A solution inspired by the spiderweb and based on 3D printing


CATEGORY: New advances

The spider is no longer the only one that weaves webs with unbreakable resistance: 3D printers do this job too. A team of researchers from Polytechnique Montreal has just demonstrated how a canvas designed with additive manufacturing absorbs up to 96% of the energy of a crash without yielding.


An innovation that paves the way towards the creation of unbreakable plastic covers, details of which were recently published in Cell Reports Physical Science. The idea behind this post is meant to be relatively simple. Frédérick Gosselin and Daniel Therriault, professors in the Department of Mechanical Engineering at Polytechnique Montreal, as well as PhD student Shibo Zou, wanted to demonstrate how a plastic mesh could be incorporated into a window to prevent it from cracking on impact. A simple idea at first glance, because the plastic net is nothing ordinary. To do this, the researchers were inspired by the properties of cobwebs to design it. "If a cobweb is able to withstand the impact of an insect colliding with it, it is because it has the ability to deform through sacrificial bonds at the molecular level, in the 'within the silk proteins", explains Professor Gosselin , "We build on this strategy in our approach."


Biomimicry by 3D printing

To achieve their coup, the researchers bet on polycarbonate. When heated, this plastic becomes viscous like honey. Professor Gosselin's team took advantage of this property to "weave" a series of fibers less than 2mm thick using a 3D printer, then repeated the process by printing a new series of filaments perpendicularly before the whole did not solidify. And it is precisely during this process that the final product acquires all its properties. As the 3D printer slowly extrudes it to form a fiber, the molten plastic describes circles that eventually form a series of loops. "Once solidified, these loops become sacrificial bonds and give additional strength to the fiber," explains the researcher. "When there is a shock, they take energy and break down to preserve the integrity of the fiber, just like the proteins in silk." Professor Gosselin's team demonstrated the principles behind the manufacture of these fibers in a paper published in 2015. The Cell Reports Physical Science study now reveals how they behave when interwoven into a network.


Shibo Zou, first author of the study, took the opportunity to illustrate how such a canvas could behave inside a protective screen. After coating a series of canvases on transparent resin wafers, he conducted impact tests. The result: the plastic pads dissipated up to 96% of the energy of an impact without breaking. Instead of cracking, they deformed locally, preserving the integrity of the platelets.


© Shibo Zou



According to Professor Gosselin, this nature-inspired innovation could lead to the manufacture of a new type of bulletproof glass or lead to the manufacture of durable plastic protective screens for smartphones. "It could also be used in aeronautics as a protective casing for aircraft engines," said the researcher. In the meantime, you intend to explore the possibilities that might be presented to you with this approach. Professor Gosselin and his team have been supported by the Fonds de Recherche du Québec: Nature et Technologies (FRQNT), the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canadian Foundation for Innovation (CFI).







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