摘要
力学超材料(或超结构)因其独特的微观结构设计而展现超常的物理和力学特性.将力学超材料设计思想与智能柔性(简称智柔)材料相结合,可以制备出具有自感知和自驱动功能的智柔力学超材料(简称智柔超材料).本文对近年来智柔超材料的研究现状和进展进行了评述,分析了此类材料的基本设计思想、变形机理及力学特性,重点关注了基于形状记忆聚合物和水凝胶智柔超材料的设计原理和性能分析方法;阐释了先进制造技术为智柔超材料发展带来的机遇,并讨论了此类材料在设计和开发方面面临的关键问题以及未来发展趋势.
Abstract
Mechanical metamaterials(or meta-structures)exhibit extraordinary physical and mechani-cal properties due to their unique microstructural designs.By combining the design ideas of mechanical metamaterials with intelligent and flexible materials(IFMs),it is possible to create intelligent flexible me-chanical metamaterials(IFMMs)with self-sensing and self-actuating capabilities.This paper takes conven-tional mechanical metamaterials as a starting point and analyzes the fundamental design ideas,deformation mechanisms,and mechanical properties of IFMMs.According to recent research progress on IFMMs,this novel metamaterial is categorized as mechanical metamaterial based on shape memory polymers(SMPs),hydrogel,magnetoactive soft materials,and dielectric elastomers,with a particular focus on the first two types.On the basis of our previous work,we present a general approach that utilizes analytical methods and numerical simulations to analyze the mechanical properties of negative Poisson's ratio,negative expan-sion,and multi-stable metamaterials under the assumptions of small deformation and large deformation with multi-field coupling,respectively.In the case of small deformation,the use of beam theory and ener-gy methods proves to be essential for obtaining fundamental mechanical parameters of the materials.More-over,accurate constitutive models and numerical implementation under large deformation and multi-field coupling offer the possibility to analyze more complex deformations and structures.In addition,the prepa-ration and performance testing of IFMMs remain crucial.Advanced manufacturing techniques have intro-duced new opportunities for the preparation of IFMMs,and currently,various methods are available to ef-fectively prepare these materials.The performance testing of IFMMs includes both experiments applicable to traditional materials and specialized experiments only for IFMs.Finally,this paper concludes by high-lighting some key issues and potential trends of IFMMs.These challenges primarily revolve around materi-al properties,fabrication methods,mechanical models,and structural designs.This review may bring ben-eficial inspiration for the future development of IFMMs.
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