Wave Propagation of Porous Nanoshells.

Behrouz Karami,Davood Shahsavari,Francesco Tornabene,Rossana Dimitri,Maziar Janghorban

doi:10.3390/nano9010022

Abstract

This study aims at investigating the wave propagation of porous nanoshells. The Bi-Helmholtz non-local strain gradient theory is employed in conjunction with a higher-order shear deformation shell theory, in order to include the size-dependent effects. The nanoshells are made of a porous functionally graded material (P-FGM), whose properties vary continuously along the thickness direction. A variational approach is here applied to handle the governing equations of the problem, which are solved analytically to compute the wave frequencies and phase velocities as function of the wave numbers. The sensitivity of the wave response is analyzed for a varying porosity volume fraction, material properties, non-local parameters, strain gradient length scales, temperature, humidity, and wave numbers. Based on the results, it is verified that the size-dependence of the response is almost the same to the one of plates, beams and tubes.

Highlights

Over the past few years, the research on nanomaterials has gained an increasing attention in the scientific community
We combine the bi-Helmholtz non-local theory and strain gradient theory to study the wave propagation in doubly-curved nanoshells made of porous functionally graded material (P-functionally graded materials (FGMs)), immersed in a hygrothermal environment
Due to the authors’ best knowledge, there is a general lack of works in the open literature in which the size-dependent wave propagation of P-FGM doubly-curved nanoshells was investigated

Summary

Introduction

Over the past few years, the research on nanomaterials has gained an increasing attention in the scientific community. Due to the benefits of nanomaterials, many engineering components are gradually becoming lighter, smaller, stronger, and less expensive. Recent requirements in design and manufacturing has led to an increased development of nanoshells, carbon nanotubes, and paramagnetic nanoparticles for many engineering applications, e.g., biomedicine [1], drug or gene delivery [2], aerospace facilities [3] automobile industry [4] and energy devices [5]. An Equivalent Single Layer (ESL) theory [8,9], for example, represents a sensible way of analyzing the behavior of shell structures, whereas other approaches, such as the

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Conclusion