*FILM together with *TRANSFORM

Analysis issues
1

Hello,

has anyone tried to define *FILM for convective heat transfer on the outer surface of a cylinder when the nodes of the surface are transformed in a cylindrical COS using *TRANSFORM?

I am getting a strange temperature field if I try to run a coupled temperature-displacement calculation with the described boundary conditions. There might be some problems on the edges where the outer surface and the symmetry-planes meet, but I did expect the same temperature field as in the comparative calculation without transformed and constrained nodes in the outer surface.

model
model2220×1906 131 KB

temp_rad_free
temp_rad_free2450×2100 218 KB

temp_rad_const
temp_rad_const2450×2100 208 KB

The part in my input looks like this:

**================================================
** Temperature
**================================================
*BOUNDARY
Nrin,11,11,363.15
*FILM
*INCLUDE,INPUT=routface.flm
**================================================
** Radial clamping
**================================================
*TRANSFORM,NSET=Nrout,TYPE=C
0,0,0,0,0,1
*BOUNDARY
Nrout,1,1,0

Is there a problem with the nodes of the faces used for *FILM being transformed in a cylindrical COS?

2

*TRANSFORM should affect only mechanical DOFs. From Abaqus documentation:

This option is used to specify a local coordinate system for displacement and rotation degrees of freedom at a node.

and:

A nodal transformation is used to define a local coordinate system for:

  • the definition of concentrated forces and moments;

  • the definition of displacement and rotation boundary conditions;

  • the definition of linear constraint equations; and

  • the output of vector-valued quantities.

CalculiX is more vague regarding this:

This option may be used to specify a local axis system X’-Y’-Z’ to be used for defining SPC’s, MPC’s and nodal forces.

Can you share the whole input file (you could upload it on some hosting website and paste the link here) ?

Abaqus doesn’t allow BCs in global or local coordinates to meet. CalculiX accepts this but you could try excluding the problematic edges from one BC.

3

Here is a link to the whole input files, one version with *TRANSFORM and radial fixation, and the one without *TRANSFORM that leads to the expected temperature field:

I will try to exclude the edges where BCs in global and local coordinates meet, but in my understanding this should not affect the temperature calculation.