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goldm066
2008-07-29, 19:32
I am still trying to model a hyper-elastic tube, in a displacement dependent elongation. I was originally using 3D solid elements. It has been suggested to me that using shell elements may work much better, as my stress levels are incorrect for altered tube geometries, (e.g. I get the same tension result for the hole tube, regardless of how many holes I place in it).

In ABAQUS I do the following steps:

1. Build Model (shell extrusion of a circle to create the solid tube)
2. Define Materials (I use a custom material fit, to the Ogden 3rd order energy potential)
3. Assign Material Orientation for Shell elements (I have interchanged this step with steps 4 and 5 with no different results).

4. Create shell element Section, membrane, specify thickness: 0.003175 M
5. Assign Shell element Section to the part
6. Apply loads, mesh part, and run job.


I immediately receive this error when performing the data check, or running the job:

"15672 Elements have Missing Property Definitions."

When I use the query tool prior to running the job, it shows the shell normals, and the material orientations like it should.

Using this same procedure for the Homogenous Shell elements I do NOT get this error. If anyone knows what must be done differently it would be much appreciated.


Thanks,
David

CF
2008-07-31, 00:14
This error kind of rings a bell with me. I assume you are running the analysis from CAE. If so, I would open the *.inp file and check

(a) There is a *shell section keyword line eg.

*Shell Section, elset=_SetName, material=MatlName, orientation=OrientationName
0.01, 5

(b) There is an *ORIENTATION keyword line eg.

*Orientation, name=OrientationName
1, 0, 0., 0, 1, 0.
1, 0.

(c) and a *MATERIAL eg.

*Material, name=MatlName
*Density
9.5e-10,
*Hyperelastic, neo hooke
2e-05,0.

Make sure MatlName, OrientationName match those in *SECTION SHELL.

Hope that helps.

Cormac