新型冷弯箱形组合构件力学性能研究

基于箱形截面具有双轴对称、抗弯扭刚度大的特点,提出将冷弯∑形截面两两翼缘相对,并将其卷边焊接形成一种新型冷弯箱形组合截面——DS。应用非线性有限元方法分析新型截面构件在轴压、弯矩及压弯荷载作用时的诸如屈曲模式、承载力、刚度、延性及相关曲线等方面力学性能。同时,还对相同参数的新型截面构件与C形截面构件的单位承载力耗钢量进行比较。分析表明:新型截面构件在承受轴压力时具有高承载力及较高的截面模量,截面加劲充分而使子板件局部屈曲不易出现等力学性能优势。特别适宜承受轴压荷载,同时也适宜承受弯矩和压弯荷载的作用。轴压构件的单位承载力耗钢量一般仅为相同参数C形构件的50%左右,经济效益明显。新型箱形组合构件适于深入试验研究并合理应用于实际工程。

STUDY ON MECHANICAL PROPERTIES OF A NEW KIND OF COLD-FORMED BOX COMPOSITE MEMBERS

Cold-formed steel box shape section has the special features both its mass center and moment center being unified as double symmetry section and its outstanding advantage in moment and torsion rigidity.This paper presents a new kind of cold-formed steel box shape composite sections,that is flanges opposite being welded to form a composite section DS.The mechanical properties such as buckling modes,load carrying capacity,rigidity,ductility and correlation curves of new section members subjected to axial compression,flexure,combined compression and bending were analyzed by using nonlinear finite element method.The consumed steel quantities of per unit load carrying capacity between new section members and the same section dimensions of cold-formed C-section members were also compared systematically.Some conclusions could be drawn from above work that the DS section members had some superiority properties such as higher load carrying capacity and section modulus especially subject to compression load,sufficient section stiffener and difficult for the sub element local buckling to happen and so on.They were very suitable to carry compression,and flexure loads,and combined compression and bending load,too.The consumed steel quantities were almost 50% as the same dimension C-section compression members.The DS section members could go deep into the experiment study as to be used in the practical projects.