Inelastic stability of laterally unsupported i-beams

摘要: Abstract A computer method to study the inelastic stability of laterally unsupported steel I-beams and based on a general non-linear theory is presented. Traditionally, problem flexural-torsional beams treated as lateral buckling problem. Some draw-backs these earlier studies are given below: The classical assumes that deformations small. In addition deformation field linearized. This therefore valid only when major axis flexural rigidity much greater than its minor rigidity, so before onset negligible. for straight beams, with loads applied rigorously in plane symmetry. Practical have initial imperfections unavoidable load eccentricities. So true behavior better described by phenomenon. For intermediate length which occurs range, tangent modulus generally used. ideally provides an estimate collapse slightly conservative. However, practical deformations, this need not be case. majority existing buckling, differential equations under uniform moment used without modification gradient. later case shear center line inclined centroidal geometrical axes. should modified adding additional terms. limited isolated simple end-conditions beneficial effect adjacent members beam cannot studied accurately. describe spatial doesn't deficiencies mentioned above, developed present paper. paper also presents solving using finite differences. Several numerical examples presented comparison theoretical experimental results show applicability wide range problems.