THERMAL STRESSES FOR FUNCTIONALLY GRADED MATERIALS (FGMS) SUBJECT TO HEAT FLUX

2021 ◽  
Author(s):  
NILABH KRISHNA ◽  
SEIICHI NOMURA
Keyword(s):  
Heat Flux ◽  
Thermal Stress ◽  
Functionally Graded Materials ◽  
Thermal Stresses ◽  
Spherical Inclusion ◽  
Homogeneous Medium ◽  
Functionally Graded ◽  
Far Field ◽  
Graded Materials ◽  
Weighted Residuals

In this paper, the thermal stress due to heat flux at the far field is derived for an infinitely extended elastic medium which contains a spherical inclusion made of functionally graded materials (FGMs). The 3-D heat conduction equation subject to uniform heat flux at the far field is solved analytically to derive the temperature distribution. Based on the temperature solution, the thermal stress field due to heat flux is obtained by solving a set of two ordinary differential equations using the method of weighted residuals. Unlike the two-phase homogeneous medium, the von Mises stress distribution is continuous at the interface of the FGM-matrix medium.

Thermo-Elasto-Plastic Analysis of Thick-Walled Spherical Pressure Vessels Made of Functionally Graded Materials

2016 ◽  
Vol 08 (04) ◽  
pp. 1650054 ◽  
Author(s):  
Zeinab Mazarei ◽  
Mohammad Zamani Nejad ◽  
Amin Hadi
Keyword(s):  
Heat Flux ◽  
Functionally Graded Materials ◽  
Poisson’S Ratio ◽  
Pressure Vessels ◽  
Functionally Graded ◽  
Material Behavior ◽  
Poisson's Ratio ◽  
Uniform Heat Flux ◽  
Plastic Behavior ◽  
Graded Materials

An exact closed-form analytical solution is presented to solve the thermo-elasto-plastic problem of thick-walled spherical vessels made of functionally graded materials (FGMs). Assuming that the inner surface is exposed to a uniform heat flux, and that the outer surface is exposed to an airstream. The heat conduction equation for the one-dimensional problem in spherical coordinates is used to obtain temperature distribution in the sphere. Material properties are graded in the thickness direction according to a power law distribution, whereas the Poisson’s ratio is kept constant. The Poisson’s ratio due to slight variations in engineering materials is assumed constant. The plastic model is based on von Mises yield criterion and its associated flow rules under the assumption of perfectly plastic material behavior. For various values of inhomogeneity constant, the so-obtained solution is then used to study the distribution of limit heat flux, displacement and stresses versus the radial direction. Moreover, the effect of increasing the heat flux and pressure on the propagation of the plastic zone are investigated. Furthermore, the effect of change in Poisson’s ratio on the value of the critical material parameter is demonstrated. The present study is also validated by comparing the numerical results for thick elasto-plastic spherical shells available in the literature. To the best of the authors’ knowledge, in previous studies, exact thermo-elasto-plastic behavior of FGM thick-walled sphrical pressure vessels has not investigated.

An Analysis of Thermo-Mechanical Behavior in a Multilayer Composite Pipe Under Temperature Variation

2010 ◽  
Author(s):  
Wei Yang ◽  
Jyhwen Wang
Keyword(s):  
Finite Element ◽  
Thermal Stress ◽  
Analytical Solution ◽  
Mechanical Behavior ◽  
Temperature Change ◽  
Thermal Stresses ◽  
Element Model ◽  
Functionally Graded ◽  
Element Analysis ◽  
Graded Materials

A generalized analytical solution of mechanical and thermal induced stresses in a multi-layer composite cylinder is presented. Based on the compatibility condition at the interfaces, an explicit solution of mechanical stress due to inner and outer surface pressures and thermal stress due to temperature change is derived. A finite element model is also developed to provide the comparison with the analytical solution. It was found that the analytical solutions are in good agreement with finite element analysis result. The analytical solution shows the non-linear dependency of thermal stress on the diameters, thicknesses and the material properties of the layers. It is also shown that the radial and circumferential thermal stresses depend linearly on the coefficients of thermal expansion of the materials and the temperature change. As demonstrated, this solution can also be applied to analyze the thermo-mechanical behavior of pipes coated with functionally graded materials.

Fracture Mechanics of Functionally Graded Materials

MRS Bulletin ◽  
1995 ◽  
Vol 20 (1) ◽  
pp. 43-44 ◽  
Author(s):  
F. Erdogan
Keyword(s):  
Fracture Mechanics ◽  
Functionally Graded Materials ◽  
Bonding Strength ◽  
Thermal Stresses ◽  
Material Design ◽  
Thermomechanical Properties ◽  
Functionally Graded ◽  
Life Assessment ◽  
Inhomogeneous Materials ◽  
Graded Materials

In today's highly demanding technological environment, one of the main challenges in new material design is combining seemingly irreconcilable thermomechanical properties in the same component (e.g., high heat and corrosion resistance, high strength in elevated-temperature applications and high resistance to wear, and high toughness in load-bearing elements). In many cases, the problem may be solved by using coatings or by layering dissimilar materials. From a structural viewpoint, a major disadvantage of these techniques, particularly in ceramic coating of metals, has been the resulting high thermal and residual stresses and relatively poor bonding strength. Thus, in thin films, coatings, and layered materials, surface cracking and debonding or delamination have been common forms of mechanical failure. One effective way of reducing residual and thermal stresses and enhancing bonding strength has been to eliminate material-property discontinuities by grading the material composition near the interfaces or through the coating. These new materials, with continuously varying compositions or volume fractions, are known as functionally graded materials (FGMs).In developing FGMs, research on the mechanics, and particularly on the fracture mechanics of these inhomogeneous materials, is needed to provide technical support to materials scientists and to manufacturing and design engineers. In the past, fracture mechanics has been useful both as a screening tool during material processing and as a design and maintenance tool for service-life assessment. Broadly speaking, fracture mechanics involves studying the effect of the applied loads, the component/flaw geometry, and the environmental conditions on the fracture of engineering materials.

High Heat Flux Testing of B4C/Cu and SiC/Cu Functionally Graded Materials Simulated by Laser and Electron Beam

2002 ◽  
Vol 4 (1) ◽  
pp. 1171-1176 ◽  
Author(s):  
Liu Xiang ◽  
Chen Ji-ming ◽  
Zhang Fu ◽  
Xu Zeng-yu ◽  
Ge Chang-chun ◽  
...  
Keyword(s):  
Heat Flux ◽  
Electron Beam ◽  
Functionally Graded Materials ◽  
High Heat ◽  
Functionally Graded ◽  
High Heat Flux ◽  
Graded Materials
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