Learning Forum

[AR]

Hello,

I am doing a static analysis, followed by a modal analysis and then a Harmonic Response to test a support.

At first I only had the static and modal analysis and, after several hours, it finished calculating. It is a large model with 653,610 nodes and quite a few contacts. The modal took about 15 hours to calculate and took up about 40 GB of the entire model folder. The modal also contains more than 1000 vibration modes in frequencies from 0 to 2200 Hz.

Later, I added the harmonic analysis and therefore had to run the modal again. However, the modal does not finish calculating. I get an error that there is not enough space on the hard drive (I had 500 GB free) and it is because it fills up all that memory.

I know that to reduce the size of the results I can reduce the number of nodes or the size of my model. However, I cannot apply any asymmetry or remove parts. As for the mesh, it already has a considerable element size, so I would not like to have to reduce it further. Increasing the computer's RAM capabilities is also not an option. I am using the Direct solver for the modal and it is running out of RAM, but my computer will not accept more (it has 32 GB).

Also, Ansys is not using all of the RAM I have installed. The program tells me the following:
Total memory allocated for solver = 20495.361 MB
Total memory required for in-core solution = 16644.119 MB
Total memory required for out-of-core solution = 4495.383 MB

However, the task manager tells me that 27.1 GB is being used and 4.7 GB is free.

1) Is there a way to reduce the size of the project output folder?
2) Is there any way to make Ansys not save the vibration modes that are not significant? I mean those that have an effective mass to total mass ratio less than 1e-4 or something similar.
3) Can you give me any advice to perform this analysis?
4) Is there any way to make Ansys use all the available RAM? In this way, I think it would not go out of RAM and would calculate faster.

 

Regards,

[Gary_S]

Hello

 A few ideas:

Try the Iterative (PCG) solver as it may not require as much RAM.
Considering using Linear elements where appropriate. (Add an Element Type control to specific bodies)
In the Solver Output Controls, you can turn off unneeded quantities written to the result files.  You may want to test on a smaller model to confim you are not disabling anything you need.