含竖杆、斜杆的摩擦型高强度螺栓连接节点受力性能研究及参数分析

发布时间：2018-03-25 14:17

本文选题：大节点　切入点：摩擦型高强度螺栓　出处：《西南交通大学》2017年硕士论文

【摘要】：钢桥的跨越能力大、适于工业化制造、便于运输、便于安装等优点使其快速发展,并且摩擦型高强度螺栓连接的拼接接头广泛应用于钢结构桥梁中;但是在高强度螺栓拼接头中螺栓折断现象广泛存在于钢结构桥梁中,为了保证该类桥梁的正常使用,分析含有竖杆、斜杆的高强度螺栓连接大节点的传力性能有重要的意义。本文利用ANSYS建立了高强度螺栓连接的大节点的整体有限元模型及局部模型,并分析了节点中螺栓群的传力比、芯板及拼接板应力分布规律、荷载-滑移关系等,并对比分析了螺栓缺失、拼接板板厚、螺栓孔径对螺栓群传力性能的影响,具体结论如下:(1)螺栓群(含三列螺栓)中各排螺栓的传力比沿纵向呈马鞍型分布,第一排和最后一排螺栓的传力比较大,中间各排螺栓的传力比较小;含有六列螺栓的螺栓群中各排螺栓传递的剪力沿板横向成W型分布;随着螺栓排数的增加,各排螺栓的传力比的差异性加大,但是各螺栓群中第一排螺栓的传力比几乎不变,中间各排螺栓的传力比减小。(2)芯板横截面上轴向应力沿板横向呈波浪形分布,在螺栓轴向连线上应力较小,在行间应力较大;拼接板在两排螺栓之间轴向应力沿板纵向呈波浪形分布,在螺栓中心连线上应力较小,而在螺栓间应力较大。拼接板在两排螺栓之间的轴向应力沿板横向呈波浪形分布,在螺栓连线上应力较小,而在螺栓行间应力较大。(3)在使用阶段螺栓传递的剪力与外荷载呈现正比关系,只是每个螺栓的剪力值不相同。当有螺栓出现滑移后,外荷载与螺栓传递的剪力之间表现出非线性关系,越晚出现滑移的螺栓非线性关系越明显。螺栓进入局部滑移阶段后,同排螺栓的剪力值差别较大,故在用传力比分析螺栓群的受力时应考虑螺栓受力沿板宽方向的不均匀性。(4)随着拼接板厚度的增加螺栓群中各排螺栓传递剪力的不均匀性增加,即第一排螺栓的传力比增加,最后一排螺栓的传力比减小,中间各排螺栓的传力比几乎不改变;随着拼接板厚度的增加,拼接接头出现螺栓滑移的时间越早;拼接板板厚对极限滑移荷载没有影响。(5)高强度螺栓的压力影响区随着螺栓孔径的增加而加大,压力影响区的直径大约为螺栓孔径的2.85倍;随着螺栓孔径的增加,第一排螺栓的传力比递减,最后一排螺栓的传力比递增,中间排螺栓的传力比改变不大;拼接板与芯板之间的接触压应力随着螺栓孔径的增加而减小。(6)在大节点中,螺栓的缺失仅对相邻螺栓群中靠近杆件中心交点的几排螺栓的传力比有影响,但是这种影响较小;在局部模型中螺栓的缺失仅对2倍栓距范围内螺栓的受力有影响;螺栓的缺失会使相应螺栓群的初始滑移荷载下降,极限滑移荷载减小;螺栓的缺失对相邻螺栓群的荷载-滑移曲线影响较小。
[Abstract]:The steel bridge has the advantages of large span ability, suitable for industrial manufacture, convenient transportation, easy installation and so on, and the splicing joint of friction type high strength bolt connection is widely used in steel structure bridge. But the phenomenon of bolt breaking in high strength bolt splicing head is widely existed in steel structure bridge. In order to ensure the normal use of this kind of bridge, the vertical rod is analyzed. In this paper, the finite element model and local model of large joint with high strength bolt connection are established by using ANSYS, and the load transfer ratio of bolt group in the joint is analyzed. The stress distribution law and load-slip relation of core plate and splice plate are analyzed, and the effects of bolt missing, splice plate thickness and bolt aperture on the load transfer performance of bolt group are compared and analyzed. The specific conclusions are as follows: (1) in the bolt group (including three rows of bolts), the transmission force ratio of each row of bolts is saddle distribution along the longitudinal, the first row and the last row of bolts are larger than the middle row bolts, and the transmission force of the middle row bolts is relatively small; The shear force transferred by each row of bolts in the bolt group with six rows of bolts is distributed in W shape along the plate; with the increase of the number of bolts, the difference of the load transfer ratio of each row bolt increases, but the transfer force ratio of the first row bolt in each bolt group is almost unchanged. The axial stress distribution along the cross section of the core plate is wave shape, and the stress on the axial line of the bolt is smaller, and the stress between rows is larger. The axial stress of the splice plate distributed along the longitudinal wave shape between the two rows of bolts, and the stress on the central line of the bolt was small, but the stress between the bolts was larger. The axial stress of the splice plate distributed along the transverse wave shape along the plate between the two rows of bolts. The stress on the bolt line is smaller, but the stress between the lines of the bolt is greater. 3) the shear force transmitted by the bolt is proportional to the external load during the use stage, except that the shear value of each bolt is different. When the bolt slips, There is a nonlinear relationship between the external load and the shearing force transferred by the bolt, and the more obvious is the nonlinear relationship of the bolt with slip, when the bolt enters the local slip stage, the shearing value of the same row bolt is different greatly. Therefore, the inhomogeneity of bolt force along the width of the plate should be taken into account in the analysis of bolt group forces by force transfer ratio. 4) with the increase of the thickness of splice plate, the non-uniformity of the shearing force of each row of bolts in the bolt group increases, that is, the transmission force ratio of the first row bolt increases. The ratio of transmission force of the last row of bolts is reduced, the ratio of the middle row bolts is almost unchanged, with the increase of the thickness of the splicing plate, the bolt slip of the splice joint appears earlier. The pressure affected zone of high strength bolt increases with the increase of bolt aperture, and the diameter of pressure affected zone is about 2.85 times of bolt diameter, with the increase of bolt aperture, the plate thickness has no effect on ultimate slip load. The transmission force ratio of the first row bolt decreases, the transmission force ratio of the last row bolt increases, the transmission force ratio of the middle row bolt does not change much; the contact compression stress between the splice plate and the core plate decreases with the increase of bolt aperture. The lack of bolts only has an effect on the transmission ratio of several rows of bolts near the central intersection of the bar in the adjacent bolt group, but this effect is small, and the lack of bolts in the local model only affects the force of the bolt in the range of 2 times the distance between the bolt and the bolt. The lack of bolt will decrease the initial slip load and limit slip load of the corresponding bolt group, and the lack of bolt will have little effect on the load-slip curve of the adjacent bolt group.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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