TNT炸药爆炸场中三波点的数值模拟

准确预测三波点的位置和揭示三波点的规律,对工程防护和实现弹药的高效损伤有着重要作用。基于LS-DYNA有限元软件,利用数值模拟方法研究了TNT炸药在混凝土地面上形成爆炸冲击波的三波点运动轨迹,并初步揭示了炸高、药量和炸药形状等因素对三波点高度的影响。研究表明:在爆炸场中,爆炸冲击波以炸药为中心向四周传播,三波点轨迹的高度均呈现逐渐增高的变化趋势。不论改变炸药的药量还是炸高,三波点高度的增速在中场(4.0~7.0 m)都较缓,而进入远场(7.0 m)增速骤增。当炸药的炸高和药量相同,炸药形状不同时,圆柱状炸药在中场爆炸形成的三波点高度比长方体炸药略高,且高度增速都较缓;而在远场三波点的高度基本相等,且增速急剧上升,趋于定值。与炸药形状的影响相比,炸高和药量对TNT炸药爆炸冲击波的三波点高度的影响较大。

Numerical simulation of triple point in the explosion field of TNT explosive

Accurately predicting the position of triple point and revealing the propagation law of triple point plays an important role in engineering protection and achieving high efficiency damage of ammunition. Based on LS-DYNA software,numerical simulation method is used to study the burst trajectory of triple point of blast shock wave when detonating TNT explosive in the air above concrete ground. The influence of the explosion height, quantity of the explosive, and shape of the explosive on the heights of triple point is also discussed. The results show that the blast shock wave propagated around the center of the explosive in the explosion field, and the height of the triple points increased gradually. Regardless of changing the quantity of the explosive charge or the explosion height, the growth rate of the triple point is slow in the midfield(4.0~7.0 m) of blasting and the growth rate in the far field(>7.0 m) increased sharply. When detonating the same explosive charge and the same explosion heights of the explosive with the different shapes, the height of the triple points formed from detonating the cylindrical explosive in the midfield are slightly higher than that formed from cubic explosive; meanwhile the growth rate of it also is relatively slower. The height of triple point substantially in the far field is almost equal and the growth rate is rising sharply and reaches a certain value, however. Compared with the influence of explosive shape, the blasting height and the quantity of the explosive have more influence on the height of triple point of the blast wave formed from detonating TNT explosive.