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Best way to connect QUAD4 elements to a neighbour of half the size?

User: "Wesley_Peijnenburg2"
Altair Community Member
Updated by unknown

 

A simple model is defined: left side fixed, right side fixed displacement. 

image

We should get a uniform stress field, as shown in below Figure with uniform mesh:

image

The problem is that red nodes on the T-junction are not connected as continuous solid, shown below (magnified displacement X):

image

This causes a Von Mises stress deviation of approx. +10%/−18%:

image

 

Potential solution 1: 
RBE2 elements, they reduce this deviation to approx. +3.7%/−10%. 

 

Potential solution 2: 
Thanks to Greg Harte's answer to an earlier forum question, RSpline elements were tested as well. They give the best result so far at +2%/−10% percent. 

image

 

The question: 
A 10% deviation still feels large to me. Is this really the best way to do it? Or is there an even better solution (aside from using a triangle/trapezoid) transition mesh? Model is attached.

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    User: "Adriano_Koga"
    Altair Employee
    Updated by Adriano_Koga

    is this a solid or shell?

    If this is solid, you might think on using contacts (FREEZE or TIE) to couple these.

    RSPLINE and RBE3 connections are alternatives.

    But usually these transition zones are expected to present some deviation. Usually we try to keep them away from the interest area.

    User: "Wesley_Peijnenburg2"
    Altair Community Member
    OP
    Updated by unknown

    is this a solid or shell?

    If this is solid, you might think on using contacts (FREEZE or TIE) to couple these.

    RSPLINE and RBE3 connections are alternatives.

    But usually these transition zones are expected to present some deviation. Usually we try to keep them away from the interest area.

    It is a shell. 

    Following your advice, I tried to couple them with FREEZE contact. However, they don't seem to work because it is inside the volume? The out file warns (among others) for: "... nodes are included by both the Slave and the Master of TIE(CONTACT)". 

     

    Attached is the file, can you help me understand how to properly create the FREEZE or TIE contact?