汽车炸弹爆炸作用下的刚性防爆墙设计方法

Design Method of Rigid Blast Wall Under the Explosion of Vehicular Bomb

防爆墙可以阻挡袭击车辆的行进,在一定程度上削减爆炸冲击波的威力。然而现有研究大多集中于冲击波的传播和防爆墙对冲击波传播的影响方面,缺乏防爆墙主要设计参数分析。为此,本文采用有限元程序LS-DYNA设计防爆墙,通过建立几种不同网格尺寸的有限元模型,探讨有限元模型的收敛性,并经模型验证确定防爆墙模型的最终网格尺寸。最后,通过数值模拟得到了冲击波在防护建筑表面的超压分布,以进行防爆墙的设计。设计过程中首先确定了防爆墙的几何参数,然后重点讨论了安全距离对建筑物表面超压的影响,并最终确定防爆墙的设计参数。模拟结果表明:当超压小于2 kPa时,建筑外墙玻璃不会产生飞溅破片对人体造成伤害,因此将其作为设计准则。确定后的防爆墙高度取3 m,厚度取1 m,安全距离取35 m。按所提的防爆墙设计方法得到的设计参数可作为设计参考。

Blast wall can prevent vehicles from approaching the protective building and can reduce the destructive power of shock wave to a certain extent.However,majority of studies on blast walls have some shortcomings.The explosion test data are few.Most exsiting studies focus on the propagation of shock wave and the influence of blast wall on the propagation of shock wave.Discussion on the main parameters of blast wall design is meagre,such as the design of safety distance,the distance from the blast wall to the protective building,height and width of the blast wall.This paper uses the finite element programme LS-DYNA to design the blast wall.To analyze the convergence of the finite element model and to determine the mesh size of the model,this paper establishes several finite element models with different sizes of meshes to verify the model.Then,the overpressure distribution of the shock wave on the protective building is simulated to implement the blast wall design.The geometric parameters of the blast wall are preliminarily determined.And the influence of the safety distance on the overpressure of the building surface is mainly discussed,so as to determine the final design parameters.When the overpressure is less than 2 kPa,it is considered that there will be no damage to people caused by flying fragments.Eventually,the blast wall height is 3 m,the thickness is 1 m,and the safety distance is 35 m.The proposed method is used to demonstrate the design method,and the final design parameters of the blast wall can thus be used for reference.