冷弯薄壁型钢偏压构件稳定性能与直接强度法

发布时间：2018-05-12 06:49

  本文选题：冷弯薄壁型钢 + 稳定性能　； 参考：《沈阳建筑大学》2014年硕士论文

【摘要】：冷弯薄壁型钢构件的稳定问题一直是钢结构科研工作者和规范编制人员工作中的重点。新型截面形式的出现以及超薄、高强钢材的应用,带来了许多新的稳定问题。目前,对冷弯薄壁型钢受压构件的稳定问题的研究和成果大多集中在截面形式简单的槽钢和卷边槽钢类构件,对于设置加劲肋和复杂卷边等复杂截面形式的研究成果相对较少。现有的关于复杂截面形式的研究大都是针对轴心受压构件,对于偏心受压构件的研究还很少见。另外,现有的有效截面计算方法已经不足以满足各种新型截面形式构件的计算。因此,国外学者提出直接强度计算方法来代替有效截面法计算冷弯薄壁型钢构件的承载力。目前,各国规范中采用的直接强度计算方法只适用于计算轴压状态或纯弯状态下的槽钢和卷边槽钢构件,关于偏压状态下的槽钢和卷边槽钢构件的直接强度计算方法还没有明确的计算公式。针对这些问题,本文分别对复杂卷边槽钢、腹板中间∑形加劲复杂卷边槽钢、腹板中间V形加劲复杂卷边槽钢三种截面形式,共计12根简支偏心受压构件进行了承载力试验。研究了构件的极限承载力、破坏模式及变形等特性。试验结果表明,腹板加劲有效地减小了板件宽厚比,大幅度提高向腹板一侧偏心受压构件的极限承载力,使畸变屈曲代替局部屈曲起主要控制作用,但对向卷边一侧偏心受压构件的极限承载力影响很小采用非线性有限元软件ANSYS对试验进行了有限元模拟,验证了模拟的有效性。在此基础上,对3种不同截面形式共计302个算例的复杂卷边槽钢偏心受压构件稳定性能进行了模拟分析。结果表明：腹板加劲可以提高向腹板一侧偏心受压构件的极限承载力和钢材利用率,其中∑形加劲要优于V形加劲。有效形心偏移对偏压构件承载力的影响不可忽视,构件极限承载力最大值出现在荷载作用于有效形心位置处时。板厚变化对腹板中间V形加劲复杂卷边槽钢影响显著。以我国现有的偏心受压构件的有效截面计算方法为基础,结合轴心受压构件和纯弯构件的直接强度法,提出了偏心受压构件的直接强度计算方法。通过对125个构件的已有试验和103个算例模拟结果进行验算确定,本文提出公式适用于计算荷载作用在对称轴平面内的普通卷边槽钢和复杂卷边槽钢偏心受压构件的承载力。
[Abstract]:The stability of cold-formed thin-walled steel members has always been the focus of scientific research workers and code compilers of steel structures. The appearance of new cross-section and the application of super-thin and high-strength steel have brought many new stability problems. At present, most of the researches and achievements on the stability of cold-formed thin-walled steel compression members are focused on channel steel and crimped channel steel members with simple section form, but the research results on the complicated section form such as stiffening rib and complicated edge are relatively few. Most of the existing researches on complex cross-section are aimed at axial compression members, but the research on eccentric compression members is rare. In addition, the existing effective section calculation methods are not enough to meet the calculation of various new cross-section members. Therefore, foreign scholars put forward direct strength calculation method instead of effective section method to calculate the bearing capacity of cold-formed thin-walled steel members. At present, the direct strength calculation methods used in national codes are only suitable for calculating channel steel and crimped channel steel members under axial compression or pure bending. There is no clear formula for calculating the direct strength of channel steel and crimped channel steel members under the state of bias. Aiming at these problems, the bearing capacity of 12 simply supported eccentrically compressed members were tested in this paper, including complex crimped channel steel, sigma-shaped stiffened channel steel with complex edge, and V-shaped stiffened and complicated crimped channel steel with V-shape in the middle of web plate. The ultimate bearing capacity, failure mode and deformation of the members are studied. The test results show that the stiffening of web can effectively reduce the width to thickness ratio of the plate, greatly increase the ultimate bearing capacity of eccentric compression members on one side of the web, and make the distortion buckling play a major role in controlling the local buckling instead of the local buckling. But the ultimate bearing capacity of eccentric compression members on one side of the crimping edge is very small. The nonlinear finite element software ANSYS is used to simulate the finite element test, and the validity of the simulation is verified. On the basis of this, the stability performance of eccentric compression members of complicated crimped channel steel with 302 different cross section forms is simulated and analyzed. The results show that the ultimate bearing capacity and steel utilization ratio of eccentric compression members on one side of the web can be improved by stiffening the web, in which 鈭，

本文编号：1877559