300MW火电厂空冷系统排汽管道抗震分析

Seismic analysis of exhaust pipe of air-cooled system in 300 MW thermal power plant

基于Ansys有限元软件,建立了300MW空冷系统排气管道的有限元模型。通过模态分析,计算了排气管道的动态特性,得到了排气管道的固有频率、振型,表明主要影响地震响应的振型是平动振型,而扭转振型影响较小。应用反应谱法计算了排气管道的地震响应,并用SRSS法对地震荷载组合后再与重力荷载进行组合。计算结果表明,在地震荷载和重力荷载作用下,排气管道整体应力水平很低,其强度满足规范要求。

Based on ANSYS software,the finite element model of exhaust pipe of 300 MW air-cooled power plant was set up,the structural dynamic characteristics of the pipe were analyzed by modal method.The natural frequencies and vibration modes of the pipe were obtained and it is shown that horizontals sway mode shape influences structural dynamic response dominantly and the effect of the torsional mode shape is not obvious.The earthquake response of the pipe was calculated by response spectrum method,and the seismic responses of different mode shaps loads were combined by SRSS method and after that it was combined with gravity load again.The results show that the overall stress level of the exhaust pipe under seismic and gravity loads are very low and its strength may satisfy demand of corresponding specification.