I have a long hollow steel pipe which has a slot at a location 1/4th from the end. In the test, there is external load at the center of the pipe with the ends being supported vertically and horizontally leaving axial direction free to move. As the load is incremented, the steel pipe is undergoing bucking right at the end of the slot.
Now the problem I am having is, I am not able to replicate the same failure in simulation. I am using non-linear arc length control with direct sparse solver. I left rest of the setting at default.
Attached screenshot of the model with constraints I am using for the analysis and also the failure in the lab. Any help you can provide is appreciated.