【作者】 张浩；

【导师】 田力；

【作者基本信息】 天津大学 ， 土木工程， 2018， 硕士

【摘要】 近年来,世界各地恐怖袭击事件、局部战争和爆炸事故频发,以往暴恐袭击目标主要针对军事及政府建筑,近年来逐渐向普通民用建筑发展。钢结构在普通民用建筑中应用日益广泛,钢柱作为钢结构的主要承重构件,其抗爆能力直接关系着整个结构的抗爆水平。因此研究钢柱的抗爆能力具有重要的现实意义。本文运用ANSYS/LS-DYNA软件模拟了H型钢柱在近距爆炸冲击波和预制破片联合作用下的损伤破坏。主要研究工作和成果如下:(1)建立了由炸药、破片、空气、钢柱和刚性地面5部分组成的数值模型,通过对装药驱动金属平板、爆炸冲击波对钢板作用、联合载荷对钢板作用进行数值模拟,将其结果与理论公式和试验数据进行对比分析,验证了耦合算法、接触类型和本构模型的合理性。(2)对比分析了H型钢柱在不同载荷作用下动力响应的差别。研究表明:冲击波和破片群的破坏机理不同,冲击波主要引起钢柱的挠曲变形,而破片群主要为局部侵彻破坏。联合载荷作用比二者单独作用时线性叠加的破坏效果还要严重,说明破坏作用具有叠加增强效应。在近爆联合载荷作用下,钢柱首先受到冲击波的作用,而后受到破片群的冲击作用。(3)研究了近距爆炸冲击波和破片联合作用下各参数对H型钢柱动力响应的影响。研究表明:抗爆设计时,应合理选择钢材强度等级,而不应盲目选择高强度钢材;通过改变柱高来改变长细比对钢柱破坏影响不大;在相同用钢量下,圆管型截面钢柱的抗爆能力最好,H型截面次之,箱形截面最差;为提高钢柱抗爆能力,应尽量选择翼缘宽度与腹板高度比值小于等于1的截面类型,较厚的腹板厚度、较小的高厚比和较小的宽厚比都有利于提高钢柱的抗爆能力。(4)研究了近距爆炸冲击波和破片联合作用下荷载参数因素对H型钢柱抗爆性能的影响。研究表明:在钢柱抗爆设计时应将炸药量作为主要考虑因素;比例距离公式中随着距离因素R的增加,对钢柱的破坏作用呈现趋同的效果;随着炸药量的增加,其破坏作用并不是简单的线性增长,破坏效果具有加速增大趋势;炸药高度对钢柱抗爆性能的影响差异化明显;在钢柱抗爆设计时,对钢柱施加的轴向压力应有所限制,轴压比不宜大于0.4;外粘CFRP材料对H型钢柱能起到良好的防护效果。更多还原

【Abstract】 In recent years,terrorist attacks,local wars and explosions have frequently happend in various parts of the world.The targets of terrorist attacks were military and government buildings in the past,but the targets are gradually changed to the ordinary civil buildings in recent years.As the steel structure is widely used in the civil construction,steel column was rearged as the main bearing structure and it’s anti-explosive ability is directly related to the entire structure’s anti-explosive level.Therefore,it is of great practical significance to study the anti-blast ability of steel column.In this paper,ANSYS/LS-DYNA software is used to simulate the damage of H-section steel column under blast waves and prefabricated fragments.The main work and results are as follows:(1)A numerical model consisting of explosives,fragments,air,steel column and rigid floor was built.Through numerical simulation,such as explosion-driven metal plate,explosive shock wave effect on steel plate and combined load on steel plate,some comparative analysis were carried out between the theoretical formula and experimental data.The rationality of coupling algorithm,contact type and constitutive model were verified.(2)The dynamic response of H-section steel column under different loads were analyzed.The reaults show that the destruction mechanisms of shock wave and fragments are different.The shock wave mainly causes the deflection of the steel column,while the fragmens mainly causes local erosion.The combined load is bigger than the linear superposition of single load effect,the destruction effect has a superposition enhancement effect.The steel column was first subjected to the shock wave effect and then to the impact of the fragments in the close-range explosion.(3)The dynamic response of H-section steel column under the combined effect of shock wave and fragments was studied by parameter method.The reaults show it should be reasonable to choose steel strength in the antiknock design,and the high-strength steel should not been blindly choosen;under the same amount of steel,tubular cross-section steel column has the best anti-blast ability,H-section is the second,and the box section is the worst;In order to improve the anti-explosive ability of steel column,the section type should to designed to make the width of flanges lessthan the hegiht of web;Thicker web thickness,smaller width-to-thickness ratio of flanges and smaller height-to-thickness ratio of web are beneficial to improve the anti-blast ability of steel column.(4)The effect of load parameters on the anti-blast performance of H-section steel column under the combined loads were studied.The results show that the explosions should be considered as the major factor in the anti-explosive design of steel column;In the scale distance formula,with the increase of the distance factor R,the effect of the failure of the steel column showing convergence effect;With the increase of the quantity of explosions,its destructive effect is not a simple linear superposition,the destruction effect has the superposition enhancement effect;The effect of the height of the explosive on the anti-blast performance of the steel column is different;In the anti-blast design of steel column,it should control the value of the axial pressure,and the axial compression ratio should not bigger than 0.4;The CFRP material which stick to the H-section steel column has a good protective effect.更多还原