الفهرس 
Basic concepts of Elasticity and viscoelylasticityOnly 14 pages are availabe for public view
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Abstract
This thesis is devoted to study the visco-elastic response for inhomogeneous composite sandwich plates. Two types of sandwich plates are considered. In the first one, the core is made from an isotropic viscoelastic material and the faces are made from an isotropic elastic material with the same elastic properties. In the other type, the core is an isotropic elastic material while the faces are isotropic viscoelastic material with the same viscoelastic modulus properties. In Chapter 1 Chapter one is devoted to present the basic concepts and fundamental equations of the theory of elasticity and the theory of viscoelasticity. This chapter contains two parts. The first part includes the generalized Hooke’s law, the engineering elastic constants of anisotropic materials, the equilibrium equations, strain-displacement relations, boundary conditions and the principal equations of elasticity for axisymmetric plane strain and plane stress problems. The second part includes some definitions and notations of viscoelastic materials, the creep test, the relaxation test, stress-strain relations for linear viscoelastic structures, effective moduli method and Illyushin’s approximation method for solving quasi-static problems in viscoelastic composite materials. Chapter 2 Studies the bending response of homogenous and inhomogeneous viscoelastic sandwich plates. The solutions according to different plate theories are presented. The classical plate theory (CPT), first-order shear deformation plate theory (FSDPT), higher-order shear deformation plate theory (HSDPT) and sinusoidal shear deformation plate theory (SSDPT) are all used for this purpose. The governing equations of various plate theories are converted into a single system of equations. Analytical solutions are developed using the Navier procedure and separation of variable technique. The method of effective moduli and Illyushin’s approximation method are used to solve the equations governing the bending of simply-supported inhomogeneous fiber-reinforced viscoelastic sandwich plates In Chapter 3 The different kinds of symmetric sandwich plates are presented. Computations were carried out to study the effect of the time parameter on deflection and stresses at different values of the aspect ratio b/a, side-to-thickness ratio a/h and constitutive parameter . Results of (SSDPT) are compared with those obtained by (HSDPT), (FSDPT) and (CPT). The obtained results show how the dimensionless stresses and deflection depend on the elastic properties of the layers i. e, the layer is elastic or viscoelastic.