• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.4
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• pp.386-393
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• 1995

A Abstract Producing process of FGM by SHS process has been investigated and $TiB_2$/Cu based FGM was fabricated by the process. When raw material powders were stacked on, Cu substrate, composition profile can be graded. This stacked body was compressed and vacuum­s sealed into the capsule for the synthesis. This sample was ignited and compressed under high h hydro - pressure. By the observation of the crystal phases and microstructures of produced $TiB_2$/Cu FGM samples, the compositional gradient was able to be identified.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1753-1763
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• 2002

Stress and displacement fields for a propagating crack in a functionally gradient material (FGM) which has shear modulus as $\mu$=$\mu$$\_$0/(1＋ζX) are derived. The equations of motion in FGM which is nonhomogeneous material are different from those of homogeneous material. The stress intensity factors in stress fields have influence on odd terms of γ$\^$n/2-1/(n=1,3,5,...,) but stress at crack tip only retains term of γ$\^$-1/2/, where the γ is a radius of cylindrical coordinates centered at crack tip. When the FGM constant ζ is zero or γ→0, the fields for FGM are almost same as the those for isotropic material.

• Journal of the Korean Ceramic Society
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• v.43 no.4 s.287
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• pp.247-252
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• 2006

Joining Yittria Stabilized Zirconia (YSZ) to NiCr metal was fabricated using YSZ/NiCr Functionally Graded Materials (FGM) Interlayer by hot pressing process. Microscopic observations demonstrate that the composition and microstructure of YSZ/NiCr FGM distribute gradually in stepwise way, eliminating the macroscopic ceramic/metal interface such as that in traditional ceramic/metal joint. The thermal characteristics of this YSZ/FGM/NiCr joint were studied by thermal shock testing and therml barrier testing. Thermal shock test was conducted by gas burner rig. Acoustic Emission (AE) monitoring was performed to analyze the microfracture behavior during the thermal shock test. It could be confirmed that FGM was the excellent performance of thermal shock/barrier resistance at above $1000^{\circ}C$.

• Structural Engineering and Mechanics
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• v.54 no.3
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• pp.579-595
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• 2015

A general geometrically non-linear model for lateral-torsional buckling of thick and thin-walled FGM box beams is presented. In this model primary and secondary torsional warping and shear effects are taken into account. The coupled equilibrium equations obtained from Galerkin's method are derived and the corresponding tangent matrix is used to compute the critical moments. General expression is derived for the lateral-torsional buckling load of unshearable FGM beams. The results are validated by comparison with a 3D finite element simulation using the code ABAQUS. The influences of the geometrical characteristics and the shear effects on the buckling loads are demonstrated through several case studies.

• Geomechanics and Engineering
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• v.9 no.5
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• pp.631-644
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• 2015

This article considers the problems of cylindrical bending of functionally graded plates in which material properties vary through the thickness. The variation of the material properties follows two power-law distributions in terms of the volume fractions of constituents. In addition, this paper considers orthotropic materials rather than isotropic materials. The traction-free condition on the top surface is replaced with the condition of uniform load applied on the top surface. Numerical results are presented to show the effect of the material distribution on the deflections and stresses. Results show that, all other parameters remaining the same, the studied quantities (stress, deflection) of P-FGM and E-FGM plates are always proportional to those of homogeneous isotropic plates. Therefore, one can predict the behaviour of P-FGM and E-FGM plates knowing that of similar homogeneous plates.

• Earthquakes and Structures
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• v.16 no.5
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• pp.601-609
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• 2019

The effect of the porosity and its distribution shape on the normal and shear interfacial stresses of the FGM beam strengthened with FRP plate subjected to a uniformly distributed load are investigated analytically in the present paper. Basically, the governing equations of FGM beams with porosity strengthened with composite plates are identical to the ones without porosity. Nonetheless, when the effect of the porosity and its distribution shape are taken into account, the rule of mixture was reformulated to assess the material characteristics with the porosity phases and its distribution shape. This work discusses the influence of the gradient index, the porosity and its distribution shape on the interfacial stresses.

• Advances in aircraft and spacecraft science
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• v.9 no.6
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• pp.507-523
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• 2022

This study is aimed to accurately predict the vibration response of two types of functionally graded sandwich plates, one with FGM core and another with FGM face sheets. The gradation in FGM layer is quantified by exponential method. An efficient zig-zag theory is used and the zigzag impacts are established via a linear unit Heaviside step function. The present theory fulfills interlaminar transverse stress continuity at the interface and zero condition at the top and bottom surfaces of the plate for transverse shear stresses. Nine-noded C-0 FE having 8DOF/node is utilized throughout analysis. The present model is free from the obligation of any penalty function or post-processing technique and hence is computationally efficient. Numerical results have been presented on the free vibration behavior of sandwich FGM for different end conditions, lamination schemes and layer orientations. The applicability of present model is confirmed by comparing with published results. Several new results are also specified, which will serve as the benchmark for future studies.

• Advances in nano research
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• v.12 no.3
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• pp.337-344
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• 2022

In this work, the vibrational frequency of two layered FGM cylindrical shell with and without the effects of internal pressure under ring support are discussed in detailed. The functionally graded materials of a cylindrical shell are designed for specific purpose and studied under various boundary conditions. The Love shell dynamical equations theory is utilized to find the relationship between the curvature displacement and strain displacement. Natural frequency vibrations are analyzed by using volume polynomial for bi-layered FGM shell under ring support both for with and without internal pressures.

• Structural Engineering and Mechanics
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• v.88 no.4
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• pp.355-368
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• 2023

Employing the non-local strain gradient theory (NSGT), this paper investigates the nonlinear resonance characteristics of functionally graded material (FGM) nanoshells with initial geometric imperfection for the first time. The effective material properties of the porous FGM nanoshells with even distribution of porosities are estimated by a modified power-law model. With the guidance of Love's thin shell theory and considering initial geometric imperfection, the strain equations of the shells are obtained. In order to characterize the small-scale effect of the nanoshells, the nonlocal parameter and strain gradient parameter are introduced. Subsequently, the Euler-Lagrange principle was used to derive the motion equations. Considering three boundary conditions, the Galerkin principle combined with the modified Lindstedt Poincare (MLP) method are employed to discretize and solve the motion equations. Finally, the effects of initial geometric imperfection, functional gradient index, strain gradient parameters, non-local parameters and porosity volume fraction on the nonlinear resonance of the porous FGM nanoshells are examined.

• Coupled systems mechanics
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• v.13 no.2
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• pp.171-186
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• 2024

In the present paper, thermal buckling characteristics of functionally graded rectangular plates made of porous material that are integrated with surface-bonded piezoelectric actuators subjected to the combined action of thermal load and constant applied actuator voltage are investigated by utilizing a Navier solution method. The uniform temperature rise loading is considered. Thermomechanical material properties of FGM plates are assumed to be temperature independent and supposed to vary through thickness direction of the constituents according to power-law distribution (P-FGM) which is modified to approximate the porous material properties with even and uneven distributions of porosities phases. The governing differential equations of stability for the piezoelectric FGM plate are derived based on higher order shear deformation plate theory. Influences of several important parameters on the critical thermal buckling temperature are investigated and discussed in detail.