挡墙后爆炸冲击波绕流现象研究

重要建筑通常采用防爆挡墙以防范恐怖主义袭击和意外爆炸。在爆炸冲击下,绕流作用使挡墙墙后的冲击波流场产生变化,导致墙后一定距离处的超压大幅提高,建筑承受比预期更大的荷载。本文用LS-DYNA对近地爆炸下刚性墙后的绕流现象进行了数值模拟,研究了超压时程规律及影响因素。研究发现,距离墙后1.5～2.5倍墙高区域内绕流超压较大,在2倍墙高处出现马赫反应,比无墙时更为危险。研究成果可为重要建筑物防爆挡墙的布置及挡墙后建筑抗爆分析提供参考。

Research on diffraction flow effect of explosion shock wave behind blast wall

Blast walls are widely used to prevent important architecture from terrorist attacks and accidental explosion. Diffraction flow effect makes the explosive shock flow field change and overpressure at a certain distance behind the wall is greatly increased. LS-DYNA was employed to study the diffraction flow and overpressure time-history behind blast walls in the case of an explosion near above ground. It is observed that the diffraction flow overpressure behind a wall about 1. 5 ~ 2. 5 times wall height is large,and it is more dangerous than there is no wall owing to Mach reaction happened around double wall height behind the wall. The research provides a reference for arrangement of blast walls and blast-resistant design of buildings behind the blast wall.