AMS DIvergence with only RADIOSS v14.0?

Altair Forum User

Hi,

I have started applying AMS in RADIOSS v14.0 .Initially the simulation is running and after some time (around 2 hours). Later an error is sprouting .Pl see the below error message.

 

** ERROR : AMS IS LIKELY DIVERGING:
  
 ... RUNNING DIAGNOSIS
 **  INFO : COULD NOT IDENTIFY THE ISSUE.

 

Can you suggest a possible soultion to curb this? The values recorded in .OUT file are normal. in the sense there is no abnormalities in %energy error or mass error%. However it suprises me that after almost half of the simulation is done with AMS,divergence happens.

 

I have converted the same input files(Starter and Engine files,) into v13.0 and run in RADIOSS v13.0. The simulation is running with no error. I am using a time step of 5microseconds for the simulation. I have laso tried with smaller and larger time steps just in case to verify if it is because of DTMIN value. But  the scenario is same even with that case.

 

I have also gone through the release notes for v14.0 . It has included some relevant points while using INTER7 and INTER2 which I have taken care.

 

Thanks for your support in advance.

Altair Forum User

Maximum allowed iterations before sending a divergence message is 1000 by default.  Anything above this maximum value, RADIOSS stops with this error message. 30 iterations or less is considered as a good convergence.

Monitoring the number of iterations taken in your analysis before showing this error. 

Choose a minimum time step, Tmin, from 10 to 20 times than the one used in /DT/NODA/CST. Tsca sued is 0.67 for /AMS.

Please recheck the Tmin value and try rerunning the analysis.