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3D Printed Fractal Metamaterials with Tunable Mechanical Properties and Shape Reconfiguration |
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| Authors: | Dong Wang Le Dong Guoying Gu |
| Affiliation: | 1. Robotics Institute, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China;2. Robotics Institute, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai, 200240 China Meta Robotics Institute, Shanghai Jiao Tong University, Shanghai, 200240 China |
| Abstract: | Lattice metamaterials constructed by curved microstructures exhibit large stretchability and are promising in soft electronics and soft robotics. Fractal structures are particularly efficient in improving stretchability as it shows multiple-order uncurling. However, the development of fractal metamaterials is hindered by hierarchical structures and large deformations. In this study, a design framework combining experiments, hierarchical theoretical models, and finite element simulations is developed to program the mechanical behaviors of fractal metamaterials. For 3D printing, a digital design tool is developed to visualize the structure and automatically generate the manufacturing representations. Results show that large stretchability (≈360%), bionic stress–strain curve matching, and imperfection insensitivity can be programmed by tuning the geometric parameters. An integrated device of an electromyogram sensor embedded in an imperfection-insensitive fractal metamaterial that matches the J-shaped stress–strain curve of human skin is demonstrated. Light-emitting diode devices based on fractal metamaterial with shape reconfiguration are also presented. This st paves a new way to realize multifunctional soft devices using fractal metamaterials. |
| Keywords: | fractal metamaterials imperfection insensitivity shape reconfiguration tunable mechanical properties |