ELASTIC-PLASTIC TRANSITION IN FUNCTIONALLY GRADED THIN ROTATING ORTHOTROPIC DISK WITH EXPONENTIALLY VARIABLE THICKNESS AND VARIABLE DENSITY

A thin rotating functionally graded disk whose thickness and density varies exponentially has been investigated. Angular speed, radial stresses and circumferential stresses at initial yielding and fully plastic state have been obtained using transition theory which helps to eliminate the assumption of yield condition. On the basis of numerical and graphical analysis of angular speed and circumferential stresses, it has been found that for designing purposes, functionally graded disk made up of isotropic material (steel) with non-homogeneity parameter is a better option than functionally graded orthotropic disk (topaz and barite) as the disk of isotropic material with non-homogeneity parameter has less circumferential stress than that of orthotropic material.