筒壳网架在瞬时强风作用下的风振响应分析

Wind-Induced Vibration Response Analysis of Cylindrical Shell Grid Structure under Instantaneous Strong Wind Excitation

2017年8月华北地区某电厂大跨双筒壳干煤棚网架在瞬时强风作用下,结构局部发生倒塌现象。以该工程案例作为研究对象,运用网架结构设计软件STADS,借助Matlab和Fluent平台,对该网架倒塌部位在瞬时强风作用下的风振响应进行了模拟分析。首先基于Matlab平台采用谐波叠加法生成了多点输入的非平稳风速谱,然后运用STADS的转换程序生成Fluent精确的风工程计算模型,其次通过UDF定义将生成的多点输入非平稳脉动来流风引入流场,运用大涡模拟(LES)进行了瞬时强风的瞬态计算,获得了结构表面的风压时程进而转换成节点压力时程,最后返回STADS采用Newmark法进行时程分析,计算得到各点位移时程,进而获得了垮塌部位的位移风振系数。通过STADS转换程序提高了筒壳网架结构瞬态风场模拟效率,深化了非平稳风场下结构风振响应的认识,供此类大跨网架结构抗风设计参考。

In August 2017,a long-span double cylindrical shell dry coal shed grid of a power plant in North China was subjected to local collapse of the structure under the action of transient strong winds.Taking this engineering case as the research object,the wind vibration response of the collapsed part of the grid structure under the action of transient strong winds was simulated and analyzed using the STADS with the help of Matlab and Fluent platforms.Firstly,based on Matlab platform,the multi-point input non-stationary wind speed spectrum is generated using the harmonic superposition method,and then the accurate Fluent wind engineering calculation model is generated using the conversion procedure of STADS.Secondly,the generated multi-point input non-stationary pulsation wind is introduced into the flow field by UDF definition,and the transient calculation of the instantaneous strong wind is carried out using Large Eddy Simulation(LES)to obtain the wind pressure time series at the surface of the structure and then converted into the nodal pressure time series.Finally,the time course analysis was carried out by returning to STADS using the Newmark method to calculate the displacement time series at each point and then obtain the displacement wind vibration coefficient at the collapse site.The STADS conversion procedure improves the efficiency of the transient wind field simulation of cylindrical shell grid structure and deepens the understanding of the wind vibration response of the structure under non-stationary wind field.It is used as a reference for the wind resistance design of such large-span grid structures.