Study on the Modified Shock Wave Overpressure Peak Expression of Large Equivalent TNT Airburst

Nuclear explosion has high lethality, besides the nuclear effect to lives, the effect of the shock wave overpressure to environment is also drastic. Existing shock wave overpressure peak formulations are mainly obtained by data fitting to the results of small equivalent TNT airburst experiments, which are unsuitable to the nuclear explosion conditions. To study the overpressure transmission process of nuclear explosion, the nuclear bomb is treated as a spherical large equivalent TNT. A finite element model including the spherical TNT and air domain is built by Hypermesh and the explosion process is calculated by LS-DYNA. Based on the convergence analysis, a modified formulation of overpressure peak for spherical large equivalent TNT explosion is proposed in this paper, which is fitted by the simulation result of 9 different explosion process. The accuracy of the modified expression is firstly verified by an airburst experiment of 7.5 kg TNT, the predicted value of the proposed overpressure peak is the proximate one to the measured value by the comparison with existing empirical formulations. Furthermore, different equivalent TNT airburst are calculated by the proposed expression, empirical formulations and LS-DYNA, respectively, the result comparison shows that for the shock wave overpressure peak prediction of both small and large equivalent TNT airburst conditions, the proposed expression has higher accuracy and applicability than existing empirical formulations.