TNT爆炸的数值计算及其影响因素

Numerical Calculation and Influence Parameters for TNT Explosion

应用LS-DYNA有限元程序建立了模拟TNT爆炸的数值计算模型并进行了空爆冲击波超压等数值计算。通过数值计算结果与经验公式和试验数据的对比分析,验证了计算模型和参数取值的可信性。基于数值计算结果,分析了炸药材料参数、TNT药量、单元网格密度、建模方式、空气域形状和炸药形状等参数变化对爆炸冲击波超压的影响。结果表明,与试验结果相比,数值计算结果可以作为爆炸冲击波超压的下限值,而Henrych公式、Sadovskyi公式和GB6722-2003公式给出的是超压的中位和下位值;炸药材料参数的取值、单元网格密度和炸药形状对数值模拟结果的影响与比例距离相关,比例距离小于2.0时,不能忽视其影响;冲击波超压会随TNT药量的增加而小幅度增加,但建模方式和空气域形状对数值计算结果的影响可以忽略不计。

A numerical calculation model for simulating the TNT explosion was established by using LS-DYNA finite element program and the numerical calculation of explosive shock waves for air explosion was carried out. Through comparative analysis of the numerical results with empirical formula and experimental data,the credibility of the calculation model and parameter selection was verified.Based on the numerical calculation results,the effects of change in material parameters of explosive,TNT dosage,unit mesh density,modeling ways,air domain shapes and shapes of explosive etc.on the explosive shock wave overpressure were analyzed.The results show that compared with the experimental results,the numerical calculation results can be used as the lower limit of the explosive shock waves overpressure,whereas the overpressures from Henrych formula,Sadovskyi formula and formula in GB6722-2003 are the median and lower value.The effects of parameter selection of materials,unit mesh density and explosive shapes on the numerical simulation results are related to the scaled distance,and the effects can not be ignored when the scaled distance is less than 2.0 .The shock wave overpressure slightly increases with the increase of the TNT dosage.But the influences of modeling ways and air domain shapes on the calculated results can be neglected.