In layered material systems, the presence of interfacial damages such as delaminations reduces the strength of the structure, leading to a premature failure. In order to reduce these effects, in recent years, some researchers proposed to use a new generation of composites, the so-called functionally graded material (FGM), in which the elastic properties vary continuously in the thickness of the structures. In this paper, the effect of functionally graded (FG) interlayers on the elasto-static behavior of a double-sided coated circular plate is investigated in the framework of the elasticity theory. In particular, two perfectly bonded interlayers, with an exponential variation of Young’s modulus along the plate thickness are considered between the core and the coatings of the circular plate. Furthermore, axisymmetric transversal load and boundary conditions on the transversal displacement of the lateral surface are assumed. The elastic solution is obtained by using Plevako’s representation form in cylindrical coordinates that permit us to solve the elasticity equations, also in inhomogeneous layers, in terms of a suitable potential function that satisfy a four-order partial differential equation. The elasticity equations are so written for each layer of the plate-system (core, two coatings and two interlayers) and, in order to construct the solutions of these equations, zero-order Bessel expansions with respect to the radial coordinate are adopted to write the potential functions, in according to a semi-inverse solution method. The explicit three-dimensional solution is obtained using the boundary and interface conditions and the detailed conditions on the lateral surface are determined by the solution method. The accuracy and reliability of the analysis presented is validated by comparing the numerical results obtained by the analytical solution with a three-dimensional finite element analysis. A comprehensive comparative study shows the inherent advantages of the present coating system compared to a conventional homogeneous coating system and a simple system of circular plates with FGM coating layers.

Elastic Analysis of a double side-coated circular plate with functionally graded interlayers

SBURLATI, ROBERTA;
2015-01-01

Abstract

In layered material systems, the presence of interfacial damages such as delaminations reduces the strength of the structure, leading to a premature failure. In order to reduce these effects, in recent years, some researchers proposed to use a new generation of composites, the so-called functionally graded material (FGM), in which the elastic properties vary continuously in the thickness of the structures. In this paper, the effect of functionally graded (FG) interlayers on the elasto-static behavior of a double-sided coated circular plate is investigated in the framework of the elasticity theory. In particular, two perfectly bonded interlayers, with an exponential variation of Young’s modulus along the plate thickness are considered between the core and the coatings of the circular plate. Furthermore, axisymmetric transversal load and boundary conditions on the transversal displacement of the lateral surface are assumed. The elastic solution is obtained by using Plevako’s representation form in cylindrical coordinates that permit us to solve the elasticity equations, also in inhomogeneous layers, in terms of a suitable potential function that satisfy a four-order partial differential equation. The elasticity equations are so written for each layer of the plate-system (core, two coatings and two interlayers) and, in order to construct the solutions of these equations, zero-order Bessel expansions with respect to the radial coordinate are adopted to write the potential functions, in according to a semi-inverse solution method. The explicit three-dimensional solution is obtained using the boundary and interface conditions and the detailed conditions on the lateral surface are determined by the solution method. The accuracy and reliability of the analysis presented is validated by comparing the numerical results obtained by the analytical solution with a three-dimensional finite element analysis. A comprehensive comparative study shows the inherent advantages of the present coating system compared to a conventional homogeneous coating system and a simple system of circular plates with FGM coating layers.
2015
978-88-7488-886-3
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/823005
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