折纸超材料折展稳态特性研究

STUDY ON FOLDING STABILITY OF ORIGAMI METAMATERIALS

可折展折纸超材料可通过自身内部微结构连续变形来调控宏观变形,使其泊松比、刚度、模量等力学性能发生转变.本文针对新型折纸超材料稳态机理不清晰的问题,采用扭转弹簧等效法和能量原理,对折纸超材料在复杂内部构型及折展运动协同作用下的力学行为进行理论研究,建立超材料构型在折展变形过程中的力学模型,分析构型几何参数对折展外载荷的影响规律.通过参数分析发现,该折纸超材料的外载荷在展开过程中呈现出单调性,不具有稳态特性.外载荷在折叠过程中可呈现出单调性、单稳态和双稳态等多种情况,不同稳态之间的调控与边长比p和q、内角α、折展角θ和间距尺寸比r等构型参数密切相关,从而揭示折纸超材料稳态特性的转变机理.本文对于提高折纸超材料的构型设计及其性能调控具有重要的理论指导意义.

Origami metamaterials can regulate and control macroscopic deformation by continuous deformation of their internal microstructure. Hence, mechanical properties such as Poisson’s ratio, stiffness, and modulus of the metamaterials can be adjusted and designed. This work theoretically studied the mechanical behavior of origami metamaterials under the synergy of complex internal configuration and folding motion, with the methods of torsion spring equivalent and energy principle. Here, we established a mechanical model to describe the folding deformation of the metamaterials, and analyzed the influence of geometric parameters on external loading. Through parameter analysis, it is found that the external loading exhibits monotonicity during the unfolding process and does not have stability. The external loading can show three situations such as monotonicity, mono-stability and bi-stability during the folding process, which are closely related to the parameters. This work provides important guidance to origami metamaterials for improving the design of the configuration and the regulation of their performance.