Eigenvalue Buckling Analysis

An eigenvalue buckling analysis looks at the potential for buckling on a structure with a given load. Unlike a modal dynamic analysis, which characterises the structure, a buckling analysis characterises the structure for a given load.

When a column is subjected to an increasing compressive axial load its ability to carry transverse load is reduced until the Euler load is reached when it can no longer carry any transverse load. For a given axial load the ratio of the Euler load to the actual load is the load factor for that mode. If the column is supported at its midpoint then the first mode will be suppressed and higher modes with corresponding higher loads factors are possible. The eigenvalue buckling analysis extends this concept from a simple column to the whole structure, to determine global modes of buckling.

Sufficient modes should be selected for the buckling analysis to ensure that all the modes of concern are identified.