TAGS: 3D Printing Nanotechnologies Metal Replacement
Researchers from University of Glasgow have developed a new plate-lattice cellular metamaterial, capable of impressive resistance to impacts. The new form of 3D-printed material made by combining commonly used plastics with carbon nanotubes is tougher and lighter than similar forms of aluminum.
The material could lead to the development of safer, lighter and more durable structures for use in the aerospace, automotive, renewables and marine industries.
Investigating Metamaterial for Advanced Properties
One form of metamaterials, known as plate-lattices, are cubic structures made from intersecting layers of plates that exhibit unusually high stiffness and strength, despite featuring a significant amount of space between the plates. Those spaces, which are a property engineers call porosity, also makes plate-lattices unusually lightweight.
The researchers set out to investigate whether new forms of plate-lattice design, manufactured from a plastic-nanotube composite they developed, could make a metamaterial with even more advanced properties of stiffness, strength and toughness.
The composite uses mixtures of polypropylene and polyethylene and multi-wall carbon nanotubes, tiny filaments constructed from carbon atoms.
Dr. Shanmugam Kumar, University of Glasgow, lead researcher, said, “
This work sits right at the intersection of mechanics and materials. The balance between the carbon nanostructure-engineered filaments we’ve developed as a feedstock for 3D printing, and the hybrid composite plate-lattice designs we’ve created, has produced an exciting result. In the pursuit of lightweight engineering, there is a constant hunt for ultra-lightweight materials featuring high performance. Our nanoengineered hybrid plate-lattices achieve extraordinary stiffness and strength properties and exhibit superior energy absorption characteristics over similar lattices built with aluminum."
Impact Testing the Nanoengineered Composite
Researchers used their nanoengineered filament composite as the feedstock in a 3D printer which fused the filaments together to build a series of plate-lattice designs. Those designs were then subjected to a series of impact tests by dropping a 16.7kg mass from a range of heights to determine their ability to withstand physical shocks.
First, the team tested three types of typical plate-lattices they designed and built – a simple cube formed from the intersection of three plates, a more complex cube with additional intersecting plates, and a more multifaceted design. Those typical plate-lattices were made in two batches – one from polypropylene and one from polyethylene.
Then, they tested three more ‘hybrid’ plate-lattices which incorporated features from the simpler designs in the first experiments – a simple cube/complex cube hybrid, a simple cube/multifacet hybrid and one which amalgamated all three. Again, batches made from polypropylene and polyethylene were made.
The hybrid design which amalgamated elements of all three typical plate-lattice designs proved to be the most effective in absorbing impacts, with the polypropylene version showing the greatest impact resistance. Using specific energy absorption, the team found that the polypropylene hybrid plate-lattice could withstand 19.9 joules per gram – a superior performance over similarly designed micro architected aluminum metamaterials.
Application in Automobile Manufacture
One application for this new kind of plate-lattice might be in automobile manufacture, where designers perpetually strive to build more lightweight bodies without sacrificing safety during crashes. Aluminum is used in many modern car designs, but the plate-lattice offers greater impact resistance, which could make it useful in those kinds of applications in the future.
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The recyclability of the plastics we’re using in these plate-lattices also makes them attractive as we move towards a net-zero world, where circular economic models will be central to making the planet more sustainable,” said Dr. Kumar.
Source: University of Glasgow