A modified formula to predict the penetration depth for jet penetrating spaced target plates
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Abstract In order to predict the penetration depth for jet penetrating spaced target plates, a modified formula with exponential form is proposed in this work based on the existing method. The processes of jet penetrating homogeneous target plate and spaced target plates are observed by simulation, and the penetration depth of different layers is obtained. The relationship between the number of layers and the penetration depth is described by the proposed formula, in which the parameters are determined by the simulation results. The penetration depth for jet penetrating spaced target plates can be predicted by the proposed formula. By comparison, the predictions well agree with the actual data, which indicates the modified formula can be a reference to predict the penetration depth for spaced target plates.Keywords:
Penetration (warfare)
Consideration of the problem of modeling the penetration of heavy metals of exhaust gases of automobile engines is carried out for the soil with permeability coefficient cp and diffusion coefficient D. As a result of mathematical modeling, an exponential equation is obtained, the input variables for which are the surface concentration of harmful components c, permeability coefficient cp, diffusion coefficient D and soil depth l. The output variables for the obtained exponential equation is the concentration of harmful components C1 at a depth l.According to the obtained equation, the depth of penetration of heavy metals into the soil – l is theoretically investigated, depending on the surface concentration с1˂с2 and at constant ratio cp/D. As a result, the penetration depth of heavy metals increases, which is due to an increase in the driving force of the diffusion process. Having studied the effect of an increase in the cp/D ratio on the penetration depth of heavy metals into the soil at constant surface concentrations c1 and c2, a decrease in their penetration depth is found, which is due to a decrease in the diffusion process.The obtained theoretical results are confirmed by experimental studies of the depth of penetration of heavy metals – exhaust gases of the ZMZ-511.10 petrol engine into the soil. It is found that the content of heavy metals in the soil at an arbitrary depth corresponds to theoretical calculations, and the discrepancy is within the measurement error. When measuring the lead concentration, the discrepancy is within 12.5–15 %, zinc 5.5–7.5 %, manganese 8.5–11 %. So, the concentrations of heavy metals, measured at arbitrary depths, are 0.1 and 0.2 m for lead; 0.1, 0.2 and 0.3 m for zinc; 0.1; 0.2 and 0.25 m for manganese. This indicates the validity of the results obtained by the exponential equation. Therefore, the proposed model provides high accuracy in determining the concentration of heavy metals in the soil and can be used for forecasting their penetration depth if the surface concentration is known
Penetration (warfare)
Exponential decay
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Obliquity effect of thick homogeneous target in anti-penetration was studied by shooting test with homogeneous target( 29. 6° /400 mm). The simulation model was built. ANSYS / LS-DYNA finite element was used in numerical simulation of anti-penetration of homogeneous target at different obliquity; the obliquity effect of homogeneous target on anti-penetration with same vertical depth was got. Those conclusions have some practical significance to armor testing.
Penetration (warfare)
Armour
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Abstract In order to predict the penetration depth for jet penetrating spaced target plates, a modified formula with exponential form is proposed in this work based on the existing method. The processes of jet penetrating homogeneous target plate and spaced target plates are observed by simulation, and the penetration depth of different layers is obtained. The relationship between the number of layers and the penetration depth is described by the proposed formula, in which the parameters are determined by the simulation results. The penetration depth for jet penetrating spaced target plates can be predicted by the proposed formula. By comparison, the predictions well agree with the actual data, which indicates the modified formula can be a reference to predict the penetration depth for spaced target plates.
Penetration (warfare)
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Abstract : The penetration mechanics of a thick walled tubular penetrator is examined as ratio of the outer to inner diameter is increased from values of 0.4 to 0.74. Since the craters are characterized by depth and radius, analytical models for the crater radius due to tubular penetrators are developed. A two stage cavity expansion model is provided, which is based on the observations that in the first stage, the eroded penetration element exerts pressure on the target and opens a cavity. In the second stage, the inertia imparted to the target is responsible for the further expansion of the cavity. The analysis includes the centrifugal force exerted by the penetrator, radial inertia of the target, and the strength of the target. The crater radius is also determined from the energy and momentum principles and the results are compared with other results. The results obtained from the momentum principle provide good agreement with the other models in spite of its simplicity. The penetration velocity for tubes, which is less than that of rods, thus cannot be obtained from the modified hydrodynamic theory, is determined from computer simulations on behalf of the penetration efficiency. Numerical simulations using AUTODYN-2D are conducted for comparison with the analytical predictions and these confirm the phenomenological assumptions in the models.
Penetration (warfare)
Moment of inertia
Rod
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We present experimental measurements of the penetration depth of the bubble cloud generated by a plunging water jet, when this jet is oscillated parallel to the free surface. We demonstrate that when the Reynolds number is larger than 104 the penetration depth can be adequately described with the model introduced by Clanet and Lasheras (1997) for a non-oscillating jet tilted relative to the normal of the liquid surface, provided an effective inclination angle is introduced to account for the jet translation velocity. In the case of jets with a Reynolds number smaller than 104, we find that the penetration depth of the oscillated jet can be increased of up to 30% by moderate oscillation velocities. This increase of the penetration is due to the decrease of the mixing layer angle when the symmetry around the bubble cloud is broken by the oscillation. We finally discuss the shape of the overall region impacted by the oscillating bubble cloud. We show that there is a regime for which the penetration is maximum at the center of this region, and a regime for which the penetration is maximum at the periphery. We propose a cartography to predict when each regime is relevant.
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Oscillation (cell signaling)
Free surface
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In this study, a combined experimental, numerical and theoretical investigation is conducted on the penetration of semi-infinite 4340 steel targets by a homogeneous 93W rod and two types of jacketed rods with striking velocities of 0.9–3.3 km/s. The results show that the jacketed rods produced typical "co-erosion" damage at all test velocities, except for the 93W/1060Al jacketed rod, which switched from an early "bi-erosion" damage to later "co-erosion" damage at a striking velocity of 936 m/s. However, the homogeneous 93W rod always forms a large mushroom head during the penetration process. The damage mechanisms of these two types of jacketed rods differ for striking velocities of 0.9–2.0 km/s, but this difference gradually decreases with increased striking velocity. For velocities of 2.0–3.3 km/s, all three types of projectiles exhibit typical hydrodynamic penetration characteristics, and the damage mechanisms of the two types of jacketed rods are almost identical. For the same initial kinetic energy, the penetration performance of the jacketed rods is distinctly superior to that of the homogeneous 93W rods. Compared with jacket density, jacket strength shows a more significant influence on the damage mechanism and penetration performance of the jacketed rod. Finally, an existing theoretical prediction model of the penetration depth of jacketed rods on semi-infinite targets in the co-erosion mode is modified. It transpires that—in terms of penetration depth—the modified theoretical model is in good agreement with the experimental and numerical observations for 93W/TC4 and 93W/1060Al jacketed rods penetrating semi-infinite 4340 steel targets.
Penetration (warfare)
Rod
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A model is proposed to predict the depth of penetration of the air bubbles entrained by a round water jet impacting into a flat, liquid pool. This depth is shown to be determined only by the initial jet momentum and by the non-monotonic nature of the bubble terminal velocities as a function of their size. The model is shown to be in excellent agreement with measurements of the depth and width of penetration of the bubbles performed over a wide range of jet diameters, velocities, and plunging angles.
Penetration (warfare)
Momentum (technical analysis)
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A new structure of post-composited rod is designed to improve the penetration ability of rod penetrator. The comparison experiment of post-composited rod and homogeneous rod with the same overall structure invertically penetrating a semi-infinite steel target is conducted. The result indicates that the penetration ability of post-composited rod is superior to that of homogeneous rod. The maximum penetration depth of post-composited rod is 25% more than that of homogeneous rod. The reason of the result is analyzed by the numerical simulation and verified by experimental result. The further simulation of postcomposited rod with four different configurations in penetrating a semi-infinite steel target at impact velocity from 1 000 m /s to 1 600 m /s is carried out. The corresponding relationship between the penetration efficiency of post-composited rod with different configurations and the impact velocity is obtained.
Penetration (warfare)
Rod
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