topic Re: Not possible to reload a FEM file in Simulation Mechanical Forums (Read-Only)

Not possible to reload a FEM file

Anonymous — Fri, 12 May 2017 15:58:47 GMT

I launched a few analysis with "mechanical simulation" v.2017 with the option "Nastran" for the solver. When I try to relaunch the file I have the following message.

I cannot read the FEM file anymore. What is the matter ? Could you please help me asap because I need urgently to open this file

Re: Not possible to reload a FEM file

John_Holtz — Fri, 12 May 2017 17:14:28 GMT

Hi @Anonymous

Based on some notes that we have, it sounds like the file is corrupt. It may not be possible to recover it. Do you remember if anything odd happened the last time you saved or closed the model?

Here are some things to try:

Is the .FEM file in the same location as it was when it was working? In other words, has it been moved to a different folder? (I do not think that this is related to the problem, but it is worth asking.)
You may be able to at least view the results as follows:
1. Start Simulation Mechanical
2. Go to the Open file dialog.
3. In the File Type, set it to Simulation Mechanical Results.
4. Select the file and open it.
5. Does this work? If not, then the .fem file is corrupt. If it opens, hopefully you can get the results or input that you need to continue your work.
If step 2 does not open the model in the Results environment, here is another way to view the results:
1. Start Simulation Mechanical
2. Go to the Open file dialog.
3. In the File Type, set it to Algor Simulation Legacy FEA Model.
4. Browse to the .ds_data folder for the model, then into the design scenario folder.
5. Select the file ds.asd and open it. Hopefully, the FEA Editor is shown, but it will be empty.
6. Switch to the Results tab, and the model and model browser should be visible.

Let us know what happens.

Re: Not possible to reload a FEM file

Anonymous — Sun, 14 May 2017 13:39:43 GMT

Hi John.

Thank you for answer. I will check your proposals as soon as I can. As I remember, when I launched the analysis, all of them were marked with a "finished" information. I keep you informed but I'm afraid that I will have to rebuild the whole model...

Another question: I have a large amount of contact areas in the model (two rib stiffened structures in contact) In the CAD assembly file (it comes from Solidworks) the contact is real and there is no gap (I use a "step" tranfer file). In some areas the contacts are detected and in some other, the system cannot detect them and I have to build them manually and it is a tedious work... Is there something that I could do to avoid this ?

Thank you and best regards.

Re: Not possible to reload a FEM file

Anonymous — Mon, 15 May 2017 09:45:22 GMT

Hello John.

I could load the results by importing the legacy FEA model. Unfortunately, it wasn't possible to recover the data file (FEM) and I have to rebuild the model.

Nevertheless thank for your help.

If you have any idea to generate all the contact areas when importing a model (see question before), that could be very helpful...

Re: Not possible to reload a FEM file

John_Holtz — Mon, 15 May 2017 17:56:47 GMT

Hi @Anonymous

What type of model is it? Is it a surface model (used to create plate elements)? Is it a solid model (used to create brick elements)?

Each model seems to be different. Here are some general guidelines to try. (Note that you should be able to transfer the model from SolidWorks directly to Sim Mech. Or, you should be able to open the SolidWorks file directly from Sim Mech. In theory, it will not make a difference, but the added step of going to the STEP file may introduce some effect that is causing a problem.)

Using similar mesh sizes on all parts can help. Uncheck (turn off) the option "Mesh > Mesh > 3D Mesh Settings > Option > Model " Use automatic geometry-based mesh size function"
The mesh size may affect how well it matches. If there is a thin part making contact with a large area (like a rib projecting out from the side of a tank wall), a mesh size closer to the thickness of the rib may be helpful. You can try using refinement points or refinement surfaces in local areas if you do not want to try a finer mesh on the same model.
Since the parts have a gap of 0 between them, the default mesh matching tolerance should be good enough. But I often change the "Mesh > Mesh > 3D Mesh Settings > Option > Mesh Matching > On-surface tolerance based on" from "Fraction of mesh size" to "Absolute length dimension". Sometimes, a tolerance that is larger than "it should be" is helpful. A value less than half the thickness of the parts should be reasonable.
For a solid-to-solid contact, you can split the faces in Solidworks where they meet. When both parts have edges around the contact area, the mesh at least has to follow those edges, and it might help with the mesh matching.

Re: Not possible to reload a FEM file

Anonymous — Thu, 18 May 2017 08:48:38 GMT

Hello John.

Thank you for your advices. I will check next time (the current model is a full 3D analysis with brick elements).

Concerning the FEM file that I couldn't read anymore, I had to rebuild the model. Now it is Ok. I think that the reason was the lack of disk space during the writing results process.

Regards.