Not able to find the actual problem

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  • Last Post 07 October 2019
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SJ123 posted this 05 October 2019

Below is the archive file of my model.

https://drive.google.com/open?id=1IoE4wgJAWmKqIL6FGATcW8TVZhKPGMJD

Please suggest the solution for the problem.

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peteroznewman posted this 05 October 2019

Here is the ERROR I get on a big workstation.

 Number of equations was about 7.3 million.

 *** ERROR ***                           CP =     739.492   TIME= 08:11
 There is not enough memory for the Distributed Sparse Matrix Solver to 
 proceed using the out-of-core memory mode.  The total memory required  
 by all processes = 336902 MB.  The total physical memory that is       
 available on the system = 176879 MB.  Please decrease the model size,  
 or run this model on another system with more physical memory.  

Looking at your model, you have too many elements, use a larger element size.

You also have multiple contacts on the same surfaces. Delete all but the necessary ones.

If I double the size of all mesh controls, it will solve on my workstation.

 DISTRIBUTED SPARSE MATRIX DIRECT SOLVER.
  Number of equations =     1201042,    Maximum wavefront =    552

  Total memory allocated for solver              =  90260.131 MB
  Total memory required for in-core solution     =  82303.980 MB
  Total memory required for out-of-core solution =  29984.555 MB

 The Distributed Sparse Matrix Solver is currently running in the       
 in-core memory mode.  This memory mode uses the most amount of memory  
 in order to avoid using the hard drive as much as possible, which most 
 often results in the fastest solution time.  This mode is recommended  
 if enough physical memory is present to accommodate all of the solver  
 data.                                                                    

How much memory is installed in your computer?

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SJ123 posted this 06 October 2019

Hi Peter

Thanks for looking at my model.

The installed memory is 24 GB.

If possible, could you please remove the unnecessary contacts from my model and upload it again. If not, suggest those unnecessary contact to be removed.

 

peteroznewman posted this 06 October 2019

The version I edited will not run on your computer because it requires 30 GB of free memory and you have only 20 GB of free memory. You have to increase the element size even more.

Most of the contacts labeled Contact were automatically generated and should be deleted. Look at each contact and see what surfaces light up and just keep the ones that are correct.

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peteroznewman posted this 06 October 2019

 

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Gorgar posted this 06 October 2019

Pteroznewman could you please, since I had to log in with my new email, because otherwise I am not able to log in even if I try to change my password, it says that I do not know the password, so I have now new email, but I am not able to find out all these ideas you have made for me with the oil that you were helping a month ago and before, so it looks a bit crazy, so do you know how to find your comments? Thanks for you ideas...Jiri

Gorgar posted this 06 October 2019

The main problem for me is to long in with my original email and it was georgiro@hotmail.com, but it does not want to accept my password, but I know absolutely well the password! Thanks for your ideas, I just do not know how to log in by this email....

peteroznewman posted this 06 October 2019

Jiri, sorry for your troubles.  Open a browser and go to Google.com in the search bar type this:

site:studentcommunity.ansys.com Georgiro1 posted

it will return a link to every post you have made.

SJ123 posted this 06 October 2019

Hi Peter

I have made changes suggested by you regarding the contact and element size but still, I am getting some error. Please help me out.

Below is the link for the archive file of my model.

https://drive.google.com/open?id=1ST93TEfvlnsS0jaAZVV7h7owj6WpBESg

Gorgar posted this 06 October 2019

Peter, thanks a lot, of course I do not know who shall I tell him the issue not to be able to log in?

But thanks!

Jiri

Gorgar posted this 06 October 2019

Peter, yes, I found it, this was the best. Thanks a lot!

Jiri

peteroznewman posted this 06 October 2019

Shobhit,

I don't know why the solver is trying to run incore on a 24 GB memory machine when it calculated it needs 31 GB for incore.

DISTRIBUTED SPARSE MATRIX DIRECT SOLVER.
  Number of equations =      752990,    Maximum wavefront =   4314

  Local memory allocated for solver              =   6804.421 MB
  Local memory required for in-core solution     =   6196.708 MB
  Local memory required for out-of-core solution =    751.710 MB

  Total memory allocated for solver              =  34117.895 MB
  Total memory required for in-core solution     =  31117.943 MB
  Total memory required for out-of-core solution =   4888.666 MB

 *** NOTE ***                            CP =      18.750   TIME= 22:12:1
 The Distributed Sparse Matrix Solver is currently running in the       
 in-core memory mode.  This memory mode uses the most amount of memory  
 in order to avoid using the hard drive as much as possible, which most 
 often results in the fastest solution time.  This mode is recommended  
 if enough physical memory is present to accommodate all of the solver  
 data.                                                                    

Insert a command object to force it to run outofcore, pay attention to the double comma!

DSPOPTION,,outofcore

DISTRIBUTED SPARSE MATRIX DIRECT SOLVER.
  Number of equations =      752990,    Maximum wavefront =   4314

  Local memory allocated for solver              =   1843.666 MB
  Local memory required for in-core solution     =   5289.458 MB
  Local memory required for out-of-core solution =   1631.345 MB

  Total memory allocated for solver              =  10534.168 MB
  Total memory required for in-core solution     =  36135.412 MB
  Total memory required for out-of-core solution =   9367.275 MB

 *** WARNING ***                         CP =      43.805   TIME= 14:52:24
 The Distributed Sparse Matrix Solver is currently running in the       
 out-of-core memory mode.  This memory mode may provide significantly   
 worse performance compared to the in-core memory mode, depending on    
 the amount of available system memory and I/O speed.  Please monitor   
 the solver performance to ensure that the large amount of I/O to the   
 solver files does not create a bottleneck for performance.              

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peteroznewman posted this 06 October 2019

Under Analysis Settings, turn on Auto Time Stepping and set the initial substeps to 10.

Under Solution Information, set the Newton-Raphson Residuals to 3.

Why did you change the threads over to bonded contact?

 

SJ123 posted this 07 October 2019

I have given the bonded contacts over the threads in order to simplify my model. Is it going to make much difference in the solution?

Is it correct to give frictional contact over threads?

 

I had made the changes suggested by you in my model but still getting an unknown error. Please help.

Below is the archive file of my model.

https://drive.google.com/open?id=1oZ8t96XqB0GfG1V7y4H6dGpgE95sMzI8

peteroznewman posted this 07 October 2019

You did not insert a Command Object into the model.

Click on Static Structural, then on the Environment tab click on the Commands button.

Type the text shown.  Make sure to use two commas!

DSPOPTION,,outofcore

As I said above, your computer only has 24 GB of memory, and ANSYS should automatically choose outofcore, but it is wrongly choosing incore which requires > 30 GB of memory.


What is the purpose of this analysis?  If it is to see the effect of the screw preload tension on the body under the screw head, you could get a good result much faster if you went back to CAD and sliced off the screw threads and the body they screw into at the plane where the cylindrical face of the screw ends. Just put a fixed support on the faces in that plane.  Now the model will solve much faster and you won't need the Command object, it will solve incore.

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SJ123 posted this 07 October 2019

Hi Peter

This time I have changed the thread contacts to frictional one and Ansys has automatically chosen outofcore memory.

But now I am getting some other error. Please have a look. 

https://drive.google.com/open?id=1o9G9k22Oe16ULmjh2SMkBArT4o0g1UjW

peteroznewman posted this 07 October 2019

Shobhit, you need to develop your own skills at diagnosing problems with ANSYS solutions.  The previous errors where the solver suddenly stops running because it runs out of memory are a bit more difficult to diagnose, but I helped you get past that. Take a look at the Solver Output from this latest solve, find the error and try to figure out what it means. Depending on the error, there are different remedies. Examples of how to get past them can be found on this site, but first you have to understand the error.

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