[GRASBOCK]

Hello,


This is my first post here, so please be forgiving if I accidentally break a rule.


I am trying to model the relaxation due to initial stress of a simple beam in Abaqus CAE 2021. The beam is pinned on the left end. The top surface has a compressive stress of -100MPa and the bottom a tensile stress of +100MPa. I neglected shear stress here, because they do not change the results significantly.

In the following image you can see the initial stress condition.



I would expect the beam to now bend upwards. The simulation runs fine and completes without errors. Looking at the image, however the beam is bending downwards. The stresses are almost 0, so the model relaxed.




Why is the beam bending downwards even though the stresses at the bottom are tensile and at the top compressive?