基于修正Rayleigh-Ritz法的工字钢梁预弯阶段侧向失稳分析  

Lateral-torsional buckling analysis of steel I-beams in pre-bending stage based on modified Rayleigh-Ritz method

作　　者：田林杰 鞠秀颖 李喆 常山 杨明[1] Tian Linjie;Ju Xiuying;Li Zhe;Chang Shan;Yang Ming(School of Transportation,Southeast University,Nanjing 211189,China;China Road and Bridge Corporation,Beijing 100011,China;Tongji Architectural Design(Group) Co.,Ltd.,Tongji University,Shanghai 200092,China)

机构地区：[1]东南大学交通学院,南京211189 [2]中国路桥工程有限责任公司,北京100011 [3]同济大学建筑设计研究院(集团)有限公司,上海200092

出　　处：《东南大学学报（自然科学版）》2019年第4期679-687,共9页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51078078)

摘　　要：为精确分析工字钢梁在预弯阶段的侧向失稳规律,对施加可变位置的双集中荷载并布置不同个数侧向支撑的工字钢梁建立计算模型,用Rayleigh-Ritz法求解.考虑侧向支撑分段布置引起的梁段约束效应,对Rayleigh-Ritz法的求解结果进行修正.选取不同工字钢梁尺寸及加载参数作为分析指标,采用ABAQUS有限元进行大量模拟分析,验证修正公式的精确性.结果表明:随着侧向支撑个数的增多,传统Rayleigh-Ritz法的求解误差逐渐增大,提出的修正Rayleigh-Ritz法可将传统Rayleigh-Ritz法求解结果的相对误差最大减小约13%,有良好的精确性和适用性.参数研究表明:预弯加载阶段,工字钢梁侧向失稳临界弯矩随着集中荷载作用点参数的增大而减小,随着侧向支撑个数的增多呈增幅逐渐减小的增大趋势;侧向稳定安全系数随着侧向支撑个数和上下翼缘板对称度的增大而增大.In order to accurately analyze the law of lateral-torsional buckling (LTB) of steel I-beams in the pre-bending stage, a mathmatical model of a steel I-beam,which was subjected to two movable concentrated loads and with different numbers of lateral braces,was established. The restraint effect of beam segments caused by the segmental arrangement of lateral braces was considered,and the solution of the Rayleigh-Ritz method was modified.Additionally,different sizes and loading parameters of steel I-beams were selected as analysis indexes,and a large number of simulation analyses were carried out by the finite element method ABAQUS to verify the modified Rayleigh-Ritz method.The comparison results show that as the number of lateral braces increases,the error of the traditional Rayleigh-Ritz method increases gradually.The modified Rayleigh-Ritz method can minimize the relative error of solution results of the traditional Rayleigh-Ritz method by about 13%,and the modified Rayleigh-Ritz method has proved to be of good accuracy and applicability.The results of the parameter study show that in the pre-bending stage,the LTB critical moments of steel I-beams decrease with the increase in the value of concentrated loading location parameter,and increase slowly with the increase in the number of lateral braces.The safety factor of LTB increases with the increase in the number of lateral braces and the degree of monosymmetry.

关 键 词：工字钢梁 侧向支撑 侧向失稳 能量法 临界弯矩 

分 类 号：U448.21[建筑科学—桥梁与隧道工程]