Shaped Charge Jet Research Articles

Effect of explosives charges types on the jet characteristics, penetration performance and fragmentation patterns of shaped charges

Different explosive materials have been studied numerically and experimentally to assess the efficiency of a small diameter shaped charge in terms of produced jet characteristics and penetration depth into RHA steel targets. 26 different explosives have been simulated numerically using Autodyn hydrocode, whereas recommended explosives have been loaded into small diameter shaped charges by pressing technique and tested by static firing against RHA targets in order to validate the numerical calculations. The numerical analysis has presented an intensive global view about the variation of the shaped charge jets as a potential of the loaded explosive charge efficiencies. A successful trial has been performed to measure the shaped charge jet velocity using detonation velocity VOD 812 apparatus, where its measured value was only 3.6% different from the numerical one for HMX-V5 explosive. Besides, TITAN (L3) flash X-ray radiograph has also been implemented to explore the jet profile using the same explosive type and to measure its jet tip velocity, which has only 2.1% different from that estimated numerically. Extensive fragmentation analysis has been presented, which showed increase in both the fragment number and the fragment speed when the used explosive charge is of high detonation velocity. CL-20 explosive exhibited the largest jet tip velocity and its scaled collapse velocity was found to be 140% of TNT explosive. The calculated average fragment speed has been validated and the measured fragment speed has only 2.3% difference when compared to the SPH calculations.

Characteristics of Shaped Charge Jets by the Shape of the Inhibitor Inserted into the Liner

The performance of a shaped charge bomb depends on the explosive performance, liner precision machining and manufacturing quality. The key performance is how uniformly the liner transforms into a jet. In order to reduce the performance of the shaped charge bomb from a protection point of view, this study investigated the characteristics of the jet formation and progression by inserting inhibitors of different shapes into the liner using flash X-ray experimental analysis techniques. The larger the volume filled inside the liner, the lower the rate of high-speed jet generation, which was well confirmed by experiments. Due to the effect of the inhibitor, it takes a considerable amount of time delay to form a jet after explosion compared to a normal shot, and quantity and mass of jet particles that can contribute to penetration are decreased, and the penetration power is also greatly reduced due to the scattering of segmented jets.

Influence of Liner Form and Explosive on the Velocity and Mechanical Action of a Shaped-Charge Jet

Influence of Liner Form and Explosive on the Velocity and Mechanical Action of a Shaped-Charge Jet

Analysis of the influence of charge liner on the penetration effect of shaped charge jet assisted window sidetracking

In order to improve the efficiency and success rate of sidetracking in high-strength thick-walled casing, we use shaped charge jet to penetrate the casing to reduce the milling workload of milling cone. This paper established a model of shaped charge jet penetrating casing, and analyzed the effects of charge liner structures, charge quantity, and charge liner material. The results show that with the decrease of standoff distance, the velocity attenuation rate of the jet will increase in the process of penetrating the casing. Under standoff distance of 1D, the velocity attenuation rate of the trumpet-shaped liner (TSL) is the smallest, the TSL has a good ability to expand the aperture, and can form a funnel-shaped hole with a large diameter at the front end, and has the largest penetration volume. The charge quantity does not directly affect the penetration volume. The 70-1D charge combination has the largest penetration depth, the largest front diameter of the hole, and the larger penetration volume. The jet velocity of aluminum and titanium is much higher than that of other materials; tungsten and titanium have the largest penetration volume. When the material density in the charge liner's truncation is greater than that of the curve section, such combination material charge liners achieve better penetration effects. The titanium-tungsten charge liner exhibits the best penetration performance on the casing, forming a hole with a volume of 11369.2 mm3 and an outlet diameter of 18.8 mm on the TP110TS casing. In summary, at standoff distance of 1D, the TSL with 70-1D charge combination and titanium-tungsten material combination has the best penetration effect on casing. This study has certain guiding significance for the application of shaped charge jet assisted window sidetracking technology.

Pressure and temperature effects resulting from impact onto materials of different reactivity

The pressure and temperature increase resulting from the impact of different threats onto target materials is analyzed with a unified laboratory-scale setup. This allows deriving qualitative information on the occurring phenomenology as well as quantitative statements about the relative effects sizes as a function of target material and threat. The considered target materials are steel, aluminum, and magnesium. As threats, kinetic energy penetrator, explosively formed projectile, and shaped charge jet are used. For the investigated combinations, the measured overpressures vary by a factor of up to 5 for a variation of the material, by a factor of up to 7 for a variation of the threat, and by a factor larger than 15 for a simultaneous variation of both. The obtained results as well as the experimental approach are relevant for the basic understanding of impact effects and risks due to material reactivity. The paper combines two main aims. Firstly, to provide a summary of own prior work in a coherent journal article and, secondly, to review and discuss these earlier results with a new perspective.

Research on the penetration performance of shaped charge jet into block stone concrete targets

Experiment and numerical simulation were conducted to investigate the penetration performance of shaped charge jet into block stone concrete targets. The experiment has shown that the jet undergoes deflection and other phenomena during its penetration of block stone concrete. Improvements have been made to the methods used by previous scholars for constructing aggregate particles, resulting in a particle model that more closely resembles the true shape of the aggregate. A novel method for judging the intersection of aggregate particles based on the Plucker coordinate system was proposed. In comparison with traditional methods, this method is not constrained by the shape of aggregate particles. By utilizing dynamic simulation software to replicate aggregate settlement during the production process of concrete targets, a 3D meso-scale model of concrete was successfully established. Numerical simulations were conducted according to the experimental settings, with the results demonstrating good consistency between the experimental and numerical simulations, thus confirming the reliability of the model and methodology presented in this article. Additionally, the numerical simulation results suggest that the aggregate content significantly influences the degree of interference, penetration depth, and damage zone range of the jet, while the impact position primarily affects the deflection of the jet. This article provides a numerical simulation method for future research on the penetration and damage mechanism of shaped charge jet considering the 3D meso-scale model of concrete.

Explosively driven Richtmyer–Meshkov instability jet suppression and enhancement via coupling machine learning and additive manufacturing

The ability to control the behavior of fluid instabilities at material interfaces, such as the shock-driven Richtmyer–Meshkov instability, is a grand technological challenge with a broad number of applications ranging from inertial confinement fusion experiments to explosively driven shaped charges. In this work, we use a linear-geometry shaped charge as a means of studying methods for controlling material jetting that results from the Richtmyer–Meshkov instability. A shaped charge produces a high-velocity jet by focusing the energy from the detonation of high explosives. The interaction of the resulting detonation wave with a hollowed cavity lined with a thin metal layer produces the unstable jetting effect. By modifying the characteristics of the detonation wave prior to striking the lined cavity, the kinetic energy of the jet can be enhanced or reduced. Modifying the geometry of the liner material can also be used to alter jetting properties. We apply optimization methods to investigate several design parameterizations for both enhancing or suppressing the shaped-charge jet. This is accomplished using 2D and 3D hydrodynamic simulations to investigate the design space that we consider. We also apply new additive manufacturing methods for producing the shaped-charge assemblies, which allow for the experimental testing of complicated design geometries obtained through computational optimization. We present a direct comparison of our optimized designs with experimental results carried out at the High Explosives Application Facility at Lawrence Livermore National Laboratory.

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

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

Theoretical calculation and analysis of the velocity of shaped charge jet with modified collapse velocity model

The application of perforating completion technology in oil and gas field development has gained widespread popularity. Enhancing the efficiency of oil and gas wells relies on increasing the penetration depth, which is influenced by the design of the perforation charge and the strength characteristics of the rock material. However, as a crucial objective function for optimizing perforating charge structures, jet velocity lacks a rapid and accurate calculating method. This article addresses this issue by proposing an improved collapse velocity model using the DP46RDX42-Y perforating charge as a case study. It presents a novel approach for calculating jet velocity based on the unsteady Pugh-Eichelberger-Rostoker (PER) theory. To validate the effectiveness of the proposed method and analyze the impact of different characteristic parameters on jet tip velocity, a series of numerical simulations were conducted using LS-DYNA software combined with Arbitrary Lagrange-Euler (ALE) techniques. Results indicate excellent agreement between the proposed method and the numerical results, demonstrating its superiority over the traditional Gurney formula with an impressive 34.15% increase in accuracy. Notably, this method is particularly suitable for perforating charges with low detonation velocity. Increasing the liner density and decreasing the liner thickness and cone angle is recommended to achieve higher jet tip velocity. Furthermore, the proposed method has the potential for broader application in other perforating charges with varying liner shapes. This study provides a comprehensive and efficient solution for calculating jet velocity, which facilitates optimizing perforating charge structures and calculating penetration depth.

An investigation on the jet formation and penetration characteristics of the CuCoCrFeNi high-entropy alloy liner

This study performs a series of mechanical tests, quasi-static and dynamic, on CuCoCrFeNi high-entropy alloys (HEAs) using an experimental setup to explore the performance of Cu-based HEAs in shaped charges. It derives the parameters for the Johnson–Cook constitutive model through fitting. A static penetration test is conducted with a small cone angle and a thin-walled liner. The outcomes are then compared to simulation data generated by AUTODYN software. They indicated that the CuCoCrFeNi HEA liner can produce a shaped-charge jet that achieves both penetration and reaming effects when driven by explosives. In a C45 steel target, the diameter of the penetration hole is 46.43% of the charge diameter. The experimental findings align closely with the simulations, indicating discrepancies of less than 12.13% in the diameters of the penetration holes and ∼2.56% in penetration depths. Hence, the numerical simulation approach and its parameters can be utilized to investigate the penetration characteristics of Cu-based HEA jets, providing a groundwork for future optimization of HEA-shaped charge designs.

Effect of Structural Parameters on the Jet Formation and Penetration Capability of Small Caliber Shaped Charges

Take small caliber high explosive antitank cartridge as research platform, establish 35mm diameter warhead model. Numerical simulation for the process of shaped charge jet forming and penetrating the target has been done through explosion mechanics analysis software AUTODYN. Effect of liner thickness, cone angle and charging length-diameter ratio on shaped charge jet performance has been analyzed. And the optimal combination of the structural parameters of the shaped charge has been determined by orthogonal optimum design. Results show that optimized shaped charge structure can penetrate 105mm steel target under simulation conditions and the maximum penetration depth of main charge in the explosion test is 100mm, the average value of penetration depth is 86.67mm. The minimum and average of relative error between results of static explosion test and numerical simulation are 4.76% and 17.46% respectively. The research results can provide theoretical and technical support for the optimization design and engineering application of small caliber shaped charge.

Numerical study on the damage of liquid-filled containers subjected to shaped charge jet impact

In the studies of the vulnerability of armored vehicles, the impact of high-velocity penetrators on liquid-filled container components is one of the critical concerns. The purpose of this study is to investigate the structural damage of the liquid-filled container subjected to shaped charge jet impact utilizing the Structural Arbitrary Lagrangian–Eulerian method in ANSYS/LS-DYNA. The numerical model is validated against available experimental data. The validation effort of the numerical model showed very good agreements with experiments in terms of radial shock wave and radial crater formation as a function of time. Using the validated model, the liquid pressure, the energy transfer as well as the influence of overmatch on the impact process were analyzed. The results indicate that the structural damage modes of containers under shaped charge jet impact include perforation and wall deformation. Perforation results from the penetration of the jet tip and tail, while wall deformation is caused by the high-velocity impact of the flowing liquid. In cases where the overmatch (OM) is equal to 1, the contribution of the tip to front and back wall perforation increment primarily depends on the impact velocity. In cases with OM less than 1, the “filtering effect” of the Rolled Homogeneous Armor (RHA) armor plate leads to the loss of the tail's contribution to front wall perforation.

Studying the Effectiveness of Shaped Charge Jets Created by Graphene-containing Shaped Charge Liners

The paper presents selected results of studies conducted within the framework of the following research project: “Use of graphene and new multilayer explosive technologies in materials for shaped charge liners" (The National Centre for Research and Development in Poland: project No: DOB-BI08/03/01/2016). This study was performed by a consortium made up of the following entities: Institute of Precision Mechanics, Military University of Technology and the Mototechnika company (Poland). The main objective of the performed experiments was to test the effectiveness of shaped charge liners produced with the use of powder metallurgy methods, from mixtures containing copper powder and graphene-coated copper powder. The content of the latter equaled 0%, 1%, 5% and 10%, respectively. Shaped charge jets created with the use of liners made from the powder mixtures tested were recorded with the help of X-ray technology. Firing tests were conducted against steel barriers and the depth of penetration was determined. The obtained results showed that the addition of graphene powder to pure copper powder practically does not increase the depth of penetration of the shaped charge jet compared to scenarios in which sintered liners without this additive were used.

Reducing Richtmyer–Meshkov instability jet velocity via inverse design

In this work, we detail a novel application of inverse design and advanced manufacturing to rapidly develop and experimentally validate modifications to a shaped charge jet analog. The shaped charge jet analog comprises a copper liner, a high explosive (HE), and a silicone buffer. We apply a genetic algorithm to determine an optimal buffer design that can be placed between the liner and the HE that results in the largest possible change in jet velocity. The use of a genetic algorithm allows for discoveries of unintuitive, complex, yet optimal buffer designs. Experiments using the optimal design verified the effectiveness of the buffer and validated the machine learning approach to hydrodynamic design optimization.

Numerical Study and Theoretical Model of Shaped Charge Jet Penetrating Into Thick‐Walled Target With Following Velocity

Numerical Study and Theoretical Model of Shaped Charge Jet Penetrating Into Thick‐Walled Target With Following Velocity

Влияние параметров токового воздействия на радиальное рассеивание металлических кумулятивных струй

To reduce penetration effect of a shaped charge, powerful current effect on the shaped charge jet could be introduced. Based on numerical simulation within the framework of a model of the uniformly elongating cylindrical rod, the paper analyzes features of the metal shaped-charge jets stretching, when passing a powerful electric current pulse through them. Main attention is paid to the effect of jet material radial dispersion behind its exit from the interelectrode gap. The role of magnetic energy stored in the jet elements during exposure was clarified in this phenomenon. For the shaped-charge jet middle sections formed by charges with diameter of 50 to 150 mm, distributions along the jet radius of the material density and the material radial velocity were obtained immediately after the current “cutoff”. They indicated that as a result of current exposure, the jet material surface layer could be torn off and dissipated with maintaining continuity of its central part. With an increase in strength of the current passed through the jet, thickness of its destroyed layer acquiring radial velocity directed from the axis and increases. Critical currents corresponding to the jet surface layer breakdown and its complete destruction were determined.

Jet formation and penetration performance of a double-layer charge liner with chemically-deposited tungsten as the inner liner

This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition (CVD) that has tungsten as its inner liner. The feasibility of this design was evaluated through penetration tests. Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners. The microstructures of the tungsten layers were analyzed using a scanning electron microscope (SEM). The feasibility analysis was carried out by pulsed X-rays, slug-retrieval test and static penetration tests. The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method. The results showed that the double-layer liners could form well-shaped jets. The errors between the X-ray test results and the numerical results were within 11.07%. A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug. Compared with the traditional pure copper shaped charge jet, the penetration depth of the double-layer shaped charge liner increased by 11.4% and >10.8% respectively. In summary, the test results are good, and the numerical simulation is in good agreement with the test, which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner.

The effect of three-layer liner on the jet formation and penetration capability of shaped charge jet

In order to solve the problem of insufficient penetration ability of common liner, a new three-layer liner was proposed. AUTODYN software was used to simulate the efflux forming process of three-layer liner. The influence of four different impact impedance liner materials and different thickness ratio of three-layer liner on efflux performance was studied. In order to study the penetration ability of shaped charge to semi-infinite target plate, the penetration calculation of the target plate was carried out by taking several standoff under different thickness ratios. The optimal thickness ratio of three-layer liner was determined by studying the penetration depth and opening size of the target plate. The results show: By comparing the matching of liner materials with different impact impedances, the head velocity, effective length, total energy, total kinetic energy and effective jet mass of the jet formed when the three-layer liner material is AL 2024, copper and nickel from the outside to the inside are the best. In the analysis of the matching of the thickness ratio of the three-layer liner, the key to the jet forming is the thickness ratio of the outer liner. Within a certain range, the greater the proportion of the thickness of the outer liner, the better the jet forming; when the material of the three-layer liner is AL 2024-copper-nickel from outside to inside, the thickness ratio of the liner is 4/1/1 from outside to inside, and the jet forming is the best. The maximum penetration depth of the shaped charge with a thickness ratio of 1/1/4 from the outside to the inside of the three-layer liner is 395.5 mm, which is 52.3% higher than that of the shaped charge with a double-layer liner. Compared with the shaped charge with single-layer liner, the penetration depth is increased by 62.6%. When the thickness ratio of the three-layer liner is 1/1/4 from the outside to the inside, the maximum entrance diameter of the target plate is 14.3 mm, which is the same as that of the shaped charge with the double-layer liner. Compared with the shaped charge with single-layer liner, the entrance diameter is in-creased by 14.4%.

Theoretical Study on Interference of Shaped Charge Jet with Liquid-Filled Enclosed Structure

Theoretical Study on Interference of Shaped Charge Jet with Liquid-Filled Enclosed Structure

Linear shaped-charge jet optimization using machine learning methods

Linear shaped charges are used to focus energy into rapidly creating a deep linear incision. The general design of a shaped charge involves detonating a confined mass of high explosive (HE) with a metal-lined concave cavity on one side to produce a high velocity jet for the purpose of striking and penetrating a given material target. This jetting effect occurs due to the interaction of the detonation wave with the cavity geometry, which produces an unstable fluid phenomenon known as the Richtmyer–Meshkov instability and results in the rapid growth of a long narrow jet. We apply machine learning and optimization methods to hydrodynamics simulations of linear shaped charges to improve the simulated jet characteristics. The designs that we propose and investigate in this work generally involve modifying the behavior of the detonation waves prior to interaction with the liner material. These designs include the placement of multiple detonators and the use of metal inclusions within the HE. We are able to produce a linear shaped-charge design with a higher penetration depth than the baseline case that we consider and accomplish this using the same amount of or less HE.