Purpose: The purpose of this paper is to present study of thermal creep stresses and strain rates in a circular disc with shaft having variable density by using Seth’s transition theory.Design/methodology/approach: Seth’s transition theory is applied to the problem of thermal creep transition stresses and strain rates in a thin rotating disc with shaft having variable density by finite deformation. Neither the yield criterion nor the associated flow rule is assumed here. The results obtained here are applicable to compressible materials. If the additional condition of incompressibility is imposed, then the expression for stresses corresponds to those arising from Tresca yield condition.Findings: Thermal effect increased value of radial stress at the internal surface of the rotating disc made of incompressible material as compared to tangential stress and this value of radial stress further much increases with the increase in angular speed as compared to without thermal effect. Strain rates have maximum values at the internal surface for compressible material.Originality/value: The model proposed in this paper is used in mechanical and electronic devices. They have extensive practical engineering application such as in steam and gas turbines, turbo generators, flywheel of internal combustion engines, turbojet engines, reciprocating engines, centrifugal compressors and brake disks.

The objective of this research paper is to present the study of elastoplastic deformation in an orthotropic spherical shell subjected to a temperature gradient by using Seth’s transition theory. Seth’s transition theory includes classical macroscopic solving problems in plasticity, creep and relaxation and assumes semi-empirical yield conditions. The nonlinear transition regions through which yielding occurs are neglected. Apparently, transition theory is used to solve problems in a general way, employing the concept of generalized strain measure and asymptotic solution at the transition points of differential equations. The problems of elastoplastic and creep transitions are solved through principal stress and principal stress difference and in consideration of the nonlinear part of the transition.

The purpose of this paper is to present a study of creep deformation and stress analysis in a transversely material disk subjected to the rigid shaft by using Seth’s transition theory. It has been observed that radial stress has the maximum value at the inner surface of the rotating disk made of isotropic material as compared to the hoop stress and this value of radial stress further increases with the increase in the value of angular speed. Strain rates have maximum values at the inner surface for the disk made of transversely material.