Dong Le, Zhang Mengjie, Wang Dong
State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Shanghai Key Laboratory of Intelligent Robotics, Meta Robotics Institute, Shanghai Jiao Tong University, Shanghai 200240, China.
Mater Horiz. 2025 Jul 14;12(14):5236-5251. doi: 10.1039/d4mh01582g.
Lattice metamaterials made of stiff polymers, ceramics, and metals have been extensively designed to reproduce the mechanical behaviors of biological tissues, holding promising applications in biomedical devices and tissue engineering. However, lattice metamaterials composed of soft materials have been far less explored due to challenges posed by material nonlinearity and large deformations. Here, hyperelastic lattice metamaterials with curved microstructures are fabricated by 3D printing elastomers and are developed to mimic bionic S-shaped stress-strain behaviors. We propose a design framework for 3D printed hyperelastic lattice metamaterials that integrates digital geometry generation, hierarchical mechanics modeling, and validation by finite element (FE) simulations and experiments. The microstructures are modeled through deriving a Timoshenko-type beam theory governed by hyperelastic strain energy potentials. The model is then combined with the deformation and equilibrium analysis considering non-rigid connections between microstructures to predict the mechanical responses of hyperelastic lattice metamaterials. Using the developed design framework, programmable S-shaped stress-strain behaviors and high fracture strains (over 800%) are achieved. We demonstrate S-shaped stress-strain curves that match skeletal and cardiac muscles and highly stretchable lattice sensors for remote controls. This study provides design methods and theoretical guidelines for hyperelastic lattice metamaterials, holding promise for robotic sensors with bionic performance and functionality.
由硬质聚合物、陶瓷和金属制成的晶格超材料已被广泛设计用于重现生物组织的力学行为，在生物医学设备和组织工程中具有广阔的应用前景。然而，由于材料非线性和大变形带来的挑战，由软材料组成的晶格超材料的研究还很少。在此，通过3D打印弹性体制造出具有弯曲微结构的超弹性晶格超材料，并将其开发用于模拟仿生S形应力-应变行为。我们提出了一种用于3D打印超弹性晶格超材料的设计框架，该框架集成了数字几何生成、分层力学建模，并通过有限元（FE）模拟和实验进行验证。通过推导由超弹性应变能势控制的铁木辛柯型梁理论对微结构进行建模。然后将该模型与考虑微结构之间非刚性连接的变形和平衡分析相结合，以预测超弹性晶格超材料的力学响应。使用所开发的设计框架，实现了可编程的S形应力-应变行为和高断裂应变（超过800%）。我们展示了与骨骼肌和心肌相匹配的S形应力-应变曲线以及用于遥控器的高拉伸性晶格传感器。本研究为超弹性晶格超材料提供了设计方法和理论指导，有望用于具有仿生性能和功能的机器人传感器。
