Problem with ANSYS

I require modeling two concentric cylindrical stainless steel tubes, which induced the inner pressure by ANSYS. Before doing it I am going to model a simple one. A cylindrical stainless steel tube that the inner pressure is 100 MPa and the outer pressure is 0 MPa. I solved it by solid45 element and the solution was wrong. I don't know which element type and/or proper option select for it. I want to model 3D and obtaining the change of inner and outer diameter of each cylinder and stress components of them.

Aref E-mail: snipped-for-privacy@yahoo.com

You can get the outer and inner surface stresses from shell elements. That's about all I can tell you since I'm not an ANSYS user.

I'm not a big ANSYS user either, but I use NASTRAN all the time. Some things you have to be wary of when using solids (in NASTRAN) is that solid elements don't calculate node rotation (I'm guessing ANSYS maybe the same way). This can cause some weird effects when you've got shearing AND your model is only 1 element thick in some places. So you may want to make your tube, say, 4 elements thick, rerun it, and see if the results are better. However, for what you're doing, it sounds like using plate/shell elements would be adequate.

Dave

Refining the mesh like that is a good idea. It's not done enough.

To pick up a the bending stress distribution, 4 linear order elements would be a minimum. For higher order elements use a minimum of 2 through the thickness. Shell elements assume linear stress distribution through thickness like a beam.