Merging nodes between components 1

[HugoR]

Hi,

I imported 4 components into hypermesh, but they aren't attached together in any way in hypermesh.

I want to realize a topology optimization, but I cannot get them to attach together, a teacher told me I have to merge the nodes in the surfaces that connect the components, but I am at a loss how to do this.

Thank you for your time,

Hugo

 

[GregLocock]

Duffers guide to Hypermesh/Optistruct

I rarely use this program, but it does one thing (optimisation of FE models) so nicely that it is a handy tool even so. I found the HM tutorials rather dull since none of them really started from scratch and ended with a solution.

So as a memory jogger for me, and maybe a useful intro for you, here goes:

0) /tool /delete is the most often used subpanel

1) //files /import geom iges double click in box and find your iges file, set cleanup tolerance manually <import> <return>

2) /global select optistruct template

3) VERY IMPORTANT /tools/rotate the surfaces into the correct axes. select the surfaces by selecting and clicking surfs and hitting all. select the base point for the rotation by clicking base and then edit. Select the axis of rotation by clicking the idiotic N1 N2 N3 dropdown menu and selecting an axis.

4) and /tool/scale it +25.4 is in->mm

5) //collector create/edit a material collector using card image mat1 E nu rho 2.1e4 .3 7.843e-6 called steel

and a comp collector psolid

6) IMPORTANT save the model as an hm file and retrieve it. This will show the free edges. Use geom cleanup to toggle free edges. god knows how this is supposed to work. random switching using lmb and rmb seems to work. in vis opts you can switch shared edge display off, which helps. read help.

7)Save it again, the meshing can be a bit annoying.

8) 2d automesh, /trias only/, shift F3 to see if any edges have opened up. Equivalence merges coincident nodes. Use it

9)delete all surfaces (not sure if this is necessary)

10) 3d automesh

11) delete all ctria3

12)/BCs add some constraints.

13) add some loads


14) solve it

15) Optimisation - do the a arm tutorial.






Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[HugoR]

So...

I did tetramesh part by part... are you saying I should 2D automesh all my parts then 3d automesh all my parts in order to get it to stick together?

 

[GregLocock]

no

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[BenAltair]

HugoR, Did you import surface data or mesh?

If you imported a mesh you can use the equivalence button in Edges panel on the Tools page to combine nodes together.

If you are working with surfaces, on the Geom page there is an Edge Edit panel. You access Toggle then click on the surfaces' edges to combine them. For more control, you can also use the Replace toggle to select two edges and have them merged together.

 

[HugoR]

I imported Step geometry from Catia, so they are solids without mesh.

After importing the volumes are already made. I will try both those options and see what happens. I'll keep updated on the results, thank you very much