Buckling of shells, Nonlinear analysis

[hd1989]

Hello,

I'm working on the buckling of cylindrical shells subjected to axial loading. In my case the cylinder is resting on 4 columns, so there is a possibility of local buckling above the support. I'm carrying out the non linear analysis in abaqus using riks procedure.

The problem is when I plot the LPF vs displacement (radial displacement of a node in the buckle region) I notice some regions of abrupt variations and overlaps in the curve, which is not expected. I have attached a snapshot of that. can anyone suggest me the possible reasons for that?

Thanks,

 

[BAretired]

Where is the snapshot?

BA

 

[hd1989]

Sorry, forgot to paste the link...here it is

 

[ishvaaag]

I muse if this points to a locally failed shell at the level of loading where the first folds closer to the support are smaller than those further from the support, and then no detection of the collision of the buckled plate zones by the software make the rest.