No VM results in crash analysis

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

Hi

I have been trying to simulate crash between two cars using RADIOSS. The solver seems to be working perfectly and doesn't show any errors/ warnings. But when I load the results in HyperView the Von-Mises stress tends to be Zero (0). I'm getting the results for Displacement and Hourglass just not VM. I'm not able to troubleshoot the error. can you please advise?

 

I can share the files with you via some secure dropbox or something like that.

 

Thank You.

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    Hi @charlesfm

     

    Can you share a screenshot of the results from HV and also the engine file rad?

  • charlesfm
    charlesfm Altair Community Member
    edited November 2020

    <?xml version="1.0" encoding="UTF-8"?>image.thumb.png.252404ad6000b583457bec7abd5825df.png

    Unable to find an attachment - read this blog

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited November 2020

    Hi Charles,

     

    in the model you shared the interface between cars is set to type1 Fluid/Structure Interaction (ALE/Lagrange Interface).

    So I defined type 7 general purpose interface instead and redifined self contact only on segments that actually experience contact for computational efficiency.

    Output requests should be set up- the most convenient way is by Utility>engine file assistant

    I also applied Advanced Mass Scaling to speed up the computation.

    Results as well as model files are shared bellow:

    <?xml version="1.0" encoding="UTF-8"?>crashtest.gif

    Unable to find an attachment - read this blog

  • charlesfm
    charlesfm Altair Community Member
    edited August 2018

    Thanks Ivan. I don't know how i missed that type 7.

    can you please explain the cards you added to the file?

     

    <?xml version="1.0" encoding="UTF-8"?>Capture4.PNG

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited August 2018

    Hi Charles,

     

    most of the cards were generated from the Engine file assistant (Utility>engine file assistant).

    The tool generates typical output requests, such as stress, strain, velocity, etc. by checking generate default output requests.

    ANIM keywords generate data for element, vector and nodal animation output requests. Please check the radioss help for more information on output requests.

    ENG_RUN defines simulation duration. ANIM_DT  defines the frequency of writing the animation files (A-files). ENG_TFILE defines the frequency of writing the time history file (T-file).

    ENG_DT_NODA is the mass scaling which I replaced with Advanced Mass Scaling (ENG_DT_AMS & AMS keywords).