Simulation of the Effects of an Air Blast Wave - ELSA - Europa

CON13The angle of this model is increased. The aspect ratio of the hexahedrons is 1.5, of the pyramid 7.5.The results for the elements near the tip show that the pressure value in the hexahedrons isrepresented better if the aspect ratio is smaller.CON14The pressures in the pyramid are decreasing with an aspect ratio of 3.75. The calculations do notshow better results.CON22, CON23, CON24These models use only cubic elements. Therefore, the element size near the explosive is similar tothe other models. The size of the elements increases with the distance to the explosive. Then, theonly parameter for this model is the opening of the cone (or the angle of the cone). The number ofelements is relatively small but the time step size depends on the smallest element.Case opening/ length Number of ChargeelementsCON22 0.1/4.0 386 12.8CON23 0.05/4.0 711 12.8CON24 0.02/4.0 1595 12.8Table 5: Calculations with a conical meshThe peak pressures show a big dependency on the element size. (see Figure 25). The influence ofthe element size on the impulse is much smaller (see Figure 26). Therefore, for further calculationsit has to be checked if the element size is small enough.36