摘要
作为一种新颖的风敏感结构,直筒-锥段型钢结构冷却塔曲面形状和动力特性复杂、结构柔性和风致效应明显增大,整体稳定性能是其结构设计的瓶颈之一,尤其是结构几何、材料非线性及其高阶振型的影响。本文采用CFD技术数值模拟获得钢结构冷却塔表面风荷载分布模式,基于ANSYS软件建立主筒+加强桁架+附属桁架(铰接)耦合的一体化钢结构冷却塔有限元模型,以不同特征值屈曲模态作为初始几何缺陷分布形式,并基于几何及材料双重非线性有限元方法,系统研究了此类钢结构冷却塔在不同风速下低阶和高阶模态的稳定性能,涉及分歧失稳形态、极值失稳形态、临界失稳风速和静风响应。研究表明:考虑几何及材料双重非线性下钢结构冷却塔临界屈曲承载力下降;基阶屈曲波形相对较小,对几何初始缺陷不敏感;随着风速的增大,附属桁架最先发生失稳屈曲,然后依次为加强桁架和主筒。几何初始缺陷系数及阶数的改变对失稳临界风速影响较小,但随着阶数的增加,非线性分析过程中的变形趋势由附属桁架逐渐转移到主筒。所得主要结论可为此类新型钢结构冷却塔的抗风稳定性验算提供参考。
As a novel wind - sensitive structure,the shape and dynamic characteristics of the cylindrical - cone steel structure cooling tower is complex,the structural flexibility and the wind-induced effect are significantly increased. Its overall stability is one of the key problems in structural analysis and design,especially the influence of structure geometry,material nonlinearity and high order mode. Firstly,CFD numerical simulation was used to obtain the wind load distribution model. Then,we established a finite element model of the integrated steel structure cooling tower with the main cylinder + stiffening truss + accessory truss(hinged).The buckling modes with different eigenvalues are used as the initial geometric defect distribution. As well as,based on the finite element method of geometric and material dual nonlinearities,we systematically researched the stability of the steel structure cooling tower under different wind speeds,which involves divergent instability,extreme instability,critical wind speed and static wind response. The results show that the critical buckling bearing capacity of steel structure cooling towers is reduced by considering the geometric and material dual nonlinearities. The fundamental buckling waveform is relatively small and is not sensitive to the initial geometric imperfections. With the increase of wind speed,the order of buckling occurs as auxiliary truss,reinforced truss and the main cylinder. The influence of geometric imperfection coefficient and the order number on buckling critical wind speed is small,but with the increase of order,nonlinear analysis in the process of deformation trend by affiliated truss gradually transferred to the main cylinder. The main conclusions can be used as a reference for the verification of wind stability of such new steel structure cooling towers.
作者
柯世堂
朱容宽
王浩
KE Shitang;ZHU Rongkuan;WANG Hao(College of Civil Aviation,Nanjing University of Aeronautics&Astronautics,Nanjing,211106,China)
出处
《南京航空航天大学学报》
EI
CAS
CSCD
北大核心
2019年第5期719-727,共9页
Journal of Nanjing University of Aeronautics & Astronautics
基金
国家自然科学基金（U1733129,51878351）资助项目
江苏省优秀青年基金（BK20160083）资助项目
博士后科学基金（2013M530255,1202006B）资助项目
江苏省六大人才高峰计划（JZ-026）
江苏高校“青蓝工程”联合资助项目
关键词
直筒-锥段型
钢结构冷却塔
数值模拟
材料非线性
几何非线性
风致稳定性
cylindrical-cone
steel structure cooling tower
numerical simulation
material nonlinearity
geometrical nonlinearity
wind-induced stability
