hey guys, i am working on a project of comparing simulation results to experimental results using ls dyna for column buckling, but all my models fail to buckle but rather crushing failure occurs at the point of contact of the rigid plate to the column, what could be a possible solution to this issue, i am using cscm concrete material model. thanks in advance for any input you may provide.
Hi @nhdjndn,
It sounds like it could be a contact breakdown between the column and the rigid plate. To check, you can create a node set of the bottom of the column and constrain all degrees of freedom using *Boundary_SPC_Set. If you still see a similar crushing failure, then it doesn't have to do with the contact that you have.
If your finite element model is perfectly symmetric and you are applying the load in the center of the cross-section, there is no reason for buckling to occur. The software might identify that the determinant of your stiffness matrix becomes negative when you reach the buckling load, but that's it. A simple way to force buckling would be to impose a very small lateral displacement to your model in the beginning of the simulation.