Error when meshing and simulating a part!

[medinh]

I have a problem when meshing my model.

I get this text when the error is find:

fem2esh - Make esh file from fem file for a specified design scenario
Version 2014.00.00.0513-W64/X64 22-Feb-2013
Copyright (c) 2013, Autodesk, Inc. All rights reserved.

Version of fem2esh.exe : 2014.00000513
Version of dcx1-win-x64.dll : 2014.00000513
Version of femapi-win-x64.dll : 2014.00000513
Version of agsdb_ar-win-x64.dll : 2014.00000513
Version of tsx2tsy.exe : 2014.00000513

Input Model : C:\Autodesk\2014-13-26\Ram_simulering.ds_data\1\ds
Input File : C:\Autodesk\2014-13-26\Ram_simulering.fem
Output File : C:\Autodesk\2014-13-26\Ram_simulering.ds_data\1\ds.mod\group.esh
Log File : C:\Autodesk\2014-13-26\Ram_simulering.ds_data\1\ds.mod\group.ldx
Design scenario : 1
Analysis type : Linear Stress
Start time : 2014/03/28-11:17:39

--- Get 34 active element parts in range [1, 34] from fem file
--- 1 enabled L&C groups are defined
--- Get 233086 points defined in range [1, 270785] from fem file
Calling the Surface Topology Generator (tsx2tsy)...
tsx2tsy: Update part surface contact/bonding data (duration=1 sec.)
Making interior points for midside nodes...
--- Made 75209 interior points for midside nodes
Set up nodal properties such as admissible BC etc. by adjacent elements...

In working on FEM file for a FEA model
Terminal Error: FEM2ESH#63
NO_3D_ELEMENT: please check meshing phase 11
2014/03/28-11:17:41

Its a problem with part 11 (se picture below), there is a (i) marked on the part. What does this mean? And I get a error when meshing this part.

And as you can se, the joint lookes wird at the nearest wheel. I dont know if its a bug or something but when i created the joint, I selected the area in the holes where the joint should run through. It should look like the other wheel but it dosent.. Is it just a bug or something wrong?

[KubliJ]

Hi Medinh,

The Terminal error refers to a part not have a solid mesh.  Looking at the screen shot, it does appear to be part 11.  The little 'i' icon for the part; it means that Sim Mech sees disconnected surface edges, i.e. not a solid part.  This usually means a CAD problem with the part.  What CAD package was the model created in?  Is part 11 supposed to be a solid body or is it a surface body?

Thanks,

James

[medinh]

Thanks for quick answer!
I use Autodesk Inventor. There is no problem with the cad file in inventor. I can run some simultaions there without warninngs. 
The part should be solid like the other ones, i dont understand why it shouldn't. I use solid parts in mesh settings. It has the same settings as other parts.
Somehow it managed to create a tetrahedron mesh after a few times trying. BUT there is another problem now!
When i run the analasys, nothing happens! Everything is zero! The displacement, von mises stress, evertything. I have a gravity load with 20G! and I put the general constrains (fixed) at the four wheels. 

When I run the simulations i get these warnings:

Warning: zero stiffness replaced by 1.0E+20 in EQN#51106 at NODE#17038 DOF Tx

Warning: zero stiffness replaced by 1.0E+20 in EQN#51107 at NODE#17038 DOF Ty

Warning: zero stiffness replaced by 1.0E+20 in EQN#51108 at NODE#17038 DOF Tz

Warning: zero stiffness replaced by 1.0E+20 in EQN#51109 at NODE#17039 DOF Tx

Warning: zero stiffness replaced by 1.0E+20 in EQN#51110 at NODE#17039 DOF Ty

And this is how it looks like:

[dharhay]

If I understand a portion of what you are experiencing, I may have had a similar problem. Last year I spent several weeks trying to solid mesh large linear models. A solid meshing error randomly occurred from part to part that was thought to be a problem with the Inventor modeling. I was given a lot of help from Autodesk on this with Beta software versions, etc. and the solution was to get more ram! Now I have 16 gig and the solid meshing issue is gone.

This may be a long shot and I may not understand your issue, but look into your ram on the computer.

[cid:image001.png@01CF4D89.4FBF5030]



David HARHAY

Principal Engineer

- Steel

Fives Bronx Inc.

8817 Pleasantwood Avenue NW

North Canton, Ohio, 44720 - United States

Tel: +1 (330) 244 1960 ext. 264

Fax: +1 (330) 244 1961


david.harhay@fivesgroup.com

www.fivesgroup.com

[cid:image002.png@01CF4D89.4FBF5030][cid:image003.png@01CF4D89.4FBF5030]

[medinh]

Thank you for the tip! But the computer have 4gb RAM, and the system requires only 2gb, so it shouldnt be a problem.. 

[KubliJ]

Hi Medinh,

The zero stiffness warnings are likely caused by elements being removed due to being highly distorted.  Still sounds like a meshing issue.  I want you to remesh the model with the following mesh setting tweak.  Go to 3D mesh settings -> Options -> Model and deselect Use Automatic Geometry based mesh size function.  Now remesh the model.  That will give you a more uniform mesh, which is handy when solid meshing thin parts.

Thanks,

James

[medinh]

It dosen't help, still same problem..

[KubliJ]

Hi Medinh,

Can you upload the model to look at?

Thanks,

James