Weird strain at the corners of the beam

Hello everyone, I'm modelling a beam of steel under pure bending. I considered the NL Structural Steel that Workbench offers me, but I changed the Tangent Modulus to 100 MPa (in order to have a material without hardening by plastic deformation).


I considered a 2D plane stress beam with symmetry, rectangular cross section (width 1 mm and height 10 mm) and a large of 100 mm.


I computed the moment which provocates yielding, obtaining the value of 4166 Nmm (M*).

In the other hand, I computed the moment which fully plastify the beam, obtaining a value of M** = 1.5 M* = 6250 Nmm.

My boundary conditions are the followings: Applied moment on the right edge of 6250 Nmm and a remote displacement with all DOF set to 0 and behaviour deformable at the symmetry line.

When load is fully applied, I get this result of normal stress in X direction:

This is true scale. I want to know why I get higher stresses at the edges and consequently, those larger deformations in the corners, making them look like horns.

Maybe I should just ignore that if I think in Saint Venant's principle, but I want to know why that happens because I get a similar behaviour in other simulation of this kind (with torsion instead of bending).

Best regards.

Bruno.

Best Answers

Answers

  • @peteroznewman

    Thank you! That did the work!

    I applied a 10 ° rotation on the edge and I get 6265 Nmm on the Moment Probe, almost the same value of M** I computed.


    If I want to try this on a pure torsion model instead of a pure bending one, I would need to also apply a rigid rotation through a remote displacement in a whole face?

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