A new material inspired by grapefruits and shells has been developed by British engineers and it blunts any angle grinder or drill that it comes in contact with.
It has been named Proteus after the shape-changing Greek god of the sea and is both lightweight, strong and also capable of dispersing any waterjet.
The material was developed by a team from Durham University and the Fraunhofer Institute, Germany who say it acts more like a living animal than inanimate object.
It is a ‘smart material’ that has been made from ceramic spheres that are encased in a cellular aluminium structure and could be used to create new lightweight armour.
The international research team got the idea for the new material from the tough cellular skin of the grapefruit and the fracture resistant shells of molluscs.
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When cut with an angle grinder or drill, the vibrations created by the ceramic spheres inside the casing blunt the cutting disc or drill bit
It is a ‘smart material’ that has been made from ceramic spheres that are encased in a cellular aluminium structure and could be used to create new lightweight armour
The researchers say the material could also be used to make impenetrable bike locks and protective equipment in construction and maintenance.
When cut with an angle grinder or drill, the vibrations created by the ceramic spheres inside the casing blunt the cutting disc or drill bit.
The interaction between the two creates an interlocking, vibrational connection that resists the cutting tool and turns the destructive force back on itself, weakened and destroyed by its own attack.
In addition, the fine particles in the ceramics fragment hardens at the speed of the cutting tool rendering the tool useless and unable to continue cutting.
‘The blade is gradually eroded, and eventually rendered ineffective as the force and energy of the disc or the drill is turned back on itself, and it is weakened and destroyed by its own attack,’ the team explained.
Water jets were also found to be ineffective because the curved surfaces of the ceramic spheres widen the jet, which substantially reduces its speed and weakens its cutting capacity.
Dr Stefan Szyniszewski, Assistant Professor of Applied Mechanics, in the Department of Engineering, Durham University, said it all started with a grapefruit.
‘We were intrigued by how the cellular structure of the grapefruit and the tiled structure of mollusc shells can prevent damage to the fruit or the creatures inside, despite being made of relatively weak organic building blocks,’ he explained.
‘These natural structures informed the working principle of our metallic-ceramic material, which is based on dynamic interaction with the applied load, in contrast to passive resistance.
‘Essentially cutting our material is like cutting through a jelly filled with nuggets. If you get through the jelly you hit the nuggets and the material will vibrate in such a way that it destroys the cutting disc or drill bit.’
He said the ceramics in the flexible material are made of very fine particles that stiffen and resist anything trying to cut it.
Abalone sea creatures are built from tiles interlinked with a biopolymer material that make them resistant to fractures, the team explained.
As can be seen in the rear view of this material – top right – the angle grinder is unable to penetrate through the Proteus material. Researchers say it would make a good impenetrable bike lock
The international research team got the idea for the new material from the tough cellular skin of the grapefruit and the fracture resistant shells of molluscs
To resist the most violent forcible entry tools, organic materials such as aragonite tiles – found in mollusc shells – were replaced in the new material with industrial, alumina ceramics and an aluminium, metallic foam matrix.
‘This material could have lots of useful and exciting applications in the security and safety industries,’ explained Dr Szyniszewski.
‘In fact, we are not aware of any other manufactured non-cuttable material in existence as of now,’ he said.
Dr Miranda Anderson, Department of Philosophy, University of Stirling said, said the name came about because the material undergoes internal transformations.
‘In 1605, Francis Bacon compared natural materials to Proteus who ‘ever changed shapes’ and he argued that through experimentation we can reveal the metamorphic qualities of materials,’ Anderson explained.
Dr Szyniszewski added: ‘This is what we’ve achieved with this new material and we’re excited by its potential.’
The researchers have a patent pending for their material technology and they hope to work with industry partners so it can be developed into products for the marketplace in the future.
The findings are published in the journal Scientific Reports.