Research Of Torque Effect On The Overall Stability Of Cantilever I-section Steel Beam

Steel is widely used because of its advantages of high strength, light weight,good mechanical properities and so on. But in actual engineering, the bearing of thesteel structure and steel members are often affected by the stability, and overallstability is one of the most important parts in stability. Many scholars at home andabroad have done a great deal of theoretical researches and experimental analysisabout the overall stability of steel beam, and great achievements have been achieved.Cantilever beam is often due to eccentric loading in practical engineering, the beam isunder the effect of bending as well as torsion. However, there are few studies on thestability of I-section steel beams in composite force of bending and torsion,“Code fordesign of steel structures”(GB50017-2003) of China doesn’t provide the designformula either. In order to solve this problem, I think it is necessary to put forward aclear and concise design formula.The thesis firstly used the traditional method to research the overall stability,then done theoretical analysis for I-section steel beam subjected to bending andtorsion,at last got equilibrium differential equation and the total potential energyequation.And then the thesis analyzed the overall stability of cantilever I-section steelbeam under the effect of simple bending、lateral load and eccentric lateral load. At lastdrawing lessons from overall stability calculation formula of “Cold-formed steelstandard”(GB50018-2002) of China, I introduced two coefficientsk yandk ωrelating tobending and torsion, so as to consider the overall stability of the steel beam under theimpact of bending and torsion.In order to get the coefficients relating to bending and torsion, the thesis used thegeneral finite element ANSYS to model and analyse two kinds of typical eccentricloads, analyzed the influence of the eccentric distance e, span l, the compressionflange width b on the coefficients. When data analysis was completed, the thesisapplied statistical software for data regression analysis and finally got the coefficientsexpressions. This formula can provide reference on the design of the overall stabilityof cantilever I-section steel beam under the impact of bending and torsion.