腹板开孔对冷弯薄壁C型钢简支檩条受力性能影响

Effects of web openings on mechanical properties of cold-formed thin-walled C-section simply supported purlin

为了研究腹板开孔对冷弯薄壁C型钢简支檩条受力性能的影响,选取不同孔洞直径和间距的腹板开孔冷弯薄壁C型钢简支檩条进行有限元受力性能分析,分析腹板开孔冷弯薄壁C型钢简支檩条的刚度、承载力、应力分布和破坏模式,研究孔洞离支座距离、孔径和孔间距对简支檩条受力性能的影响。结果表明:仅距支座檩条高度(H)以上处开直径不超过檩条高度1/2孔洞时,开孔基本不影响C型钢檩条的受力性能。腹板沿全长均匀开孔会降低檩条的受力性能,随着孔径增大,孔距减少,檩条的受力性能降低,弹塑性阶段越短,屈服荷载、极限荷载明显下降,构件整体刚度下降,位移增大明显。当开孔直径不大于H/3、孔间净距不小于3H时,开孔对檩条极限荷载基本没影响,位移增大不到1.4%。开孔对檩条破坏模式没有影响,均表现为跨中上翼缘屈曲,跨中上、下翼缘应力达到屈服。

In order to study the effect of web openings on the mechanical properties of cold-formed thin-walled C-section simply supported purlins,the finite element analysis of the cold-formed thin-walled C-section simply supported purlins with different hole diameters and spacings were carried out.The stiffness,bearing capacity,stress distribution and the failure mode of the cold-formed thin-walled C-section simply supported purlins with web openings were analyzed.The influence of the distance of the hole from support,the diameter of hole and the space of hole on the mechanical behavior of the simply supported purlins was studied.Results showed that when the distance of hole was above the purlin height H and the diameter of hole was not more than 1/2 of the purlin height H,the force performance of C-section purlins would not be affected.For the purlins with uniform web openings along the whole length,the mechanical properties of the purlins would reduced.With the hole diameter increased and the hole spacing decreased,the load-displacement curve was lower and the elastic-plastic stage was shorter.While the yield load and ultimate load decreased,the stiffness decreased and displacement increased significantly.When the net distance between the holes was not less than 3H and the diameter of the holes was not greater than H/3,the holes basically had no influence on the ultimate load and the displacement increased by less than 1.4%.The holes had no effect on the failure mode of purlins.The upper flange of the purlins buckled at the mid-span.The stress of the upper and lower flange at the mid-span reached the yield stress.