【摘要】 为建立复合荷载作用下简支钢梁弹性弯扭屈曲的设计理论,提出不同类型、不同作用点的横向荷载和不等端弯矩共同作用下的弯扭屈曲总势能方程。采用Rayleigh-Ritz法推导复合荷载作用下临界弯矩Mcr的通用计算式及系数(参数)C’1、C’2a、C’3的计算式,并得到复合荷载作用的C’1、C’2a、C’3与单一荷载作用的系数C1、C2、C3的关系。采用RayleighRitz法推导临界荷载的通用计算式,并通过数值算例验证其正确性,最后分析钢梁自重对弯扭屈曲临界荷载的影响。研究表明:复合荷载作用下的临界弯矩Mcr通用计算式可完全采用单一荷载作用下的Mcr通用计算式表示;钢梁自重对其弯扭屈曲临界荷载的影响较小,计算中可忽略不计。更多还原

【Abstract】 In order to establish the design theory for elastic flexural-torsional buckling of simply supported steel beams under combined loads,the total potential equation considering the combination of transverse loads of different types, different loading points and unequal end moments was proposed first. Then the general calculation formula for critical moment Mcrand for the coefficients C’ 1,C’ 2a and C’ 3were derived by employing Rayleigh-Ritz method. The relationships of C’ 1,C’ 2a and C’ 3for combined load and C1,C2and C3for single load were established. The general calculation formula for critical loads was also derived by employing Rayleigh-Ritz method,and the correctness of the general formula was checked by numerical example. Finally,self-weight of steel beams was considered for checking its influence on the critical loads. The conclusions show that the general formula of Mcrfor combined load has the same form as the formula for single load. The self-weight of steel beam has a negligible effect on the values of critical loads.更多还原