Shells and grapefruits inspire the first non-cut material manufactured

Engineers have drawn inspiration from peel and grapefruit to create what they say is the first non-cuttable material made.

This new material, which could be used in the health and safety industries, can push the force of a cutting tool back on itself.

Called Proteus by the mythical shape-shifting god, the lightweight material is made of ceramic spheres encased in a cellular aluminum frame that in tests couldn’t be cut with angle grinders, drills, or high-pressure water jets.

An international research team, led by Durham University, UK, and the IWU Fraunhofer Institute for Machine Tools and Training Technology at Chemnitz in Germany, came up with the idea for the new material for the hard cell skin of grapefruit and peels. of fracture resistant molluscs.

Abalone sea creatures are built from interlocking tiles with a biopolymer material that makes them resistant to fractures. To resist the most violent forced entry tools, organic materials such as aragonite tiles, found in shellfish shells, were replaced in the new material with alumina industrial ceramic and an aluminum metal foam matrix.

The new material is strong, light and non-cuttable. The researchers say it could be used to make bicycle locks, lightweight armor, and protective gear for people who work with cutting tools.

The findings are published in the journal. Scientific reportsThe new materials system is dynamic with an evolving internal structure that creates high-speed movement where it interacts with cutting tools. The dynamic response is more like living structures.

The material is made of an aluminum cellular structure wrapped around ceramic spheres and this has a double destructive effect on cutting tools. When cut with an angle grinder or drill, vibrations created by the ceramic spheres inside the housing break the cutting disc or bit.

The interaction between the disc and the ceramic sphere creates an interlocking vibratory connection that resists the cutting tool indefinitely.

The blade gradually erodes, and eventually becomes ineffective as the force and energy of the blade or drill turn on itself, and it weakens and destroys by its own attack.

In addition, the ceramic fragments into fine particles, which fill the cell structure of the material and harden as the speed of the cutting tool increases due to the interatomic forces between the ceramic grains. In this way, the adaptive nature of the material further rejects any attack.

The water jets were also ineffective because the curved surfaces of the ceramic spheres widen the jet, substantially reducing its speed and weakening its cutting ability.

Lead author Dr. Stefan Szyniszewski, Assistant Professor of Applied Mechanics, Department of Engineering, University of Durham, said: “We were intrigued by how the cellular structure of grapefruit and the mosaic structure of mollusk shells can avoid damage to the fruit or creatures inside, despite being made of relatively weak organic building blocks.

“These natural structures informed the operating principle of our metal ceramic material, which is based on dynamic interaction with the applied load, in contrast to passive resistance.

“Essentially cutting our material is like cutting a jelly filled with nuggets. If you go through the jelly, you hit the nuggets and the material will vibrate in such a way as to destroy the cutting disc or bit.

“The ceramic embedded in this flexible material is also made of very fine particles that harden and resist the angle grinder or drill when cut at speed in the same way that a sandbag would resist and stop a bullet at high speed.”

“This material could have many exciting and useful applications in the security and protection industries. In fact, we are not aware of any other non-cuttable manufactured materials that exist so far.”

Study co-author Dr. Miranda Anderson, University of Stirling Department of Philosophy, said: “Because the successful resistance of our material system requires it to undergo internal transformations, we chose the name Proteus.

“In 1605, Francis Bacon compared natural materials with Proteus who ‘once changed shape’ and argued that through experimentation we can reveal the metamorphic qualities of materials.”

Dr. Szyniszewski added: “This is what we have accomplished with this new material and we are excited about its potential.”

The researchers have a patent pending for their materials technology and look forward to working with industry partners to make them products for the market.