A valuable technique for analysis of components and systems whose stiffness changes as the material is strained. Either the load direction changes, it has non-linear material properties or the loadpath has altered.

For many structures the effect of buckling is critical, the initiation of which is often difficult to assess for complex geometry, loadings or boundary conditions. This analysis allows us to predict the onset of instability and extends understanding still further by allowing the resultant internal load redistribution to be clearly recognised.

A classic application is a plastic snap-fit connection. In addition to the non-linear material properties, the solution's boundary condition would include clearance, gaps, sliding joints and the effect of friction.