• 한국재료학회:학술대회논문집
• /
• 한국재료학회 1999년도 춘계학술발표강연 및 눈문개요집
• /
• pp.59-59
• /
• 1999

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2002년도 추계학술발표강연 및 논문개요집
• /
• pp.171-171
• /
• 2002

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 1999년도 추계학술발표강연 및 논문개요집
• /
• pp.32-32
• /
• 1999

• 대한기계학회논문집A
• /
• 제21권9호
• /
• pp.1441-1451
• /
• 1997

This paper addresses method which can be used for analyzing thermal stresses of a functionally graded material(FGM) using semi-analytical approach. FGM is a nonhomogeneous material whose composition changes continuously from a metal surface to a ceramic surface. An infinite one dimensional FGM plate is considered. The temperature distribution in the FGM is obtained by approximate Green's function solution. To expedite the convergence of the solutions, alternative Green's function solution is derived and shows good agreement with results from finite difference method. Thermal stresses are calculated using temperature distribution of the plate.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.516-521
• /
• 2004

In unmanned aerial vehicles (UAV), the high temperature results from friction among the air, combustion of fuel in engine and combustion gas of a nozzle. The high temperature may cause serious damages in UAV structure. The Functionally Graded Material (FGM) is chosen as a material of thc engine duct structure. Thermal stress analysis of FGM is performed in this paper. FGM is composed of two constituent materials that are mixed up according to the specific volume fraction distribution in order to withstand high temperature. Therefore, hoop stress, axial stress and shear stress of duct with 2 layers, 4 layers and 8 layers FGM are compared and analyzed respectively. In addition, the creep behavior of FGM used in duct structure of an engine is analyzed for better understanding of FGM characteristics.

• 대한기계학회논문집B
• /
• 제20권5호
• /
• pp.1679-1688
• /
• 1996

Laser flash technique was applied to measure thermal properties of FGM made by a CVD method. System stability and reproducibility of this measuring system were proved and calibrated with glassy carbon used as reference material. Specimens was prepared by cutting FGM diagonally. Measurements were performed for a wide range of temperatures up to 1500K. Relative heat capacity of the FGM specimen was scattered with in $\pm$13% at room temperature and at high temperature above 1200K, and $\pm$3% at medium temperature range. On the other hand, thermal diffusivity data showed excellent reproducibility and stability through the whole temperature range. In conclusion, the multi-target radiometer can be applied to measure the thermal properties of non homogeneous materials like FGM.

• 한국소음진동공학회논문집
• /
• 제15권4호
• /
• pp.474-482
• /
• 2005

A theoretical method is presented to investigate the thermoelastic and dynamic response of functionally graded material (FGM) rectangular plates made up of metal and ceramic. The temperature is assumed to be constant in the plane of the plate and to vary in the thickness direction only. Material properties are assumed to be temperature-dependant, and vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The third order shear deformation theory (TSDT) to account for rotary inertia and transverse shear strains is adopted to formulate the theoretical model. The modal analysis technique is used to develop the analytic solutions of the dynamic problem. The effect of material compositions and temperature fields is examined. The present theoretical results are verified by comparing with those from finite element analysis by ANSYS.

• 한국소음진동공학회논문집
• /
• 제19권11호
• /
• pp.1119-1125
• /
• 2009

The coupled fluid-structure interaction problem is analyzed using the theoretical method to investigate the coupled vibration characteristics of functionally graded material(FGM) cylindrical shells conveying an incompressible, inviscid fluid. Material properties are assumed to vary continuously through the thickness according to a power law distribution in terms of the volume fraction of the constituents. The steady flow of fluid is described by the classical potential flow theory. The motion of shell represented by the first order shear deformation theory(FSDT) to account for rotary inertia and transverse shear strains. The effect of internal fluid can be taken into consideration by imposing a relation between the fluid pressure and the radial displacement of the structure at the interface. Numerical examples are presented and compared with exiting results.

• 한국결정성장학회지
• /
• 제12권3호
• /
• pp.144-148
• /
• 2002

수산화아파타이트/티타늄 복합체를 스파크 플라즈마 소결(SPS) 장치를 이용하여 4층 경사 기능 재료 (FGM)로 제조하였다. 수산화아파타이트/티타늄 복합체의 최대 밀도와 이축 강도는 $1200^{\circ}C$에서 8분 동안의 SPS 조건에서 얻었다. 그러나, 수산화아파타이트는 $1100^{\circ}C$에서 사칼슘인산염(TetCP)으로 분해되었고, 티탄산칼숨 화합물 ($CaTiO_3$)이 형성되었다. 수산화아파타이트에 티타늄을 첨가하면 수산화아파타이트가 저온에서 쉽게 분해되었다.

• 한국소음진동공학회논문집
• /
• 제23권8호
• /
• pp.742-751
• /
• 2013

The vibration analysis of a rotating cantilever beam made-up of functionally graded materials is presented based on Timoshenko beam theory. The material properties of the beams are assumed to be varied through the thickness direction following a simple power-law form. The frequency equations, which are coupled through gyroscopic coupling terms, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of power-law exponent, angular speed, length to height ratio and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their results.