密闭空间内爆炸缩比相似模型研究

Scale similarity model of internal explosion in closed field

以相似理论为基础,对密闭空间内爆炸毁伤参数进行量纲分析,建立密闭空间内爆炸相似模型,用LSDYNA进行原模型装药递增直至结构破坏计算,并以结构产生裂纹的临界装药量进行缩比系数分别为0.8,0.6,0.4,0.2,0.1的缩比模型仿真计算。结果表明,结构尺寸不变而药量变化时壁面的冲击波服从相似规律;反射超压服从以受单、双及三面墙影响分开考虑的相似规律;冲量由于受结构破损影响不服从相似规律;缩比系数不小于0.1时缩比模型与原模型壁面的冲击波超压、比例脉冲宽度及比例冲量服从相似规律,缩比模型冲击波超压、比例脉冲宽度及比例冲量与原模型最大相对误差分别为3.3%、4.96%、5.1%;随缩比系数的减小,结构壁面的冲击波超压及冲量呈现出离散分布特性,相似程度有所降低。在研究的缩比系数范围内,可利用缩比模型试验结果预测原模型内爆炸毁伤效应。

The damage parameters of internal explosion in closed field were analyzed by using the dimension analysis principle, and the scale similarity model of internal explosion in closed field was established based on the similarity theory. The internal explosion according to the original model under seceessively incremental charging until structural damage and the scale model under critical charging of structural crack appearance with different scale coefficient values of 0.8, 0.6, 0.4, 0.2 and 0.1 respectively were simulated by using LS-DYNA code. The results show that, when the structure size maintains constant and the explosive quantity is changed, the arrival time of shock wave on the wall obeys similarity law; the shockwave overpressure also obeys similarity law when the wall is considered seperately and the effects of one wall, two walls and three walls were inspected respectively; however the impulse does not fit similarity law due to the influence of structural damage. The shockwave overpressure, scale pulse width T/Q ^-1/3 and scale impulse i/ Q^-1/3 on the wall in the scale model and original model obey similarity law when the scale coefficient is not less than 0.1, and the maximum relative errors of shockwave overpressure, scale pulse width and scale impulse between the scale model and original model are less than 3. 3% , 4. 96% and 5. 1% respectively. As the scale coefficient decreases, the shockwave overpressure, scale pulse width and scale impulse on the wall show a discrete distribution and the similarity degree decreases gradually. So if the scale coefficient is within the scope of this study, it is feasible to predict the damage effect by the original model of internal explosion by using the results of scale mode experiments.