An Assessment of Thick Nanocomposite Plates’ Behavior under the Influence of Carbon Nanotubes Agglomeration

Maria A. R. Loja,Débora S. Craveiro

doi:10.3390/jcs5020041

Abstract

The influence assessment of carbon nanotubes (CNTs) agglomeration on CNT-reinforced composite (CNTRC) thick plates’ behavior is the main aim of the present work. CNTs are known to agglomerate into clusters even for relatively low volume fractions, which imposes the need to characterize the effects this may introduce in structures behavior, also knowing that recent works have concluded that neglecting agglomeration phenomenon may lead to an overestimation of the mechanical properties of nanocomposites. Hence, it matters to understand how the arising of these clusters may affect the static and free vibrational behaviors of low side-to-thickness nanocomposite plates. To this purpose, the nanocomposite plate properties’ estimation is performed by using the two-parameter model of agglomeration based on the Eshelby–Mori–Tanaka approach, while for behavioral analyses one considers a Higher-order Shear Deformation Theory (HSDT) based on the displacement field of Kant, implemented through the finite element method. The analyses developed consider a set of parametric studies involving the assessment of the influence of side-to-side ratios, side-to-thickness ratios, boundary conditions, and CNTs’ distributions along the thickness. The results obtained allow concluding that the transverse deflections and fundamental frequencies of these structures are significantly influenced by the CNTs’ agglomeration.

Highlights

Carbon nanotubes (CNTs) have excellent mechanical, thermal, and electrical properties, besides their high aspect ratio and large surface area, which make them a desirable material in many engineering applications [1,2,3]
Another study developed by the same author [14] addressed the response of CNT-reinforced plates and shells under a static loading and CNTs agglomeration using Carrera Unified Formulation, having this study revealed that the stresses and the strains of these structures were highly affected by the agglomeration effect
The property estimation is based on the two-parameter agglomeration model based on the Eshelby–Mori–Tanaka approach described for the first time by Shi et al [8], which is based on an equivalent fiber concept

Summary

Introduction

Carbon nanotubes (CNTs) have excellent mechanical, thermal, and electrical properties, besides their high aspect ratio and large surface area, which make them a desirable material in many engineering applications [1,2,3]. Assessing the material properties of a CNTRC is of utmost importance, using the traditional homogenization schemes for particle-reinforced composites might lead to an over estimation of the material properties, since CNTs tend to bundle together forming inclusions within polymeric matrices, which affects the mechanical properties of the resulting CNTRC, usually in a non-desirable manner. This phenomenon occurs due to their high aspect ratio, van der Waals forces and their low bending stiffness values [4,5,6,7]. This model is appropriate for modelling the material properties of randomly oriented CNTs within a matrix, based on an equivalent CNT fiber

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