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Restart Analysis

[ Edited ]
I'm trying to run a model in "steps". I would like to have Run1 be the solution from time 0 to 5 seconds, and Run 2 to be the solution from 6 to 10 seconds. I'm using advanced nonlinear 601, 106 solutions for both. I have a slightly complicated model of "assembling" the part and then loading it, and I'm getting tired of wasting 2 hours solving the "assembly" portion of it each time.
For an example I have created a simple model of 2 beams (se attached image). From 0 to 5 seconds the magenta beam moves up 5mm. Then it stays there and the green beam moves down 5mm. The beams have surface to surface contact between them.
I edited the Run1 solver parameters and switched the scratch to 'no' and have solved Run1 and got results. I then went into Run2-->edit solution--> case control--> strategy parameters-->restart and changed it from 'normal' to' restart' and set start time to 5 sec. right click run2 and solve... job fails.
.fo6 file shows:
COMPUTER VERSION: Windows 64-BIT VERSION



NOTE: ELEMENT GROUP NUMBERS ARE EQUIVALENT TO
ELEMENT PID NUMBERS

Initializing ... Stage 2
Initial ADINA memory allocation - 4000.0 mb (or 500.0 mw)
Starting Solution Process ...

Checking for restart file dual_beam_assy_sim1-run2.res
Note: scratch=no must be used for a restart analysis

*** ERROR NO. A1004 ***

Program not able to open the restart file, please check your input


Looks like its trying to start from run2 not run1? there is a run1.res file in the directory.

Can anyone tell me what I'm doing wrong?

Thanks in advance,
Nate
5 REPLIES

Re: Restart Analysis

Nate,

You need to copy run1.res to run2.res (dual_beam_assy_sim1-run2.res in this case). This allows run1.res to be copied as "input" to any number of subsequent restart analyses.

Regards,
Jim
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm

Re: Restart Analysis

Jim,

Worked like a charm.

Is there a way to "append" or merge the results of Run1 and Run2 for animation purposes (animate t= 0 to t=10). Basically have all time steps in one solution? or animate through two different soultion sets?

Thanks,
Nate

Re: Restart Analysis

Nate,

If you are using NX 7.5 as the post processor, you can right click on the results item for the first run in the Simulation Navigator and select "Add Companion Result Data". Browse for the .op2 file from the restart run to attach it. Make sure the Append method is set to Create New Load Cases.

Now, if you open the results for the initial run, both sets of results will show up in the Post Navigator. Since the results from both .op2 files are now all grouped under one solution, you can set the post animation to start with the first step in the initial run and end with the last step in the restart run to get a full animation.

Regards,
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm

Re: Restart Analysis

Jim,

What are the differences in these workflows if one is using FEMAP for pre/post with NX Nastran?

Dave P.

Nate,

If you are using NX 7.5 as the post processor, you can right click on the results item for the first run in the Simulation Navigator and select "Add Companion Result Data". Browse for the .op2 file from the restart run to attach it. Make sure the Append method is set to Create New Load Cases.

Now, if you open the results for the initial run, both sets of results will show up in the Post Navigator. Since the results from both .op2 files are now all grouped under one solution, you can set the post animation to start with the first step in the initial run and end with the last step in the restart run to get a full animation.

Regards,

Re: Restart Analysis

In Femap, read both .op2 files into the same .MOD file
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm