Large recoverable elastic energy in chiral metamaterials via twist buckling

• 成果类型: Article
• 署名作者: Fang, Xin; Yu, Dianlong; Wen, Jihong; Dai, Yifan; Begley, Matthew R.; Gao, Huajian; Gumbsch, Peter
• 署名单位: National University of Defense Technology - China; University of California System; University of California Santa Barbara; Tsinghua University; Helmholtz Association; Karlsruhe Institute of Technology; Fraunhofer Gesellschaft; Fraunhofer Germany; Fraunhofer Mechanics of Materials
• 刊物名称: Nature
• ISSN/ISSBN: 0028-1705
• DOI: 10.1038/s41586-025-08658-z
• 发表日期: 2025-03-20
• 关键词: mechanical metamaterials; strain-energy; storage

摘要

Mechanical metamaterials with high recoverable elastic energy density, which we refer to as high-enthalpy elastic metamaterials, can offer many enhanced properties, including efficient mechanical energy storage1,2, load-bearing capability, impact resistance and motion agility. These qualities make them ideal for lightweight, miniaturized and multi-functional structures3, 4, 5, 6, 7-8. However, achieving high enthalpy is challenging, as it requires combining conflicting properties: high stiffness, high strength and large recoverable strain9, 10-11. Here, to address this challenge, we construct high-enthalpy elastic metamaterials from freely rotatable chiral metacells. Compared with existing non-chiral lattices, the non-optimized chiral metamaterials simultaneously maintain high stiffness, sustain larger recoverable strain, offer a wider buckling plateau, improve the buckling strength by 5-10 times, enhance enthalpy by 2-160 times and increase energy per mass by 2-32 times. These improvements arise from torsional buckling deformation that is triggered by chirality and is absent in conventional metamaterials. This deformation mode stores considerable additional energy while having a minimal impact on peak stresses that define material failure. Our findings identify a mechanism and provide insight into the design of metamaterials and structures with high mechanical energy storage capacity, a fundamental and general problem of broad engineering interest.