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Active Contributor
lahkar
Posts: 48
Registered: ‎10-24-2010

High Aspect Ratio

2281 Views, 8 Replies
11-01-2010 01:45 AM

How to reduce this components aspect ratio ? Plz help.

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Valued Contributor
nishit78
Posts: 82
Registered: ‎08-05-2009

Re: High Aspect Ratio

11-03-2010 07:41 AM in reply to: lahkar

Perhaps you should share a model without the aspect ratio diagnostic so get a clearer image of what the elements look like.

My guess is you haven't removed the small radii from the corners and as a result your mesh size is too coarse to caputre the radii well.

 

If you really want to use the radii in the analysis you can work with local mesh densities to ensure that the radii are meshed with a finer setting. Ofcourse this will be at the expense of much higher element count and longer analysis times.

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Active Contributor
lahkar
Posts: 48
Registered: ‎10-24-2010

Re: High Aspect Ratio

11-03-2010 08:18 PM in reply to: lahkar

Thanks for your response. Yes, I didn't remove the radius of the component. I am using Autodesk Moldflow Insight 2010-R2, while I am trying to give local mesh density. Its not appearing. I don't whats the problem going on.

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Valued Contributor
nishit78
Posts: 82
Registered: ‎08-05-2009

Re: High Aspect Ratio

11-04-2010 03:11 AM in reply to: lahkar

In my experience, local densities only work when the areas where the finer mesh is required is assigned the local mesh density. If you do it the other way you don't get the coarse mesh you only get the fine mesh.

 

I don't know this for sure and haven't tried it in the new version but if you assign the coarser mesh using the local density then the smaller value of the global edge length over-rides the local setting and you get the entire model with a finer mesh setting.

 

I hope i am trying to explain this properly.

 

Ni****

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Contributor
MehtaMJ
Posts: 12
Registered: ‎08-27-2009

Re: High Aspect Ratio

11-04-2010 12:57 PM in reply to: lahkar

Yes, Filet and Blends give rise to large number of high aspect ratio triads.  to over come this problem I use Degenerate Element tolerance Value  between 0.1 and 0.4 in mesh repair tool and/ or Global  merge use value between 0.1 and 0.4. Some time this action switch edges.

Either correct it the same or live with.

 

Mukund Mehta

Livonia, MI. USa

 

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Active Contributor
lahkar
Posts: 48
Registered: ‎10-24-2010

Re: High Aspect Ratio

11-08-2010 12:47 AM in reply to: lahkar

Thank you Mr. Ni**** and Mr. Mehta for sharing your experience. Eventually I removed the small radii and rounds from the original CAD model and meshed it. Now I got good result.

 

Regards.....

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*Expert Elite*
madhukeshwart
Posts: 289
Registered: ‎03-18-2009

Re: High Aspect Ratio

11-13-2010 12:23 AM in reply to: lahkar

Yes, Filets or Blends  will results in  large number of high aspect ratio trias.

 

1. you can first suppress smaller Filets or Blends by using any cad software/moldflow cad doctor/ cad fix tools.

 

2. Then import the same cad model in moldflow  , try with smaller GEL.

 

3. Try with enabling " Optimize aspect ratio by surface curvature control"

 

4. If not  try with enabling " Optimize aspect ratio by proximity control"

 

5. If not try with smaller quad heights,

 

6. If not try by increaing merge tolerances.

 

7. If not try Mesh smoothing/ area remeshing.

 

8. You can try with various combinations of any of the above

 

9. Lastly you can try with mesh reparing tools like insert node, swap elements, merge nodes. etc.

 

10. If nothing from above said things din't help. then go with higher aspect / with 3d mesh.

 

Madhukeshwar Talwar

FIAT-CHRYSLER ATC, Chennai
mail: madhukeshwart@gmail.com
09600060862
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Active Contributor
lahkar
Posts: 48
Registered: ‎10-24-2010

Re: High Aspect Ratio

11-13-2010 01:16 AM in reply to: lahkar

Extremely pleasurable reply. Thank you a lot. I will try to strive it.

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Contributor
klp2kor
Posts: 24
Registered: ‎12-29-2009

Re: High Aspect Ratio

04-15-2013 01:58 AM in reply to: madhukeshwart

Hello,

 

Can anyone explain me how "Optimize aspect ratio by Proximity control" works and how it helps in accuracy of results.

 

Thanks and regards.

KLP

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