Vibration of motors can annoy: especially in buses are extremely unpleasant, if the seats in the cylinder stroke swing with. Read on the way to work then becomes an ordeal. Researchers from at ETH Zurich can hope that’s soon quieter on the bus. But also in aircraft, helicopters and space rockets.
It is extremely uncomfortable especially at red lights: in buses, the vibration of the motor transmits very heavily on the seats of passengers. It is often not possible to continue reading the just so exciting thriller, because the letters before the eyes dance. Propeller aircraft and helicopters, vibrations are a nuisance: the propeller or rotor vibrations make restless and in particular according to the flight. What is more, that they lead to fatigue the material of driving and flying machines.
Soft materials only limit suitable
It is therefore a permanent task of engineers, to avoid or minimize such vibrations. So far, the engineers used special, mostly soft materials that absorb this vibration. The downside: It can catch only a small range of vibrations.
Steel cubes as resonators
Scientists of ETH Zurich have now expanded the possibility of vibration insulation conducted by Chiara Daraio, Professor of mechanics and materials, with a new three-dimensional lattice structure. It is a spatial structure with a grid spacing of approximately 3.5 mm, produced plastic Daraio’s team using 3D printing. In this grid, researchers embedded steel cubes, which are slightly smaller than dice. This steel cube act as resonators in the lattice structure.
At the same time force-bearing component
“Vibrations move from one end not through the whole structure, but are absorbed by the steel cubes and the inner plastic rods. The other end of the structure does not move”, explains Kathryn Matlack, postdoc in D’Rivera group.
The special highlight of the new vibration-resistant structure of the ETH researchers: You is rigid and can thus at the same time as force-carrying component in mechanical engineering or aircraft rotors or Helicopter are used. This saves weight and is a huge advantage for aircraft.
Fast and slow vibrations intercept
Theoretically it is possible such a lattice instead of plastic from aluminum and other light metals build, Matlack says. The principle is simple: it is a combination of a light trellis fabric and embedded resonators with large mass density. The geometry of lattice structure and Resonators in terms of the expected vibrations must be optimally co-ordinated. The new lattice can intercept the fast and slow vibrations.
Not suitable for the mass market
“We can measure so the geometry of the structure, thus to dampen vibrations with frequencies from several hundred to several thousand times per second”, emphasizes ETH Professor Chiara Daraio. “In this area are also noticeable with the ear vibrations that cause unwanted noise and reduce the efficiency of machines and vehicles.”
The ETH researchers are still somewhat cautious, with regard to the use in a mass market. Still is, says Matlack, the 3D Printer mini series directed and wise disadvantages compared to traditional production methods on the capacity of materials.
It is clear: If the 3D printing technology is ripe for industrial use, the anti-vibration lattice structure from Zurich will find wide application fields. So a minimization of vibrations in the rotors of wind turbines will increase their efficiency. Not only that: even when rockets can come the lattice structure of Zurich in future use.
But also Brunswick researchers want to reduce the noise of helicopters, which sound like a huge carpet beater. What they concocted a clever trick, can be found here. For home use, Fraunhofer researchers have developed a solution again. Your mini speaker creates opposite sound and fit in window frames. The only 20 cm long device, for example aircraft noise is reduced by half.