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

Transitional and fully plastic stresses for a thin rotating disk made up of functionally graded material with variable thickness and density have been investigated in this paper using the transition theory which eliminates the assumption of yield condition. Analytical expressions for angular speed and circumferential stresses at initial yielding and fully plastic state have been obtained. From the numerical discussion on angular speed and circumferential stresses, it has been analysed that rotating disk made up of functionally graded isotropic material (steel) is a better choice for engineering design as compared to functionally graded orthotropic disk (barite and topaz) because disk of isotropic material has less circumferential stress than that of orthotropic material.