摘要
由于剪力滞效应及剪切变形的存在,箱梁的弯曲振动频率按照初等梁理论计算往往存在较大的误差.综合考虑箱梁的剪切变形及剪力滞效应,利用能量变分原理分析简支箱梁的自由振动,推导出考虑剪力滞效应及剪切变形的简支箱梁的各阶自振频率的解析解,较以前只能计算振动基频有所推广.验证算例计算表明本文方法理论推导正确,计算精度较初等梁理论大大提高.最后对剪力滞效应及剪切变形对箱形梁自振特性的影响进行了讨论,发现考虑剪力滞效应以及考虑剪切变形均使简支箱梁的振动基频降低,且对于箱梁的高阶振动频率降低程度尤为明显;而箱梁的宽跨比是影响其降低程度的最重要因素.
The vibration frequency of box gird is usually calculated by the elementary beam theory, but it will lead to a large error because of the existence of shear lag effect and shear deformation. Based on energy variational principle, this paper proposes a new method to calculate the vibration of simply supported box gird, which includes the effect of shear lag and shear deformation, and the closed - form solutions to the natural frequencies are derived. It extends the usage of the methods of the past. Numerical examples show the analysis is feasible and the precision is improved greatly compared with the elementary beam theory. Finally, the effect of shear lag and shear deformation to the vibration of box girder is discussed. It is found that the natural frequencies of simply supported box girder decreases when the effects of shear lag or shear deformation is taken into account, especially in the high order frequencies＇calculation, and the decrease is closely related to the width span ratio of the box gird.
出处
《郑州大学学报（工学版）》
CAS
2007年第1期51-55,共5页
Journal of Zhengzhou University（Engineering Science）
基金
国家自然科学基金资助项目(10072041)
关键词
剪力滞后
剪切变形
简支箱梁
固有振动
变分原理
shear lag
shear deformation
simply supported box gird
natural frequencies
variational principle
