Residual Thermal Stresses in Multilayered Functionally Graded Material Plates

概要

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The one-dimensional calculations of thermally induced residual stresses that are generated during the fabrication of multilayered functionally graded material plates (FGMs) because of a continuous macroscopic variation in the composition are presented. In this study, a laminated plate theory is used on the alumina/nickel FGM system to analyze the residual and thermal stresses in the multilayered FGM plates fabricated with a powder metallurgy method. Furthermore, the modeled ratios of thermo-mechanical parameters are employed to evaluate the residual thermal stress. The influences of residual thermal stress during thermal shock testing were also evaluated. The analytical results indicate that the residual thermal stress distributions can be controlled by adjusting the compositional gradient across the thickness of the FGM plates and the characteristics of thermal residual stress are more strongly dependent on the thermal expansion coefficients mismatch between ceramics and metal, in comparison with the mismatch of elastic moduli. It also indicates that during thermal shock process the thermal shock stress on the alumina surface does not change much by altering the compositional gradient in the FGM plate, and the release of thermal stress on the alumina surface is accomplished mainly by decreasing the tensile residual thermal stress.
2003-06-15