General Mechanical

General Mechanical

Moment Reaction in Symmetry Model

    • Johnson


      in the models down below a Fixed Support is put on the one side and a moment is applied on the other side.

      The solutions of deflection and stress are very similar. But unfortunately I get strange results regarding the moment reaction in my symmetry model.

      Full model makes sense (I applied 100000Nmm around X)

      For my symmetry model I get a very large values around Z (I applied 50000Nmm):

      I really do not understand that...

    • claudiocozza

      i've a similar problem with a bending moment on a stepped shaft.. when i run the full model it's ok, when i run 1/4 there are a lot of mistakes.. i really don't know

      in my case, i apply a moment of 10000 and i've a reaction of 3000

    • Johnson

      I let you know, if I find something out!

    • peteroznewman


      I assume you have a correct symmetry condition on the cut face of the half pipe.

      Try this, delete the moment and apply the moment using Components and set the Behavior to Rigid.

    • jj77

      This is an interesting one - we do get that because of some of the reactions that need to be there on the symmetry plane ( I have checked with Strand7 and the same results are achieved, thus there will be torque moment due to these reactions).


      Now the displacements and bending stresses for the 1/2 sym. are the same as the full model as expected so it is fine, but if not feeling 100% sure, just use a full model, simple

      of course always check and validate results

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