Simulation Moldflow Insight

Posts: 4
Registered: ‎09-25-2012

3D mesh

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01-08-2013 12:33 AM

Hello everybody,


Have you any experience with Bias ratio function? ( in 3D meshing: Tetra Advance - Bias ratio )


I have a big different results if I use function bias ratio 1.5 or use even distrubution without biasing. The differnet is about 18MPa in filling pressure ( example in the attachment ). The process conditions are the same.

Which kind of 3D meshing is accurate?


In another studies ( parts ) the different in filling pressure is more than 50MPa.


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*Expert Elite*
Posts: 323
Registered: ‎03-18-2009

Re: 3D mesh

01-08-2013 07:24 AM in reply to: mholka
bias option is not meant for general analysis...

It should be used for gas assisted simulation.
Madhukeshwar Talwar

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Active Member
Posts: 10
Registered: ‎03-27-2012

Re: 3D mesh

01-08-2013 09:17 PM in reply to: mholka

Hi mholka,


I remember sometime reasding in the moldflow help, that, if you want to exactly predict the shear heating within the thickness, it is recommended to have bias ratio more than one. By doing this there will be more nodes close to the surfaces of the part, which will help in capturing shear heating occuring between the frozen layers and the molten plastic while flowing.


Similarly we will be giving bias ratio less than one when we are looking at defects like jetting in the part, as there will be more nodes towards  the center of the part.




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Posts: 4
Registered: ‎09-25-2012

Re: 3D mesh

01-08-2013 10:42 PM in reply to: ashwinkumarnr

Thanks for yours answers.


I never used used bias ratio in meshing 3D...but our customer made analysis in competitor. The results of competitor are very different that our results, mainly pressure results ( different results about 50%, our pressure 60Mpa - competitor 125Mpa ). Both analysis are in 3Dmesh, conditions ( material, temperatures...are the same). But competitor use Moldex3D and BLM function in 3D meshing ( boundary laeyr mesh - similar function as bias ratio in Moldflow ).


If I use bias ratio 1.5 my pressure result growth from 60 Mpa to 115Mpa ( similar result as competitor ). Now, we don' t know which pressure result will be correct in reality.


So my question: Is suitable use bias ratio in 3D meshing for accurate pressure results?

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