Spherical coordinate system - ANSYS explicit workbench 1

[danz001]

Good day all!

I am in desperate need of anyone out there who has an success in this matter. I'm looking at assigning a transversely isotropic material, along a spherical coordinate system in ANSYS explicit (workbench).

Now I have done a lot of searching, and have had little success. What I was able to determine is that spherical coordinate systems are available, but only in ansys classic (ADPL). This does not suit my scenario, mainly due to the complex CAD geometry that I am working with. I understand that elements of ANSYS ADPL and workbench can be linked through command (snippets), however I'm not sure if this is my answer. From what I've been able to determine, commands cannot be implemented in the coordinate system tree, and commands can only be used in ansys static structural? Please correct me if in wrong.

I am asking anyone with any experience of this, or similar to contribute and it would be greatly appreciated. I look forward to hearing off you all.

Any other details you need then please let me know!

 

[rickfischer51]

I dont have Ansys Explicit loaded, so I cant say if snippets are allowed there, but the certainly are not limited to static structural. The way to check is to Right Click, Insert in the tree and see if the snippet icon appears, usually at the bottom of the list.

Keep in mind that the same program is run by both Workbench and Classic. Workbench writes a command script (sort of a mega-snippet) and runs it in Classic in batch mode. What you can do is use both WB and Classic and do the same thing interactivly. Get the model where you want it in WB, highlight Solution, then go up to the toolbar and pick Tools, Write Input File. That will create the mega-snippet with the solve command commented out. Now open a session in Classic and input the file (/input,filename,inp at the command line. After it reads in the file, type solve and it will run. If you want to change it before solving, have at it. You can use the classic GUI, the command line, or write another script and input that. You can even read in the WB script, save the database with any name you want, then run a script that starts with RESUME,anyname,ext. The file must be a database file created with the save command.

I dont know how this would work with Explicit, but it works great with implicit. I do some work with high frequency emag that is not supported in WB. I use WB as a model builder, write out an input file, read it in to classic and save it as a database file, then resume it and perform multiple structural and EMAG analyses with a script.

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[danz001]

Rick, firstly can I say big thanks for your more than informative reply! So the signs seem to suggest that it may be possible. As you may be able to tell, my experience is fairly limited in ANSYS ADPL so please excuse my inexperience. To clarify, the snippet icon you refer to, is this the 'C' shape button that appears? If this is the case, then it doesn't appear in the coordinate system tree.

One other quick question, in regards to your write and read input file, I would be able to read in external cad geometry through workbench, then set the rest of my simulation up through APDL?

Thanks again!

 

[rickfischer51]

Yeah, the icon looks like a red C with a piece of lined paper behind it. If you click on an item, the icon will also show up at in the toolbar. If the icon is grayed out, it means that you cant put the snippet at that level, but at an item in the subtree.

Regarding your last question, yes that's exactly right. Before WB, all you had was the XOX geometry engine in Classic. It worked but was buggy and outdated. When they decided to update, they decided to make a totally new preprocessor based on Parasolids, and that became WB. I was told that the reason you pay extra for Design Medeler is because there is a Parasolids license in there someplace. both preprocessors still work, and you can mix and match. The only gap is that when you start in WB, no solid model gemotry comes into Classic, only FE stuff(elements, nodes materials, loads, etc.) You can add geometry if needed, and mesh it, but the original geometry stays in WB. I typically take CAD geometry into Design Medeler, fix it and make it fit for analysis, go to WB for meshing, and if needed, take an input file into classic. Sometimes when I do the whole job in WB, I still go into classic for debug, because you can look at sometings ther eyou cant get to in WB,

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[danz001]

Rich! Thanks once again, it certainly looks as though none of snippets are available in ansys explicit. I was able to write an input file through static structural and read it in ADPL, so that suggestion will probably work. However when I went to write the same file through ansys explicit, the write input file was greyed out, any idea if this means I cannot export my geometry/mesh from WB to ADPL?

Dan

 

[rickfischer51]

Are you using Autodyne or LS/Dyna?

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[danz001]

Good question! LS DYNA I do believe, which I see as Explicit Dynamics (through WB)

 

[rickfischer51]

OK. Write input file is grayed out, eh? Bastards!! OK, Plan B is go into Analysis Settings, Analysis Data Management, and set save MAPDL .db to yes. Run the analysis as is. You can make a dummy run with trivial loads just so it will run quick and generate the .db file. Save and close WB and open the MAPDL launcher. Click on the File management tab and set Working directory to the folder with the .db file. For a project called SPUD and with one analysis system it will be at SPUD_files\dp)\SYS-1\mech. Set job name to file and hit run. In MAPDL, type RESUME at the command line. You should now be in. This would work with regular ANSYS, but I dont know for sure with LS/Dyna.

The issue here may be exportabilty to various parts of the world. When I used Ansys/LSDyna about 12 years ago there were certain features that were not available through the ANSYS gui and commands because they had strategic significance. If this is still an issue, it could explain the grayed out write input file button. The work around was to create the LS Dyna database file and then run LS/Dyna from the DOS prompt, where you could add any Dyna commands you wanted. I was trying to simulate penetration of HMS Hood's armor belt by a shell from Bismarck's fifth salvo based on data supplied in Bill Jueren's 1987 paper, and needed access to some features excluded by ansys. I ran out of computer power, technical expertise and interest, in that order, but it was fun to try.

Rick Fischer
Principal Engineer
Argonne National Laboratory

 

[danz001]

Wow Rick, what an interesting read! I will most certainly give your first suggestion a go, and report back. Thanks once again!

Dan

 

[danz001]

Rick, I have selected the option to allow WB to save the .db file, but I cannot seem to find it in the MECH directory. Please note this directory is not blank, it contains other files just not a .db file

Any ideas?

Dan

 

[danz001]

I think I may have figured out my issue, LS DYNA works with ADPL, my solver is set to Autodyn, which I understand is not compatible with APDL.

How the devil am I going to get spherical coordinates into my analysis? I can't understand why this is so awkward!

Dan