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Titanium hydride (TiH2), a promising high-energy additive, is doped into PTFE/Al to optimize the energy output structure of the reactive jet and strive for better aftereffect damage ability to the target. Six types of PTFE/Al/TiH2 reactive liners with different TiH2 content are prepared by the molding and sintering method. The energy release characteristics of PTFE/Al/TiH2 reactive jet are tested by the transient explosion energy test, and are characterized from pressure and temperature. The reaction delay time, pressure history, and temperature history of the energy release process are obtained, then the actual value of released energy and reaction efficiency of the reactive jet are calculated. The results show that the peak pressure and temperature of the PTFE/Al/TiH2 jet initially increase and then decrease with increasing TiH2 content. When the TiH2 content is 10%, the actual value of released energy and reaction efficiency increased by 24% and 6.4%, respectively, compared to the PTFE/Al jet. The reaction duration of the reactive material is significantly prolonged as the TiH2 content increased from 0% to 30%. Finally, combined with the energy release behaviors of PAT material and the dynamic deformation process of liner, the enhancement mechanism of TiH2 on energy release of the reactive jet is expounded. [ABSTRACT FROM AUTHOR]

Titanium hydride (TiH2), a promising high-energy additive, is doped into PTFE/Al to optimize the energy output structure of the reactive jet and strive for better aftereffect damage ability to the target. Six types of PTFE/Al/TiH2 reactive liners with different TiH2 content are prepared by the molding and sintering method. The energy release characteristics of PTFE/Al/TiH2 reactive jet are tested by the transient explosion energy test, and are characterized from pressure and temperature. The reaction delay time, pressure history, and temperature history of the energy release process are obtained, then the actual value of released energy and reaction efficiency of the reactive jet are calculated. The results show that the peak pressure and temperature of the PTFE/Al/TiH2 jet initially increase and then decrease with increasing TiH2 content. When the TiH2 content is 10%, the actual value of released energy and reaction efficiency increased by 24% and 6.4%, respectively, compared to the PTFE/Al jet. The reaction duration of the reactive material is significantly prolonged as the TiH2 content increased from 0% to 30%. Finally, combined with the energy release behaviors of PAT material and the dynamic deformation process of liner, the enhancement mechanism of TiH2 on energy release of the reactive jet is expounded.

Testing rocket and space technology objects in ground conditions for resistance to the impact of meteoroids and fragments of space debris can be carried out using shaped charges. To substantiate the design parameters of shaped charges that ensure the formation of aluminum particles in a wide velocity range (from 2.5 to 16 km/s), numerical modeling of the formation process was carried out within the framework of a two-dimensional axisymmetric problem of continuum mechanics using three different computing codes to increase the reliability of the results. The calculations consider shaped charges with a diameter of 20–100 mm with aluminum liners of various shapes. It is shown that the formation of particles with velocities close to the lower limit of the considered range is ensured by gently sloping segmental liners of degressive thickness. To form higher-velocity particles with velocities over 5 km/s, it is proposed to use combined liners, the jet-forming part of which has the shape of a hemisphere of constant thickness or the shape of a semi-ellipsoid or semi-superellipsoid of rotation of degressive thickness.

Testing rocket and space technology objects in ground conditions for resistance to the impact of meteoroids and fragments of space debris can be carried out using shaped charges. To substantiate the design parameters of shaped charges that ensure the formation of aluminum particles in a wide velocity range (from 2.5 to 16 km/s), numerical modeling of the formation process was carried out within the framework of a two-dimensional axisymmetric problem of continuum mechanics using three different computing codes to increase the reliability of the results. The calculations consider shaped charges with a diameter of 20-100 mm with aluminum liners of various shapes. It is shown that the formation of particles with velocities close to the lower limit of the considered range is ensured by gently sloping segmental liners of degressive thickness. To form higher-velocity particles with velocities over 5 km/s, it is proposed to use combined liners, the jet-forming part of which has the shape of a hemisphere of constant thickness or the shape of a semi-ellipsoid or semi-superellipsoid of rotation of degressive thickness. [ABSTRACT FROM AUTHOR]

Blasting and shaped charges are the main forms of underwater weapons, and their near-field underwater explosions (UNDEX) can severely damage structures. Therefore, it is of great importance to study underwater explosive load characteristics of different forms of charges. The full physical process of a typical underwater explosion of a sphere/column blasting charge and a shaped charge was simulated using the Eulerian method. The loading characteristics of the underwater blast shock wave and bubble, as well as the projectile, were studied. The results show that the shock wave loads of spherical, cylindrical, and polygonal charges propagate outward in spherical, ellipsoidal–spherical and ellipsoidal–spherical wavefronts, respectively. When the shock wave reaches 16 times the distance-to-diameter ratio, its surface is approximately spherical. In addition, in the shaped charge underwater explosion, the shaped charge liner cover absorbs 30°–90© of the shock wave energy and some of the bubble energy to form a high-speed shaped penetrator. Spherical, ellipsoidal, and ellipsoidal bubbles are generated by underwater explosions of spherical, cylindrical, and shaped charges, respectively. The obtained results provide a reference for evaluating the power of underwater weapons. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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.

Tests of rocket and space equipment objects in terrestrial conditions for shock resistance to the impact of meteoroids and space debris can be carried out using shaped charges. To substantiate the design parameters of shaped charges ensuring the formation of aluminum particles in a broad velocity range (from 2.5 to 16 km/s), numerical simulation has been conducted for the process of the said formation within the framework of a two-dimensional axisymmetric problem of continuum mechanics using ANSYS/AUTODYN, ERUDIT, and KOLDUN computer systems. In calculations, consideration has been given to shaped charges with a diameter from 20 to 100 mm with aluminum liners of various shape. It has been shown that the formation of particles with velocities close to the lower boundary of the considered range is ensured by gently sloping segmental degressive-thickness liners. For the formation of higher-velocity particles with velocities above 5 km/s, it is suggested that use be made of combined liners whose jet-forming portion has the shape of a hemisphere of constant thickness or the shape of a semi-ellipsoid or semisuperellipsoid of rotation. [ABSTRACT FROM AUTHOR]

An analytical model for calculating the pressure of detonation product on the liner surface was presented. Calculation results show that when the liner structure is the same, increasing the inscribed circle diameter of the charge cross section can reduce the influence of the charge nonaxisymmetry, when it is greater than the critical value, that is, 1.66× liner diameter, the pressure on liner surface is distributed axisymmetrically. Therefore, the jet of the shaped charge with isosceles trapezoidal cross section can be prevented from having an offset velocity by the above-mentioned method. This finding is verified through numerical simulation. [ABSTRACT FROM AUTHOR]

Canted fins can significantly improve the flight stability and the on-target accuracy of Explosively Formed Projectiles (EFP). The current work uses the effective charge theory to derive the formation of periodic tails from shaped charge with stepped casing by considering the detonation impulse. According to the established model, the distribution of velocity along the circumference of the liner increases linearly with the square root of the casing thickness. There are two stages in the formation of canted fins influenced by the stepped casing: (1) the distribution of velocity along the circumference of the liner upon initiation, and (2) the torsion and folding of the liner edge during deformation. Numerical simulation was carried out with LS-DYNA for shaped charge (56 mm in diameter) with regular and stepped casing. The expansion of the casing and the deformation of the liner with velocity distribution at initial times were compared between the regular and the stepped casing. The distribution regularities and the final velocity of the canted fin EFP from the simulation agree well the established velocity distribution model. Soft recovery experiments were also carried out to prove the feasibility of using shaped charge with stepped casing. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineer Military Bulletin / Muszaki Katonai Közlöny is the property of National University of Public Service and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. Review and analysis of the studies results of the functioning the cumulative charges with different liners for forecasting, or obtaining correlation dependencies such as «detonation velocity of explosives – velocity of elements of shaped charge jets (SCJ)», «angle at the top of a conical liner – velocity of SCJ»; evaluation and experimental verification of engineering theories of CJ penetration into dense materials for projecting charges in practical applications; analysis of the effectiveness of shaped charge (SC) with liners made of different materials. Method. The methodological basis of research is a systematic approach to the problem of increasing the efficiency of a cumulative explosion. In accordance with the specifics of research aimed at achieving the set goals and obtaining technological dependencies, analytical, graph-analytical methods and physical and mathematical modeling were used in the work. Findings. Quantitative relationships between the velocity of the main part of the CSJ and the detonation velocity of the explosive in the charge with an angle at the top of the conical liner of 42º and the dependence of the speed of the main part of the CJ on the angle at the top of the conical copper liner was revealed. Engineering theories of CSJ penetration into dense barriers was analyzed. It is shown that the best results, which are close to the experimental data, are predicted by the theory based on the A–V model (Allison and Vitali). The most promising materials for liners of cumulative charges with the aim of increasing the penetration depth or increasing the diameter during shallow penetration have been determined. Some practical applications of short-circuiting was considered, in particular, the disposal and utilization of ammunition and non-traditional methods of destruction of reinforced concrete and rocks. Originality. A linear dependence of the CSJ velocity on the explosive velocity detonation for a charge with a conical liner and an angle at the top of 42º was established, as well as a dependence of the CSJ velocity on the angle at the top of a conical copper liner, which is close to a power law. Practical implications. The obtained results are important and useful for the design of equipment and technologies in various fields where the energy of a directed explosion is used: for the disposal and utilization of ammunition, for the opening of oil and gas reservoirs, for the reconstruction of construction facilities, in military affairs.

In this paper, the penetration mechanism of reactive jet with non-uniform density distribution is studied. The simulations show that the density deficit occurs in the whole reactive jet, and the density increases from the jet tip to tail. The density of jet tip is approximately 1.5 g/cm3, which is lower than that of the reactive liner materials. The X-ray experiments show similar results with the simulations. The density decreasing effect of jet tip has a significant influence on the penetration behavior when the reactive jet impacts steel plate. According to the simulation results, this paper assumes that the density gradient in the jet section has linear distribution. Then, the deflagration pressure generated by each jet element at the bottom of crater is introduced into the Bernoulli equation. Based on the virtual origin model and Szendrei-Held equation, the analytical models for penetration depth and radial cratering of reactive jet with the density reduction are obtained. Moreover, to further prove the validity of analytical models, the penetration experiments of the reactive liner shaped charge against steel plate under different standoffs are carried out. There is a convergence between the analytical crater profiles and experimental results when reactive jets penetrate steel plates under different standoffs, especially at standoff of 1.5 and 2.0 charge diameters.

The dynamic formation, shock-induced inhomogeneous temperature rise and corresponding chemical reaction behaviors of PTFE/Al reactive liner shaped charge jet (RLSCJ) are investigated by the combination of mesoscale simulation, reaction kinetics and chemical energy release test. A two-dimensional granular model is developed with the randomly normal distribution of aluminum particle sizes and the particle delivery program. Then, the granular model is employed to study the shock-induced thermal behavior during the formation and extension processes of RLSCJ, as well as the temperature history curves of aluminum particles. The simulation results visualize the motion and temperature responses of the RLSCJ at the grain level, and further indicate that the aluminum particles are more likely to gather in the last two-thirds of the jet along its axis. Further analysis shows that the shock, collision, friction and deformation behaviors are all responsible for the steep temperature rise of the reactive jet. In addition, a shock-induced chemical reaction extent model of RLSCJ is built based on the combination of the Arrhenius model and the Avrami-Erofeev kinetic model, by which the chemical reaction growth behavior during the formation and extension stages is described quantitatively. The model indicates the reaction extent highly corresponds to the aluminum particle temperature history at the formation and extension stages. At last, a manometry chamber and the corresponding energy release model are used together to study the macroscopic chemical energy release characteristics of RLSCJ, by which the reaction extent model is verified.

Combining the methods of theoretical, numerical and experimental, this research focuses on the jet formation behavior and optimization of trunconical hypercumulation shaped charge structure. With the three-stage division, formation theory of trunconical hypercumulation shaped charge jet is established based on micro element method. By dimensional analysis, main control parameters are identified and their effect on jet formation are analyzed. Through numerical modelling and orthogonal optimization method, influence of the factors and their levels over the indicators of jet tip velocity and jet length as well as order of the significance of each factor and level are obtained. Penetration experiments of trunconical hypercumulation shaped charge based on the orthogonal optimization reveals its advantage over traditional conical shaped charge structure, and finally determines the optimal influence factor level combination. The research and results would provide useful guide for the design and application of trunconical hypercumulation shaped charge structure.

Roadways are the arteries of coal production. Based on the construction of rock roadway drilling and blasting method, from the aspects of key blasting technology, tunneling equipment, blasting equipment, etc., the development process of rock roadway blasting in China's coal mines has gone through three stages: blasting quality control, driving speed increase, and roadway safety service guarantee. On the basis of summarizing and analyzing the development characteristics and history of the three stages, the research progress and engineering application of the new technology of rock roadway blasting in coal mines are mainly introduced: ① Peripheral directional fracture control blasting technology controls the distribution of blast energy in the medium, and verifies the effect of shaped charges on improving the quality of roadway profile formation, reducing surrounding rock damage and reducing the number of blast holes. ② In terms of parameter optimization technology for ultra-deep blasting of cutting holes, the ultra-depth is related to the cycle footage and the area of the roadway profile surface, and the ultra-depth value directly affects the utilization rate and unit consumption of the blast hole. For the typical case of Gubei Mine in Huainan, the blasting effect is the best when the over-depth is 400 mm. ③ In terms of segmental charge blasting technology in the hole, the optimal proportion of the upper explosive is 0.382, combined with the digital electronic detonator for segmental detonation, creating a precedent for the use of digital electronic detonator blasting in coal mine roadways. ④ In terms of similar-cut blasting technology, the difference between traditional notch blasting and similar-cut blasting is analyzed theoretically, and the importance of equalized resistance line is proposed and confirmed. The comprehensive application of the above blasting technologies reduces the number of blastholes in full-face blasting from an average level of (5−6) S to (3−4) S (S is the cross-sectional area of the roadway). The effects of increasing single-cycle footage, improving blast hole utilization, controlling roadway profile forming quality, and reducing surrounding rock damage have been achieved. From the perspective of the entire life cycle of the coal mine underground space project, the continuously optimized blasting technology reduces the cyclic dynamic disturbance to the surrounding rock and structure, and ensures the long-term service safety of the coal mine rock roadway project.

The research of LEFP (linear explosive forming projectile) is of great value to the development of new warhead due to its excellent performance. To further improve the damage ability of the shaped charge warhead, a special shell overhanging structure was designed to increase the charge based on the traditional spherical charge, in which case the crushing energy of LEFP could be guaranteed. LS-DYNA was used to simulate different charge structures obtained by changing the number of detonation points, the length of shell platform, the radius of curvature and the thickness of liner. The RSM (response surface model) between the molding parameters of LEFP and the structural parameters of charge was established. Based on RSM model, the structure of shaped charge was optimized by using multi-objective genetic algorithm. Meanwhile, the formation process of jet was analyzed by pulsed X-ray photography. The results show that the velocity, length-diameter ratio and specific kinetic energy of the LEFP were closely related to the structural parameters of the shaped charge. After the optimization of charge structure, the forming effect and penetration ability of LEPP had been significantly improved. The experimental data of jet velocity and length were consistent with the numerical results, which verifies the reliability of the numerical results.

In this paper, the reaction characteristic and its application in shaped charge warhead of a novel reactive material, which introduced copper (Cu) and plumbum (Pb) into traditional polytetrafluoroethylene/aluminum (PTFE/Al), are studied. The thermal analysis and chemical reaction behavior of the PTFE/Al/Cu/Pb mixture are investigated by Differential Scanning Calorimetry (DSC),Thermo-gravimetry (TG), and X-ray Diffraction (XRD) techniques. Then, the shaped charge liners with PTFE/Al/Cu/Pb reactive materials are fabricated, and the X-ray experiments show that they could form reactive jets with excellent performance under the detonation effects of the shaped charge. Based on that, the penetration experiments of shaped charge with PTFE/Al/Cu/Pb reactive liner against steel plates are carried out, and the results demonstrate that the PTFE/Al/Cu/Pb reactive jets could produce a deeper penetration depth compared to the traditional PTFE/Al reactive jets. Meanwhile, the PTFE/Al/Cu/Pb reactive jets also show significant inner-blast effects, leading to dramatically cracking or fragmentation behavior of the penetrated steel plates. This new PTFE/Al/Cu/Pb reactive liner shaped charge presents enhanced penetration behavior for steel targets that incorporates the penetration capability of a high-density and ductility jet, and the chemical energy release of PTFE-matrix reactive materials.

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the penetration and cratering effect of reactive material composite jets, a series of experiments are carried out for the shaped charge (SC) with different composite liners damaging steel targets. The inner layer of composite liners is metal and the outer one is a polytetrafluoroethylene/aluminum (PTFE/Al) reactive material. Copper (Cu), titanium (Ti) and Al inner liners are used in this paper. The reactive material liner is composed of 73.5 wt.% PTFE and 26.5 wt.% Al powder through mass-matched ratios. Reactive material composite liners are prepared through machining, cold pressing and a sintering process. The SC mainly consists of a case, a composite liner, high-energy explosive and an initiator. The steel target is steel 45#, with a thickness of 66 mm. A standoff of 1.0 CD (charge diameter) is selected to conduct the penetration experiments. The experimental results show that when the inner layer of the composite liner is composed of Ti and Al, the hole diameters on the steel target formed by the reactive material composite jet are significantly larger than that of the inner Cu liner. By introducing the initiation delay time (τ) and detonation-like reaction model of PTFE/Al reactive materials, an integrated numerical simulation algorithm of the penetration and detonation-like effects of reactive material composite jets is realized. Numerical simulations demonstrate that the initial penetration holes on the steel targets are enlarged under the detonation-like effects of PTFE/Al reactive materials, and the simulated perforation sizes are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space were investigated through experiments and simulations. The volume of the enclosed concrete space is about 15 m3. The reactive liner enhanced shaped charge utilizes reactive copper double-layered liner, which is composed of an inner copper liner and an outer reactive liner, while the reactive material liner is fabricated by PTFE/Al (Polytetrafluoroethylene/Aluminum) powders through cold-pressing and sintering. Static explosion experiments show that, compared with the shaped charge which utilizes copper liner, the penetration cavity diameter and spalling area of concrete by the novel shaped charge were enlarged to 2 times and 4 times, respectively. Meanwhile, the following reactive material had blast effect and produced significant overpressure inside the concrete closed space. Theoretical analysis indicates concrete strength and detonation pressure of reactive material both affect the penetration cavity diameter. To the blast behavior of reactive material inside the concrete space, developing TNT equivalence model and simulated on AUTODYN-3D for analysis. Simulation results reproduced propagation process of the shock wave in concrete space, and revealed multi-peaks phenomenon of overpressure-time curves. Furthermore, the empirical relationship between the peak overpressure and relative distance for the shock wave of reactive material was proposed.

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Optimum process parameters (temperature, pressure, and time) for diffusion welding of aluminium and copper have been achieved with better shear strength for application in shaped charges using the Taguchi method. The study involved characterising the type thickness of intermetallic compounds formed at the faying surfaces using optical microscopy, scanning electron microscopy and electron probe micro analyser, lap shear strength assessment, microhardness, and X-ray diffraction. It is confirmed that intermetallic compounds of type Al4Cu(σ), Al2Cu (θ), and AlCu (η1)with traces of Al2Cu3 (δ) and AlCu4 (α2) were formed at the interface. The optimum shear strength of 42.2 N was achieved with diffusion welding at temperature 510°C, pressure 0.5MPa and time 5400s. By diffusion welding at these conditions, the shape charge cones fabricated and explosively filled such shaped charges paved, an increase of 0.42 times in the penetration of target with diffusion welded copper-aluminium shape charge cones compared with that from conventional monolithic copper sheet. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The formation behavior of coated reactive explosively formed projectiles (EFP) is studied by the combination of experiments and simulations. The results show that the coated EFP can be obtained by explosively crushing the double-layer liners, and the simulation agrees with the experiment well. Then, the interaction process between the two liners is discussed in detail, and the formation and coating mechanism are revealed. It can be found that there are three phases in the formation process, including the impact, closing and stretching phases. During the impact phase, the velocities of two liners rise in turns with the kinetic energy exchange. In the closing phase, the copper liner is collapsed forward to the axis and completely coats the reactive liner. It is mentioned that the edge of the copper liner begins to form a metal precursor penetrator in this stage. During the stretching phase, the coated reactive EFP is further stretched and fractured, resulting in the separation of the metal precursor penetrator and the following coated reactive projectile. Further studies show both the edge thickness and the curvature radius of the copper liner have significant influences on formation behaviors. By decreasing the edge thickness or the curvature radius, the difficulty of closing decreases, but the tip velocity and the length of precursor penetrator increases. As the thickness and diameter of the reactive liner decrease, the coating velocity increases slightly, but the total length of coated reactive EFP tends to decrease. [ABSTRACT FROM AUTHOR]

The formation characteristics of the shaped charge jet (SCJ) from the shaped charge with a trapezoid cross-section is analyzed in this work. A theoretical model was developed to analyze the collapsing mechanism of the liner driven by the charge with a trapezoid cross-section. Based on the theoretical model, the axial and radial velocities of the SCJ from different trapezoid cross-section charges. The pressure model was employed to calculate the velocity for the subcaliber shaped charge, which was verified through numerical simulation. The results show that the influence of the angle of the trapezoidal charge (acute angle) on the axial velocity of the SCJ is not distinct, whereas the variation of the radial velocity of the shaped charge jet is obvious as the change in the angle of the trapezoidal charge. In addition, the related X-ray experiments were conducted to verify the theory. The theoretical results correlate with the experimental results reasonably well. [ABSTRACT FROM AUTHOR]

In order to study the similarity law of penetration of concrete targets by shaped charges, penetration tests of concrete targets with different sizes of shaped-charge jets were carried out, and the prototype and the model projectiles met the similarity law with a simulation ratio of 1:1.5. LS-DYNA finite element software was used to simulate the tests, and the accuracy of the ALE algorithm, fluid–solid coupling algorithm, material model, equation of state, and corresponding material parameters was verified. Numerical simulations were further conducted for the different types of shaped-charge jets (jets, rod jets, and explosively formed projectiles) formed by different liner angles penetrating into the concrete target, and the results show that the shaped-charge jets basically meet the similarity law when penetrating concrete targets. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) with a face-centered cubic structure offer numerous advantages, including high plasticity, good processability, and high-temperature resistance. They are also suitable for use as materials in shaped-charge liners, which can cause significant damage. In this study, CoCrFeNi HEAs were prepared, and their mechanical characteristics were examined. The results indicated that the alloy exhibited good plasticity and processability. After dynamic compression, the samples were analyzed using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). It was found that dislocation was the primary deformation mechanism at low strain rates. However, as the strain rate increased, the deformation mechanism shifted from dislocations to a combination of dislocations and twinning. The damage performance of the CoCrFeNi HEA was verified through a static penetration experiment using a conical charge. The results were then compared with simulation results obtained using the AUTODYN software. This study demonstrated that the CoCrFeNi HEA could form a condensed, stable-shaped charge jet, leading to efficient damage after penetrating the steel target plate. Therefore, after uniform treatment, the CoCrFeNi HEA can be utilized as a high-energy structural material to design shaped charge structures that achieve highly efficient damage. • CoCrFeNi HEA has excellent comprehensive mechanical properties. • CoCrFeNi HEA liner can form a continuous jet. • CoCrFeNi HEA jet has excellent penetration ability. • CoCrFeNi HEA exhibits the property of releasing impact energy. [ABSTRACT FROM AUTHOR]

This paper studies the shaped charge jet performance in terms of different liner shapes including conical, bell, hemispherical and bi-conical liners. The critical angles and the relevant flow velocities for the zirconium liner material were calculated analytically and numerically using Autodyn hydro-code. The relationship between the critical collapse angle and the flow velocity was determined for the conditions of jet formation and coherency. Penetration tests according to the standard testing procedures of API-RP34 (Section-II) were performed to validate the numerical predictions of the jet performance of the studied liners. It was found that the four shaped charge liners all produced coherent jets with different performances. The penetration depth of the shaped charges with the bell and the bi-conical liner shapes increased by 10.3% and 22%, respectively, while the crater diameter of shaped charge with hemispherical liner increased by 85% representing the formation of an explosively-formed-projectile (EFP), when they are compared with the corresponding jet characteristics of a conical liner shaped charge.

In the military field, determining how to increase the hole-expanding ability of shaped charge warheads is a key and difficult issue with respect to warhead development. Amorphous alloys have grains or grain boundaries, with unique mechanical properties. Zr41.2Ti13.8Cu12.5Ni10Be22.5 can be used as the liner material of shaped charges, resulting in high-speed particle flows that differ from those of traditionally shaped charges. In this paper, based on the analysis of the mechanical response characteristics of Zr41.2Ti13.8Cu12.5Ni10Be22.5 and its fracture morphology under impact, combined with the formation theory of shaped charge jets, a semi-empirical formula is derived to calculate the velocity of non-cohesive high-speed particle flow considering the elastic strain energy loss. Additionally, the reliability of the proposed theoretical model is verified through experiments. The penetration process of Zr-based amorphous alloy high-speed particle flow into a concrete target is theoretically analyzed, and the penetration stages of the high-speed particle flow into the target are clearly distinguished. Combined with the penetration theory of shaped charge particle jets, a high-speed particle flow penetration model is proposed, and a pore expansion model is established through an energy method. The experimentally obtained data on depth of penetration are in agreement with the theoretical calculation results. [ABSTRACT FROM AUTHOR]

Explosive propelling devices are used to test objects of rocket and space technology for resistance to the effects of meteoroids and fragments of space debris. Based on numerical simulation carried out with the use of computational complexes ANSYS/AUTODYN and ERUDIT, the possibilities of obtaining aluminum particles with velocities of up to 16 km/s with the aid of shaped charges with a combined cumulative coating are considered. For achieving this goal, the thickness of the jet-forming part of the coating was built up degressively, with the surfaces limiting it having the shape of the surfaces of a semiellipsoid or a semisuperellipsoid of revolution. [ABSTRACT FROM AUTHOR]

Shaped charge (SC) is a mechanism used by defence industries in antitank weapons to penetrate armored plates. Numerous studies have been conducted on shaped charge effects. However, experimental studies on this topic are limited by the great safety requirements and limited access to high-grade explosives. Due to these limitations, an experimental study on a small-scale shaped charge mechanism (SCM) penetration blast test was conducted against five types of target materials. The experimental data were then verified by simulation to prove that they can be used to predict SC penetration data. This paper presents a comparative study on the effect of shaped charge blasts conducted by comparing simulation results with actual experimental results. In order to conduct this study, the Autodyn 2D software was used to develop an SC blast model against five types of target materials. This study concluded that Autodyn 2D simulation results can predict the hypervelocity penetration for all target materials compared to the experimental test with an average difference of 9.1%. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the mechanical properties of Zr‐based amorphous alloy at high strain rates and its use as a shaped charge liner. A split Hopkinson pressure bar (SHPB) was used to carry out dynamic mechanical performance tests, and a scanning electron microscope (SEM) was used to observe the fracture morphology of the test piece. The X‐ray test of the jet formation and the static penetration test of the Zr‐based amorphous alloy jet were performed. It was found that the amorphous alloy material exhibits typical brittle fracture characteristics under high strain‐rate compression. As the strain rate increases, molten droplet‐like structures appear in the fracture morphology, and the melting area is proportional to the strain rate. The Zr‐based amorphous alloy liner forms a non‐cohesive jet driven by explosive explosion. The actual projection angle of the liner is slightly larger than the theoretical value of Taylor's projection angle because of the unique mechanical properties and fracture mechanism, while the collapse angle is slightly smaller. Compared with copper jet penetrating concrete, the aperture of Zr‐based amorphous alloy jet is increased by 58 % and the caving volume is increased by 32 times. The results provide reference for the application of Zr‐based amorphous alloy in the field of shaped charge liner. [ABSTRACT FROM AUTHOR]

Copyright of Military Engineer / Hadmérnök is the property of National University of Public Service and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Numerical simulation based on SPH method, compared with laboratory experiments, using the grey correlation theory to analyze the correlation between the parameters of the elliptical bipolar linear shaped charge and the performance of the shaped charge jet. The structure of shaped charge is optimized by machine learning to obtain the optimal structural parameters, and it is compared with the rock crack development of shaped charge blasting in practical application. The results show that the structural parameters of the shaped charge have the same influence on the jet head velocity, and there are certain differences in the impact on the jet length. The fitted curve of the support vector machine (SVM) regression model based on the genetic algorithm (GA) is high prediction accurate. By comparing the optimization results with the actual engineering application of the shaped charge structure, the rock breaking effect has been significantly improved, which has important guiding significance for the actual engineering application.

In order to enlarge the crater diameter of shaped charge jet penetration into steel targets, this paper investigates the penetration and cratering characteristics of steel targets by shaped charge jets from titanium alloy liners. Titanium alloy shaped charge liners are prepared separately with mechanical processing and selective laser melting (SLM), and pulsed X-ray radiography is used to identify jet formation characteristics. Jet formation is numerically simulated by AUTODYN-3D, and steel target penetration tests are carried out at a short jet stand-off distance. The results show that AUTODYN-3D can realistically simulate jet formation from titanium alloy liners and that the SLM-processed liner exhibits better penetration performance than the mechanically processed liner. The existing cratering formula of jet penetration is modified to make it consistent with the aperture variations of jet penetration from titanium alloy-lined shaped charges at a short stand-off distance. The findings of this study are expected to provide technical and theoretical support for research on the penetration characteristics of the jets from titanium alloy-lined shaped charges. [ABSTRACT FROM AUTHOR]

The liner is an important part of shaped charge. In this paper, the spherical cone composite structure liner composed of a spherical missing body and truncated cone (hereinafter referred to as the SCS liner) is studied. The SCS liner is made of copper. Based on this, a shaped charge structure based on the explosion pressure-coupling constraint principle is designed, filling an 8701 explosive (RDX-based explosive). Through pulse X-ray tests, numerical simulation, and static explosion tests, the significance of the detonation pressure-coupling constraint principle, as well as the forming law and penetration efficiency of the SCS liner are studied. The results show that in the pulsed X-ray test, a split jet with high velocity is formed in the SCS liner. The explosion pressure-coupling constraint principle delays the attenuation of the internal explosion pressure and improves the shape of jet. After the SCS liner is selected, the penetration depth is increased by 70.38%. The average head velocity of the explosive charge jet is 7594.81 m/s. The diameter of the hole formed by the jet of the explosive charge is 20.33 mm. The hole expands inside, and the perforation depth is 178.87 mm. The numerical simulation is in good agreement with the test. [ABSTRACT FROM AUTHOR]

Metal materials still dominate the separation shell of pyrotechnic separation devices in space launch vehicles. Moreover, research on carbon-fiber–reinforced polymer (CFRP) composites as a separation shell material has mainly focused on the exploration and test stages. Based on safety and environmental adaptability, the buffer substance in separation devices has a great influence on the cutting results of laminates. In this study, compared with the traditional separation device, a new separation device with a shaped charge and buffer substance was designed by finite-element analysis (FEA), and a test was carried out. The predesigned cutting strategies were divided into three categories: no buffer, expansion–deformation energy-absorbing (EDEA) material buffer, and low-density energy-absorbing (LDEA) material buffer as the control group. Based on the separation time of the laminate, delamination of the laminate, deformation of the protective cover, and environmental applicability of the device, the results show that the proposed separation device with LDEA as a buffer is the best, and the trend of delamination is consistent in FEA and the test. The LDEA buffer can effectively reduce the secondary damage of detonation products to the laminate by crushing and absorbing energy to improve the separation effect of the separation shell, providing guidance for the design of CFRP-based separation devices with shaped charges. [ABSTRACT FROM AUTHOR]

Copyright of Military Engineer / Hadmérnök is the property of National University of Public Service and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineer Military Bulletin / Muszaki Katonai Közlöny is the property of National University of Public Service and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)