Study On Performance Of Steel Channel Beams Under Bending And Torsion

In actual project,as the load deviate from the shear center in the cross-section of steel beams, steel beams are often subjected to combined bending and torsion. In this case, the bearing capacity and deformation characteristics of steel beams are influenced by a certain degree. But the existing theory and specifications regulate little about the overall stability of steel beams under combined bending and torsion. Besides, most of studies are on steel I-beams and cold-formed channel beams but seldom about hot rolled channel beams which is widely used in actual project. Thus, this paper start to conduct some studies on the hot rolled channel beams under combined bending and torsion.Firstly, elastic analysis about hot rolled channel beam is carried out according to the basic theory of mechanics, specific content as follows:(1) Conduct studies on hot rolled channel beam under uniform bending, and draw the stress diagram of it according to the calculation formula of stress;(2) Conduct studies on hot rolled channel beam under torsion, and derived the stress calculation formula of it according to the theory of open thin-walled bar under constrained torsion. Then draw the stress diagram of it;(3) Conduct studies on hot rolled channel beam under combined bending and torsion. Through making analysis of the stress components of the hot rolled channel beam under combined bending and torsion,find the discipline of how stress distributed in the cross-section of the beam.Then,with considering the nonlinearity of the material and the geometric nonlinearity, the finite element model is established to analysis the hot rolled channel beams under combined bending and torsion. And compare the FEA results with the results according to the?code for design of steel structure?(GB50017-2003)and?Technical code of cold-formed thin-walled steel structures?(GB50018-2002). Make analysis of these two specifications about their methods to calculate the overall stability of channel beams. And compared with the conclusion of relevant literature to prove that the finite element model established is correct.At last, non-linear bucking analysis of hot rolled channel beam under eccentric lateral load is carried out to obtain the limit load of it. Make analysis of how the torsion affect the bearing capacity of the channel beam. By using the MATLAB, a linear interaction equation is obtained from the FEA results with the introduced nominal Limit torque. And then compare the linear interaction equation with the Put&Pi equation to prove that the work done in this paper is necessary and reasonable.