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Hello all,

 

I've been trying to recreate the example problem seen here: https://connect.altair.com/CP/SA/training/self_paced/optimization/content/opt3/pdf/ex1a.pdf

 

But with a couple of modifications:

1. I have written a script to run the model in batch mode, however, the script cannot handle RBEs at this point. I've substituted all RBEs with loads and constraints assigned directly to the surfaces, effectively creating tractions instead of RBEs.

2.  The script meshes everything in tetra elements. 

 

Everything else should be the same (material definitions, boundary conditions, objective function, etc). I'm thinking that these two modifications shouldn't change the outcome very much, but maybe that's an incorrect assumption? I keep getting an error in Optistruct that the compliance is huge and optimization can't be performed. Any ideas as to why? The model is attached. Any help or guidance is greatly appreciated!

vf0.3_min30_wcomp.mvw

vf0.3_min30_wcomp_des.h3d

vf0.3_min30_wcomp.hm

vf0.3_min30_wcomp.fem

vf0.3_min30_wcomp.log

vf0.3_min30_wcomp_003.out

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Looks like there are modeling issues. Either nodes are not connected (free edges) or loads and BCs are not applied properly. If possible please share .fem and .out file?

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Hi Rahul, 

 

Thank you for taking a look - yes there appears to be an issue somewhere in the model, however, I believe the loads and BCs are applied the same as in the example (except that I have substituted the RBEs for tractions). I am going back through again and checking. I uploaded the other files - I thought I had uploaded the .hm yesterday but appear to have selected the wrong one! The files you requested are uploaded now. Thank you!

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I took a quick look into the .fem file and found there is no node to node connectivity between the design /nondesign region. Please correct it and run again.

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