chalk is very brittle and easily broken . However , the body of the starfish demonstrates high strength and flexibility . Uncovering the underlying principles of this structure may help solve the challenges of making stronger porous ceramics .
What the team found was unexpected . As in other starfish species , the skeleton of the knobby star consists of many millimeter-sized skeletal elements called ossicles . These ossicles connect with soft tissue , allowing the animal to be flexible and move . Li and his team discovered that each ossicle is constructed of a microlattice structure so uniform that it can be described mathematically , composed of branches connected through nodes in similar vein to the structure of the Eiffel Tower . Even more interesting , the team found the uniform structure of the microlattice , because of the alignment of its atoms , is essentially a single crystal structure at atomic level .
“ This unique material is like a periodic lattice carved from a piece of single crystal of calcite ,” Li said . “ This nearly perfect microlattice has not been reported in nature or fabricated synthetically before . Most highly regular lattice materials are made by combining materials with small crystals to create composites , but this is new . It ’ s grown as a single piece .”
This structure allows a starfish to reinforce its skeleton strategically in particular directions , offering enhanced protection . In addition , it appears the animal can thicken branches along selected directions and in particular regions , improving its mechanical performance in a similar manner to how the human body possesses the ability to alter the local geometry of its porous bones to adapt to physical activity . In the starfish , researchers also found regions where the structure appeared to modify the regular lattice pattern of its design , a feature that inhibits crack expansion when the microlattice fractures .
Patricia Dove , an expert in biomineralization , a University Distinguished Professor , and the C . P . Miles Professor of Science in the Virginia Tech Department of Geosciences , said this biological discovery could have a major impact on the field of bio-inspired innovation .
“ Starfish and other echinoderms living in highly predatory sea floor environments are revealing a world of materials innovations that are critical to survival ,” Dove said . “ Using little more than seawater and some organic components , biology directs the formation of remarkable skeletons such as those in starfish . This novel study of the underlying mechanical engineering properties has tremendous potential as a frontier for new materials design .”
WHAT ’ S NEXT ?
Knowing the architecture of natural microstructures represented a huge step forward , but Li and his team had more questions . Was there a key to the way in which the creatures grow their skeletons that might shed some light on a way to reproduce them ?
Li and his collaborators used 3D printing to model and generate large-scale versions of these complex lattice structures for both research and educational purposes , a useful approach in understanding the complexity of these unique geometries . While the 3D-printed models created by Li ’ s team were indeed visually inspiring , the technology needed to bring new , stronger ceramic micro-architectures to market still lay in the future . Currently , 3D printers produce structures at the micrometer level , but printing ceramics still requires firing the final product , which possibly introduces many
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