Buckling Errors
A buckling analysis was rejected or produced no positive load factors. Why, and how to fix it.
If you only have 2 minutes
Buckling analysis solves for the critical load factors at which a prestressed structure becomes unstable. It needs solid elements and a prestress (reference stress field) that actually contains compression. Most failures are the element type, a prestress with the wrong sign, or the eigensolver not converging.
Common errors
- Error 358: the mesh contains a non-solid element. Linear eigenvalue buckling supports only solid (3D) elements. Re-mesh with solid elements.
- Error 365: the prestress produced no positive buckling load factors. The load factors scale the prestress, so the reference state must contain compression (in the tension-positive convention); a purely tensile reference state has nothing to buckle. Check the sign and direction of the reference load. This is the most common buckling setup mistake.
- Error 368: the buckling solver returned fewer modes than requested, even after enlarging its workspace and restarting. Request fewer modes, or accept that the problem is numerically hard (the message reports the best residual reached).
How buckling analysis works, and what the prestress and load factors mean, is explained in Buckling Analysis.