Steady state creep behavior of thermally graded isotropic rotating disc of composite taking into account the thermal residual stress

Abstract

The present paper investigates the steady-state creep behavior of thermally graded isotropic disc rotating at elevated temperature. The composite discs are made of aluminum matrix reinforced with silicon-carbide particulate. The creep analysis is carried out using isotropic Hoffman yield criterion. The stress and strain rate distributions have been calculated for the discs. The creep parameters vary along the radius of the disc and have been estimated by regression fit of the available experimental data. Investigations for disc operating under linearly decreasing temperature from inner to outer radii has been done taking into account the phase-specific thermal residual stress. Further work has been done for discs operating under linearly increasing, parabolically decreasing and parabolically increasing temperatures. The results are displayed and compared graphically in designer friendly format for the above said temperature profiles. It is observed that there is a significant change in the stress distribution due to the presence of thermal residual stress. The radial strain rate is compressive for the discs operating at elevated temperature in the absence of residual stress, but due to the presence of residual stress the strain rate becomes tensile as one gradually moves along the radial distance and again becomes compressive near the outer radius. However, the presence of residual stress led to an increase in the tangential strain rate in the discs as compared to the discs without residual stress. Thus it is concluded that there is a need to extend the domain of thermal gradation in designing rotating discs.