考虑剪力滞后的薄壁箱形梁桥弯扭耦合分析

发布时间：2018-04-22 00:29

本文选题：薄壁箱梁 + 剪力滞后　；参考：《河北工程大学》2014年硕士论文

【摘要】：箱形截面具有利用效率高,抗弯抗扭刚度大等特点，因此在桥梁结构中得到了广泛应用。然而箱形截面梁桥在外荷载作用下纵向弯曲时存在剪力滞后现象,若忽略此现象将会低估箱梁结构产生的实际应力,使得结构不安全。随着箱形梁桥向长悬臂板、大肋间距的简洁型单箱单室截面方向发展，其剪力滞效应日益受到人们关注。鉴于实际工程的需要，箱形截面梁桥剪力滞效应的研究不容忽视。本文以薄壁杆件的弯曲和扭转理论为基础，以箱形截面梁桥为分析对象，放弃了符拉索夫提出的沿杆件横截面剪应变等于零的假定,计及其剪切变形，建立箱形截面梁桥弯扭分析的哈密顿对偶求解体系，此体系摒弃了初等梁理论和乌曼斯基理论对纵向翘曲位移的假定，用插值的思想描述结构的纵向翘曲位移，，能很好地描述剪力滞后现象。对此求解体系，运用两端边值问题的精细积分法，通过MATLAB语言编制的程序求解结构在弯扭作用下的纵向翘曲位移和翘曲正应力。选择不同的箱型截面梁作为算例，在结构上施加不同的外荷载，通过具体算例的求解并与其他文献方法进行对比，表明本文方法的合理性与可行性，为箱形桥梁的设计提供一定的参考。本文提出了一种新的分析箱形截面梁桥的理论方法，构造了一个十分灵活的样条函数的插值系统。方法采用分段三次样条函数模拟杆件横截面的翘曲位移场,并考虑了杆壁中面上剪切变形的影响,能有效地反映剪力滞后效应。分段三次样条函数以实际的结点位移为未知量,易于满足横截面各分肢交接处的位移协调；而且每个分肢划分结点的数目可以不同,从而增加了方法的灵活性；这套样条插值系统特别适用于带分肢截面形状的薄壁结构,为样条函数的应用开辟了一条新的途径。本课题的研究成果可供桥梁工程的研究和设计人员借鉴。
[Abstract]:Box section is widely used in bridge structure because of its high utilization efficiency and high bending and torsional stiffness. However, there is shear lag phenomenon in the longitudinal bending of box section girder bridge under external load. If this phenomenon is ignored, the actual stress generated by box girder structure will be underestimated, which makes the structure unsafe. With the development of box girder bridge towards long cantilever plate, the shear lag effect of single box and single chamber section with large rib spacing has been paid more and more attention. In view of the need of practical engineering, the study of shear lag effect of box girder bridge can not be ignored. Based on the theory of bending and torsion of thin-walled members and taking the box section girder bridge as the analysis object, the assumption that the shear strain along the cross section of the member is equal to zero is abandoned in this paper, and the shear deformation is taken into account. A Hamiltonian dual solution system for bending and torsional analysis of box girder bridges is established. The assumption of longitudinal warping displacement of the structure is abandoned by elementary beam theory and Umansky theory, and the longitudinal warping displacement of the structure is described by interpolation. The phenomenon of shear lag can be described well. In this system, the precise integration method of the boundary value problem at both ends is used to solve the longitudinal warping displacement and warpage normal stress of the structure under the action of bending and torsion by the program compiled by MATLAB language. Different box section beams are selected as examples, and different external loads are applied on the structure. By solving the concrete examples and comparing them with other literature methods, the rationality and feasibility of this method are shown. It provides some reference for the design of box bridge. In this paper, a new theoretical method for analyzing box section beam bridges is presented, and a very flexible interpolation system of spline functions is constructed. Methods the warping displacement field of the cross section of the bar is simulated by using the piecewise cubic spline function, and the effect of shear deformation on the middle plane of the bar wall is taken into account, which can effectively reflect the shear lag effect. The piecewise cubic spline function takes the actual node displacement as an unknown quantity, which is easy to meet the displacement coordination of the cross section, and the number of nodes in each limb partition can be different, thus increasing the flexibility of the method. The spline interpolation system is especially suitable for thin-walled structures with split limb section, which opens a new way for the application of spline function. The research results of this subject can be used for reference by bridge engineering researchers and designers.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.213

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