Nature is an engineer’s greatest teacher. Humans have developed surgical needles from mosquitos, LED bulbs from fireflies, and even helicopter tech from hummingbirds. To create some of the toughest aerospace materials, engineers also ripped a page from evolution’s playbook by recreating the lattice structures in hollow struts found in Victorian water lilies and hardy organ pipe coral.
However, recreating these natural structures has been an engineering headache, as limited manufacturing ability means these lattice structures don’t live up to their load-bearing potential. Luckily, the era of 3D printing now offers a level of finesse that finally allows engineers to unlock nature’s light-yet-durable secrets.
In a new paper published in the journal Advanced Materials, scientists from Royal Melbourne Institute of Technology (RMIT) University in Melbourne, Australia have created a 3D-printed metamaterial that’s 50 percent stronger than the cast magnesium alloy WE54 used in the aerospace industry (which is of a similar density). The team overcame a common problem with these hollow “cellular structures” due to stress being concentrated on certain areas of the strut, which leads to a premature failure. Instead, the scientists designed a multi-topology lattice that distributes load stress evenly to avoid load-bearing “hot spots” while also deflecting cracks along the structure.
“For most topologies, it is common for less than half of the material to mainly bear the compressive load, while the larger volume of material is structurally insignificant,” RMIT University professor and study co-author Ma Qian said in a press statement. “We designed a hollow tubular lattice structure that has a thin band running inside it. These two elements together show strength and lightness never before seen together in nature… by effectively merging two complementary lattice structures to evenly distribute stress, we avoid the weak points where stress normally concentrates.”
To read more, click here.