Numerical simulation of buckling of pretwisted non-circular bars

This paper presents finite element (FE) analysis to study the buckling capacity of pretwisted steel bars of rectangular solid cross sections. The FE simulation are conducted using the commercial software ABAQUS. The samples include bars of 30mm width, 6mm thickness, and three different lengths of 300mm, 400mm and 500 mm. The bar ends are griped and embedded in cylindrical slips. A set of twisting angles ranging between 30° and 300° is considered for each length. Before twisting, the simulated steel bars are compared with the experiments and the AISC Code to verify the FE model. The steel bars are then twisted beyond their elastic limit, unloaded to remove elastic recovery, then subjected to axial displacement. The FE simulations showed that the permanent twists have positively influenced the axial strength and the static performance of the pretwisted bars. This improvement is exhibited by the considerable increase in the critical buckling loads of the bars for certain angles of twists.