Researchers maximise stiffness of lightweight materials

3D printing makes it possible to manufacture materials with complex internal structures, such as those with a high proportion of voids that nevertheless remain stable. Achieving this requires the internal structures to be “intelligently organised for maximum efficiency”, explained the Federal Institute of Technology (ETH) in a statement.

Now, researchers from the ETH and colleagues from the Massachusetts Institute of Technology (MIT) have developed such materials. With their method, the stiffness in the material’s interior is achieved through repeated plate-lattices rather than trusses.

“The truss principle is very old; it has long been used for half-timbered houses, steel bridges and steel towers, such as the Eiffel Tower,” explained ETH Professor Dirk Mohr. With his team, he has been able to show that plate-lattice structures are up to three times stiffer than truss-lattices of the same weight and volume. According to the ETH, the researchers’ development approaches “theoretical maximum values” with stiffness and strength.    

The new construction method boasts universally applicable advantages – for all materials and on all length scales, highlighted Mohr. Manufacturing with 3D printing is still too expensive to render the method cost-effective for mass production. However, once 3D printing is cheap enough for mass production, “the breakthrough will come”, said Mohr. While the current costs of lightweight construction limit its practical use to aircraft manufacturing and space applications, it could later be used for a wide array of applications in which weight plays a role, according to Mohr. Examples cited in the statement include medical implants, laptop casings and ultralight vehicle structures.