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Paulo Araujo

Micro-Porosity results interpretation

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Hi everyone!

I would like to ask some help to interprete the results of my simulation regarding micro-porosity. Micro-porosity relates to the Niyama and also porosity but I couldn't to evaluate if in this simulation a problem of these mentioned will ocuur. If yes, what can I do to fix it?


here is the file https://we.tl/t-j4pINRizqA


SOLIDIFICATION-MICRO POROSITY-PIC1-snapshot2019.16.10_10.10.14.png

SOLIDIFICATION-MICRO POROSITY-PIC2-snapshot2019.16.10_10.11.5.png

SOLIDIFICATION-MICRO POROSITY-PIC3-snapshot2019.16.10_10.11.25.png






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Hello Paulo,


Mirco Porosity result is based in niyama criterion but more factors are considered besides thermal gradient and cooling rate.

This result avoids the need to know the threshold Niyama value below which shrinkage porosity forms by showing results as form of a percentage.

Maximum percentage will be the maximum contraction value of the material used. 

So in your case, results are showing that 4.17% of the red areas is a void.


Regarding to your question about avoiding porosity in your part, what you can do is to place cooling lines close to the porosity regions. 

Anyway, you have to think that avoid all the porosity sometimes is very difficult and having porosity is not always a problem If porosity is not in a region prone to suffer defects (structural regions, leakages, outhern surfaces..) 

In your case for example, it looks that central region of the door handle is worst than the regions of the corner where the bigger porosities are since those areas are prone to structural damage due to mechanical stresses.


I attached a paper where MicroPorosity is explained.


1-Prediction of Shrinkage Pore Volume Fraction Using a Dimensionless Niyam...pdf

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Thank you Pau for you reply!

So I would say that porosity is not a worry because they are placed just on the filling system as you can see in the image. I'm correct with this conclusion?


I'm more worried about the micro-porosity and Nyama results, because i can see a beginning of incidence slicing the bar values when the color start to change from yellow to red (as you can see in the image). In your opinion this result represent a need to change something in the project or it can be considered as insignificant?

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