Calculation of the Stress-Strain State of TiNi Cylinder and Coupling Sleeve

A connected thermomechanical boundary problem for an infinite shape memory alloy cylinder loaded by an external force and subjected to heating or cooling from the surface is solved. The evolution of stress-strain state is calculated for processes of the transformation plasticity and the shape memory effect. The mechanical properties of a material point are given by a micromechanical model. The influence of the ambient temperature rate on the transformation plasticity is investigated. It is shown, that the transformation plasticity strain decreases with the increasing ambient temperature rate. This phenomenon can be explained by an inhomogeneity of the temperature and stress fields causing different conditions for the phase transformation in different points of the body. Computer simulation of the processes preparation and installation of TiNi coupling sleeve is performed. The sleeves with different thickness are considered. The stress-strain state of the sleeve in each stage is calculated. Distributions of the radial stress in the sleeve during the heating on the tube and change of the contact pressure with time are obtained.