Reanalyse with unsmoothed structure

Rahul_P1

Hi,

Is there a way to reanalyse a optimized structure without any smoothing of the surfaces ?

My Idea is:
After a first optimization with a coarse Hex-mesh i want to delete all elements with low density and split the rest. Then make a second optimization with a lower 'mindim'. The first optimization should give me a rough shape and the second one a thin-walled structure.

Rahul_P1

Hi Linus,

Can you not start your optimization with the refined element density for better results?

If I understand you correctly, you are following the optimized shape with some more iterations, this is not very reasonable as the result itself is optimal,

In any case perhaps you can reduce your iso surface threshold value to 0 or close to 0 in OSSmooth to get a non smoothed shape, please try with these parameters and share the results.

Rahul_P1

Hi Rahul

If I refine the mesh before the first optimization the FE-Model would be too big. After the first optimization the volume is about 40% of the start volume. But the stresses are still very low. So i want to remesh the optimized volume with a finer mesh to get thinner structures. But if I smooth the shape I can only use tetra-elements for remeshing, which make my model very big again.
That's why i want to use the original Hex-mesh and refine the 'important' elements.

Rahul_P1

Hi Linus,

I understand your request and there is a way to do this

After your Optimization run with a manageable hexa element density,

Post process in HyperView > Plot the element density contour

Go to Model pull down > create sets > change entity to elements > click on elements (yellow button) to open the extended entity selection menu > click on By contour > enter the value of the element density for eg >=0.3, so that all elements above this density are selected, you should determine this density from isosurface to understand exactly what density value best represents the shape you want for your re - optimization > add to set > export > patran session file.

Then go to HyperMesh > load the original model > go to tools pull down > set browser > in set browser > right click > import .ses > choose the file created above

Then go to mask > elements > by set > choose the set imported as above > mask > reverse

you have your model now in hexa elements, delete the other elements after organizing these displayed elements into a collector or any other way to reuse these elements.

Then you can split your hexa elements from 3d > split > hexa

Or try with the below script which will allow multiple element selection in different planes and also split in multiple directions.

You can download the documentation that has a video describing all the methods of splitting available in the macro.

You need to download the script and then run this script from the downloaded location by going to file > run tcl tk from within HyperMesh.
see http://www.altairuniversity.com/support-forum/?mingleforumaction=viewtopic&t=87

you will find this and other scripts in the altair script exchange, go to learning > script exchange from the altair university website or here http://www.altairhyperworks.com/Script-Exchange.aspx?%3ftop_nav_str=1
you will need to log in with your university mail id and login credentials you get after registering to the client centre.

search for the script by just entering split hexa in the keyword section.

once you have found the script click on the download button, once you have downloaded the script place it in a convenient location, then you need to do a file > run tcl tk from within HyperMesh. make sure you have a relevant model loaded in HyperMesh when you run the script.