Numerical simulation on shock waves generated by explosive mixture gas from large nuclear blast load generator based on equivalent-energy principles

Based on the nonlinear explicit dynamic finite element program LS-DYNA and the multi-material Euler algorithm, the shock wave propagations were numerically simulated for the two explosion resources of the TNT dynamite and the acetylene-air gaseous mixture in free air field, respectively. The overpressures of the shock waves and the propagation principles were compared between the two blast-loading methods. Based on the equivalent-explosion energy, a formula for calculating the nominal scale distance of gas explosion was obtained in terms of overpressure. The results show that the Euler method can be used to calculate the propagation process of two kinds of explosion sources and the numerical results agree well with the ones based on the empirical equations. With the increasing of the propagation distances, the overpressures decrease sharply and the overpressure relative error between the two load methods decreases gradually. When the shock wave overpressure was lower than 0.5 MPa, the acetylene-air gaseous mixture can replace the chemical dynamite for generating blast shock waves by the large nuclear blast load generator.