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LS-DYNA runs into Segmentation Violation (SIGSEGV) error. What can I do?

Content:

  1. Error message (Segmentation Violation)

  2. Checknan option (Segmenation Violation)

  3. Error message (MPI)

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Error message (Segmentation Violation )

>>>>>  Process 18  <<<<<
>>>>> Signal 11 : Segmentation Violation <<<<<

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Possible procedure for the debugging of the LS-DYNA Error:

1. Is it possible to reproduce the LS-DYNA Error?

  • Run the identical input with identical configurations
  • Compare the two runs: diff between both NODOUT and both GLSTAT files
    • For MPP Run: extract NODOUT from the BINOUT* via l2a

--> No comparability: Hardware problem? (cpu, memory, disk, network, ...)

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2. Identify the LS-DYNA Error

  • activate checknan option (*CONTROL_SOLUTION, ISNAN=1)
  • Check the energy progression (GLSTAT, MATSUM, if necessary SLEOUT)
    • Can irregularities be detected immediately before the termination?
    • Which structural parts are affected?
  • Do elements fail immediately before the termination?
    • check-failed –l mes*
    • check-failed –pid –l mes* (Which PIDs are affected?)
  • Which are the last messages in STDOUT / STDERR / mes00xx?
  • Are there any problems with viscoplasticity (VP=1, “…did not converge”)?
    • check-hsp d3hsp –xcon mes*
  • Have unreasonable contact settings been applied? (e.g. large penalties- or thickness scaling etc.)
    • check-hsp d3hsp –cfac
  • Can initial penetrations be detected? How many? How large?
    • e.g. check-c mes* -buc –typ –typ
  • Are there any problems with spot welds or tied contacts? (e.g. untied nodes = cold spot welds)
    • e.g. check-c mes* -select tied
  • Within which phase the error occurs?
    • Keyword processing, initialization, decomposition 1-3, solution

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3. Debug-Run

  • Switch-off „Plotcprs“ (velocity, stress, strain … available)
  • Termination Cycle = <Error Cycle> - 1
  • investigate last plot state w.r.t. max. velocities, max. plastic strains, etc..

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Checknan option (Segmentation Violation)

How can I activate the checknan option?

  • Command-Line:  checknan=1
  • Keyword:     *CONTROL_SOLUTION, ISNAN=1

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Which output is produced by checknan option?

  • Output to screen (e.g. jobout (STDOUT)):
*** NaN detected.  Please check message file from processor for detail.
*** Error NaN detected on processor # 30 <<<
  • Output to messag-files (e.g. grep ‘out-of-range‘ mes0030):
*** termination due to out-of-range forces
 number of nodes has out-of-range forces       364
Node list:
37502068  37502162  37502192  37502206  37502357 ....

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Visualization of output by checknan option (nodes)?

  • DYNA Tool:    check-failed  –xnan  –a4nan
  • Animator:  Read in the Session-File ´fail-ide.ses´

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What does NaN mean?

  • Node forces/ -moments/ -velocities with NaN occur due to different reasons – e.g. division by zero

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check-hsp, check-failed, check-c, plotcprs are DYNAmore tools (free for customers: http://www.dynamore.de/tools)

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Error message (MPI)

MPI Application rank 0 exited before MPI_Finalize() with status 13
forrtl: error (78): process killed (SIGTERM)
  • „…MPI_Finalize() with status 13“ is an MPI message due to a possible LS-DYNA  Error
    • Is not important for debugging of the LS-DYNA error.

 

gp 04/14