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The Effect of the Liner Metallurgical State on the shaped charge jet break‐up time
Author(s) -
Hirsch Eitan
Publication year - 1990
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19900150409
Subject(s) - shaped charge , jet (fluid) , mechanics , elongation , break up , materials science , instability , shear (geology) , deformation (meteorology) , explosive material , flow (mathematics) , plasticity , ultimate tensile strength , composite material , physics , chemistry , organic chemistry
The effect of the liner metallurgical state on the shaped charge jet break‐up time has been widely investigated experimentaly but the experimental results were never explained by a model sufficiently detailed to even explaining them qualitatively. The model presented here shows for the first time a direct mathematical connection between the V pl break‐up parameter and the processes which affect the liner metallurgical state during the initial stages of the flow: the drive of the liner by the explosive and the jet formation. The model shows how both the deformation energy heating the sliding shear bands during the localization process and the rate of the instability growing in the plastic flow during this process, combine to determine the V pl parameter. This parameter is then shown to be both the velocity of the information of the plastic deformation and the component of the maximum slide velocity allowable to shear band in the elongation direction. The model predicts the shaped charge jet segment normalised length over diameter (L/D) distribution with good accuracy. It also explains the pattern of shear bands observed on the surface of jet segments recovered by Zernow, including their width. Furthermore, the model is strongly supported by its ability to show good agreement between measurements of aluminum dynamical elongation obtained in different ways, which were so far believed to be unrelated. When the jet temperature measurements by Von Holle and Trimble are reinterpreted in view of the model it is found that the average jet temperature is lower than the value they found and the temperature basically agrees with Racah's predictions.