Creep Behavior of Pressurized Tank Composed of Functionally Graded Materials

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
JianJun Chen ◽  
KeeBong Yoon ◽  
Shan-Tung Tu
Keyword(s):  
Functionally Graded Materials ◽  
Stress Level ◽  
Creep Behavior ◽  
Creep Property ◽  
Closed Form Solution ◽  
Functionally Graded ◽  
Radial Coordinate ◽  
Time Step ◽  
Graded Materials ◽  
Creep Stress

The creep behavior of a pressurized tank, which is assumed to be made of functionally graded materials, is studied in this paper. The elastic response under the internal and external pressures is first obtained when Young’s modulus obeys a power function along with the wall thickness. If the creep exponent remains constant and the creep coefficient varies with the radial coordinate, a closed-form solution can be derived for the time-dependent behavior of the spherical tank. The effects of material gradients on the creep stress and strain are investigated in detail. The results show that the stress level under the steady creep state is determined by the distribution of the creep properties. However, the magnitude of the creep strain is influenced by the elastic modulus distribution, as well as the creep property distribution inside the functionally graded materials. Compared with the finite element analysis results, the optimum time step value is also investigated. Some fundamental knowledge of the materials distribution is achieved to reduce the maximum creep stress/strain and to uniformize the stress level inside the functionally graded materials tank.

Applications of the symplectic method in quasi-static analysis for viscoelastic functionally graded materials

2017 ◽  
Vol 34 (4) ◽  
pp. 1314-1331 ◽  
Author(s):  
W.X. Zhang ◽  
R.G. Liu ◽  
Y. Bai
Keyword(s):  
Functionally Graded Materials ◽  
Correspondence Principle ◽  
Separation Of Variables ◽  
Closed Form Solution ◽  
Form Solution ◽  
Functionally Graded ◽  
Symplectic Method ◽  
Graded Materials ◽  
Content Type ◽  
Displacement Constraints

Purpose For general quasi-static problems of viscoelastic functionally graded materials (VFGMs), the correspondence principle can be applied only for simple structures with a closed form solution of the corresponding elastic problem exists. In this paper, a new symplectic approach, according to the correspondence principle between linearly elastic and viscoelastic solids, is proposed for quasi-static VFGMs. Design/methodology/approach Firstly, by employing the method of separation of variables, all the fundamental eigenvectors of the governing equations are obtained analytically. Then, the satisfactions of boundary conditions prescribed on the ends and laterals are discussed based on the variable substitution and the eigenvector expansion methods. Findings In the numerical examples, some boundary condition problems are given. The results show the local effects due to the displacement constraints. Originality/value The paper provides an innovative technique for quasi-static problems of VFG Ms. Its correctness and the efficiency are well suported by numerical results.

scholarly journals Free vibrations of planar serial frame structures in the case of axially functionally graded materials

2020 ◽  
pp. 17-17
Author(s):  
Aleksandar Obradovic ◽  
Slavisa Salinic ◽  
Aleksandar Tomovic
Keyword(s):  
Differential Equations ◽  
Boundary Conditions ◽  
Functionally Graded Materials ◽  
Separation Of Variables ◽  
Closed Form Solution ◽  
Free Vibrations ◽  
Functionally Graded ◽  
Frame Structures ◽  
Variable Cross ◽  
Graded Materials

This paper considers the problem of modal analysis and finding the closed-form solution to free vibrations of planar serial frame structures composed of Euler-Bernoulli beams of variable cross-sectional geometric characteristics in the case of axially functionally graded materials. Each of these beams is performing coupled axial and bending vibrations, where coupling occurs due to the boundary conditions at their joints. The numerical procedure for solving the system of partial differential equations, after the separation of variables, is reduced to solving the two-point boundary value problem of ordinary linear differential equations with nonlinear coefficients and linear boundary conditions. In this case, it is possible to transfer the boundary conditions and reduce the problem to the Cauchy initial value problem. Also, it is possible to analyze the influence of different parameters on the structure dynamic behavior. The method is applicable in the case of different boundary conditions at the right and left ends of such structures, as illustrated by an appropriate numerical example.

scholarly journals Study on Transient Thermal Response for Functionally Graded Materials Based on Peridynamic Theory

2019 ◽  
Vol 37 (5) ◽  
pp. 903-908
Author(s):  
Fei Wang ◽  
Yu'e Ma ◽  
Yanning Guo ◽  
Wei Huang
Keyword(s):  
Heat Conduction ◽  
Functionally Graded Materials ◽  
Thermal Response ◽  
Functionally Graded ◽  
Temperature Fields ◽  
Distribution Area ◽  
Conduction Time ◽  
Time Step ◽  
Graded Materials ◽  
Temperature Load

The transient heat conduction formula of functionally graded materials (FGMs) is presented based on peridynamics (PD). The simplified micro-heat conductivity model for FGMs is proposed and the numerical discretization and the peridynamic numerical formation are also illustrated. A FORTRAN program is coded to implement calculations. The accuracy of the program is verified by comparing the FEM and analytical results with PD solution. The FGM rectangle plate composed by titanium alloy coating zirconium oxide is performed to calculate temperature fields. The effects of material gradient, porosity and temperature load on thermal response are studied. It is shown that the ceramic proportion of FGMs is increased with an increasing material shape parameter and the thermal shielding performance of FGMs is also improved. The effect of the porosity on thermal response is more and more significant with the increasing time step. The increasing temperature load only affects the temperature response of FGM ceramic area. The thickness of temperature distribution area is increased with the increasing of heat conduction time.

Creep Property of Functionally Graded Materials

2005 ◽  
Vol 492-493 ◽  
pp. 599-604 ◽  
Author(s):  
Peng Cheng Zhai ◽  
Gang Chen ◽  
Qing Jie Zhang
Keyword(s):  
Functionally Graded Materials ◽  
Creep Property ◽  
Pure Metal ◽  
Functionally Graded ◽  
Ceramic Component ◽  
Metal Component ◽  
Graded Materials ◽  
Temperature Environment ◽  
The One ◽  
Graded Interlayer

The present paper investigates the creep phenomenon of the functionally graded materials under high temperature environment by the computational micromechanical method (CMM). Based on the real microstructure of the functionally graded interlayer with different component volume fractions, the emulation experiment is implemented for the creep test numerically and the creep parameters are obtained. A further series of simulation works are carried out to investigate the creep phenomenon of FGM interlayers in more detail. Numerical results show that the creep phenomenon is obvious not only for the metal-rich interlayers but also for the ceramic-rich interlayers. The creep property of ceramic/metal interlayer depends on the material’s properties of the ceramic obviously. It is remarkable that the creep strain rate of the ceramic/metal interlayer is larger than the corresponding one of pure metal under the same load when the modulus of the ceramic component is lower than the one of the metal component.

Dynamic Analysis with Stress Recovery for Functionally Graded Materials: Numerical Simulation and Experimental Benchmarking

2014 ◽  
Vol 2 (1) ◽  
pp. 21
Author(s):  
Carlos Alberto Dutra Fraga Filho ◽  
Fernando César Meira Menandro ◽  
Rivânia Hermógenes Paulino de Romero ◽  
Juan Sérgio Romero Saenz
Keyword(s):  
Numerical Simulation ◽  
Dynamic Analysis ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Stress Recovery ◽  
Graded Materials
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