Stop iterations due to out of range residual

[Kalani Ranasinghe]

Hi ,

I am doing a time history analysis using implicit FE code. After some seconds of applying ground motion, it terminated with an error showing that stop iterations due to out of range residual.

Could you please suggest any solution for that?

Thank you

Kalani

[James Kennedy]

Dear Kalani,

 

The "out-of-range residual implicit ls-dyna" message may indicate an instability in LS-DYNA, a finite element code used to simulate structural problems. Other messages that may indicate instability include: Termination due to mass increase, Out-of-range velocities, and Negative volume in brick element. 

 

Here are some things you can try to combat instability in LS-DYNA:

 

Use the latest version of LS-DYNA

Write plot states frequently

Reduce the timestep scale factor

Try hourglass type 4 with a coefficient of 0.05

Avoid type 2 solids

Set the number of cycles between bucket sorts to zero

Eliminate loads and/or contacts, one by one, to identify the trigger for the instability

Set ISNAN=1 in *CONTROL_SOLUTION to identify node IDs where out-of-range forces first appear 

 

https://ftp.lstc.com/anonymous/outgoing/support/FAQ/instability.tips#:~:text=%2D%20Eliminate%20loads%20and/or%20contacts,anything%20out%20of%20the%20ordinary.

 

Sincerely,

James M. Kennedy

KBS2 Inc.

June 28, 2024

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[James Kennedy]

Presentation:

 

Erhart, T., "Tips and Tricks for Successful Implicit Analyses with LS-DYNA", Moglichkeiten mit LS-DYNA/Implizit, DYNAmore GmbH, Stuttgart, Germany, February, 2016.

 

https://www.dynamore.de/en/downloads/infodays/dokumente/download-informationstag-Implizit-2016/05-2016-02-dynamore-infotag-implizit-tipstricks.pdf

To view this discussion on the web visit https://groups.google.com/d/msgid/ls-dyna2/CH2PR13MB352776534AC28014D034AC7D91D02%40CH2PR13MB3527.namprd13.prod.outlook.com.

[l...@schwer.net]

Try reducing the loading rate.   --len

 

From: ls-d...@googlegroups.com <ls-d...@googlegroups.com> On Behalf Of Kalani Ranasinghe

Sent: Thursday, June 27, 2024 7:09 PM
To: LS-DYNA2 <ls-d...@googlegroups.com>

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