunt of an ex-wife, as I said. Anyway, I wish she had the time to perceive she drove sheet metal origamis. And that a larger origami is not necessarily better than a smaller one. It depends more on what is used to build it, as well as on the ability with which it is folded. As the video below clearly shows.

The use of the term “origami” is not just a metaphor. When you see a car, you normally think it is a solid object. Nothing is further from the truth. As the video above shows, but cutaways demonstrate even better. And body-in-white structures, such as the ones pictured below the cutaway.

The New Jaguar XF. (08/28/07)

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From a graphic point of view, it could not be more evident than that. That was probably the inspiration Lexus had when it created its cardboard IS Sedan in October 2015. Even if it was willing to pay a tribute to its Japanese origins.

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Origami_Lexus_IS-2 Origami_Lexus_IS-5 Origami_Lexus_IS-4 Origami_Lexus_IS-3

The folded and hollow structures that form a car exist not only to house the harness, glasses, panels and mechanical components. They have many other functions, such as keeping the wheels always in contact with the soil, with the demanded stiffness, and absorbing energy in case of impacts. The latter is the one that interests us more in this article.

Energy absorption

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This funny piece of wisdom from Jeremy Clarkson sums up what energy absorption represents. When a car accelerates, it needs energy to move its mass from standstill into high speeds. Ironically, the same energy that puts the car in movement has to be dissipated. This is what brakes are for. And this is why they heat up and even glow when they are working hard.

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When brakes do not manage to dissipate the energy, it has to disappear in some other way. The harder a car body is, the less efficient it is in absorbing energy by deforming. Imagine if you were a Mike Tyson sparring. If your helmet was not made of a soft material, all the power of one of his punches would get straight to your skull. Another good example is the safety net firemen use to rescue people who fall from buildings. If they were not able to dissipate the energy the person acquires in the free fall, with gravity acceleration, they would kill instead of save. The same principle applies to car bodies.

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Mercedes-Benz was the first company to realize this in a practical manner. In other words, to make something about that. The Mercedes-Benz W111, also known as Fintail, was the first vehicle ever to present crumple zones in 1959. It was the same year of production of the Chevrolet Bel Air above. If the Bel Air had softer front and rear ends, as well as a more rigid cabin, it would have performed better against the Malibu.

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Also from Daimler is a demonstration that tiny vehicles can be as safe or even safer than larger cars. In fact, this evidence comes from another of Daimler companies, smart. And from the guys from Fifth Gear.

The little smart fortwo hits a concrete wall at 113 km/h and its cabin suffers minor damages, even if there is an intrusion that could have harmed passengers. But that is also true for a Opel/Vauxhall Corsa, which is a much larger car, with a wider crumple zone. The fact is that no car offers additional protection just because it is bigger. If it has not been conceived with safety in mind, it can be even worse. One of the factors that make people buy SUVs and crossovers nowadays is the same that pushed that aunt of an ex-wife towards big cars. To no use. If you want to be safe, you have to look for the cars that perform better at crash tests. And they can be as tiny as a smart fortwo.

There are parts of the car that have to remain as intact as possible. To manage that, they depend on other parts to deform in the best way they can. “In the deformation and crumple zones we are looking for materials with high ductility in combination with high strength level. In the short-term, we will mainly have a mix of aluminium and steel. Depending on the material, there are different solutions used by either extrusions or tubular shapes that suits the design in the best way. Robustness to secure no material failure in deformation zone is of highest interest”, the Volvo Cars Safety Centre told MotorChase.

 

Puzzle of materials

In the past, car bodies were made entirely of steel, but them aluminium sounded a better idea. The Audi A2 and the A8 were examples of that, but steel started to evolve as well. The reaction came in the form or HSS (High Strength Steel), UHSS (Ultra High Strenght Steel) or even AHSS (Advanced Ultra High Strength Steel). “In the short-term, the hot-formed boron steel is the base for our safety cage while steel/aluminium is the base for our body panels”, Volvo Cars Safety Centre told MotorChase. And it is not only Volvo who is researching on this puzzle of materials this complex origami demands. Check below Renault EOLAB concept’s structure. And its motto: “the right material in the right place”.

Renault-EOLAB-Concept-Body-In-White-materials

The focus of EOLAB, presented at the 2014 Paris Motor Show, was on fuel efficiency. According to Renault, the B-segment concept was 400 kg lighter than a Clio would be. It weighed 955 kg. Anyway, it is easy to see the materials chosen for the cabin: advanced high strength steel, extruded and casted aluminum and continuous fiber reinforced thermoplastics, something we normally call just carbon fiber. Away from the cabin, we see stamped aluminum and fiber glass panels. The parts that are meant to absorb energy in impacts.

“For hot formed materials there are also several new alternatives offered in terms of both strength and ductility that could be of interest for further development. Composites are studied for reinforcements in the body structure. In the long-term, we look into many different alternatives with a mix of advanced materials to further improve our strength and at the same time reduce car body weight. Composites will also be investigated for body panels”, continues the Volvo Cars Safety Centre. BMW has advanced the study phase with the new 7 Series and its Carbon Core.

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All the black parts that appear in the image above are made from carbon fiber. It is in all columns (A, B and C), door sills, roof and transmission tunnel. In other words, all around the passengers, so that they are protected as much as possible. The clearer parts, meant to minimize the effects of a crash, are made of aluminium.

 

Folding techniques

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Making the body stronger in some areas is not only a question of materials. It can also be obtained with folding techniques, as Francisco Satkunas, director of the Brazilian section of SAE, tells MotorChase. “In some areas of the body, we can use what we call ribs as structures for the panels, placing an outer skin that is welded or bonded to these ribs.”

The Volvo Cars Safety Centre mentions some other strategies. “The hotforming process is a good example where we use the stamping process to increase the strength of the material. This can be done also to tailor the properties in a specific area of the single component by altering the cooling process. Furthermore we also use tailored welded blanks, for mixing either the thickness and/or the material grades.”

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“Another alternative used to vary the thickness is tailored rolled blanks to utilize the best performance and strength where it is needed. By the use of Dual Phase (DP) steel, where we have an additional hardening effect from the stamping process, we obtain an opportunity to further benefit from the material. Furthermore, additional production processes will be investigated to handle the UHSS in the future”, completes the Volvo Cars Safety Centre.

 

Graham

Imagining a world in which everyone had cars, and all of them were models like the Chevrolet Bel Air that rolled off of production lines in 1959, Darwin would prevail. Only the more adapted to car crashes would survive. And procreate. And more natural selection would occur. Have you ever given it a thought on what we would look like? Would rubber skin, muscle and bones solve the problem? Should we have springs in our chest? The Transport Accident Commission in Australia has imagined this parallel universe. And they came up with Graham.

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Graham has all it takes to survive a car crash. He has a brain that is tied to the skull by a number of ligaments. He has a bigger skull, full of “crumple zones”. He has no neck, which could snap in abrupt decelerations. But mind you: surviving does not necessarily mean to keep on living well. It just means you would not die instantly. As the people involved in the project explain in the video below.

Here is the detailed description of the changes the human being would have to develop in order to become Graham. And crash resistant.

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It is not difficult to see a much easier path is to develop technologies that effectively protect the fragile beings we are. As we currently are.

When no origami can protect you

But there are situations in which not even Graham would make it. There is a limit for the amount of energy that sheet metal origamis are prepared to handle. If you go beyond that, cars will crush in the same way a piece of paper would against your hands. Once again, Fifth Gear gives us a hand in showing that.

This is the best motion evidence of our origami thesis. Or could you imagine that a Ford Focus, as solid as it looks, could become this little piece of distorted steel the video presents? It has happened at 193 km/h, a speed that is legal in some roads, such as the German autobahnen. And that some drivers do not care if it is legal or not where they are, going even faster than that. Always out of the belief they are fully protected. The video below reinforces that this is not exactly correct. Even when you do not hit a fixed concrete barrier, as the Focus above did.

These crash tests were performed at 200 km/h. The cars that reach this speed end up very damaged. But what about the ones that get hit in the way? They are completely destroyed. Mostly because they are hit in their sides or in their rear, areas that are not so reinforced as the engine bay. We would have a fairer idea if both cars were doing 100 km/h and crashed . Or if the one that is parked did not have blocks of concrete behind it. As they were performed, the tests result in pretty damaged cars. Even if not as much as if they were hit by a rocket sled, as the Mythbusters have done once.

Nothing of the kind will ever happen in streets or roads, but high-speed crashes are more common than they should. This is why it is important to be fully aware of what you are driving. At all times. If you cross a lava river in an old rope-plank, you tend to be careful. And acting any differently would be a stupidity testimony. The same principle should be applied to something you deem as solid, but that is, in fact, a bunch of bent steel plates welded together.

We are not saying you cannot enjoy the high speeds your sports car can achieve. After all, the goal with cars is to reach a destination in the fastest time possible in a safe way. These must be the criteria in establishing the top speeds in roads. If it was not like that, it would suffice to walk. Even bicycles aim to save your time. In case you do not want to be subject to any limitation but the laws of physics, do so in a controlled environment. A race track, for example. But be aware that not even there you are totally safe, as the accident with 2 fatal victims yesterday at Nürburgring Nordschleife unfortunately shows.

The picture below was taken moments before the crash. The driver and the lady beside him have died in the crash. Apparently, they have hit a rescue car that was already helping another crashed car at the “fourth left” of Kesselchen. Two marshalls were also injured, one of them seriously.

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If a race track can have so many variables, imagine how many more are there in the open. It is not advisable not to be fully aware and at a compatible speed. Remember: we drive sheet metal origamis. Sophisticated, powerful, but origamis nonetheless. The sense of vulnerability is what has kept us from extinction. Or from becoming Graham.

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Gustavo Henrique Ruffo

I have been an automotive journalist since 1998 and have worked for many important Brazilian newspapers and magazines, such as the local edition of Car and Driver and Quatro Rodas, Brazilian's biggest car magazine. I have also worked for foreign websites, such as World Car Fans and won a few journalism prizes, among them three SAE Journalism Awards and the 2017 IAM RoadSmart Safety Award. I am the author of "The Traffic Cholesterol", a book about bad drivers that you can buy at Hotmart, Google Play, Amazon and Kobo.