Based on a linear static analysis the related buckling modes with load factors and mode shapes can be determined. A shift method is available to be able to skip eigenvalues with a certain sign or value and to accelerate convergence.

The calculation of modal participation factors allows for the assessment of the nonlinearity of the pre-buckling behavior. This is also applicable within a nonlinear buckling analysis with PERMAS-NLS. Some properties of linear buckling analysis:

• Fast failure check: If linear buckling case gives minimal eigenvalue smaller than 1.0 your model will be unstable! This is a fast way to verify such a case.
• Imperfection shape: The buckling shape obtained my be used as imperfection shape.
• Model verification: You can quickly check if everything “works” in your model and compare design changes quickly.
• Quick estimate: You can see which regions will have stability issues. You will also get an estimate on how close your model is to stability failure. A combination with nonlinear analysis completes the understanding of structural behavior.

Load factors and mode shapes are available for any kind of post-processing. For further informations see also buckling.

Since buckling is a stability problem, parametric studies are often of interest, see buckling of laminate structures for further informations. Moreover, an integration of the analysis with parametric optimimization or with topology optimization is possible.

Sampling of buckling modes with increasing stiffener height