近距离爆炸作用下工字形截面钢柱荷载分布与动态响应数值模拟研究  

Numerical investigations of blast load distribution and dynamic response of I-shaped steel columns subjected to close-in explosions

作　　者：肖伟芳 陈思琦 赵宪忠[1] XIAO Weifang;CHEN Siqi;ZHAO Xianzhong(College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《建筑结构学报》2024年第1期12-26,共15页Journal of Building Structures

基　　金：国家自然科学基金项目(52278521);中央高校基本科研业务费专项(22120210415,22120220208,22120230230)。

摘　　要：作为钢结构中主要承重构件的钢柱,其在近距离爆炸作用下的荷载分布和动态响应,尤其是入射角对钢柱爆炸荷载和动态响应的影响规律等方面研究较为匮乏。为此,采用LS-DYNA有限元分析软件,研究近距离爆炸作用下工字形截面钢柱在不同入射角下的爆炸荷载分布和动态响应。结果表明:当冲击波加载于钢柱截面强轴时,翼缘板爆炸荷载受稀疏波效应影响显著,与无限大反射面的相比,其反射冲量下降10%~50%;近距离爆炸工况下稀疏波传播速度远大于现行抗爆设计规范中所假设的环境声速,表明环境声速假设在近距离爆炸工况下并不适用;在弱轴加载工况下,稀疏波效应并不明显,由于冲击波在截面内发生多次反射,延长了其正相持时,因而腹板上的峰值冲量反而高于无限大反射面条件下的峰值冲量;当入射角小于同时通过迎爆侧翼缘板边缘点与工字形截面形心的入射角时,冲击波的主要作用区域为两翼缘板与腹板所围内凹区域,其爆炸荷载和腹板局部变形在入射角为30°时达到最大值,两个半翼缘板呈向外张开态势,且张开幅度随入射角的增大而减小;而当入射角大于同时通过迎爆侧翼缘板边缘点与工字形截面形心的入射角时,冲击波则主要作用于迎爆侧翼缘板,其爆炸荷载和整体挠度在入射角为90°时达到最大值,两个半翼缘板向内闭合,且闭合幅度随入射角的增大而增大。Steel columns are the important load-carrying members in steel structures.However,there is still a lack of studies on the blast load distribution and dynamic response of steel columns subjected to close-in explosions,especially for the effect of angles of incidence on the blast load and dynamic response of steel columns.In this study,LS-DYNA software is used to investigate the blast load distribution and dynamic response of I-shaped steel columns subjected to close-in explosions under different angles of incidence.The following conclusions can be drawn when the strong axis of the column is loaded with shock wave,the clearing wave effect has a significant influence on the blast load distributed over the flange on the attack side.Compared with the case of an infinite reflecting surface,the reflected impulse on the flange is reduced by 10%-50%.The velocity of the clearing wave in close-in explosions is much higher than the ambient sound velocity assumed in the current blast-resistant design guidelines,which indicates that the ambient sound velocity assumption is not applicable to close-in explosions.When the shock wave impacts on the weak axis,the clearing effect is insignificant.Due to the multiple reflections of the shock wave in the region between the flanges and the web,the positive phase duration is enlarged.This gives a rise to a higher maximum impulse on the web than that in the case of an infinite reflecting surface.For α<α_0(α_(0) is the critical angle of incidence which goes through the end of the flange on the attack side to the center of the I-shaped cross section),the main action zone of the shock wave is the flange-web-flange region.The blast load and local deformation of the web achieve the maximum at 30°.The two half-flanges open outwards,and the opening amplitude decreases with the angle of incidence.For α>α_0,the shock wave is mainly loaded on the flange.Its blast load and global deflection reach the maximum at 90°.The two half-flanges close inwards,and the closing amplitude increases with t

关 键 词：工字形截面钢柱 近距离爆炸 爆炸荷载 数值模拟 变形模式 入射角 稀疏波效应 

分 类 号：TU392.1[建筑科学—结构工程] TU311.41