新型冷弯箱形组合截面受弯构件力学性能研究

MECHANICAL BEHAVIOR OF TWO NEW KINDS OF COLD-FORMED BOX COMPOSITE SECTION BEND MEMBERS

冷弯薄壁双轴对称箱形截面具有形心、弯心重合的特点,与单轴对称开口截面相比具有抗弯、扭刚度大的优点。基于箱形截面的以上特点,应用冷弯∑形构件两两电弧点焊连接,形成两种新型箱形组合截面——翼缘对焊箱形组合截面和翼缘叠焊箱形组合截面。采用非线性有限元的分析方法,通过对两种新型截面与相同参数的单肢∑形构件的细致比较分析,以及单一参数变化条件下新型截面构件的屈曲模式、变形过程、弯矩-曲率关系等方面的分析,全面研究两种新型截面受弯构件的静力学性能。研究表明:两种新型截面构件与其单肢∑形构件相比,具有抗弯承载力明显提高,构件不会出现畸变屈曲、局部变形小等性能优势,可以深入研究并合理推广使用。

Box section has the special features both its mass center and moment center unification as double symmetry coldformed section and its outstanding advantage in moment and torsion rigidity. According to which, it is put forward two new kinds of cold-formed box composite sections-flanges opposite welded box composite section and flanges lapped welded box composite section. On the basis of precise finite element model, nonlinear finite element method is adopted to study the static behaviors including buckling modes, deformed process, moment-curvature curves of two new kinds of section members under flexural loads. The buckling behaviors and static behaviors of the two kinds of sections are analyzed completely. It is compared every side of static behavior with those of channel sections that have the same dimensions. The two new type sections have some superior static behaviors including higher ultimate bending capacity, distortional buckling can escape and smaller local buckling in the member are verified. These two new kinds of sections can go deep into the experiment study as to be used in the practical engineering.