Unexplained distortion of mesh at contact region without any external force.

Rachit Semalty
Rachit Semalty Altair Community Member
edited November 2022 in Community Q&A

Hi. I am trying to run a radioss implicit simulation but some unreal distortion of elements at the contact area is taking place. For example, the initial and after 1 frame image of a stake of parts is shown below.

image image

 

The elements are distorted before the application of external force.

I am attaching the model file with this post. Please try to find the error in my model.

Regards,

Rachit

 

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Best Answer

  • PaulAltair
    PaulAltair
    Altair Employee
    edited November 2022 Answer ✓

    You didn't share your implicit run controls (engine file), so not sure on your settings for that

    But you have type 7 contacts for solid-solid that have no gapmin and no inacti set, set a small gapmin and inacti = 5 on them all and it sorts it out I think

    My version attached, you can substitute your own engine file again

    Paul

     

Answers

  • PaulAltair
    PaulAltair
    Altair Employee
    edited November 2022 Answer ✓

    You didn't share your implicit run controls (engine file), so not sure on your settings for that

    But you have type 7 contacts for solid-solid that have no gapmin and no inacti set, set a small gapmin and inacti = 5 on them all and it sorts it out I think

    My version attached, you can substitute your own engine file again

    Paul

     

  • PaulAltair
    PaulAltair
    Altair Employee
    edited November 2022
    Paul Sharp_21301 said:

    You didn't share your implicit run controls (engine file), so not sure on your settings for that

    But you have type 7 contacts for solid-solid that have no gapmin and no inacti set, set a small gapmin and inacti = 5 on them all and it sorts it out I think

    My version attached, you can substitute your own engine file again

    Paul

     

    When the run completed, I noted it was very hourglassy, better to use fully integrated elements, see attached

  • Rachit Semalty
    Rachit Semalty Altair Community Member
    edited November 2022
    Paul Sharp_21301 said:

    When the run completed, I noted it was very hourglassy, better to use fully integrated elements, see attached

    Hi Paul. Thanks for your reply. Yes, you are right. That problem is there. I hope your suggestion may correct it. But the model you have shared is maybe in the 2022 version of radioss. May you please re-share the model in 2018 or a lower version?

     

    Also, I needed a suggestion. We tested this component in our lab and it fails for large displacement (nearly 40mm) of the impactor plate. But in the simulation, the component reaches its failure strain much earlier than that. I tried using second-order tetra elements but the run did not converge. May you please suggest some solution to overcome this problem?

     

    Thanks and regards,

    Rachit

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