Error % keeps increasing

nara4838
nara4838 Altair Community Member
edited October 2020 in Community Q&A

Can someone please help me out as to why the error % keeps increasing throughout the run. The node no. 30657 is the one where the error is.

 

Thank you

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Answers

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited February 2019

    Hi, 

     

    there are intersections in the 'self dummy' contact- all intersections and penetrations should be removed before running the model.

    Check and remove manually or automatically any initial intersections and penetration in your model by using Tool>> Penetration or in Hypercrash by Quality>>Check all solver interfaces. Please go through HM-3320: Penetration tutorial in Help Menu which shows fixing penetrations.

    9afbe617ffc32a67b5e54a3a9d8a484615022f79.jpg?image_play_button_size=2x&image_crop_resized=960x515&image_play_button=1&image_play_button_color=54bbffe0

    New Feature in HW 2017 - Collision Detection Tool - Altair University

    Try to run the attached solver deck. There are some other modeling issues remaining.

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  • nara4838
    nara4838 Altair Community Member
    edited February 2019

    Thank you for your response. I ran the model without any intersections or penetrations. It gave me a normal termination but the error % still keeps increasing.

     

    Capture.PNG.09a40c12541b2e14f2a7a9d85c288819.PNG

     

    Can you explain why is this happening?

     

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  • Simon Križnik
    Simon Križnik Altair Community Member
    edited February 2019

    Negative Energy Error is dissipated from the system with:

    -plastic deformation

    -hourglass energy

    -contact with friction

    -contact intersection & penetration

    

     

    Open the run_nameT01 time history file in Hypergraph and plot the Global variable>Internal, Kinetic, Contact, Hourglass, Total energy.

    See attached documents for details (from Introduction to Explicit Analysis using RADIOSS – A Study Guide)

     

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  • nara4838
    nara4838 Altair Community Member
    edited February 2019

    So is this normal or should I change something?

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited February 2019

    Negative energy can be reduced:

    -Ishell=12 or 24 (hourglass control on property card)

    -Ifric=0 (no contact friction)

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  • nara4838
    nara4838 Altair Community Member
    edited February 2019

    It gives me an error of Mass error Limit reached. 

     


    205000  0.1025      0.5000E-06 NODE       30658  99.9%   3867.      0.1269E+06  0.2799E+05 -0.1302E+05   71.74    
         ANIMATION FILE: seatbelt_negative_energyA207 WRITTEN
    206000  0.1030      0.5000E-06 NODE       30658  99.9%   3967.      0.1269E+06  0.2797E+05 -0.1297E+05   71.74    
         ANIMATION FILE: seatbelt_negative_energyA208 WRITTEN
    207000  0.1035      0.5003E-06 NODE       31463  99.9%   4056.      0.1269E+06  0.2795E+05 -0.1292E+05   71.74    
         ANIMATION FILE: seatbelt_negative_energyA209 WRITTEN
    208000  0.1040      0.5001E-06 NODE       31463  99.9%   4148.      0.1268E+06  0.2793E+05 -0.1287E+05   71.74    
     WARNING INTERFACE         10
     NODE      21756 DE-ACTIVATED FROM INTERFACE

    MESSAGE ID :          207

     ** RUN KILLED : TOTAL MASS ERROR LIMIT REACHED
     

     

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited February 2019

    If the last column is MAS.ERR then probably too high timestep is imposed. There is possibly deep contact penetration on node 21756 (dummy chest). Review the animation at time 0.1 to identify the issue.

    8f463b80afef8461af97eb889aee5f6736edc29d.jpg?image_play_button_size=2x&image_crop_resized=960x540&image_play_button=1&image_play_button_color=7b796ae0

    3_Timestep - Altair