Browsing by Author "Lu, Ting-Chu"

Now showing 1 - 2 of 2

Characterizing load transfer efficiency in double-walled carbon nanotubes using multiscale finite element modeling
(2013-01-01)
Lu, Ting-Chu
;
Tsai, Jia-Lin
;
機械工程學系
;
Department of Mechanical Engineering
Load transfer efficiency from matrix to carbon nanotubes (CNTs) plays an important role in the mechanical response of CNTs nanocomposites as it may affect the effectiveness of the nano-reinforcements. For double-walled carbon nanotubes (DWCNTs), the outer graphene layer as well as the inner layer may be responsible for the load bearing capacity. In this study, the load transfer efficiency within DWCNTs was investigated using a multiscale simulation scheme. The multiscale simulation consists of two steps. First, the atomistic behaviors between the adjacent graphite layers in DWCNTs were characterized using molecular dynamic (MD) simulation, from which a cylindrical equivalent continuum solid of DWCNTs with embedded spring elements was proposed to describe the interactions of neighboring graphene layers. Two kinds of interatomistic properties in DWCNTs, i.e., van der Walls (vdW) interactions and artificial build-up covalent bonds, were considered in the equivalent solid. Subsequently, the equivalent solid was implemented as reinforcement in the micromechanical model of CNTs nanocomposites for evaluating the load transfer efficiency. Results indicated that the DWCNTs with covalent bonds exhibit superior load transfer efficiency than those with only vdW interactions. In addition, when the DWCNTs get long, the load transfer efficiency of DWCNTs increases accordingly. (C) 2012 Elsevier Ltd. All rights reserved.
Investigating the load transfer efficiency in carbon nanotubes reinforced nanocomposites
(2009-09-01)
Tsai, Jia-Lin
;
Lu, Ting-Chu
;
機械工程學系
;
Department of Mechanical Engineering
The load transfer efficiency from surrounding matrix to the carbon nanotubes (CNTs) in the CNTs reinforced nanocomposites was studied. Both single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) were taken into account in the investigation. A cylindrical representative volume element (RVE) containing the CNTs and matrix phases were employed in the shear lag analysis from which the axial stress distribution as well as the load transfer efficiency in the CNTs was characterized. The effects of the layer number, atomistic interaction of graphite layers, and the aspect ratio of the CNTs on the load transfer efficiency were of concern. Results indicated that the SWCNTs exhibit a greater load transfer efficiency than MWCNTs associated with the same CNTs volume fraction in the nanocomposites. Moreover, the incompetent behaviors of the MWCNTs would become substantial as the number of graphite layers increases, and the deficient load transfer efficiency in the MWCNTs would not be modified effectively even though the chemical bonding between the graphite layers were constructed. (C) 2009 Elsevier Ltd. All rights reserved.