Assembling Geometry in Optistruct

Hello,

I am trying to analyse and optimize the chassis of a composite car. The body will be made out of woven carbon fiber and aluminium honeycomb but at the same time, to add stiffness, there will be spars and a dashboard made out of PVC foam, layered with carbon fiber to add to the structural strength and torsional stiffness of the vehicle. Here is a picture
image.png.c76a7866b9b25ef7e1c8ef8a2871c83d.png image.png.6e26524d3fb1885a3ee0eb78d50311f9.png

As you can see, the blackish/gray is the dashboard, the green are the spars and the red is the body.

So what I did was I imported all 3 files together. Since I've made these parts in relative to each other, they fit perfectly without having to 'mate' anything in Optistruct as you would do in Solidworks.

The problem arises when I try to upload the body AND the spars/dashboard together.

The body was originally a full solid used to run CFD. Later, it was shelled in solidworks so it was hollow but still had a thickness. This would be a problem is I were to try to layer carbon fiber on it.
So what I did was that I uploaded it to design modeler, thinned all the surfaces and I achieved a pure surface body, which was perfect for layering carbon fiber.
However, it seems that when I try to upload the surface body together with a solid body, the surface body disappears.

image.png.8b5f24e80148b3db4a7e2ba80fbc2eef.png

Everything is fine when I upload the surface body.

Now when I try to upload the dashboard,
image.png.b2db7044eaeb124716ea52892a39a29e.png
the surface body disappears and only the solid body remains.

Does anyone have any ideas how to get around this? /emoticons/default_sad.png' srcset='/emoticons/sad@2x.png 2x' title=':(' width='20' />

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Sanjay Nainani_20973

Hello,

Can you check the scale factor between them. There is a possibility that the dashboard component is very big in size as compared to the surface part and thats why it is not showing up.

To check if the surface component is still present hide the solid component and press the 'F' button to see that the surface component is till there or not.

Can you also please upload a picture of the model browser so that we can know if the surface component is still present in HyperMesh or not?

Please let me know if it showed any result.

Thankyou

Altair Forum User

Hi Sanjay,

Thanks for the reply. I just tried your solution and I just realized that the surface body is not seen because the dashboard has been magnified by 1000 times. I'm not sure why this is so. Maybe it is because Design modeler exports geometries using meters while solidworks exports geometries based on whatever units were chosen. I drew the dashboard in millimeters by the way. So I just scaled down accordingly.

Thanks for the help!

Altair Forum User

Hello,

Can you check the scale factor between them. There is a possibility that the dashboard component is very big in size as compared to the surface part and thats why it is not showing up.

To check if the surface component is still present hide the solid component and press the 'F' button to see that the surface component is till there or not.

Can you also please upload a picture of the model browser so that we can know if the surface component is still present in HyperMesh or not?

Please let me know if it showed any result.

Thankyou

Hey Sanjay,

I've ran into another issue. I realized that whenever I try to mask the body's mesh to view the mesh of the dashboard and spars, the whole mesh goes missing. I am trying to set contacts by hiding meshes one by one and selecting the relevant elements.

image.png.3ff9fad784dc2b1619b007bd5c3d90fd.png When I click on the icon circled in blue, the entire mesh disappears. I have also tried right clicking on the other components and selected 'make current' but still disappears when the body mesh is hidden. Any ideas?

Also, I am using a tetra volume mesh for the dashboard and spars and a 2D automesh for the body.

Sanjay Nainani_20973

Hello,

I think this issue is because you might have forgotten to change the Current Component collector during Meshing and that's why the whole mesh is now store in one component collector.

To correct this you have to select the mesh of each component manually and using 'Organize' panel in 'Tools' page, you have to organize them corresponding to the component.

You have to redo the mesh, keeping in mind to make the respective component collector as the current collector before you mesh that component.

Thank you

Altair Forum User

Hi Sanjay,

I did your second suggestion and it works! Thanks a lot again! /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20' />