Assessment of pressure waves generated by explosive loading

In the present study the estimation of the blast wave by two types of finite element methods is investigated: Eulerian multi-material modeling and pure Lagrangian. The main goal is to compare and study their ability to predict the clearing effect during blast. Element shape and improvements on the codes are also considered. For the Lagrangian finite element models the load is applied by using an empirical method, deriving from databases, for the time-spatial distribution of the pressure profiles. In the ideal case of the above method the blast load is applied as an equivalent triangular pulse to represent the decay of the incident and reflected pressure. The implementation of this method in LS-DYNA is improved and takes a more realistic approach, assuming an exponential decay of the pressure with time. In the case of the Eulerian models the influence of the shape of elements and its influence on the incident and reflected pressure in three types of simulations, using rectangular, cylindrical and spherical grid of air, were investigated. An analytical method to predict impulse is used to compare with the numerical and experimental results. The Eulerian models provide results closer to the experimental. Specifically, the cylindrical grid of air gives better results in comparison with the other methods.