Tensile behaviors of filaments with misfit of chirality  

手性失配细长丝的拉伸行为

作　　者：Yingbin Zhang Huichuan Zhao Hongjun Yu Qinghua Qin Jianshan Wang 张迎宾;赵辉川;于红军;秦庆华;王建山(Department of Mechanics,Tianjin University,Tianjin,300054,China;Department of Astronautic Science and Mechanics,Harbin Institute of Technology,Harbin,150001,China)

机构地区：[1]Department of Mechanics,Tianjin University,Tianjin,300054,China [2]Department of Astronautic Science and Mechanics,Harbin Institute of Technology,Harbin,150001,China

出　　处：《Acta Mechanica Sinica》2022年第11期115-127,共13页力学学报（英文版）

基　　金：the National Natural Science Foundation of China(Grant Nos.12020101001,12021002,11872273,and 11890680);Tianjin Research Program of Application Foundation and Advanced Technology(Grant No.19JCYBJC19300).

摘　　要：Slender chiral filaments are ubiquitous in both artificial and biological materials.Due to their chiral microstructures,chiral filaments usually exhibit favorable properties such as superior elasticity and unusual stretch-twist coupling deformation.However,how these chiral microstructures affect the elastic behavior of filaments remains unclear.In this paper,a refined Cosserat rod model with misfit or mismatching of chirality induced by inhomogeneous arrangement of chiral microstructures incorporated is developed.Using the refined rod model,the force-displacement relationships and variation of structural chirality during the tensile processes of two typical helical structures,i.e.,single-strand helix and double-strand helix,are investigated.The results show that the misfit of chirality can lead to a bend-twist deformation with a high coupling degree,which makes the rod much“soft”when stretched.The chiral filaments undergo an unusual twist when stretched,corresponding to an obviously nonlinear variation of structural chirality.The work suggests that the misfit of chirality can be used to tune the elastic behavior of chiral filaments,which is helpful in guiding the design of flexible actuators and soft devices.手性细长丝在人工和生物材料中普遍存在.由于具有手性微结构,手性丝通常表现出优异的弹性和拉伸-扭转耦合变形等性能.然而,手性微结构如何影响细长丝的弹性行为尚不清楚.本文提出了一种考虑手性微结构和手性失配的精细弹性细杆模型.基于此模型,研究了单股螺旋和双股螺旋等手性丝组装结构在拉伸过程中的力-位移关系和结构手性变化.结果表明,手性失配会导致明显的弯曲-扭转耦合变形,使杆在拉伸时柔性更大.手性长丝在拉伸时还表现出类似DNA的反常扭转行为,可用结构手性的非线性变化来解释.该研究表明手性失配可用于调控手性丝的性能,有助于柔性执行器和软机器等柔性器件的设计.

关 键 词：Misfit of chirality Unusual twist Bend-twist coupling deformation Structural chirality Force-displacement relationship 

分 类 号：O613.71[理学—无机化学]