基于能量变分原理的冷弯型钢拼合截面柱弯曲屈曲弹性临界荷载分析  

Critical flexural buckling load for cold-formed steel built-up columns based on energy-variational principle

作　　者：杨竞杰 李海锋[1] 高轩能[1] 石宇[2] 王卫永[2] YANG Jingjie;LI Haifeng;GAO Xuanneng;SHI Yu;WANG Weiyong(School of Civil Engineering,Huaqiao University,Xiamen 361000,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]华侨大学土木工程学院,福建厦门361000 [2]重庆大学土木工程学院,重庆400045

出　　处：《建筑结构学报》2024年第11期55-65,共11页Journal of Building Structures

基　　金：重庆市院士主持科技创新引导专项工程(cstc2021yszx-jcyj0003);国家自然科学基金项目(51878096);华侨大学科研基金项目(605-50Y23020)。

摘　　要：冷弯型钢拼合截面柱在发生弯曲变形时,各单肢截面之间会出现剪切滑移现象,从而显著影响其受力性能。而准确高效地计算拼合截面柱弯曲屈曲弹性临界荷载,是进一步研究拼合截面柱受力性能的重要基础。为此,选取工程中常见的五类典型拼合截面柱为研究对象,分析了拼合截面柱弯曲变形时各截面的相对滑移现象,并基于变形微分方程假定滑移分量的函数表达式,通过考虑紧固件布置位置与剪切刚度,建立能量守恒方程,基于能量变分原理推导弯曲屈曲弹性临界荷载计算方法。为验证计算方法准确性,采用ABAQUS建立112个数值分析模型,进行屈曲分析获取弹性临界荷载数值解,并与推导的理论计算方法计算结果对比,结果表明:理论计算方法具有较高的精度,其计算结果与数值解的误差在±10%以内。推导的计算方法适用于拼合柱自攻螺钉紧固件沿钢柱长度方向均匀布置,其间距宜在100~600 mm之间,且紧固件剪切刚度不宜超过14 kN/mm。数值分析结果还表明,螺钉间距和剪切刚度对四肢双箱形拼合截面的弹性临界荷载影响较为明显,而对于背对背开口拼合截面以及面对面箱形拼合截面影响相对较小。In the flexural deformation of the cold-formed steel(CFS) built-up section,the shear slip phenomenon will occur between the single sections,thus affecting the mechanical performance of the built-up section.In addition,accurately and efficiently calculating the critical elastic flexural buckling load of the of CFS built-up columns is an important basis for further exploring the mechanical properties of them.This paper selected five types of CFS built-up columns commonly used in engineering as research objects,analyzed the relative slip phenomenon of each single section during flexural deformation of the built-up section,and assumed the functional expression of the slip component based on the deformation differential equation.By considering the fastener arrangement and shear stiffness,the energy conservation equation was established,and the calculation method of the critical elastic flexural buckling load was derived based on the energy variation principle.In order to verify the accuracy of the calculation method,112 numerical analysis models were developed based on ABAQUS,and the numerical results of the critical load were obtained using the buckling analysis.It is found that the simulation results are in good agreements with the results obtained using the proposed calculation method(with the relative errors less than ±10%).The calculation method derived in this paper is applicable to the CFS built-up column,with self-tapping screw evenly arranged along the length of the column.The screw spacing should be between 100 mm and 600 mm,and the shear stiffness should not exceed 14 kN/mm.The results of parameter analyses also indicate that the screw spacing and shear stiffness have a significant influence on the elastic critical load of the quadruple-limbs double-box section column,while only have a relatively small influence on the back-to-back open section and the face-to-face box section columns.

关 键 词：冷弯型钢 拼合截面 弯曲屈曲 能量法 弹性屈曲荷载 

分 类 号：TU391[建筑科学—结构工程] TU311.41