受火钢拱结构的冲击响应与弯扭屈曲  

Impact response and flexural torsional buckling of steel arch structure in fire

作　　者：王欢 胡亚超 谭英华 席丰[1] WANG Huan;HU Yachao;TAN Yinghua;XI Feng(Civil Engineering School,Shandong Jianzhu University,Jinan 250101,China)

机构地区：[1]山东建筑大学土木工程学院,济南250101

出　　处：《计算机辅助工程》2020年第4期42-49,72,共9页Computer Aided Engineering

基　　金：国家自然科学基金(11672165);2018年山东建筑大学博士科研基金(X18076Z0101)。

摘　　要：为研究火灾中受质量块撞击两端固支钢拱结构的动力响应和弯扭屈曲行为,利用有限元软件Abaqus对其进行数值仿真,考虑钢材力学性能的升温退化和应变率强化效应,得到临界温度范围内钢拱发生弯扭屈曲时质量块的临界速度,以及撞击荷载作用下钢拱结构的竖向挠度、撞击力变化曲线和响应过程,并对质量块的质量-速度关系和拱脚处约束条件进行参数分析。研究结果表明,在不同温度范围内,使钢拱发生弯扭屈曲的质量块临界速度的影响因素不同:20℃≤T≤100℃时,静载荷比η起主要作用;100℃<T≤400℃时,静载荷比η和温度T共同起作用;400℃<T≤700℃时,温度T起主要作用。随着钢拱温度的升高,跨中挠度大幅增加,撞击力作用时间增长。大质量、低速撞击更易引发结构平面外弯扭屈曲。与平面外约束相比,平面内约束可以有效提高结构抗撞击性能。To study the dynamic response and flexural-torsional buckling behavior of the steel arch structure in fire with fixed supports at both ends under the impact of mass block,the numerical simulation is carried out using finite element software Abaqus.The effect of temperature degradation and strain rate strengthening on mechanical properties of steel is considered,and then the critical velocity of the mass block is obtained while the steel arch is subjected to bending and torsion buckling within the critical temperature range,and the vertical deflection,impact force curve and response process of steel arch structure under impact load are computed.The mass-velocity relationship of the mass block and the constraint conditions at the arch foot are analyzed.The results show that,while the steel arch is subjected to flexural-torsional buckling in different temperature ranges,the influence factors on the critical velocity of mass block are as follows:while 20℃≤T≤100℃,the static load ratioηplays the major role;while 100℃<T≤400℃,the static load ratioηand temperature T work together;while 400℃<T≤700℃,temperature T plays the major role.As the temperature of steel arch increases,the deflection at the middle span increases greatly,and the impact force action time increases.Large mass and low speed impact are more likely to cause out-of-plane flexural-torsional buckling of structures.Compared with out-of-plane constraints,in-plane constraints can effectively enhance the impact resistance of structures.

关 键 词：温度 撞击 钢拱 动力响应 弯扭屈曲 

分 类 号：TU328[建筑科学—结构工程] TP391.92[自动化与计算机技术—计算机应用技术]