On the Rhine river in Cologne, Germany, there is a yearly boat race that challenges participants to make the lightest and fastest vessel. This need to go for 200 metres without sinking and is only allowed to be made from concrete.
A research team from ETH Zurich made a skeletal framework using 3D-printed moulds, calling it the SkelETHon canoe. They used research to fabricate large-scale concrete building components.
Andrei Jipa, part of the team, said: “With 3D-printing we have an almost unlimited geometrical freedom for making formworks, which was not available to concrete so far. Undercuts, microstructures, high-resolution details are now possible.”
They have used recyclable plastic for the moulds which allowed them to cast slender ‘bones’, from steel fibre-reinforced concrete. By using optimisation algorithms they developed a framework that needed less material than traditional canoes and compensated that with support through a skeletal structure.
The team also created a textured rough surface for the concrete to help maximise the contact area between the skeleton and the concrete membrane that covers it. All this adding up to the canoe weighing 114 kg. Using 3D-printing also made it possible to build the canoe without any waste material.
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