考虑剪滞效应和剪切变形的曲线箱梁自振研究  

Vibration properties research on curved box girder considering shear lag effects and shear deformation

作　　者：兰玮琦 姚激[1] 黄坤[1] LAN Wei-qi;YAO Ji;LI Meng-yao;HUANG Kun(School of Construction Engineering,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学建筑工程学院,云南昆明650500

出　　处：《交通科学与工程》2020年第4期61-68,共8页Journal of Transport Science and Engineering

基　　金：国家自然科学基金资助项目(11562009)。

摘　　要：为研究剪力滞效应和剪切变形对曲线箱梁自振频率的影响,基于变分法和哈密顿原理,推导出弯、扭、剪力滞耦合的曲线箱梁自由振动微分控制方程。利用假设模态法对微分方程分离参数,近似求解出其自振频率,并将其与ANSYS有限元求解结果进行对比,进一步验证了该推导公式的精确度。依托某工程实例研究了跨宽比和曲率半径对自振频率、剪力滞效应和剪切变形贡献度的影响。研究结果表明:跨宽比的增加和曲率半径的变小,会造成曲线箱梁刚度的下降,从而导致自振频率下降;剪力滞效应和剪切变形随着跨宽比和曲率半径的增加,会对自振频率有明显影响。Curved box beams play an important role in the construction of urban bridges due to their small footprint and good integrity.In order to study the effect of shear lag and shear deformation on the natural frequency of curved box girder.Based on the variational principle and the Hamilton principle,a differential equation for free vibration of curved box girder considering bending,torsion and shear lag coupling is derived.The hypothetical modal method was used to separate the parameters and solve approximately the free vibration frequency.It was compared with the ANSYS finite element solution.The practicability and accuracy of the formula in the text is verified.Based on the formulas in the text,combined with examples to study the influence of span width ratio and radius of curvature on free vibration frequency and the contribution of shear lag effect and shear deformation in it.The results show that increasing the span ratio and decreasing the radius of curvature will lead to decreases of the rigidity of the curved box girder.It leads to a decrease in the free vibration frequency.With the increase of the span width ratio and the radius of curvature,the shear lag effect and shear deformation have a significant effect on the natural frequency.

关 键 词：变分原理 自由振动 剪力滞效应 剪切变形 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]