长持时爆炸冲击波产生方法

不同持时的爆炸冲击波对建筑结构及防护工程的作用显著不同，在试验或数值模拟中常需要得到长持时爆炸冲击波，延长爆炸冲击波正压作用时间是研究长持时爆炸荷载下结构响应的难点。在AUTODYN中建立长筒爆室小当量炸药多点延时起爆模型，分析爆炸冲击波在长筒爆室中的传播规律，研究管道长度、延时起爆时差、起爆顺序对冲击波波形的影响。结果表明：距离增加，超压峰值减小、正压持续时间增加；根据炸药量和爆室长度合理地选择起爆时差可以获得波形丰满且连续衰减的超压时程曲线；爆室底部起爆、合理控制延时间隔，可以形成类似于大当量远距离爆炸下产生的连续衰减的长持时冲击波。分别给出100、200 ms爆炸持时起爆方案，为长持时爆炸模拟装置的设计提供技术支持。

Method for production of long duration blast wave

The effect of blast wave with different duration on building structure and protection engineering are obviously different, long duration blast wave is generally essential in experimental studies and numerical simulations. However, it is difficult to prolong the duration of the positive pressure in the practice experiment of studying the structural responses under long duration blast load. A multi-point delayed detonation model with multiple small charge TNT explosives in a long tube explosion chamber is established by computational fluid dynamics software AUTODYN. The propagation law of blast wave in the long tube is analyzed. On this basis, the influences of length of explosion chamber, the delay detonation time and the initiation sequence on the blast wave form are further investigated. The results show that, as the distance increases, the peak value of overpressure decreases and the duration of positive pressure increases. The overpressure time-history curve with full and continuous attenuation of the wave form can be obtained by selecting the delay detonation time rationally according to the amount of explosive and the length of the explosion chamber. Detonating from the bottom of the explosion chamber and controlling the delay detonation time interval reasonably can form a long-duration blast wave which is equivalent with the continuous attenuation produced by a large equivalent charge long distance explosion. The parameters such as the length of explosion chamber, amount of explosive and delay detonation time are adjusted repeatedly, and the detonation schemes of 100 ms explosion duration and 200 ms explosion duration are provided, providing technical support for design of long duration explosion simulation device.