Timoshenko beam model for chiral materials

作     者：T.Y.Ma Y.N.Wang L.Yuan J.S.Wang Q.H.Qin 

作者机构：Department of Mechanics Tianjin University School of Engineering Deakin University Research School of Engineering Australian National University 

出 版 物：《Acta Mechanica Sinica》 (力学学报（英文版）)

年 卷 期：2018年第34卷第3期

页      面：549-560页

核心收录：

学科分类：08[工学] 080102[工学-固体力学] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China (Grants 11472191  11272230  and 11372100) 

主　　题：Timoshenko beam model Chiral material Chirality Deflection Microrotation 

摘      要：Natural and artificial chiral materials such as deoxyribonucleic acid （DNA）, chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton＇s principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.