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Thermoelastic stresses in functionally graded rotating annular disks with variable thickness

Allam M. N. M., Tantawy R., Zenkour A. M.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 4

1029--1041

EN

This article presents semi-analytical solutions for stress distributions in exponentially and functionally graded rotating annular disks with arbitrary thickness variations. The disk is under pressure on its boundary surfaces and exposed to temperature distribution varying linearly across thickness. Material properties are supposed to be graded in the radial direction of the disk and obeying to two different forms of distribution of volume fraction of constituents. Different conditions at boundaries for stresses and displacement are discussed. Accurate and efficient solutions for displacement and stresses in rotating annular disks are determined using infinitesimal theory. Numerical results are carried out and discussed for different cases. It can be deduced that the gradient of material properties and thickness variation as well as the change of temperature sources have a specific effect in modern applications.

2

Generalized thermoelastic functionally graded half space under surface absorption of laser radiation

Allam M. N. M., Tayel I. M.

Journal of Theoretical and Applied Mechanics

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2017

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Vol. 55 nr 1

155--165

EN

The subject of this paper is to study the thermoelastic behavior of a functionally graded semi-infinite medium heated uniformly by a laser beam having temporally Gaussian distribution. The surface of the medium is taken as traction free. The general solution is obtained in the Laplace transform domain. The inverse of the Laplace transform is computed numerically using the Riemann-sum approximation method. The numerical results for temperature, displacement and stress are obtained and presented graphically for the generalized theory of thermo-elasticity with one relaxation time.

3

Elastic and Viscoelastic Stresses of Nonlinear Rotating Functionally Graded Solid and Annular Disks with Gradually Varying Thickness

Allam M. N. M., Tantawy R., Yousof A., Zenkour A. M.

Archive of Mechanical Engineering

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2017

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Vol. LXIV, nr 4

423--440

EN

Analytical and numerical nonlinear solutions for rotating variable-thickness functionally graded solid and annular disks with viscoelastic orthotropic material properties are presented by using the method of successive approximations.Variable material properties such as Young’s moduli, density and thickness of the disk, are first introduced to obtain the governing equation. As a second step, the method of successive approximations is proposed to get the nonlinear solution of the problem. In the third step, the method of effective moduli is deduced to reduce the problem to the corresponding one of a homogeneous but anisotropic material. The results of viscoelastic stresses and radial displacement are obtained for annular and solid disks of different profiles and graphically illustrated. The calculated results are compared and the effects due to many parameters are discussed.

4

Effects of hygrothermal conditions on cross-ply laminated plates resting on elastic foundations

Zenkour A. M., Allam M. N. M., Radwan A. F.

Archives of Civil and Mechanical Engineering

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2014

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Vol. 14, no. 1

144--159

EN

The influence of temperature and moisture on the hygrothermal behavior of laminated composite plates resting on elastic foundations is investigated using a refined plate theory. The material properties of the composite are affected by the variation of temperature and moisture. The present plate theory enables the trial and testing of different through-the-thickness transverse shear-deformation distributions and, among them, strain distributions that do not involve the undesirable implications of the transverse shear correction factors. The governing equations are derived based on the present theory, including hygrothermal effects and elastic foundation parameters. The effects of Winkler and Pasternak foundation parameters, temperature, moisture concentration, transverse shear deformation, plate aspect ratio, side-to-thickness ratio on deflections and stresses are investigated.