集中荷载作用下悬臂箱型梁剪力滞效应解析分析

发布时间：2018-01-20 10:35

本文关键词： 悬臂箱型梁剪力滞效应附加挠度剪力滞系数狄拉克函数　出处：《建筑科学》2017年09期 　论文类型：期刊论文

【摘要】：考虑外荷载作用为竖向集中荷载,采用狄拉克函数处理由外荷载引起的势能,建立箱梁的总势能泛函,对总势能泛函求一阶变分可以得到箱梁挠度和附加挠度的域内控制微分方程及边界条件。求解附加挠度的二阶常系数非齐次线性微分方程可以得到集中荷载作用在梁任意位置时附加挠度的一般表达式。针对边界条件为左端固定右端自由的悬臂箱型梁,结合经典梁挠度,可以得到箱梁挠度和应力的表达式。在此基础上,推导了剪力滞系数的表达式。算例分析表明:基于附加挠度定义的应力计算方法与传统解析方法和试验方法吻合良好,但是附加挠度物理意义明确,边界条件容易处理,实际中容易量测;相对于传统基于应力定义的剪力滞系数在接近零弯矩截面时剪力滞系数就有趋于无穷大的趋势,基于挠度定义的剪力滞系数能够反映沿着远离固定端截面,剪力滞效应逐渐降低的趋势。
[Abstract]:Considering that the external load is a vertical concentrated load, the Dirac function is used to deal with the potential energy caused by the external load, and the total potential energy functional of the box girder is established. The in-domain governing differential equations and boundary conditions of box girder deflection and additional deflection can be obtained by solving the first order variation for the total potential energy functional. The concentrated load action can be obtained by solving the second order nonhomogeneous linear differential equation with constant coefficients for additional deflection. The general expression of the additional deflection at any position of the beam. The cantilever box girder with the left end fixed and the right end free is the boundary condition. The expressions of deflection and stress of box girder can be obtained based on the deflection of classical beam. An example analysis shows that the stress calculation method based on the definition of additional deflection is in good agreement with the traditional analytical method and experimental method, but the physical meaning of additional deflection is clear. The boundary condition is easy to deal with, and it is easy to measure in practice. Compared with the traditional shear lag coefficient based on stress definition, the shear lag coefficient tends to infinity when it is close to zero moment section, and the shear lag coefficient based on deflection definition can be reflected along the far away from the fixed end section. The decreasing trend of shear lag effect.
【作者单位】：广西岩土力学与工程重点实验室;桂林理工大学土木与建筑工程学院;广西珠委南宁勘测设计院;
【基金】：国家自然科学基金(51409051) 广西岩土力学与工程重点实验室开放课题基金(14-B-02) 广西防灾减灾与工程安全重点实验室开放课题基金(2014ZDK0012) 桂林理工大学博士科研启动基金(002401003442)
【分类号】：U441
【正文快照】： 0引言箱型梁是一种在桥梁中得到广泛应用的薄壁箱型截面梁,箱型截面具有良好的结构性能。考虑对称荷载作用下的弯曲,是箱型梁其中一种受力情况。箱型梁在对称荷载作用下的弯曲存在剪力滞现象。该现象是由于箱梁上下翼板的剪切扭转变形使翼板远离箱肋板处的纵向位移滞后于肋板

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