# Simulation Moldflow Insight

#### Mesh

130 Views, 6 Replies
01/10/2018 4:50 AM

Hello all,

I have met some question towards mesh, how many rows of elements should be modeled to properly represent a thickness change?

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#### Re: Mesh

01/10/2018 7:33 AM

Hi,
the basic recommendation to pick up effects such as flow hesitation, three rows of elements across a major change in thickness are required.

I think this teached in basic training and model requirements.

Also in on-line help:

Checking the mesh before analysis

"In Midplane and Dual Domain models, significant thickness changes must be represented with at least three rows of elements to ensure accurate prediction of flow issues such as hesitation or racetracking."

Hope this clarifies.

Regards,

Berndt

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#### Re: Mesh

01/10/2018 7:50 AM

Hi Berndt,

Thanks for the reply. I checked help file too, it's still confuse me, according to mesh result, dual domain mesh only have one row of element in thickness direction, and as one row can indicate the thickness of part, why do we need to mesh more than three rows of elements.

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#### Re: Mesh

01/10/2018 8:50 AM

Hi,

maybe you think about thickness at edges of part?

The comment is for thickness over the part.

Thickness change as red arrow:

Thickness change

Dual Domain matches thickness from one side to another.

Midplane assign thickness.

Midplane and Dual Domain uses laminaes through the thickness.

So if you think of part as Midplane mesh to represent, it has no thickness at part edges.

Hope this clarifies.

Regards,

Berndt

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#### Re: Mesh

01/10/2018 9:38 AM

Hi Berndt,

Thanks for the explanation, per your comments, do you mean thickness transitional area (from red to blue) should mesh at least three rows of elements? But nominated wall thickness should be divided to laminaes, the default setting is 12 rows, which means system reduce the rows from 12 to 3?

And if just to detect thickness variation instead of predict race track, the row can be reduced to 2 or maybe 1 row in thickness change area?

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#### Re: Mesh

01/10/2018 9:50 AM

Hi,

1) The dark blue is part edge. It can be as it is.
Dual Domain detects this is an edge, hence edge elements.

2) The element rows refers to thickness changes in part.
Going from red to light blue, in center of picture.
The thickness changes from 2.5 mm to 2.0 mm

3) Laminaes is a solver setting.
Not visible in mesh.
(Seen in Process settings > Advanced Options)

4) Create a simple Midplane study with thickness chanes and mesh with different element sizes/mesh density.
Run some simulations, and you will get a better understanding of behavior.

Hope this helps.
Regards,
Berndt

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