文档介绍：
移动均布荷载作用下简支梁桥动力系数分
析#
邓建良,吴定俊,李奇**
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(同济大学桥梁系,上海,200092)
摘要:将磁悬浮列车荷载简化为移动均布荷载,运用模态叠加法求解得到了简支轨道梁的动
力响应解析解,并与相应的数值解和列车—桥梁耦合振动解作了比较,指出移动均布荷载模
型可以反映轨道梁振动的主要特征和振动规律。从理论上揭示出决定动力系数大小的关键无
量纲参数,并分析了动力系数随各参数的变化规律。最后,提出了可供设计参考的轨道梁设
计频率限值和动力放大系数之间关系的图表和数学表达式。
关键词:桥梁工程;简支梁桥;动力系数;移动均布荷载;模态叠加;频率限值
中图分类号:
Impact Factor Analysis of Simply-Supported Girder Bridges
Traversed by Uniformly-Distributed Moving Loads
Deng Jianliang, Wu Dingjun, Li Qi
(Department of Bridge Engineering, Tongji University, Shanghai 200092)
Abstract: The dynamic responses of a simply supported girder bridge under the action of a maglev
train is investigated in this paper. The maglev train is assumed to be a uniformly distributed
moving line load, then a closed-form solution for the response of the bridge is achieved by an
analytical approach. Comparison of analytic with finite element solutions is conducted, and the
results shows that the behavior of the beam can be very well represented using the moving load
model. The primary parameters that govern the impact factor of the beam are then identified
analytically on the basis of the modal superposition method. The dynamic behavior of the beam,
especially the characteristics of the impact factor, is studied in detail. A design method is finally
proposed to ensure the actual impact factor not exceeding its prescribed allowance value, based on
the discussion on the relationship between the impact factor and a nondimensional parameter.
Key words: bridge engineering; simply-supported girder bridge; impact factor; moving loads;
modal superposition; frequency limit
0 引言
磁悬浮铁路作为一种面向未来的地面交通系统,自 20 世纪 70 年代以来得到了较快的发
展
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护成本小、能耗与排放少等突出的优点。磁悬浮系统通常可以分为两个子系统,即磁悬浮列
车子系统和轨道梁子系统,这两个子系统通过控制系统耦连在一起。在过去的几十年中,对
于磁悬浮铁路的研究[3-8]主要侧重于磁悬浮列车的动力性能(如运行稳定性、乘坐舒适度等),
而对于轨道梁的动力响应特性的研究则相对较少,尤其是针对轨道梁动力放大系数的研究,
往往局限在有量纲影响参数分析的范围内,所得结论通用性意义不强。
本文将磁悬浮列车荷载简化为移动均布荷载,运用模态叠加法求解得到了简支轨道梁的
动力响应解析解,从理论上分析了影响动力系数大小的主要无量纲参数以及