Create Boundary Conditions in a local coordinate system (Solver: Abaqus)

cluue
cluue Altair Community Member
edited November 2020 in Community Q&A

Hello there,

I need to create local boundary conditions in HyperMesh, which refer to a cylindrical coordinate system I just created. I am using Abaqus as a solver. image

In the picture you can see how I do assign the nodes to the local cylindrical coordinate system. 
My input file says that those nodes are assigned to that coordinate system as you can see below. 

image

I want to constrain the DOF 2 4 and 6 but not refering to a global coordinate system. 
image

My boundary conditions for that nodes look like this. I know that 2,4,6 does refer to the global coordinate system here, because it gives me the same results even if I do not create that local system before. Also if I open my Input File in Abaqus it says the boundary conditions "Boundaries" refer to the global coordinate system.

 

Is there any workaround for that? I can not find the code for the input file to change the boundary conditions to local. I know that it works for other solvers. 

Thanks for your help

cluue

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Best Answer

  • ArthurJANNOT
    ArthurJANNOT
    Altair Employee
    edited November 2020 Answer ✓

    Hello,
    Defining a reference system changes the way you define the coordinates of your nodes in your model.
    This means that if you translate this system, all the referenced nodes are also moved. Their coordinates are defined on this system.
    To apply a local axis to your nodes, you need to select set displacement.
    I suggest you to attach nodes as set, it will be easier for you to create boundary or load on set and the input file will be easier to read.
    image
    Does it answer to your question?
    Regards,
    Arthur

Answers

  • ArthurJANNOT
    ArthurJANNOT
    Altair Employee
    edited November 2020 Answer ✓

    Hello,
    Defining a reference system changes the way you define the coordinates of your nodes in your model.
    This means that if you translate this system, all the referenced nodes are also moved. Their coordinates are defined on this system.
    To apply a local axis to your nodes, you need to select set displacement.
    I suggest you to attach nodes as set, it will be easier for you to create boundary or load on set and the input file will be easier to read.
    image
    Does it answer to your question?
    Regards,
    Arthur

  • Nick Z
    Nick Z
    Altair Employee
    edited February 2021

    I'm not a ABAQUS expert, but I believe you need to add a *TRANSFORM.

    To do that in HyperMesh create a set of nodes you would like in the new system then assign the set to the system. You can verify the transform has been added using the reference tool or the input deck.

    image

     

     

     

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited November 2020

    As @Nick Zagorski say, with *TRANSFORM card , I get the same results as SAMCEF solver:

    image

    image

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