The problem studied is that of two elastic-ideally plastic thin-walled tubes, connected end to end. Their outer ends are fastened to rigid walls, and the interface between them is subjected to a combination of axial force and torque. As the geometry is simple, it is possible to obtain closed-form solutions to the plastic flow rules, even though each member supports a complex stress state. The elastic, shakedown and limit states are found in closed form, together with the internal stress and displacement history.
