Not able to obtain symmetric expansion

[Enggbot]

The purpose of my analysis is to obtain the expansion of a metal cylinder when it is heated to a higher temperature and use the deformed model as input model in another analysis.
The cylinder is modeled using brick elements. I have constrained the nodes on one flat surface of the cylinder to prevent any translation along the axial direction.
A higher temperature is provided to all the nodes as load and run a static analysis. Now the result does not show symmetric deformation. Why isn't it a symmetric expansion? I have attached a drawing just to give an idea about the model.

 

[BlasMolero]

Hello!,
Without the model in hand is difficult to know the reason of the error, post your FEMAP model here and we will take a look to it, thanks!.

Make sure the mesh is exactly symmetric. Also, you can solve the problem fully in 3-D using CHEXA 8-nodes brick elements, or in 2-D using 2-D Solid axisymmetric CQUADX4 four-node elements, the results should be exactly the same, but at a reduced cost, see two examples in the next animations of the contact between two cylindrical solids of different materials under an expansive thermal load of nodal temperature:
• In the first example a 3-D surface-to-surface linear contact "no penentration" is used.
• In the second model a 2-D edge-to-edge axisymmetric linear contact "no penetration" is used.
• Both models are solved using Simcenter Nastran linear static (SOL101).

Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

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[rb1957]

"I have constrained the nodes on one flat surface of the cylinder to prevent any translation along the axial direction."

did you constrain every node on the face ? that'd over-constrain the face, preventing the nodes from moving apart as they would under temperature.

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