Learning Forum

[VVCZ]

I am trying to perform explicit analysis using LS-DYNA. Though I know there is a possibility of submitting analysis via Workbench (Workbench LS-DYNA), I want to only export keyword file (.k file), then do some sort of adjustment, and then run it via Mechanical APDL Product Launcher.

So to do that in Workbench I activate Beta options and Unsupported features through Tools->Options->Appearance and use the block of analysis named Explicit Dynamics (LS-DYNA Export) (Unsupported). Then I simply build my model, press solve, open solver files directory, copy keyword file into some other folder I want my results etc. have in, and go into Mechanical APDL Product Launcher. There I set the environment to LS-DYNA Solver, set Analysis type to Typical LS-DYNA Analysis, set license to Ansys Academic Research LS-DYNA, set the working directory containing keyword file and set the keyword file.

Then I hit run and get following error: Error connecting to the service. There is more, so I am uploading a picture of the error message.

Additional info: when using Explicit Dynamics (LS-DYNA Export) (Unsupported) via Mechanical (and it works fine, also Workbench LS-DYNA works fine and calculations are running), I can see my computer on a licencse list that I am using Ansys Academic Research LS-DYNA license.

 

Any idea? If there is additional info needed, I can provide it. 

Vaclav

 

[tsiriaks]

Please post the screenshots inline with text including the screenshot of your Mechanical APDL Product Launcher setting on each tab.

Thanks,

Win

[VVCZ]

Tsirikas,

 

unfortunately, I am not sufficient with inserting image into the body of the text.

When I click on the insert image icon, I can see 3 rows - Upload Image, External Image and Image Description. I click on Browse to upload image, select the image, click ok. Then when I mouse over the Browse icon, there is a note displaying the name of the image (although next to Browse I expected it also, but it's nothing there).

Then I click OK to confirm upload and then it shows me that spinning wheel showing that it's processing. I let it process for an hour with no effect, so I abort it.

[VVCZ]

Dear all, 

 

I found the solution. In MAPDL Launcher in the HPC tab, I had pre setup of Type of HPC Run:  Use Distributed Computing (DMP), MPI Type: INTEL MPI (default). This setup doesn't work regardless of Number of Processors. 

When I change MPI Type to MS MPI, I can run LS-DYNA but only with 1 processor, when I try to change it to 2 processors, I get the error: Capability ANSYS Academic Research LS-DYNA Parallel does not exist in the ANSYS licensing pool.

Also, when I change type of HPC Run to None, LS-DYNA works.

Can anybody explain the problem more into detail? From above I get that the license I use does not contain the ability to use more than 1 processor.

[tsiriaks]

That was my thought. You have some issue with Intel MPI, so if you try another MPI (MS MPI in this case), it may work.

What's the LS-Dyna/ANSYS version you are using ? You are supposed to be able to solve with at least 4 cores without pulling any extra license.

The 'None' mode just simply means you are not solving it in distributed mode, but rather the shared-memory mode. For this mode, MPI is not used, so you avoid MPI issue that way.

 

[VVCZ]

Tsirikas,

 

the license is Ansys Acadameic Research 2019 R3, including LS-DYNA, Mechanical, Mechanical and CFD and some other stuff... . In workbench -> License preferences I can see in the HPC tab that there is only one license: ANSYS Academic Research HPC, including the info about the maximum number of processors.

This is quite limitating, my explicit model contains 4e6 nodes and without parallelization I can do mass scaling and increase artificial velocity one way or another, but on 1 processor it will be very time consuming.

I guess I can do nothing about it since my uni has no LS-DYNA license including parallelization. Or am I wrong? Any workaround?

[tsiriaks]

The "ANSYS Academic Research HPC" can't be used with LS-Dyna. The only Academic HPC license that would allow parallel solving for LS-Dyna is "ANSYS Academic Research LS-DYNA Parallel"

Also, I have just found the info from the below link that there is no built-in HPC for LS-Dyna solver license. This explains why you can only solve 1 core

https://www.ansys.com/academic/educator-tools/high-performance-computing

I'd recommend to consult with your department or university (whoever manages the licenses) and ask if they can approach ANSYS Account Manager to discuss about this license that you need.

 

[VVCZ]

Okay, so I am going to sum it up and mark as Solution.

• I have no "ANSYS Academic Research LS-DYNA Parallel" license, therefore I can not use parallelization.


• I can use HPC distributed computing throughout MS MPI, but only with 1 processor, which I don't think it would lead to better performance compared with not using any HPC.


• I can not use Intel MPI, my computer has some issue with it.

Just for information, the speed of simulation on 1 processor is dependent on the processor frequency, which in my case is 3.6 GHz. So my simulations are running quite quickly despite the license limitation.

 

Tsirikas, thanks for all your replies leading to solution of this problem.

[tsiriaks]

Sounds good. You are welcome.