考虑材料非线性的RC冷却塔风致动力破坏研究  

STUDY ON FAILURE OF RC COOLING TOWER UNDER FLUCTUATING WIND LOADing CONSIDERING THE MATERIAL NONLINEARITY

作　　者：张军锋[1] 徐世瑶 裴昊 刘庆帅 ZHANG Jun-feng;XU Shi-yao;PEI Hao;LIU Qing-shuai(School of Civil Engineering,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]郑州大学土木工程学院,郑州450001

出　　处：《工程力学》2023年第10期81-88,140,共9页Engineering Mechanics

基　　金：国家自然科学基金项目(51508523);桥梁结构抗风技术交通行业重点实验室开放课题项目(KLWRTBMC21-03)。

摘　　要：为明确RC冷却塔的风致动力破坏过程和极限脉动风荷载,采用ABAQUS对一代表性结构进行了计算。以分层壳单元模拟塔筒,分别采用塑性损伤模型和双折线模型模拟混凝土和钢筋的非线性本构,在对该塔规范静风极限承载力计算以及与既有弥散开裂模型结果对比的基础上,进行了试验脉动风荷载下的动力增量分析(IDA),结合变形模式、位移IDA曲线、裂缝分布、应力发展、塑性和刚度演化等方面对塔筒的破坏过程进行了系统阐述,并与静风破坏过程进行了对比。结果表明:静风荷载下,塑性损伤模型所得结构开裂荷载与弥散开裂模型结果一致,但前者所得结构极限荷载略高,结构延性更好;静力和动力风荷载作用下的结果差异来自本构模型、荷载模式和动力效应;脉动风荷载作用下RC冷却塔的结构破坏依然源于迎风子午向受拉导致的塔筒开裂和钢筋屈服,但应更关注塔筒大范围开裂导致的结构刚度下降:动力风荷载作用下塔筒破坏(V_(0)=57 m/s)时混凝土受拉开裂单元比例为63.13%,明显高于静风作用下的结果。To investigate the ultimate wind load and wind-induced failure process of cooling towers under fluctuating wind loading,a representative hyperbolic cooling tower was taken as an example and calculated in ABAQUS.The tower shell was modelled by a layered shell element,and the damaged plasticity model and a bilinear model were employed to represent the nonlinear behavior of concrete and reinforcement respectively.Based on ultimate static wind load analysis and on the comparison between the existed results attained from a smeared crack model,the incremental dynamic analysis(IDA)was conducted using the fluctuating wind load obtained from wind tunnel experiment.The failure process was illustrated from the deformation modes,from the displacement curves in IDA,from the crack distributions,from the stresses developments and,from the evolution of material plasticity and of structural stiffness.It was shown that the failure process and mechanism are identical for the damaged plasticity model and smeared crack model,but the former gave a little higher ultimate wind load and a much higher ductility.The difference between the results attained from static and dynamic calculations lies in the constitutive models,load distribution and dynamic effects.The failure of the structure under fluctuating wind load is also due to the concrete cracking and reinforcement yielding in the windward tower,where the meridian tension is predominant.However,63.13%elements of the shell have cracked when the tower fails under the fluctuating wind load(V_(0)=57 m/s),this ratio is much higher than that under the static wind load.Thusly,future attentions should be paid on the stiffness deterioration due to the large-scale cracking in the shell under fluctuating wind loading.

关 键 词：RC冷却塔 脉动风荷载 破坏过程 极限承载能力 材料非线性 塑性损伤模型 IDA分析 

分 类 号：TU332[建筑科学—结构工程] TU375