Study On Transient Thermal Stresses Of The Ceramic-metal Composite EFBC Plate With An Interlayer Of FGM Under Convective Heat Transfer Boundary

In the paper, based on the thermo-elastic theory, according to computational mechanics, the finite element method of the problem of the transient heat conduction and thermal stresses in the ceramic-metal composite EFBC plate under convective heat transfer boundary are studied. Numerical calculation is realized by computer program. The transient conduction and the transient thermal stresses of composite plate are studied. The main works are studied as follows.First of all, the functional of the thermal conduction problem is studied. The existence of the functional of the thermal conduction problem is proved, and the functional of transient thermal conduction problem of ceramic-metal composite plate with an interlayer of FGM is established. And then, in spatial domain, the variational finite element method is used. In the time domain, the finite difference method is used. The finite element fundamental equation of the ceramic-metal composite plate with an interlayer of FGM is derived. The finite element method calculation program is also developed. On the basis, the thermal stresses equation of composite plate is established, the Simpson method is used to solve the numerical integration of the thermal stresses calculation. The validity of proposed method is verified. Through numerical analysis, the transient thermal stress distributions in the ceramic-metal composite EFBC plate under convective heat transfer boundary in combination of practical example is researched. The influence of the composition variation and thickness of the FGM graded layer on thermal stresses is mainly researched.The research results showed that when the thickness of the gradient layer becomes thicker, the tensile stresses of the metal side and the compressive stresses in the ceramics side become smaller. The transition from the tensile stresses in metal side to the compressive stress in ceramics side tends to gentle. When the time is 320s, the contrast analysis shows that the maximum tensile stresses of the metal side decrease 1.3% and the maximum compressive stresses in the ceramics side decrease 1.8%. So the effect of the gradient layer thickness of composite plate on thermal stresses is obviously.On the same condition, when the distribution shape coefficient M of material composition changes, the shape bending extent and variation tendency of the curves of transient thermal stresses change obviously. When M becomes bigger, the tensile stresses in the metal side and the compressive stresses in the ceramics side become smaller. When the time is 320s, the contrast analysis shows that the maximum tensile stresses of the metal side decrease 25.9% and the maximum compressive stresses in the ceramics side decrease 12.5%. Therefore, the influence of the distribution shape coefficient variation on the transient thermal stresses distribution is obviously.The paper provides a theory calculation and analysis basis for the preparation and optimization design of the ceramic-metal composite EFBC plate.