【作者】 刘健；

【导师】 王春刚；

【作者基本信息】 沈阳建筑大学 ， 建筑与土木工程（专业学位）， 2016， 硕士

【摘要】 近年来,冷弯型钢的截面形式日趋新颖,复杂卷边新型截面冷弯型钢也在实际工程中得到更为广泛的应用。然而,在弯剪联合作用下,对于复杂卷边槽钢梁稳定性能及其计算方法的研究尚不深入,对于畸变屈曲失稳模式与其他失稳模式之间相关作用的理论研究也有待深入开展。复杂卷边和腹板加劲肋的存在,对构件稳定性和承载力的影响显著。目前,国内外学者对纯弯状态下复杂卷边槽钢梁的稳定性和承载力研究已较为成熟,但对弯剪联合作用下复杂卷边槽钢梁稳定性的研究和与其相适应的承载力直接强度方法仍有待深入。特别是弯剪联合作用下,腹板加劲的复杂卷边槽钢梁的直接强度法公式尚未建立。针对上述研究现状,本文主要以弯剪联合作用下复杂卷边C形槽钢梁、腹板V形加劲复杂卷边槽钢梁和复杂卷边∑形槽钢梁为研究对象,分别对这三种截面形式进行有限元分析。首先,研究了腹板厚度、腹板加劲高度比、翼缘宽厚比、卷边宽厚比对复杂卷边槽钢梁的极限承载力、屈曲模式以及应力分布的影响。其次,在相同截面尺寸下,对比复杂卷边C形槽钢梁与腹板V形加劲复杂卷边槽钢梁在弯剪联合作用下的抗弯承载力。最后,在复杂卷边C形槽钢梁弯剪联合作用下的直接强度法基础上,提出弯剪联合作用下腹板V形加劲复杂卷边槽钢梁、复杂卷边∑形槽钢梁的承载力直接强度计算方法。研究表明,在同等受力状态下,构件的极限承载力随截面腹板高厚比的增大而减小,但对构件的屈曲模式影响不大。其中腹板加劲构件的屈曲模式以畸变屈曲和局部屈曲为主。在构件截面参数相同的情况下,复杂卷边C形槽钢梁与腹板V形加劲复杂卷边槽钢梁的抗弯承载力相近。本文通过改变腹板加劲肋的高度,确立了复杂卷边∑形槽钢梁的抗弯承载力最大时的截面形式。此外,在有限元模拟结果的基础上,验证了复杂卷边C形槽钢梁的直接强度法在同等受力状态下可应用于腹板V形加劲复杂卷边槽钢梁抗弯承载力的求解,并在此基础上提出了复杂卷边∑形槽钢梁在弯剪联合作用下的直接强度法公式。对公式的有效性进行了验证,可供实际工程应用和规范修订参考。更多还原

【Abstract】 In recent years,cross section forms of cold-formed steel are becoming more and more novel.Cold-formed steel of new section form with complex edge is getting more extensive application in the practical engineering.However,under bending-shearing combining condition,research on stability performance and calculating method of complex edge channel steel needs a further study.It is also a subject on interact effect between distortional buckling and the other buckling modes.It influence obviously on component stability and bearing capacity for the existence of complex edge and stiffeners on the web.Nowadays,domestic researches on stability performance and bearing capacity of beam with complex edge under pure bending condition are relatively mature,but unfamiliar under bending-shearing combining condition.What is more,formula for the direct strength method(DSM)of complex edged bending channel with stiffeners on the web under bending-shearing combining condition have not yet been established.Based on current research situation,C-shape channel steel beam with complex edge,channel steel beam with complex edge and V-shaped stiffener on web and channel steel beam with complex edge and ∑-shaped stiffener on web under bending-shearing combining condition were made a research in this paper.Finite element analyses were conducted for the three kinds of section forms.Firstly,influences of web thickness,web height and stiffener height ratio on ultimate bearing capacity,buckling modes and stress distribution of channel steel beam with complex edge were studied.Secondly,bending bearing capacity under bending-shearing combining condition between C-shape channel steel beam with complex edge and channel steel beam with complex edge and V-shaped stiffener on web were made a comparison,provided that with the same section sizes.Finally,the direct strength calculation methods for the bearing capacity of channel steel beam with complex edge and V-shaped stiffener on web and channel steel beam with complex edge and ∑-shaped stiffener on web under bending-shearing combining condition were put forward,based on that of C-shape channel steel beam with complex edge.Research shows that the ultimate bearing capacity decreases with the increase of web height-to-thickness ratio under the same loading condition,but it influences little on buckling modes.The buckling modes of components with web stiffeners were mostly performing distortional buckling and local buckling.Bending bearing capacity between C-shape channel steel beam with complex edge and channel steel beam with complex edge and V-shaped stiffener on web varies little,on condition that with the same component section parameter.The optimal cross section,which bending bearing capacity is the maximum,of channel steel beam with complex edge and ∑-shaped stiffener on web was established in this paper,by varying web beam with complex edge,was also practicable for that of channel steel beam with complex edge and V-shaped stiffener on web,on base of finite element simulation results.What is more,the direct strength method of channel steel beam with complex edge and ∑-shaped stiffener on web under bending-shearing combining condition was suggested in this paper.The applicability of the formula was verified,which could be made a reference on practical engineering application and specification revision.更多还原