基于ANSYS的某铁路桁架桥的力学特性研究

Research on the Mechanical Properties of a Railway Truss Bridge Based on ANSYS

为了研究桁架桥的力学特性和其受力特点,以某在建的铁路桁架桥为工程背景,通过大型有限元软件ANSYS建立桁架桥的实体模型,全桥杆单元均采用BEAM188单元模拟,桥面板采用SHELL181单元模拟,通过对桥模型施加静力荷载生成桁架桥的位移云图和轴力图,得出了桁架桥的静力特性;通过对模型进行模态分析,生成了桁架桥的前6阶自振频率和振型图,了解了桁架桥的动力特性.研究表明:桁架桥支座处的四根竖杆和斜杆容易产生疲劳破坏,中间部分位移最大,为危险部位,并且其抗扭刚度较大,上部结构对桁架桥横向刚度影响更为显著.这些结果以后可以为桁架桥的设计、检测、维护提供参考.

In order to study mechanical properties of truss bridge and its mechanical characteristics in this paper,based on ANSYS,a constructing railway truss bridge is used as the engineering background to build a entity model of the truss bridge,The whole bridge rod unit adopts BEAM188 element and SHELL181 element is used to simulate the bridge deck. The static characteristics of truss bridge are obtained by applying the static load on bridge model. By modal analysis,natural frequencies and mode shapes are obtained to help understand the dynamic characteristics of truss bridges. Research result shows that 4 vertical bars and rods in are prone to fatigue failure,especially the middle part is the most dangerous zone. These results can provide some references for the design,testing and maintenance of the truss bridge.