弯扭联合作用下槽型钢梁的受力性能研究

发布时间：2018-11-11 17:36

【摘要】：在实际工程中,当荷载偏离钢梁截面的剪力中心,钢梁会因为偏心受力而承受弯扭联合作用。这样的受力方式在一定程度上影响到构件的承载能力以及变形特点,而现有设计规范却鲜有这方面的具体规定。另外,对于钢梁受弯扭共同作用的研究,国内外大多数工作都是关于工字型钢梁和冷弯C型钢梁,很少有涉及到并深入研究弯扭联合作用下的槽型钢梁的承载力特性。因此,本文对于槽型钢梁在弯扭联合作用下的受力性能进行研究分析。首先从力学的基础理论出发对槽型钢梁进行线弹性分析,其中包括:(1)对槽型钢梁进行受弯分析,并根据规范的应力计算公式给出相应的应力图;(2)根据开口薄壁杆件约束扭转理论,对槽型钢梁进行扭转分析,推导了槽型钢梁约束扭转应力的计算公式并得到槽型截面的约束扭转应力图;(3)在前两项工作的基础上对槽型钢梁进行弯扭联合作用下的受力分析,从而根据弯扭联合作用下槽型钢梁的应力组成,得到弯扭联合作用下槽型钢梁截面的正应力分布规律。其次,利用大型有限元软件ANSYS,同时考虑材料非线性和几何非线性,对本文的研究对象建立有限元分析模型,并采用弧长法进行求解计算。将有限元结果与我国的《钢结构设计规范》(GB 50017-2003)以及《冷弯薄壁型钢结构技术规范》(GB 50018-2002)中关于槽型钢梁整体稳定性计算的理论公式所得结果相比较,分析这两本规范中关于槽型钢梁整体稳定性计算的区别。并将分析结论与相关文献的结论对比,证明本文模型的正确性。最后,利用本文建立的有限元分析模型,对槽型钢梁承受跨中偏心集中荷载和满跨偏心均布荷载作用分别进行非线性屈曲分析,求得槽型钢梁在各荷载工况下的极限荷载,分析槽型钢梁在横向偏心荷载作用下的失稳形式及其承载力变化规律。根据PutPi相关公式进行猜测,在相关理论的基础上引入一个简化的名义极限扭矩来分析槽型钢梁在横向偏心荷载作用下极限弯矩和极限扭矩的相关关系,通过软件MATLAB的回归分析得到其相关关系的表达式,并将其与PutPi相关公式对比来验证本文工作的必要性和合理性。
[Abstract]:In practical engineering, when the load deviates from the shear center of the steel beam section, the steel beam will be subjected to the combined bending and torsion action because of the eccentric force. To a certain extent, the bearing capacity and deformation characteristics of members are affected by such a stress mode, but the existing design codes rarely have specific provisions in this respect. In addition, most of the researches on the bending and torsional interaction of steel beams are related to I-shaped steel beams and cold-formed C-type steel beams at home and abroad, and seldom involve and deeply study the bearing capacity characteristics of grooved steel beams under the combined action of bending and torsion. Therefore, this paper studies and analyzes the mechanical behavior of the groove steel beam under the action of bending and torsion. Based on the basic theory of mechanics, the linear elastic analysis of slotted steel beams is first carried out, which includes: (1) bending analysis of slotted steel beams, and the corresponding stress diagrams are given according to the stress calculation formula of the code; (2) according to the torsion theory of thin-walled open member, torsional analysis is carried out on the slotted steel beam, and the formula for calculating the constrained torsional stress of the slotted steel beam is derived, and the constrained torsional stress diagram of the slot section is obtained. (3) on the basis of the first two works, the stress of the slotted steel beam under the combined action of bending and torsion is analyzed, and according to the stress composition of the slotted steel beam under the combined action of bending and torsion, The normal stress distribution of the section of steel beam is obtained under the action of bending and torsion. Secondly, the finite element analysis model is established by using the large-scale finite element software ANSYS, to consider both material and geometric nonlinearity, and the arc length method is used to solve the problem. The results obtained by finite element method are compared with those obtained from the theoretical formulas for the calculation of the overall stability of steel girders in the Code for Design of Steel structures (GB 50017-2003) and the Technical Specification for Cold-Formed Thin-walled Steel structures (GB 50018-2002) in China. This paper analyzes the difference between the calculation of the overall stability of slotted steel beams in these two codes. The conclusion of this paper is proved to be correct by comparing the conclusion of the analysis with the conclusion of related literature. Finally, by using the finite element analysis model established in this paper, the nonlinear buckling analysis is carried out for the beam bearing eccentric concentrated load and full span eccentricity distribution load, respectively, and the ultimate load of the groove steel beam under various load conditions is obtained. The buckling mode and bearing capacity of steel beams with groove under transverse eccentric load are analyzed. Based on the PutPi formula, a simplified nominal limit torque is introduced to analyze the relationship between ultimate bending moment and ultimate torque under transverse eccentric load. Through the regression analysis of software MATLAB, the expression of the correlation relation is obtained and compared with the PutPi correlation formula to verify the necessity and rationality of the work in this paper.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU391

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