Effect Of Porosity On Transient Thermal Stress Of Two-dimension Functionally Graded Plate

In the 21st century, functionally graded material (FGM) has gotten attention of scholars in domestic and foreign with its excellent features like thermal shock resistance, conductive insulation duality, biocompatibility and so on, and FGM is widely used in aerospace, optical engineering and biomedical. This paper use FEM to research the 2D-FGM rectangular plate which is composed by Ti-6A1-4V, Al 1100, and ZrO2.First of all, in order to get the FE basic equation, we should use weighted residual method and the heat transfer formulas. By using the automatic mesh division program and stress field finite element program which is written by FORTRAN computer language, we can calculate the thermal stress distribution of the model.This study compare approximate solution obtained by the finite element method with analytical solutions obtained by mathematical analysis value method,the results show that FEM used on the model is completely correct. We analysis transient thermal stress distribution of 2D-FGM rectangular plate on different porosity control parameters, unilateral heating, heated on both sides and four sides heating in the end.The transient thermal stress distribution of 2D-FGM rectangular plate shows as follows.When the heating function of unilateral boundary of the model is constant function, the thermal stress distribution of plate increases with the value of Ay under the same time, and the stress distribution curve in nearby area relative to axis y=y/b=0 angle will be smaller. However, with the increase of the Ay, the change of stress distribution shape is not obvious. Discuss the moment of t=1.0s, and fixed Ax=0,0 unchanged. The absolute value of the maximum thermal stress of Ay=3.0 is less than Ay=1.0 by 8.91%. The minimum absolute value of thermal stress increased 274.23%. However, the absolute value of the maximum thermal stress of Ay=3.0 is increase than Ay=1.0 by 0.08% when fixed Ay.=0.0 unchanged. The minimum absolute value of thermal stress increased to 65.92%. Porosity control parameters Ay along the plate thickness direction have more effect on heating thermal stress than porosity control parameters Ax along the longitudinal direction of the plate. The geometry and boundary conditions of model are symmetrical about the axis x=x/a=0.5. But the stress field shows that the absolute value on the border presents asymmetric distribution and the stress of the absolute value in the upper boundary is the biggest. When the boundary structure is a function of other heating, the variation of the thermal stress is basically the same as changing the porosity control parameters. It shows that the applying form of external thermal load has little effect on the thermal stress field.The main works of this paper are study of what affect different porosity has on transient thermal stress distribution of the 2D-FGM rectangular plate, and the study results have reference value to design and optimize the porosity of 2D-FGM rectangular plate.