Experimental and numerical study of the interaction between a shaped charge jet and a single ERA moving plate

Abstract

An analysis of the interaction mechanisms between a Shaped Charge Jet (SCJ) and a single Moving Plate (MP) is proposed in this article using both experimental and numerical approaches. First, an experimental set-up is presented. Four collision tests have been performed: two tests in Backward Moving Plate (BMP) configuration, where the plate moves in opposition to jet, and two tests in Forward Moving Plate (FMP) configuration, where the plate moves alongside the jet. Based on the virtual origin approximation, a methodology (the Virtual Origin Method, VOM) is developed to extract quantities from the X-ray images, which serve as comparative data. $\gamma \text{SPH}$ simulations are carried out to complete the analysis, as they well capture the disturbance dynamics observed in the experiments. Based on these complementary experimental and numerical results, a new physical description is proposed through a detailed analysis of the interaction. It is shown that the SCJ/MP interaction is driven at first order by the contact geometry. Thus, BMP and FMP configurations do not generate the same disturbances because their local flow geometries are different. In the collision point frame of reference, the BMP flows in the same direction as the jet, causing its overall deflection. On the contrary, the FMP flow opposes that of the jet leading to an alternative creation of fragments and ligaments. An in-depth study, using the VOM shows that deflection angles, fragment-ligament creation frequencies, and deflection velocities evolve as the interaction progresses through slower jet elements.