THE USE OF BUBBLE FUNCTIONS FOR THE POST-LOCAL BUCKLING OF PLATE ASSEMBLIES BY THE FINITE STRIP METHOD

The finite strip displacement functions for post-local buckling are augmented with so-called bubble functions, which are extra modes associated with internal or nodeless degrees of freedom. A nonlinear finite strip method of analysis including bubble functions is described for the post-local buckling of geomtrically imperfect plate assemblies. It is shown that the use of bubble functions improves significantly the convergence of the method. The non-linear finite strip method is then used to study channel and I-section members in compression and bending.