单层MoS_(2)的热弹耦合非线性板模型  

Nonlinear plate theory of single-layered MoS_(2) with thermal effect

作　　者：黄坤 王腾飞[1] 姚激 Huang Kun;Wang Teng-Fei;Yao Ji(Department of Engineering Mechanics,Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming 650500,China;Key Laboratory of Disaster Reduction in Civil Engineering,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学建筑工程学院,工程力学系,昆明650500 [2]昆明理工大学,云南省土木工程防灾重点实验室,昆明650500

出　　处：《物理学报》2021年第13期258-264,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12050001,11562009)资助的课题.

摘　　要：单层二硫化钼(MoS_(2))是有广泛应用前景的二维纳米材料,但其力学性质还没有被深入研究,特别是其热弹耦合力学行为迄今还没有被关注到.本文首次提出了考虑热应力影响的单层MoS_(2)的非线性板理论,并对比研究了其与石墨烯的热弹耦合力学性质.对于不可移动边界,结果显示:1)有限温度产生的热应力降低了MoS_(2)的刚度,但提高了石墨烯的刚度;2)在相同几何尺寸和温度条件下,变形较小时MoS_(2)的刚度大于石墨烯,但伴随变形的增大,MoS_(2)的刚度将小于石墨烯.研究结果表明,边界预加轴向外力和环境温度可以调节单层二维纳米结构力学性质.本文建立的热弹耦合板模型,可以推广至其他单层二维纳米结构.The single-layered molybdenum disulfide(MoS_(2))is a two-dimensional nanomaterial with wide potential applications due to its excellent electrical and frictional properties.However,there have been few investigations of its mechanical properties up to now,and researchers have not paid attention to its nonlinear mechanical properties under the multi-fields co-existing environment.The present paper proposed a nonlinear plate theory to model the effect of finite temperatures on the single-layered MoS_(2).It is similar to the classical plate theory that both the in-plane stretching deformation and the out-of-plane bending deformation are taken into account in the new theory.However,the new theory consists of two independent in-plane mechanical parameters and two independent out-of-plane mechanical parameters.Neither of the two out-of-plane mechanical parameters in the new theory,which describe the resistance of MoS_(2) to the bending and the twisting,depends on the structure’s thickness.This reasonably avoids the Yakobson paradox:uncertainty stemming from the thickness of the single-layered two-dimensional structures will lead to the uncertainty of the structure’s out-of-plane stiffness.The new nonlinear plate equations are then solved approximately through the Galerkin method for the thermoelastic mechanical problems of the graphene and MoS_(2).The approximate analytic solutions clearly reveal the effects of temperature and structure stiffness on the deformations.Through comparing the results of two materials under combined temperature and load,it is found,for the immovable boundaries,that(1)the thermal stress,which is induced by the finite temperature,reduces the stiffness of MoS_(2),but increases the stiffness of graphene;(2)the significant difference between two materials is that the graphene’s in-plane stiffness is greater than the MoS_(2)'s,but the graphene’s out-of-plane stiffness is less than the MoS_(2)'s.Because the MoS_(2)'s bending stiffness is much greater than graphene’s,the graphene’s deform

关 键 词：单层MoS_(2) 石墨烯 热应力 非线性板理论 

分 类 号：TQ136.12[化学工程—无机化工]