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Contributor
sriramsheval
Posts: 24
Registered: ‎10-21-2013
Accepted Solution

Error During Non Linear Analysis

157 Views, 4 Replies
06-01-2014 06:58 PM

Hi All, 

 

Recently, while I was analysing a Component with Non Linear Static Stress Analysis, after 25 Hours of Run time i got an error as below 6.2.2014.JPG

 

I cant understand, what that error message states.

 

Thanks

Sriram

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Employee
Alex.Bakharev
Posts: 47
Registered: ‎04-10-2013

Re: Error During Non Linear Analysis

06-01-2014 08:55 PM in reply to: sriramsheval

The errors like this are usually caused by the solvers been faster than the Windows disk operation system.

 

Nonlinear analysis is done by performing thousands of linear analyses. Each linear analysis opens tens of files at the beginning and closes them at the end. If the disk operations handled by OS cannot keep up with the solvers there will be an error like this. I know that this type of the problem was fixed for many files and many types of analysis but probably was not fixed yet for this particular I/O problem (or maybe you are using an old version of the solvers?).

 

The errors might not repeat itself if run again. If it is persistent the following actions might help:

  • Speeding up the disk operations: Defragmentation of the disks, running analysis on a solid state drive, not doing anything disk intensive in parallel, making sure that there is plenty of free disk space
  • Updating solvers to the most current version
  • Reporting the issue to the support and demanding a hot fix
  • Slowing down the solver by limiting the number of threads it can use
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Employee
zhuangs
Posts: 262
Registered: ‎10-04-2010

Re: Error During Non Linear Analysis

06-02-2014 08:11 AM in reply to: sriramsheval

The error might be reated to the system.  However, we can avoid this if we can improve the convergence of the model.  From your description and the residual information shown in the log file, the model should have convergence issue.  I am wondering what kind of nonlinear material model is used.  You can try to switch the iterative method from "Automatic" to "Full Newtion with Line Search 1" and see whether it helps.  If not, please provide more information of the model: element types of part1, material model of part1, # of elements and nodes.

 

-Shoubing

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Contributor
sriramsheval
Posts: 24
Registered: ‎10-21-2013

Re: Error During Non Linear Analysis

06-03-2014 10:00 PM in reply to: zhuangs

Hi Shoubing

 

the error got resolved by increasing the number of time steps,  as i increased the number of time steps, to solve a time step it takes 7 iterations max.

 

Previously i took 30. 

 

Material in Al Alloy 1100-H18 and Element type is Von Mises with isotropic hardening.

 

Though the analysis runs well, results are not as expected. 

 

As shown in the above picture, the wire with 7 strands is pulled by giving a .05 displacement at one end and fixed at other end. I want to capture the stress and strain at all the strands. 

 

No separation surface contact should be defined between 7 strands, can Autodesk SIM Mech do such an Non Linear Analysis 

 

Thanks 

Sriram 

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Employee
zhuangs
Posts: 262
Registered: ‎10-04-2010

Re: Error During Non Linear Analysis

06-04-2014 04:19 AM in reply to: sriramsheval

You can define surface contact and use "Tied contact" among the outer surfaces of the parts.

 

-Shoubing

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