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Breakthrough: Unibody construction

1 year ago

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David Twohig | Engineer


25 April 2023

Right – it’s Blue Peter time. If you have a cereal box in the house, you should grab it now. Take out the plastic bag with the allegedly healthy breakfast flakes/pops/puffs and set it aside. Fold the flaps to close the top as best you can.

Now, imagine it’s a car body. Take hold of both ends, close your eyes and twist it. Feel the torsional stiffness? That’s the old kilo-Newtons-per-degree (kN/˚) measure that journalists love to talk about, and engineers love to explain is 45 per cent stiffer on their new car than on that crappy old model. Next, try to compress the box sharply between your hands – pretty strong, isn’t it? You’ve just simulated a frontal impact.

Finally, chop the box smartly with the outside edge of your hand, Karate Kid-style. Note how well it resists the abuse: hopefully it did not crumple to bits. That was a pole impact – the nasty test that models the Very Bad Things that happen when mobile objects like spinning cars hit immovable objects like telegraph poles or (even worse) trees.

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