Explosively Formed Penetrators Inflight Heating Compared to Hemispherical Copper Shaped Charge Jet

Performance of shaped charges jet and explosive formed penetrators (EFP) can be tailored based on initial liner design and geometry. In addition, the jet temperature gradients during liner collapse and jet stretching mechanisms are different in both cases; the EFP and the traditional jet due to the different strain rates caused by the velocity gradient. In the current research work, oxygen free high conductivity copper (OFHC) was employed with two different liner geoemtries including hemispherical and dish-shaped liners of 2 mm thickness and 33 mm charge diameter. Autodyn numerical modeling was employed to study the impact of liner geometry on the characteristics of produced jet. Moreover, the jet heating mechanisms have been investigated numerically; the ratio between the collapse heating temperature to the plastic deformation temperature was found to be 1.61 and 0.43 for the dish-shaped and hemispherical jet respectively. This finding means that the jet heating due to stretching is not predominant one in both EFP and jet as it has already been confirmed in the papers published so far. Furthermore, EFP and jet penetration performances were assessed by the static firing against 4340 steel targets; while dish-shaped demonstrated shallow but enhanced wide crater at large standoff distance (D), i.e. 30D. Hemispherical jet has achieved large penetration depth with small crater diameter at small standoff distance, i.e. 4D.