On Some Thermoelastic Problem of a Nonhomogeneous Long Pipe

The paper deals with the thermoelastic problem of a multilayered pipe subjected to normal loadings on its inner surface and temperature differences on its internal and external surfaces. Two types of nonhomogeneous pipe materials of pipe are considered: (1) a ring-layered composite composed of two repeated thermoelastic solids with varying thickness and (2) a functionally graded ring layer. The ring-layered pipe with periodic structure is investigated by using the homogenized model with microlocal parameters. A homogenization approach is proposed for the modelling of the FGM pipe. The analysis of obtained circumferential, radial and axial stress is presented in the form of figures and discussed in detail. It was shown that the proposed approach to the homogenization allows us to correctly calculate the averaged characteristics in the representative cell (the macro-characteristics) and also the characteristics dependent on the choice of the component in the representative cell (the micro-characteristics) for both microperiodic composites and functionally graded materials.

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A two-stage homogenization for modelling of elastic-plastic functionally graded composites

Engineering Computations ◽

10.1108/ec-09-2019-0432 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Witold Ogierman

Keyword(s):

Volume Fraction ◽

Mean Field ◽

Functionally Graded ◽

Two Stage ◽

Graded Materials ◽

Content Type ◽

Elastic Plastic ◽

Functionally Graded Composites ◽

Homogenization Approach ◽

Arbitrary Volume

Purpose The purpose of this study is to develop a homogenization approach that ensures both high accuracy and time-efficient solution for elastic-plastic functionally graded composites. Design/methodology/approach The paper presents a novel two-stage hybrid homogenization approach that combines advantages of the mean field homogenization and homogenization based on the finite element method (FEM). The groundbreaking nature of the developed approach is associated with division of the hybrid homogenization procedure into two stages, which allows to very efficiently determine the solution for arbitrary volume fraction of the reinforcement. This paper concerns also on modelling of composites with randomly distributed prolate and oblate particles. For this purpose, the hybrid homogenization was implemented in the framework of the discrete orientation averaging procedure involving pseudo-grain discretization method. Findings Agreement between the results obtained using the proposed approach and the standard FEM-based homogenization is very good (up to the volume fraction of 0.3). Originality/value The proposed two-stage homogenization approach allows to obtain the solution for materials with arbitrary volume fraction of the reinforcement very efficiently; therefore, it is highly beneficial for the two-scale modeling of nonlinear functionally graded materials and structures.

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Dynamic analysis of thick beams with functionally graded porous layers and viscoelastic support

Journal of Vibration and Control ◽

10.1177/1077546320947302 ◽

2020 ◽

pp. 107754632094730

Author(s):

Şeref D Akbaş ◽

Abdullateef H Bashiri ◽

Amr E Assie ◽

Mohamed A Eltaher

Keyword(s):

Time Integration ◽

Solution Process ◽

Layered Composite ◽

Functionally Graded ◽

Dynamic Responses ◽

Pulse Load ◽

Graded Materials ◽

Numerical Time Integration ◽

Thick Beam ◽

Material Gradation

This study presents dynamic responses of a composite thick beam with a functionally graded porous layer under dynamic sine pulse load. The boundary conditions of the composite beam are considered as viscoelastic supports. Three layers are considered, and face sheet layers have porous functionally graded materials in which the distribution of material gradation through the graded layer is described by the power law function, and the porosity is depicted by three different distributions (i.e., symmetric distribution, X distribution, and ◊ distribution). The layered composite thick beam is modeled as a two-dimensional plane stress problem. The equation of motion is obtained by Lagrange’s equations. In formation of the problem, the finite element method is used with a 12-node 2D plane element. In the solution process of the dynamic problem, a numerical time integration method of the Newmark method is used. In numerical analyses, influences of stiffness and damping coefficients of viscoelastic supports, material gradation index, porosity parameter, and porosity models on the dynamic response of thick functionally graded porous beam are investigated under the pulse load.

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Residual Stress Distribution in Graded PSZ/Inconel Composite Deposited by Particle Collision

Materials Science Forum ◽

10.4028/www.scientific.net/msf.449-452.761 ◽

2004 ◽

Vol 449-452 ◽

pp. 761-764 ◽

Cited By ~ 2

Author(s):

Do Won Seo

Keyword(s):

Axial Stress ◽

Maximum Shear Stress ◽

Interfacial Strength ◽

Strength Distribution ◽

Functionally Graded ◽

Particle Collision ◽

Mechanically Alloyed ◽

Composite Powders ◽

Linear Distribution ◽

Graded Materials

Interfacial strength distribution and thermal residual stresses in multi-layered or compositionally graded NiCrAlY/ZrO2 coatings are analyzed. These coatings are fabricated by detonation gun spraying using mechanically alloyed, plasma-spheroidized composite powders. The problems in design of functionally graded materials (FGMs) are outlined and their modeling approaches are reviewed. Due to the concentrational or structural gradients in FGMs, the normal approximations and models, used for traditional composites, are not directly applicable to graded materials. The goal is to show the efficiency of the simplest models to provide the most accurate estimates of the properties and even to make simple elasto-plastic analysis of FGM components without vast computations by finite element methods with an arbitrary non-linear distribution of phases and corresponding properties is presented. Results showed that bonding strengths increased gradually with increase of the composition of metals in the FGM coatings. The FGM coating was more stable on the mechanical properties than normal duplex composites. And, the maximum compressive radial stress is found to be at or near the surface of the specimen where surface cracking may be generated. The maximum axial stress is at the edge of the specimen where spallation may occur. The maximum shear stress is also at or close to the edge.

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