Learning Forum

[Abidos98]

I am trying to solve the problem I have and I keep getting the error 'Your product license has numerical problem size limits, you have exceeded these problem size limits and the solver cannot proceed.'

I am on the student version and  a screenshot of the statistics is below. I tried increasing the element size to get the number of nodes under 30k but it was still giving the error. 

Could someone help with the steps as I am new to ANSYS and trying to learn? Thanks 

[peteroznewman]

Relevant discussion.

[Abidos98]

 I have already done that before, and tried it now again and tried for solving it again but got the same error again 

[peteroznewman]

There is a 32,000 limit on nodes or elements in the Structural solver and 512,000 cells in the Fluent solver. In your case, you have exceeded the Structural limit of 32,000 because your node count is 1.1 million and your element count is 279,111.

You can reduce the node and element count by converting thin walled parts to surfaces instead of solids and meshing the surface with shell elements.  You can further reduce the node and element count by simplifying the solid bodies until you have bodies that are purely extruded, then the mesher can sweep mostly hex elements through the solid and cut the number of elements in half or more.

If your geometry and loads are symmetric, you can cut your model in half or in 1/4 by using symmetry boundary conditions.

[Abidos98]

I have already tried to increase the element size and thus the element number decreased along with the nodes, it has not got me anywhere, the solver gave me the same error. 

The simulation is of a PV panel, I had imported the geometry, it consists of the surrounding aluminum frame and 4 layers. 

I unfortunately am unclear as to the steps, is there steps for them if thats not too much trouble? As I mentioned I am new to Ansys so i am following a tutorial for now, its my first experience with it and I am trying to get the hang of it. 

[peteroznewman]

In Mechanical, right mouse click on Mesh and Clear Generated Data.  Then close Mechancial.  In Workbench, do File > Save,  then File > Archive and save a .wbpz file.  Make sure to leave checked to include External files. Use the Attach button to upload that file to your post above and I will take a look later.

[Abidos98]

Alright, I have attached the file and will await your response, again, thank you for the help, I appreciate it! 

[peteroznewman]

 

All the solids were replaced with surfaces. Some features in the solids were deleted before midsurfaces were created like holes in the frame or the slot in Teldar.

All the surfaces except PV have an assigned thickness that equals the thickness of the solid.

If you create Bonded Contact between parts that touch, that will create a path for thermal conduction.

I don't know what is important to include in the PV layer, so I just copied the rectangular outlines. You need to assign a thickness. You can click the first one and shift click the last one and assign the material and thickness to all of them at once.

This mesh is a bit less than half the limit, so you have room to make some parts higher mesh density to capture high gradients.

[Abidos98]

Thank you for the amazing help! I will assign the appropriate thicknesses and the material for the PV components, again, thank you! 

 

A couple of last inquiries, is this considered a good mesh? Also, if I wanted to increase the mesh density so that it is the maximum that I could run given the limitations of the student license, what are the steps to that? I would appreciate the steps if possible so that I learn how to do it in the future. 

 

Again, thank you for the great help. 

 

I have just tried now to run the simulation after adding the thickness and material for all the PV labels and have got a new set of errors, any idea as why they are there or how to fix them? 

 

[peteroznewman]

When you get a model to solve, you look at the areas of highest thermal gradient, and use Mesh Controls to selectively increase the mesh in those areas. Create a Coordinate System at that location then use a Sizing mesh control on the body/surface and a Sphere of Influence for the smaller elements around that Csys.

The error is due to improper boundary conditions.  Try making a simple thermal model with just a few faces or surfaces and see what a successful solve looks like first, before you try this very complicated model.

[Abidos98]

So I reduced the number of components to apply the load on as you recommended and added a sizing mesh to the 36 components of the PV as you also recommended, now I have a mesh of 20338 nodes and 18306 elements.. however, trying to solve now, I got the same error of ' Your product license has numerical problem size limits, you have exceeded these problem size limits and the solver cannot proceed.' 

 

 

[Abidos98]

 I am still trying to solve the model but I have not gotten anywhere since the last post, would appreciate some help if possible, thank you! 

[peteroznewman]

Try using Mesh Renumbering.

Also note that any contact elements are created at the solution time, so they don't show up in the mesh statistics but they do count to the limit.

[Abidos98]

I have already tried mesh numbering while compressing the node numbers and have not been successful with it as well

[peteroznewman]

If you are a student at a University that uses ANSYS, ask a Professor about getting access to a Research license.

If you want to use the free Student license of ANSYS, discard 3/4 of the PV surfaces and resize the rest of the parts to do a 1/4 sized model.

[Abidos98]

Unfortunately all of the university is closed at the time being due to the spread of the virus. 

How is it possible to do that? I have cosidered it the past couple of days but have not gotten anywhere online, sorry if I am being a hassle. 

[peteroznewman]

Attached is a quarter model of the midsurfaces.

[Abidos98]

Thank you for that, I have run the simulation, however, another error is showing up, 'Solver pivot warnings or errors have been encountered during the solution.  This is usually a result of an ill conditioned matrix possibly due to unreasonable material properties, an under constrained model, or contact related issues.  Check results carefully.' 

I am not sure why is that, i looked it up just now and havent gotten anywhere 

[peteroznewman]

That is a new topic so please create a New Discussion in the correct category, which I think would be Thermodynamics. You need to insert some more detail in that discussion so others reading it have the information needed to offer advice.

I'm glad I could help you with your original problem. Please click the link Is Solution (when you are logged in) under one of my replies to mark this Discussion as Solved.