Analysis of jet formation and penetration by conical shaped charge with the inhibitor

Abstract

This paper proposes a numerical method to simulate not only the jet formation process of the conical shaped charge with the inhibitor: approximately 11 km/s aluminum jet, but also the succeeding flight and impact processes onto the target plates. The method is demonstrated by performing a series of numerical analyses with a multi-processor type hydrocode: AUTODYN-2D™ and is successfully verified by comparing with the experiment conducted by National Aerospace Laboratory of Japan to assess the protection of orbital space debris impacts on the spacecraft in the low earth orbit (LEO). In the numerical model the shock-induced vaporization is taken into account by applying the Tillotson equation of state to the liner and the target materials. We can visually know the distribution of various field variables in the jet formed from the liner and in the jet and target after the impact: contour plots of velocity, temperature, density, energy, etc. Besides they are useful for understanding the mechanism of the phenomenon, it is truly interesting to see what physical phase the jet is in, especially by the phase indicator. The decrease effect of the jet mass during travel to the target is investigated, as well as the density and shape effect of the jet on the size of the crater formed on the target. The investigation is useful for the calibration of the jet mass and jet velocity, because it is difficult to know the accurate information on them by the experimental measurement. These numerical results are discussed over the comparison with the corresponding experimental results in the jet shape, the crater shape, the jet mass and the jet velocity.