Typically, nonlinear buckling case is more realistic buckling simulation than linear buckling case, giving lower buckling load. Nevertheless, opposite behavior can also be found. Linear buckling analysis predicts the 1st buckling load of a given structure according to its original geometry. Sometimes, the predicted linear buckling load does not collapse in reality the structure, because (i) the buckling mode is local or (ii) the geometrical configuration of the structure is such that as the initial buckling shapes start to appear and deform the structure it becomes stiffer (e.g., a plate with stiffeners), and according to that nonlinear buckling load is higher than the linear one. To reproduce nonlinear buckling analysis several techniques can be applied: -Perform a linear perturbation method. -Scale eigenvalue mode and perturb the geometry using UPGEOM command. -In case the geometry is unsymmetrical, load the structure until no convergence is achieved (this will buckle the structure). Further information about these methods can be found in Solution #2026874 – Is there an “Ask-the-Experts” webinar on buckling?