Meshing Problems

[Anonymous]

Dear all,

I would like to share a problem I have faced recently with meshing options in the moldflow Insight (2014 version).
I ran Dual Domain Mesh for my CAD model (catia). I faced following warnings and the simulation had stopped.

WARNING 98988
WARNING 98742 - 21 occurrences
WARNING 98731 - 52 occurrences

In order to fix these problems, I ran the Mesh diagnostic tool once and remeshed the areas. When I ran the simulation again, it says the elements are not oriented properly. Could anyone please help me with fixing these errors or send a link where I can learn to fix these problems.

If you need further details, I could also send the image of my cad model.

Thanks!!

[beth.mollica · Accepted solution]

hi @karthick Rajkumar!

Thank you for visiting the Moldflow Insight Forums!  I understand that after you ran the mesh diagnostics tool to correct the mesh warnings you were getting, when you reran the analysis, you are seeing in the log files that the elements are not oriented properly.  Are you seeing an actual error message accompanying the information about the incorrect orientation in the log file (possible Error 702626)?  I would like to point out that in a Dual Domain mesh, all the elements must be oriented so that the top side faces outward.  It is likely that when you used the mesh diagnostics tool/mesh repair wizard?  to clean up the mesh in certain areas, this caused the orientation of some of the elements to reverse. 

Please reference the following article from the Autodesk Knowledge Network: How to troubleshoot un-oriented elements in a Moldflow Insight dual domain mesh   This article contains information on locating and resolving un-oriented duel doman mesh that can cause errors when running the analysis. 

[mppkumar]

Hi

You are getting warnings because of poor quality of mesh; suggest to choose proper global edge length during meshing.

Mesh match percentage is very less -- for DD mesh it should be more than 85%

Aspect ratio of element is higher -- for DD mesh it should be less than 20

Thickness calculation in some local areas are very less

** WARNING 98988 ** The mesh match percentage ( match percentage value %), and reciprocal mesh match percentage ( reciprocal match percentage value %) for the Dual Domain mesh are less than the recommended minimum value of 85%. This may affect the accuracy of the results. To identify the poorly matched areas of the part, use the Dual Domain Mesh Match Diagnostic in the Mesh menu. To improve the mesh matching, use the Match Nodes mesh tool, remesh the part, or remove fine details, such as fillets, in the original CAD model

** WARNING 98742 ** Triangle element element number has a large aspect ratio ( aspect ratio value ), which may affect the analysis. Try running the Auto Repair and Fix Aspect Ratio commands from the Mesh Tools to fix the problem.

** WARNING 98731 ** The thickness of element element id is outside the expected range. Please use Modeling -> Query Entities to locate the element, check the element properties and, if necessary, rerun the analysis

before running the analysis, suggest to check for mesh quality

http://help.autodesk.com/view/MFIA/2017/ENU/?guid=GUID-41F38EA2-A28F-4A0F-8069-3480E24B3F11

fixing aspect ratio : http://help.autodesk.com/view/MFIA/2017/ENU/?guid=GUID-87E8F1C7-C491-42CD-BC6D-39E268764D74

http://help.autodesk.com/view/MFIA/2017/ENU/?guid=GUID-B562033D-B082-4763-B55A-840CCB740695

Match % correction

http://help.autodesk.com/view/MFIA/2017/ENU/?guid=GUID-E4FC1D31-81D8-45BE-A3DC-808F7B7D7F4B

For checking & correcting thickness;

http://help.autodesk.com/view/MFIA/2017/ENU/?guid=GUID-4154F278-62A6-4782-870D-0C6C7A4ACCAB

[mppkumar]

Hi

On orientation issue -- if you check the orientation diagnostics all top elements should be in blue and bottom elements should be in red color.

for correcting orientation use the below link :

http://help.autodesk.com/view/MFIA/2016/ENU/?guid=GUID-B570176D-CC4C-4371-9E66-1C2992943125

[madhukeshwart · Accepted solution]

Raj,

1. ** WARNING 98988 ** The mesh match percentage ( match percentage value %), and reciprocal mesh match percentage ( reciprocal match percentage value %) for the Dual Domain mesh are less than the recommended minimum value of 85%. This may affect the accuracy of the results.

for more details refer following link

https://knowledge.autodesk.com/support/moldflow-flex/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU...

2.** WARNING 98742 ** Triangle element element number has a large aspect ratio ( aspect ratio value ), which may affect the analysis. Try running the Auto Repair and Fix Aspect Ratio commands from the Mesh Tools to fix the problem.

for more details refer following link

https://knowledge.autodesk.com/support/moldflow-flex/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU...

3.** WARNING 98731 ** The thickness of element  is outside the expected range. Please use Modeling -> Query Entities to locate the element, check the element properties and, if necessary, rerun the analysis.

for more details refer following link

https://knowledge.autodesk.com/support/moldflow-flex/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU...

4. Here is the link to mesh editing training , it may help you

https://knowledge.autodesk.com/support/moldflow-insight/learn-explore/caas/CloudHelp/cloudhelp/2017/...

[Anonymous]

Hai mppkumar,

Thank you for the suggestion. It indeed helped me to understand better about the problem. I have attached the mesh statistics with this message.

I tried with the diagnostic tools, but since the numbe of elements outside the aspect ratio range is too high, I thik it is not possible to fix it element by element.

And also how would one choose global edge length for model. Default value was 15mm, I reduced to 5mm and I ran the mesh. Meshing alone took more than 5 hours. Does it take this much time for 12gb ram system. If only I reduce the global edge length, will it fix the mentioned errors in my original message?

Or should I use any other meshing specific software to fix the mesh and import it in moldflow?

Please guide me with this. 

Thanks,

Karthick Rajkumar 

[Anonymous]

Thank you everyone for the prompt reply.

The links shared by you took time  for me to get back!! I tried with links and I ended up still with poor mesh quality. 

So my problem is Changing global edge length alone fixes the mesh quality? if so, please tell me how should one choose it, I can learn and apply it for my model.

Because after meshing, I find lot of elements falling outside the range, lot of intersections, it seems not a good way to edit element by element.

Thanks,

Karthick Rajkumar

[Anonymous]

I'm doing a cooling analysis. I am facing the following problem. I want to start despite mesh flaws, what can I do?

Thanks already for your help

** WARNING 98988 ** The mesh match percentage (83.2%), and reciprocal mesh match
percentage (73.2%) for the Dual Domain mesh are less than the
recommended minimum value of 85%. This may affect the
accuracy of the results. To identify the poorly matched areas of
the part, use the Dual Domain Mesh Match Diagnostic in the Mesh menu.
To improve the mesh matching, use the Match Nodes mesh tool,
remesh the part, or remove fine details, such as fillets, in the
original CAD model.
Reading input data...
File name : pz31_17f771_a_alt_so_utma_mf_study~11

** ERROR 99093 ** Automatic injection time estimate is not available for
models with valve gate(s), please specify an injection time.

** ERROR 99980 ** Stopping because of previous errors.

[mppkumar]

Hi @Anonymous 

if you are not worrying about mesh match percentage and want to run the analysis

1) remove valve gate in hot runner system

2) or use different filling control other than "Automatic"