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Article
Publication date: 22 October 2018

Salvatore Brischetto

The main idea is the comparison between composites including natural fibres (such as the linoleum fibres) and typical composites including carbon fibres or glass fibres. The…

384

Abstract

Purpose

The main idea is the comparison between composites including natural fibres (such as the linoleum fibres) and typical composites including carbon fibres or glass fibres. The comparison is proposed for different structures (plates, cylinders, cylindrical and spherical shells), lamination sequences (cross-ply laminates and sandwiches with composite skins) and thickness ratios. The purpose of this paper is to understand if linoleum fibres could be useful for some specific aerospace applications.

Design/methodology/approach

A general exact three-dimensional shell model is used for the static analysis of the proposed structures to obtain displacements and stresses through the thickness. The shell model is based on a layer-wise approach and the differential equations of equilibrium are solved by means of the exponential matrix method.

Findings

In qualitative terms, composites including linoleum fibres have a mechanical behaviour similar to composites including glass or carbon fibres. In terms of stress and displacement values, composites including linoleum fibres can be used in aerospace applications with limited loads. They are comparable with composites including glass fibres. In general, they are not competitive with respect to composites including carbon fibres. Such conclusions have been verified for different structure geometries, lamination sequences and thickness ratios.

Originality/value

The proposed general exact 3D shell model allows the analysis of different geometries (plates and shells), materials and laminations in a unified manner using the differential equilibrium equations written in general orthogonal curvilinear coordinates. These equations written for spherical shells degenerate in those for cylinders, cylindrical shell panels and plates by means of opportune considerations about the radii of curvature. The proposed shell model allows an exhaustive comparison between different laminated and sandwich composite structures considering the typical zigzag form of displacements and the correct imposition of compatibility conditions for displacements and equilibrium conditions for transverse stresses.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 9
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 14 August 2017

S. Brischetto

The purpose of this paper is to propose a comparative study between different structures composed of fiber-reinforced composite materials. Plates, cylinders and cylindrical and…

274

Abstract

Purpose

The purpose of this paper is to propose a comparative study between different structures composed of fiber-reinforced composite materials. Plates, cylinders and cylindrical and spherical shell panels in symmetric 0°/90°/0° and antisymmetric 0°/90°/0°/90° configurations are analyzed considering carbon fiber, glass fiber and linoleum fiber reinforcements.

Design/methodology/approach

A free vibration analysis is proposed for different materials, lamination sequences, vibration modes, half-wave numbers and thickness ratios. Such an analysis is conducted by means of an exact three-dimensional shell model which is valid for simply supported structures and cross-ply laminations. The employed model is based on a layer-wise approach and on three-dimensional shell equilibrium equations written in general orthogonal curvilinear coordinates.

Findings

The proposed study confirms the well-known superiority of the carbon fiber-reinforced composites. Linoleum fiber-reinforced composites prove to be comparable to glass fiber-reinforced composites in the case of free vibration analysis. Therefore, similar frequencies are obtained for all the geometries, thickness ratios, laminations sequences, vibration modes and a large spectrum of half-wave numbers. This partial conclusion needs further confirmations via static, buckling and fatigue analyses.

Originality/value

An exact three-dimensional shell model has been used to compare several geometries embedding carbon fiber composites and natural fiber composites.

Details

Multidiscipline Modeling in Materials and Structures, vol. 13 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 22 June 2012

Salvatore Brischetto and Erasmo Carrera

The purpose of this paper is to consider the static analysis of nanocomposite plates. Nanocomposites consist of a small amount of nanoscale reinforcements which can have an…

305

Abstract

Purpose

The purpose of this paper is to consider the static analysis of nanocomposite plates. Nanocomposites consist of a small amount of nanoscale reinforcements which can have an observable effect on the macroscale properties of the composites.

Design/methodology/approach

In the present study the reinforcements considered are non‐spherical, high aspect ratio fillers, in particular nanometer‐thin platelets (clays) and nanometer‐diameter cylinders (carbon nanotubes, CNTs). These plates are considered simply supported with a bi‐sinusoidal pressure applied at the top. These conditions allow the solving of the governing equations in a closed form. Four cases are investigated: a single layered plate with CNT reinforcements in elastomeric or thermoplastic polymers, a single layered plate with CNT reinforcements in a polymeric matrix embedding carbon fibers, a sandwich plate with external skins in aluminium alloy and an internal core in silicon foam filled with CNTs and a single layered plate with clay reinforcements in a polymeric matrix. A short review of the most important results in the literature is given to determine the elastic properties of the suggested nanocomposites which will be used in the proposed static analysis. The static response of the plates is obtained by using classical two‐dimensional models such as classical lamination theory (CLT) and first order shear deformation theory (FSDT), and an advanced mixed model based on the Carrera Unified Formulation (CUF) which makes use of a layer‐wise description for both displacement and transverse stress components.

Findings

The paper has two aims: to demonstrate that the use of classical theories, originally developed for traditional plates, is inappropriate to investigate the static response of nanocomposite plates and to quantify the beneficial effect of the nanoreinforcements in terms of static response (displacements and stresses).

Originality/value

In the literature these effects are usually given only in terms of elastic properties such as Young moduli, shear moduli and Poisson ratios, and not in terms of displacements and stresses.

Details

Multidiscipline Modeling in Materials and Structures, vol. 8 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

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