Ansys Employee
Some images of the setup would definitely help in visualizing the problem. Is the tube free to expand in the radial direction? If yes you could use a cylindrical support, free the radial degree of freedom and fix the other two (axial and tangential). If there is any constraint on the tube edge that prevents it from expanding then you could simply use a fixed support at the end edges. And yes you could insert a user defined cylindrical system to get the hoop and axial stresses.
Regards Ishan.