复合荷载作用下简支钢梁弹性弯扭屈曲研究  

Study on flexural-torsional buckling of simply supported steel beam under combined loads

作　　者：刘占科[1,2] 周绪红[2,3] 何子奇[2] 陈明[2] 

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000 [2]兰州大学土木工程与力学学院,甘肃兰州730000 [3]重庆大学土木工程学院,重庆400044

出　　处：《建筑结构学报》2014年第4期78-85,共8页Journal of Building Structures

基　　金：国家自然科学基金项目(51308272;50978128);甘肃省科技计划项目(1107RJYA078);中央高校基本科研业务费专项资金项目(lzujbky-2013-180;lzujbky-2013-m01)

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。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 g, and for the coefficients CI, C^a and C~ were derived by employing Rayleigh-Ritz method. The relationships of CI , C2a and C3 for combined load and C1, C2 and C3 for 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 Met for 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.

关 键 词：简支钢梁 弯扭屈曲 复合荷载 Rayleigh-Ritz法 临界弯矩 临界荷载 

分 类 号：TU392.102[建筑科学—结构工程]