薄壁箱梁剪力滞动力特性的有限段法  

Finite segment method for analyzing the dynamic characteristics of thin-walled box girder considered the shear lag effect

作　　者：周旭辉[1] 罗旗帜[1] 张琪[1] 

机构地区：[1]佛山科学技术学院土木工程系,广东佛山528231

出　　处：《佛山科学技术学院学报（自然科学版）》2017年第1期70-75,共6页Journal of Foshan University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(50578019);广东省自然科学基金资助项目(9151063101000050)

摘　　要：以薄壁杆理论和有限元法为基础,提出了薄壁箱梁考虑剪力滞效应自由振动特性分析的有限段法。以剪力滞动力微分方程齐次解作为梁段单元的位移模式,利用能量泛函变分原理,导出了梁段单元的刚度矩阵和质量矩阵。通过矩阵组合,将箱梁自振频率转化为广义特征值问题,获得了振动频率和相应振型,并与有限元法和解析解的计算结果做了比较。研究表明:薄壁箱梁剪力滞效应将降低箱梁的自振频率,随着箱梁宽跨比和自振阶数的增大,对自振频率的影响更显著。Based on thin-walled bar theory and finite element method, a finite segment method was presented for analyzing the natural vibration characteristics of the thin-walled box girder considered the shear lag effect. The homogeneous solutions derived from the shear lag dynamic differential equations was used as the displacement patterns of finite segment, the mass matrix and stiffness matrix of finite segment were derived by means of energy functional variation principle. By composing the stiffness matrix, the problem of the natural vibration frequency of box girder was transformed into solving the generalized eigenvalue problem. The natural vibration frequency and the corresponding mode of vibration were obtained through it. The comparison of results among this paper, finite element method and analytical solutions prove the validity of the method of this paper. This shows the natural vibration frequency of the thin-walled box girder will decrease because of the shear lag effect. And with the increase of width to span ratio and natural vibration order, the influence of shear lag effect will be more obvious.

关 键 词：薄壁箱梁 自振频率 有限段法 剪力滞效应 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]