缀板加强冷弯薄壁C形钢受压极限承载力研究

Research on Ultimate Compressive Load of CFS C-shaped Members Strengthened by Batten Plates

为研究缀板加强冷弯薄壁C形钢受压构件的受力性能,采用ANSYS软件建立其非线性有限元模型,并与试验破坏特征、极限承载力进行对比,验证建模方法的正确性.研究缀板间距及偏心距对缀板加强冷弯薄壁C形钢在轴压及单向偏心受压作用下的极限承载力及屈曲模态的影响规律.结果表明:随缀板间距减小,C形钢的屈曲变形由畸变屈曲逐步转为局部屈曲,轴心受压及偏心受压构件极限承载力逐渐增高;随偏心距增大,偏心受压构件的极限承载力逐渐降低;建议缀板加强冷弯薄壁C形钢轴压、偏压构件的缀板间距分别取λ/3、λ/4(λ为屈曲半波长度).基于缀板加强冷弯薄壁C形钢的受力特点及直接强度法,提出缀板加强冷弯薄壁C形钢构件轴压及偏压极限承载力的修正公式,并验证了公式的准确性.

To study the mechanical behavior of Cold-formed Thin-walled Steel(CFS)C-shaped compression members strengthened by batten plates,the nonlinear finite element model of C-shaped steel was established by using ANSYS software.The correctness of the modeling method was verified by comparing the test failure characteristics and ultimate bearing capacities.The effects of batten spacing and eccentricity on the ultimate bearing capacity and buckling mode of batten-strengthened CFS C-section members under axial and one-directional eccentric compression were studied.The results showed that,with the decrease of batten plate spacing,the buckling deformation of C-shaped members changed gradually from distortion buckling to local buckling,and the ultimate bearing capacity of axial compression and eccentric compression members increased gradually.With the increase of eccentricity,the ultimate bearing capacity of eccentric compression members decreased gradually.It is suggested that the batten spacing of CFS C-shaped steel axial compression and eccentric compression members strengthened by batten plates should be taken asλ/3 andλ/4,respectively.Based on the mechanical characteristics and direct strength method of CFS C-shaped steel members strengthened by batten plates,a modified formula for the ultimate compressive capacity of CFS C-shaped members strengthened by batten plates was proposed,and the accuracy of the formula was verified.