A Bio-Inspired Approach to Material Design
MIE Postdoctoral Research Associate Richard Nash, PhD’23, and Associate Professor Yaning Li published their research, “On-demand Auxeticity and Co-existing Pre-tension Induced Compression Stage in a Sandwich Design With Kinematically Constrained 3D Suture Tiles,” in Nature Communications. The paper reported a new bio-inspired strategy to create synergy between auxeticity and tensegrity in 3D printed architected materials, as it can open up new possibilities for materials and structures for a variety of applications, including designing new multi-functional mechanical metamaterials, medical implants, sports equipment, physically intelligent materials or devices, and aerospace components.
Abstract Source: Nature
By incorporating concepts from auxeticity, kinematic constraints, pre-tension induced compression (PIC), and suture tessellations, tiled sandwich composites are designed, demonstrating behaviors attributed to the synergy between auxeticity and pre-tension induced contact and compression, simultaneously triggered by a threshold strain. The designs can theoretically achieve on-demand Poisson’s ratio in the widest range (−∞, +∞), and once triggered, the Poisson’s ratio is stable under large deformation. Also, once the overall strain goes beyond the threshold, the designs enter into a PIC stage, ensuring the middle soft layer takes the tensile load, while the tiles are under compression via contact and the 3D articulation of the tooth-channel pairs. In this PIC stage, the tooth-channel pairs provide kinematic constraints via the contact and relative sliding between teeth and channels. The deformation mechanisms and mechanical properties of them are systematically explored via an integrated analytical, numerical, and experimental approach. Mechanical experiments are performed on 3D printed specimens. It is found that the length aspect ratio and the obliqueness of the teeth significantly influence the constraint angle and therefore the auxeticity and strength of the designs.