PLASTIC COLLAPSE MECHANISMS IN COMPRESSED ELLIPTICAL HOLLOW SECTIONS

The plastic collapse response of structural steel elliptical hollow section (EHS) profiles in compression is examined in this paper. As an initial step, a parametric study to identify the factors that determine which plastic mechanisms would arise has been carried out using finite element (FE) results from the current work and experimental data from the literature. Following this, an analytical model to describe the split flip disc plastic collapse mechanism in compressed EHS is derived. The parameters controlling the shape and size of the plastic hinges have been investigated and found to be of key importance; hence, special care has been taken in their definition. Finally, the analytically derived load- displacement curves have been compared with FE results. The comparisons have revealed good agreement, confirming the ability of the developed analytical models to predict the plastic collapse response of elliptical tubes.