Increase thickness (same increment - different values)

[teopado89]

Hi everyone, 

i have a model with areas of different thickness.

I'd like to increase the thickness of some triangles adding the same increment.

I mean:

if i had some triangles with thickness 0.2, some with 0.4, some with 0.8mm, 

and the increment is +0.3mm

i'd like to obtain triangles with thickness (0.2+0.3), (0.4+0.3), (0.8+0.3).

Do you know how to do without selecting manually each group?

thanks

[Anonymous]

in the Mesh tab, in Mesh Diagnostics, use the Thickness command and set your min/max appropriatly and use the check box to "Place results in diagnostics layer".  IE.  Min 1.9 - Max 2.1 into diagnostics layer will place all 2.0 thickness elements into a new layer.  Then turn off all other layers.  Select all displayed elements and change thickness in properties.  Then move all elements back into original Tiangle layer (or rename layer to 2.0 thickness so that they would be in layers in case you want to change the thickness again).  Repeat as necessary.

Hope this helps.

Tim

[teopado89]

Hi Tim, thanks for the answer.
I knew this way, i was looking for a command like this:
i set the increment and EACH triangle of the selected zone feels the increment, so the mesh variation is not made by steps but gradual (or like the original gradient).

[teopado89]

Good morning everyone, i have another question:

if i select with the command thickness the triangles in a specified range (e.g. 1.5-1.6mm) and i change properties of thickness of these triangles (e.g. i set thickness specified at 1.7mm), does the analysis consider the plastic as a thickness of 1.7mm in the modified area?

My doubt is this:

if i select in a dual domain only one side-triangles of the mesh (with the command facing entities), and i change the thickness of only one part, what will happen?

Thanks

[teopado89]

May anyone help me with my prevoius question:

"if i select in a dual domain only one side-triangles of the mesh (with the command facing entities), and i change the thickness of only one side, what will happen?"

If the original mesh has 2mm of thickness, and i change only one side triangle face thickness increasing to 2.5mm, i have one side with 2mm, the other at 2.5mm.

Which thickness will Moldflow consider? thanks

[nordhb]

Hi,

for Dual Domain, the Specified thickness will override the Auto-determine.

If you set Specified thickness on one side of the matched elements, this setting will override the Auto-determined on matched side.

You will see this in a Thickness plot as well.

Note: this can be used as a first approach for thickness change in Fill + Pack for Dual Domain mesh type.

Not recommended for Warp, as Warp uses the actual node position.

For warp the true thickness should be modelled, hence using Auto-determine for Dual Domain mesh type.

Hope this clarifies.

Regards,

Berndt

[teopado89]

Hi nordhb, thanks for our answer.
I tried to understand your explanation, but as you can see in the pictures below there is something i don't understand:
in the first picture in the left there is my part with a thickness increment of 0.3mm made only on one side of dual domain mesh using triangles properties. in the right there is the same part with the auto-determinated thickness

In the second picture i show the thickness diagnostic result of the other side of the mesh. As you can see in the left picture (the one where i made the increment of 0.3mm on the other side) the result is the same of the original part on the right:

Last thing:

you said the warpage result starts from nodal position and it doesn't feel thikness variation made by properties.

So why do i obtain a different scale ( so a different result) ?

Thanks in advance.

Matteo

[madhukeshwart]

Matteo,

1. It is recommend to change thickness in both the sides of matched nodes. Then results of effect of thickness changes can be observed if fill+pack results only. But it is not recommended, but change 3d model and re-create DD mesh from updated 3D model.
2. It is not recommend to use DD mesh with manually assigned thickness for warp analysis at all. Distance considered is distance between matched nodes.
3. In any case, If you are using DD mesh,  Mold recommends more than 85 % match ratio for fill+pack analysis & more than 90 % match ratio for fill+pack+warp analysis. if not then go for 3d mesh.

"Results difference will be there since change in mesh properties, input data from fill+pack analysis results, which are  used for warpage analysis"

[nordhb · Accepted solution]

Hi Matteo,
I used Autodesk Simulation Moldflow Insight 2015 in my example.
And I confirm I see the same, that thickness does not change on opposite side.
Have to correct myself on that point if being unclear of matching elements and thickness display: selected side will display Specified thickness the opposite side will display Auto-determined thickness,
However, the specified thickness will override the Auto-determined thickness.

Thank you Madhukeshwar for the comments.
Is a good recommendation to change thickness on both the sides of matched nodes.
This will be a better control of where specified thickness is used in Dual Domain mesh type.
And also show on thickness plot.

As discussed:
Changing the thickness from Auto-determined to Specified can be used as a first approach for a thickness change in Fill + Pack for Dual Domain mesh type, and to get an understanding of how a thickness change can affect the results.
This thickness change will affect warp - but: it is not recommended for Warp, as Warp uses the actual node position, the matched node to node position in study.
This means Fill+Pack will use Specified thickness, and Warp Auto-determined thickness (by the actual node position, and matched distance).
If Specified thickness Warp uses Auto-determined thickness (by the actual node position, and matched distance), but process induced stress from specified thickness.

For warp the true thickness should be modelled, hence using Auto-determine for Dual Domain mesh type.
If you want to consider warp you should have correct/wished thickness for best accuracy for Dual Domain mesh type.

Hope this clarifies.
Regards,
Berndt

[teopado89]

Thanks you both.
I really appreciate your help.
If i don't have the possibility to modify the 3d model thickness, is it correct to modify the mesh "moving" the triangles with the command translate (keeping the auto-determined properties on thickness) to analyze the warpage with the thickness variation?
Or shouls i move the triangles and then switch to a 3d mesh?
Thanks in advance,
Matteo.

[nordhb]

Hi Matteo,

you can translate triangle nodes in the thickness direction for Dual Domain mesh (use thickness normal vector).

As Auto-determined thickness, the Mesh Thickness Diagnostics should show the thickness change symmetrically, on both side of part.

Then continue to simulate in Dual Domain, Fill+Pack+Warp.

If you need to simulate 3D mesh type: first translate nodes for part thickness in Dual Domain mesh type, and then move to 3D mesh type and mesh tetras.

Then continue to simulate in 3D, Fill+Pack+Warp.

Translation of nodes is a way to change the true node position to be considered for warp, and an acceptabel workaround, I would say.

Translation of nodes changes the Auto-determined thickness of Dual Domain mesh triangles.

Regards,

Berndt

[madhukeshwart]

• If you dont have posibility to modify the 3d model thickness, you switch back to DD mesh,  modify the mesh by moving the elements. Then re-convert to 3D mesh
•  In 3d thickness of element wont play role, but volume play.

[teopado89]

Hi everyone,

"(use thickness normal vector)."

is it an option in Moldflow?

Because i usually do this:

-create a random line

-using the command rotate i try to make it normal to the mesh

-i divide the line in enough nodes to obtain between two nodes the distance i want to move the mesh

-i use the command translate using as vector coordinates the two nodes i mentioned before.

Is there a smarter and more correct way?

Thanks

[madhukeshwart · Accepted solution]

Create LCS ( Local co-ordinate system ) and then try

[teopado89]

Thanks a lot!