I’m transferring from another FEA system. I’m finding the basic workflow in PrePoMax less than obvious.
I want to assign the same material to multiple parts of the imported model - do I really have to create a section in turn for each part and separately assign material to each section? Is there some option to speed this up?
You can create one section with a selected material and apply it to multiple parts - just hold LMB and drag the selection box or select multiple entities (e.g. parts) while holding SHIFT.
No - I can’t make that work. Is there any example anywhere? I may be missing something simple.
Are you referring to the Region definition in the Edit Section dialogue? I can only select one part no matter which keys I hold down.
Region type should be set to Selection. Here’s an example:
OK - that’s a bit clearer. Selection not possible in tree, only in the graphic.
Is there a limitation on numbers? I tried box selecting all parts about 15 minutes ago and am still waiting…
Does display have to be in any particular mode for this to work?
No fixed limit but if you have a huge number of parts then of course there can be some performance issues. How many parts are there in your case ?
It should work in any display mode except for wireframe.
No, it is not limited. Selecting up to 100 parts and 1.000.000 elements should finish quickly.
Had to turn off mesh display and add each part individually. Box select didn’t work.
Was still very slow.
What kind of hardware are you using. Do you have a separate graphics card, or are you using an on-chip graphics?
Nvidia GTX 1050 Ti - not the latest and greatest, but manages 3D CAD quite well - 4GB of dedicated graphics memory.
That should not be problematic, then. How big is your model in terms of a number of parts and a number of elements?
Number of parts - started off at about 120, but I’ve merged a lot of items to try to make things more manageable, and have removed one particularly complex one altogether. Now 47 parts. Initially I was running out of system memory, now still getting some crashes whilst trying to set surfaces.
Nodes - probably far more than needed. I just used defaults for meshing.
Elements - no idea how to check the count.
Thank for the tip - number of elements 15461742 which I guess is a lot.
Yes, over 15 mln elements is really a lot, especially for CalculiX. How many nodes ? Are those solid elements only ?
Nodes 23190886
Yes all solid elements.
Guess I need to re-mesh with larger mesh size? My previous system spoiled me by optimising the mesh automatically (which was great, but it’s now an old unsupported system and doesn’t always manage to successfully mesh - hence trying PPM).
Is there a simple way to re-mesh (I get 'object reference not set to instance of an object - if I try (from FE model) Model → Tools → Remesh Elements.
I’m thinking may be simpler to start over in a new project.
Yes, this mesh is huge. You should start with as coarse mesh as still reasonable in your case and refine as needed. CalculiX is quite sensitive to large meshes and it’s likely that it won’t run this analysis (you should use Pardiso solver right away to reduce that risk).
Assuming that you have the geometry imported, just go back to the first tab in the tree, change the mesh settings and remesh. Most analysis features should be reapplied properly.
Unfortunately not (though I may end up chopping it in half - even though that will introduce some errors).
Sorry - that is beyond my current experience level. What is the benefit of using hex elements in this case?
Not really. It’s a complex 3D assembly (already extracted from a much larger assembly). Simple calculations suggest bolting may be tight on design factor - so wanting to run FEA to identify any higher stress locations that may not have been noticed so far.
