CONTFEL - Contact Friedly Element

Zdenek Honzik
Zdenek Honzik Altair Community Member
edited January 23 in Community Q&A

Hello, OptiStruct Users,

I would like to know: What is CONTFEL(stand for: Contact Friendly Element) element? Why is there (it will be connected with NtS contact on second order element)? A little bit of background..  

 

Thank you.

 

 

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Answers

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited January 23

    I don't have the reference here, right now, but you could easily test it with a simple model.

    Regular 2nd order elements use shape functions to describe their formulations what often cause an undesired reaction force distribution, that is not physically consistent.

    If you apply uniform loading over a 2nd order element, and request reactions/contact forces, you will notice some odd behavior.

    Contact Friendly elements, CONTFEL, changes internally the shape functions of these elements in contact regions, in order to improve the stiffness/force distribution for these 2nd order elements, avoiding this behavior.

    To test this, create 2 solid blocks in contact, and apply a uniform load compressing them. If you compare contact forces, you will notice that standard 2nd order contact forces will not be smooth nor uniform. By activating CONTFEL, this will be more uniform for the same mesh.

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