ONE-DIMENSIONAL TRANSIENT THERMAL-STRESS PROBLEM FOR NONHOMOGENEOUS HOLLOW CIRCULAR-CYLINDER AND ITS OPTIMIZATION OF MATERIAL COMPOSITION FOR THERMAL-STRESS RELAXATION

In this study, the one-dimensional transient thermal stress problem of a nonhomogeneous hallow circular cylinder with arbitrarily distribute d and continuously varied material properties, such as functionally gr aded materials, is evaluated theoretically. Using the analytical proce dure of a laminated hollow circular cylinder model, the analytical tem perature solution for the cylinder is derived approximately. Further m ore, making use of Airy's stress function method, the thermal stress c omponents are formulated under the mechanical condition of being tract ion-free. As a numerical example, a hollow circular cylinder composed of zirconium oxide (ZrO2) and titanium alloy (Ti-6Al-4V) is considered . To optimize(i.e., minimize) the thermal stress distribution, numeric al calculations are carried out, and the optimum material composition is determined taking into account the effect of the temperaturedepende nce of the material properties. Furthermore, taking into account the v ariation in the thickness of the cylinder, the temperature rise of the surrounding medium, and the relative heat transfer coefficients on th e inner and outer surfaces, the optimum values of the material composi tion are obtained. Numerical data for the calculations are shown graph ically.