Determining the axisymmetric, geometrically nonlinear, thermoelastoplastic state of laminated orthotropic shells

A technique is developed to determine the axisymmetric, geometrically nonlinear, thermoplastic stress-strain state of laminated ortotropic shells of revolution under loads that cause a meridian stress state and torsion. The technique is based on the rectilinear-element hypotheses for the whole stack of layers. The active elastoplastic deformation of an ortotropic material is described by deformation-type equations that have been derived without resort to the existence conditions for the plastic potential. The scalar functions in the constitutive equations depend on the intensity of shear strains and temperature. The problem is solved through the numerical integration of a system of differential equations. The technique is tried out in designing tubular specimens subjected to axial force and torque. As an example, the elastoplastic state of a corrugated shell is analyzed.