BUCKLING BEHAVIOR OF UNIFORMLY AND NONUNIFORMLY PRETWISTED BEAMS

The buckling behaviour of continuously, discontinuously and oppositely pretwisted beams under a variety of combinations of twist angle and c ross-section has been analysed. Both uniformly and non-uniformly twist ed beams are considered. The twisted rod is modelled as a beam with va rying bending strength depending on the twist. A Cartesian global coor dinate system is used with a rotating local coordinate system in deriv ing the governing system of differential equations. These are then sol ved using the Galerkin finite element formulation with the Hermite pol ynomials as interpolating functions. The various combinations of param eters are compared and the characteristic behaviour of each family ind icated. The choice of combinations in order to maximize the buckling l oad have been considered.