FINITE ELEMENTS FOR THREE-MODE INTERACTION IN BUCKLING ANALYSIS

This paper presents a finite element formulation for the buckling mode interaction analysis of structures modelled as plate assemblies. The main assumptions are linear elasticity, a linear fundamental path, the existence of distinct critical states that are coincident or near coincident, and a coupled path arising from a linear combination of modal displacements due to interaction. The formulation adopted is known as the W-formulation, in which the energy is written in terms of a sliding set of incremental co-ordinates measured with respect to the fundamental path. The energy is then expressed with respect to a reduced modal co-ordinate basis and the coupled solution arising from interaction is computed. An example of a fibrereinforced composite I-beam subjected to axial compression illustrates the procedure. The results are compared to a simplified model developed by the authors. Also, an imperfection sensitivity analysis is performed.