基于模态分析法的钢组合结构支座选取分析

Selection analysis of steel composite structure support based on modal analysis method

为研究不同支座类型对结构振型和自振周期的影响,利用有限元分析软件SAP2000对西安某体育馆进行建模,研究刚性铰接支座与弹性支座两种支座类型下大悬臂桁架与网架组合结构的模态特性。结果表明:固定铰支座模型与弹性支座模型两者的自振频率相差较大,相较于弹性支座模型,固定铰支座模型第一阶自振频率由1.58741降低到1.1258,减小了41.0%,频率波动较大;弹性支座模型模态振型整体刚度分布均匀,属于整体振动,结构的第一振型以Z方向的竖向振动为主,振型-频率曲线更为平缓,更适用于大悬臂桁架与网架组合结构。

In order to study the influence of different bearing types on the vibration mode and self-oscillation period of the structure,a stadium in Xi’an is modeled by using the finite element analysis software SAP2000,and the modal characteristics of the large cantilever truss and mesh frame combined structure with rigid articulated bearing and elastic bearing are investigated under the two types of bearings.The results show that:the difference between the self-oscillation frequency of the fixed-hinge bearing model and the elastic bearing model is large,compared with the elastic bearing model,the first-order self-oscillation frequency of the fixed-hinge bearing model is reduced from 1.58741 to 1.1258,which is 41.0%,and the frequency fluctuates a lot;the modal vibration pattern of the elastic bearing model has uniform distribution of the overall stiffness,which is an integral vibration,and the first vibration pattern of the structure is dominated by the vertical vibration in the Z direction,and the vibration pattern-frequency curve is dominated by the vibration pattern-frequency curve.The first vibration mode of the structure is dominated by vertical vibration in Z-direction,and the vibration mode-frequency curve is more gentle,which is more suitable for the combination structure of large cantilever truss and net frame.