bluuebunny/crossref_metadata_2025 huggingface dataset:
Fragment Velocity Distribution of Controlled Fragmentation Warhead Under Eccentric Point Initiation
Authors: Mingxue Zhou , Xuelei Feng , Xinming Zhang , heng Wang , teng Deng , Liuqi Ji
Published: December 2024

Three-Point eccentric initiation is one of the most common technologies of directional warhead for enhancing fragment lethality against targets. The fragment velocity distribution is a significant concern in warhead design. However, there is as yet no reasonable theory for predicting the fragment velocity distribution of a specific enhanced shell under three-point eccentric initiation; existing approaches are either limited to single or double-point eccentric initiation scenarios or ignore the effects of detonation gas leakage on fragment acceleration. In this paper, through theoretical analysis and numerical simulations, a new model was established to study the fragment velocity distribution of warhead shells under the combined effects of gas leakage and three-point eccentric initiation. Firstly, an equation for detonation velocity gain of explosives under three-point eccentric initiation was developed by numerical simulations, where the shells were set to be free from disintegration and gas leakage. Secondly, the fracture strain or radius of controlled fragmentation warhead was solved by the disintegration model established in our previous work. Then the equations for detonation velocity gain and the fracture strain were associated with a proposed gas-leakage equation in which the gas expansion was assumed to be locally isentropic. Finally, theoretical analysis was conducted by solving the associated equations. Grooved cylindrical shell was explosively expanded to disintegrate to verify the proposed model. Theoretical predictions of the fragment velocity distribution showed good agreement with experimental results, indicating that the model was suitable for predicting the fragment velocity distribution of an explosively-driven metal grooved cylinders under three-point eccentric initiation. Besides, this study provides an insight into the differences of fragment velocity enhancement among single point initiation, double point initiation and three point initiation.
Study on Failure Determination of Buried Water Supply and Drainage Pipelines Near Explosions
Authors: Chun Li , Bukui Zhou , Dan Luo , Meng Mu
Published: December 2024

An experimental study was conducted on the blast resistance performance of DN200 water supply and drainage pipelines buried 1.5 m deep in sandy soil to investigate the damage effects and damage assessment of underground pipelines in the vicinity of an explosion under weapon impact. Numerical calculations were performed using the finite element software AUTODYN based on the experimental data. The results showed that at a scaled blast distance of 0.394 m/kg1/3, the pipeline could still function normally for water transport, with the steel pipe’s blast-facing surface experiencing radial indentation and overall bending deformation, but the deformation was minimal and insufficient to damage the pipeline’s function. At a scaled blast distance of 0.316 m/kg^1/3, the deformation of the pipeline increased by 34.4% compared to the former case, resulting in leakage, and the blast-facing surface and flange connections were more prone to damage. When determining pipeline damage and failure, the Ovalization Failure Criterion was introduced, and safety thresholds were given in combination with the criterion. Finally, an overpressure-impulse damage criterion and its determination formula for buried water supply and drainage pipelines were established.
Research and test of pre-controlled fragment warhead shell based on 3D printing technology
Authors: Chen Junhan , Zheng Yu , Tao Chuanyun , Liang Zhenchao
Published: December 2024

To overcome the limitations on the total number of rods in discrete rod warhead and to increase its killing range, this paper proposes a center-grooved pre-controlled warhead shell structure based on 3D printing technology. The effects of different grooved grid parameters on shell fracture and fragment formation were compared through water medium recovery test. The fragment recovery results demonstrate that the centrally grooved structure can effectively guide the shell to fracture along the grooved grid pattern, resulting in elongated fragments of the desired size. Numerical models were established by ANSYS/Autody to investigate the process of shell fracture and fragment formation of the centrally grooved pre-controlled warhead shell. The simulation results were analysed in order to ascertain the shell-breaking mechanism and the factors influencing the effective fragment formation rate under the two grooving mesh parameters. This paper provides a reference for the application and design of 3D printing technology in pre-controlled warhead shell.
Design and damage efficiency analysis of multifunctional warhead
Authors: Zhao Yao , Zhai Xin-yi , Liu Han , Guo Zhi-wei , Huang Guang-yan
Published: December 2024

As a component of modern weaponry, the structural design and damage effects of multifunctional warheads are directly linked to their combat performance. Targeting various urban combat objectives, we have proposed and designed a multifunctional warhead structure that integrates multiple destructive elements, including directional and divergent fragments, jets, and linear EFPs, along with corresponding attack modes. Through numerical simulation analysis, we evaluated the damage effects of the different damage elements within this warhead on equivalent target plates, and subsequently conducted static explosion tests to validate the warhead design. The results indicate that the proposed multifunctional warhead features reasonable structural design, and the incorporated destructive elements can reliably damage different targets. This design can be further applied to unmanned combat platforms to effectively engage lightweight armor, urban window railings, ground radars, micro-drones, and other targets, providing references for related warhead structure design and engineering applications.
A comprehensive review and a real blast test on an Earth-Covered Magazine (ECM)
Authors: Tanapornraweekit Ganchai , Dhanasekara Chamil , Tangtermsirikul Somnuk
Published: December 2024

This paper provides a comprehensive review of design recommendations for Earth-Covered Magazines (ECMs) based on various design standards The real blast test from a 40 kg TNT@8.50 m was also conducted to evaluate the blast pressure, blast impulse from the explosion, behavior, and performance of the 1/3 scaled ECM under side explosion. The tested ECM structure showed no damage in all structural components, i.e., front wall, side wall, rear wall, and roof slab. Acceptable damages, such as damage to the soil cover on the side of the ECM and the fall of the front steel door in front of the tested ECM, were observed after the test. Therefore, the tested ECM structure performed well, under the side explosion of 40 kg TNT @ 8.5 m without causing structural damage. From the calculation of blast reflected pressure and re lected impulse, the tested ECM satisfies the pressure and impulse criteria of a standard 7-Bar ECM with a maximum of 20 tons of equivalent TNT stored in a full-scale ECM structure.
Study on the self-sealing properties of POZD coated aluminium composite structure penetrated by projectiles
Authors: Shi Jian-jun , Huang Zheng-xiang , Ma Bin , Jia Xin , Huang Zi-rui
Published: December 2024

The protective technology of fuel tanks has attracted the attention of scholars at home and abroad, and higher requirements have been placed on the protective coatings of fuel tanks. They must not only meet the requirements of impact resistance but also achieve the function of self-healing of perforation. In order to explore the self-healing effect of fuel tank coatings on perforation by projectiles, a POZD-coated aluminium composite structure was designed. The self-healing mechanism of the POZD-coated aluminium composite structure was analysed using a test research method to explore the effects of coating thickness and aluminium thickness on self-healing performance. The results show that the POZD-coated aluminium composite structure exhibits strong self-healing properties when penetrated by projectiles. The self-healing characteristics are significantly influenced by the application technique and thickness of the POZD coating, whereas the thickness of the aluminum plate exerts a relatively minor effect. Through structural design, the POZD-coated aluminium composite structure can achieve complete self-sealing of perforations by 7.62 mm projectiles, providing a technical reference for the design of lightweight self-healing fuel tanks in the future.
Numerical and theoretical studies on axial impact between rods with various noses and a rigid wall
Authors: Wang Yifan , Ye Xuan , Wang Tao , Huang Guangyan
Published: December 2024

Rod drops at times and collides with a substrate, which induces vibration within the rod. The vertical impact between slender rods with different noses and a rigid flat is theoretically and numerically investigated. Equivalent linear contact model for different rod noses are established, based on which a semi-analytical model describing the longitudinal vibration of the rods are derived using 1D wave equation. The predicted displacements agree well with the numerical results. Plastic deformation is mainly concentrated in the rod nose, and the cylindrical part of the rod basically remains elastic. The displacement difference between the top and bottom point represents the compression extent of the cylindrical part, whose variation tendency is consistent with strain energy of the rod. Vibration responses and energy shares of the rods are compared, and sharper truncated-cone nose exhibits better buffering effect. Hemisphere nose is preferred when the plastic dissipation and compression extent are similar due to lower impulse.
Pressure measurement of circumferentially confined gelatin under shock wave
Authors: Xiong M M , Zang L W , Xu C , Ma X J
Published: December 2024

To investigate the pressure response characteristics of head physical surrogate under different sensor arrangement methods, the experimental study on the pressure measurement inside circumferent confined gelatin under the shock waves was conducted. A setup of one-dimensional pressure wave flatbed was constructed, consisting a pneumatic launcher, PVC pipe, and water. The pressure wave of three sensor arrangement methods were compared. The result shows that the three sensor arrangement methods have minimal influence on pressure testing results inside circumferentially constrained gelatin. When the sensitive surface flush with the inner wall (A1) is chosen as a baseline, the peak pressure and impulse differ by less than 3.44% and 5.14% in sensor arrangement method with sensitive surface flush with the pipe center (A2), and by less than 6.75% and 5.83% in sensor arrangement method with sensitive surface into a conical platform flush with the center of the pipe (A3). Smooth and reliable one-dimensional pressure waves can be obtained by the pressure testing method. The one-dimensional pressure wave obtained using this method can effectively be used to study the damage mechanisms of shock waves on the brain and air-containing organs.
Simulation Study on the Thermal Safety of Ammunition in a Multifunctional Launch Vehicle Fire
Authors: Wen Yuchen , Nie Jianxin , Liu Rui , Liang Jiahao , Zhang Tao
Published: December 2024

The multifunctional launch vehicle caught fire due to an unexpected fuel tank fire, creating a fierce flame-burning environment for the onboard ammunition, and posing a huge threat to operators and launch platforms. In order to obtain the thermal safety performance of vehicle-mounted ammunition in case of vehicle fire, the Russian SS-23 missile was taken as the research object. First, the fire dynamics software FDS was used to calculate and analyze the flame structure characteristics and the change law of ammunition ambient temperature field at different stages of fire development. Then the fluid dynamics software CFD was used to calculate and analyze the temperature field distribution characteristics and thermal stimulation response law of ammunition charge. The research results indicate that the uneven distribution of the flame temperature field formed when the fuel tank accidentally catches fire can cause a complex heating environment for on-board ammunition; The internal charge of ammunition continues to heat up under the combined effect of external heating and self-generated heat, and the high-temperature zone shifts towards the interior of the charge, further accelerating the decomposition and heat accumulation of the explosive, ultimately leading to the reaction of the warhead charge. At the same time, different residual fuel levels in the main fuel tank and different wind directions will have an impact on the firing process of the launch vehicle, and the reaction time and position of the onboard ammunition will also vary.
Numerical simulation of combined action of explosion shock wave and prefabricated fragments
Authors: Yan Liu , Jianfen Guo , Jianqin Zhang , Zhuo Lu , Anbang Sun , Zhendong Gao
Published: December 2024

This article is based on the finite element software ANSYS/LS-DYNA to numerically simulate the damage and failure process of prefabricated fragments coupled with explosive shock waves. Obtain the initial velocity law of prefabricated fragments of different shapes and sizes driven by explosive shock waves. Numerical simulations were conducted on three modes of action (fragment action, shock wave action, and coupling action between fragments and shock waves), and it was found that the maximum destructive power was achieved under the coupling action of fragments and shock waves. Under the coupling effect of fragments and shock waves, the maximum deformation of the target plate gradually decreases as the blast distance increases; The law that as the thickness of the target plate increases, the maximum deformation of the target plate gradually decreases.
Research and Optimization of Anti-Ballistic Properties of Gradient Honeycomb Sandwich Panels
Authors: Kuiyuan Sun , Shuhu Li , Jingli Xu
Published: December 2024

In addressing the penetration resistance of honeycomb sandwich panels, a finite element model is established to simulate the penetration problem. The relationship between initial and residual velocity of the fragments is studied. The effects of angle gradient, height gradient, and thickness gradient structures on the ballistic performance of honeycomb sandwich panels are analyzed. Multi-objective optimization design of honeycomb sandwich panels is conducted, resulting in a thickness gradient honeycomb sandwich panel. The results show that the relationship curve between initial and residual velocities of fragments closely matches the theoretical formula. Different gradient structures exhibit varied protective effects on the honeycomb sandwich panels. Compared to the pre-optimized panels, the optimized thickness gradient honeycomb sandwich panels show a significant improvement in protection, with the residual velocity of fragments reduced by 31.82% and the total mass of the sandwich panel reduced by 16.23%.
Experimental study on collision of a rigid wedge-shaped striking bow with ship section model
Authors: Zhao Y J , Guo T T , Li Y C , Zhang L P
Published: December 2024

In fluid-structure coupling collision tests of ship models, it is possible to obtain information about structural damage and accurately simulate the energy distribution during the collision process. Consequently, such tests are most effective in reflecting the true physical process of ship collisions. In this paper, a fluid-structure coupling collision test of a ship model was designed, where the bow of the striking ship was represented by a rigid wedge-shaped striking bow, and a scaled local section model of the struck ship was selected. The striking bow was applied to the side of the section model through a pendulum impact method. Under two different test conditions of head-on and oblique collisions, the collision forces, damage extent, and motion of the ship section model were measured and analyzed. The experimental method proposed in this paper is simple and feasible, and can be used as a means of assessing ship resistance to collision. The data obtained from this test can also provide reference for scholars engaged in related research.
Simulation study on damage effect of multi-cabin implosion on ship
Authors: Yuan Xiaoxia , Wei Chunqiang , Wang Yanye , Ma Hongliang
Published: December 2024

In this paper, the LS-DYNA finite element software was used to simulate the damage process of multi-cabin structure under the explosion in the cabin of the semi-armor-piercing warhead. The newly model of composite shock wave load and fragment load was proposed to study the damage effect of the multi-cabin structure. Combined with the propagation characteristics of the composite loads, the damage mode of the deck and bulkhead of the ship under the action of cabin implosion. Finally, the influence of the charge ratio of the semi-armor-piercing warhead on the damage effect of the multi-cabin structure was analyzed, and in this paper, a charge ratio of 0.35 is more conducive to achieving the entire process from penetration to implosion of multi-cabin.
Study on the dynamic characteristics of the revolver cannon under high-speed impact
Authors: Li H B , Gao Y , Liu D , Ren H Y , Hou J F , Zhang S Y , Wei L , Du W B
Published: December 2024

Aiming at the problems of discontinuous mechanism action, excessive energy consumption and poor matching with the chainless feeding system under the harsh working conditions of high-speed strong impact, a certain revolver cannon has the problems of discontinuous mechanism action, excessive energy consumption and poor matching with the chainless feeding system. In order to further study the dynamic characteristics of the gas-operated revolver cannon under high-speed impact load, solve the matching problem between the revolver cannon and the chainless feeding system, and improve the firing rate of the revolver cannon, based on the principle of the revolver cannon, the multi-body dynamics and gas dynamics theory are used to couple the thermomechanical coupling calculation model of the revolver cannon gas chamber and the transmission efficiency and impact numerical calculation method between the key parts into the ADAMS dynamic simulation model, and the dynamic analysis and calculation of the whole cannon of the revolver cannon are carried out. The motion characteristic curves of the key parts of the revolver cannon are obtained by simulation, the motion matching between the key parts is analyzed, and the simulation results are verified by experiments. The results show that the error of the motion characteristic parameters such as the active slide displacement and the gun box recoil displacement obtained by simulation and experiment is very small, which verifies the correctness of the calculation model. The simulation calculation method can provide technical support for the matching research between the revolver cannon and the chainless feeding system and the design and structural optimization of the revolver cannon.
Simulation study on the influence of groove depth on the lethal power performance of annular hollow pre controlled fragment warheads
Authors: Liu X R , Mao L , Wang H X , Qi Y X , Jiang Z R
Published: December 2024

The pre controlled fragment warhead can be applied in certain specific scenarios due to its excellent damage performance and structural integrity. It is widely used in different combat scenarios. In order to obtain the influence of different groove depths on the lethal power performance of warheads, this paper uses numerical simulation methods to establish a finite element model of an annular hollow pre controlled fragment warhead. It carries out numerical simulation calculations on the lethal power performance of the annular hollow pre controlled fragment warhead. The results show that the detonation wave propagation of the annular hollow pre controlled fragment warhead is affected by the cavity sparsity effect, resulting in a secondary pressure jump of 109Pa. The pressure generated by the superposition of spherical waves in the strong direction is about 200% of that in the weak direction. Within a certain range, the axial initial velocity of the pre controlled fragments increases with the deepening of the groove depth. The average initial velocity in the strong direction increases by 22.96% compared to the weak direction. The influence of different groove depths on the circumferential initial velocity of pre controlled fragments near the detonation point is the greatest, followed by the middle part of the warhead, and the influence far from the detonation point is the smallest. The scattering angle of fragments increases first and then decreases with the increase of relative groove depth. When the relative groove depth is 0.5δ

e
, the maximum scattering angle of the fragments is 14.6 °. It increases by 35.2%. This study can provide valuable references for the optimization design and damage assessment of related warheads.
Numerical simulation of reactive jet penetrating into reinforced concrete
Authors: Zhang Hao
Published: December 2024

In order to study the damage effect of PTFE/Al/W reactive jet against reinforced concrete, AUTODYN-3D numerical simulation was used to study the formation and penetration behaviors of reactive jets with densities of 2.31g/cm3~4.12g/cm3. Simulation results show that under the same charge condition, the diameter of low-density reactive jet is larger, and there is no significant difference in the axial velocity distribution of the reactive jets with different densities. For the damage effect of reinforced concrete, the penetration hole diameter of reinforced concrete formed by low-density reactive jet is larger, moreover, the steel bars can protect the concrete and reduce the damage area of concrete surface. For the penetration ability, the reactive jets with different densities can penetrate the front layer of steel bars, and the higher density of reactive jet, the deeper penetration depth of reinforced concrete. Meanwhile, hitting position of the jet against concrete target has significant effect on penetration results. The broken steel bars in penetration hole reduce the penetration depth.
Localised External Blast Response of CFRP Retrofitted Steel Cylindrical Tubes
Authors: Shuaib M M , Chung Kim Yuen S , Nurick G N
Published: December 2024

This paper presents the key outcomes derived from a series of experiments and numerical simulations aimed at understanding how carbon fibre reinforced polymer (CFRP) retrofitted cylindrical steel tubes respond to localised external blast loads. The blast tests were conducted using a ballistic pendulum on both as-received and retrofitted tubes, employing various configurations of CFRP retrofitting. The as-received mild steel cylindrical tubes had an outer diameter of 101.6mm, a wall thickness of 2.0mm, and spanned a length of 400mm. The cylindrical steel tubes were retrofitted with CFRP, stacked with four plies of fibre in four different arrangements. The tubes were subjected to lateral loading at the mid-span using plastic explosive (PE4) discs, each with a consistent diameter of 33mm, detonated at a stand-off distance of 13mm. The study investigated the influence of impulse (or charge mass) and the orientation of CFRP retrofitting on the structural response and failure behaviour of retrofitted tubes. The experiments demonstrated various combined CFRP failure modes resulting from localised blast loads, including metal-CFRP debonding, interlaminar delamination, and fibre rupture, particularly in the vicinity of the localised blast zone. Additionally, the findings indicated that CFRP tube retrofitting enhanced blast loading capacity, leading to reduced mid-point deflections compared to as-received tubes. Moreover, the results highlighted the effectiveness of CFRP retrofitting in increasing the threshold load for tearing failure in the steel tubes. The simulations from LS-Dyna were validated against the structural response and magnitude of deformation obtained from the experiments showed good correlation.
Study of the destructive response of charge array to reinforced concrete plate under contact explosion conditions
Authors: Yuan Yong-Di , Zu Xu-Dong
Published: December 2024

According to the needs of urban counter-terrorism operations, the military needs to enhance its ability to quickly maneuver in cities. The use of explosives to quickly open holes in walls is an effective means of achieving this capability. This article studies the relationship between the damage characteristics of charge array on reinforced concrete plates under contact explosion conditions and the parameters of array explosives through dimensional analysis. Numerical simulation of target plate penetration damage caused by explosive detonation using finite element analysis software, and model correction combined with experiments. Simulate using the modified model to fit the empirical formula of the damage characteristics of the target plate caused by various parameters of the charge array. The results indicate that within the range of working conditions studied in this article, the penetration diameter reaches its maximum when the spacing d between the charge blocks is 20-22cm. The spacing d corresponding to the maximum varies less under different charge block sizes and array arrangements. The ratio of the diameter of the through hole to the side length of the charge block gradually decreases with the increase of the length to height ratio of the charge block. This phenomenon indicates that the effective charge ratio is higher when the length to height ratio of the charge block is low. When the spacing between the charge blocks is too large, the combined effect of the charge array on the target plate weakens. The damage situation is close to that of a single small-sized charge damaging the target plate. The damage to the target plate at the interval between the charge blocks is relatively small. The maximum penetration diameter caused by charge array is 38% - 46% larger than that of group charge, which can effectively improve the destructive ability of explosives of the same mass and enhance combat effectiveness.
Mechanical Property and Constitutive Model of a Ti/PTFE/W
Authors: Zhu Z R , Zhang Z W , Tian W X , Wang T Y , Yang Y Z , Wang G , Guo L
Published: December 2024

Metal/polymer reactive materials (RMs) can induce chemical reactions under impact, resulting in a high damage effect due to the combination of kinetic and chemical energy. Researching the constitutive relationships of these materials can provide theoretical and data support for the impact damage process of ammunition. In this study, Ti/PTFE/W RMs with different mass ratios were prepared. Their static and dynamic compressive mechanical properties were investigated using quasi-static compression tests and Split Hopkinson Pressure Bar (SHPB) tests. The results show that at a strain rate of approximately 4000 s−1, the dynamic compressive strengths of the three material formulas reached 84.1 MPa, 119.3 MPa, and 148.9 MPa, respectively. Based on the Johnson-Cook (J-C) model and the Zhu-Wang-Tang (ZWT) model, this paper constructed dynamic compression constitutive models for Ti/PTFE/W RMs, compared and validated the predictive effects of two models. At a strain rate of 2600 s−1, the mean absolute errors of the two models for the three formulas were 2.671 and 2.106, with the model results being generally consistent with the experimental data. When predicting the experimental data at a strain rate of 4000 s−1, the ZWT model’s mean absolute errors were reduced by 71%, 89.8%, and 39.4% compared to the J-C model for W mass fractions of 0%, 50%, and 75%, respectively.
Numerical calculation of reflection overpressure distribution characteristics of small equivalent explosives at close range
Authors: Yu Hao , Wang Xiaofeng , Liu Yan , Bai Fan , Xu Yingliang
Published: December 2024

How to determine the distribution of shock wave overpressure load on small equivalent explosives acting on close-range structures has always been a research hotspot in the field of protective engineering. This article establishes a two-dimensional axisymmetric calculation model for small equivalent spherical explosives based on LS Present. Verify the accuracy of the numerical calculation model through close-range explosion experiments and comparison with the Kingery Bulmash empirical formula. Based on the peak value of positive reflection overpressure, the reflection overpressure of different oblique reflections on a rigid wall was normalized, taking into account the effects of other charges (0.5 kg, 1 kg, and 2 kg) and different incident angles (0 ° to 60 °). The influence of Mach’s reflection on the distribution of reflection pressure on a rigid wall was analyzed. In addition, the research results indicate that under the same scaled distance, the normalized reflection overpressure distribution on the rigid surface tends to be consistent after explosions of 0.5kg and 1kg charges at the same proportional distance, while the normalized reflection overpressure during the 2kg charge explosion process deviates due to the influence of detonation products, especially when the incident angle is less than 8 °. Finally, the curve of the rigid wall reflection coefficient concerning the incident angle was obtained under different ratios of detonation distances. This study reveals the distribution pattern of reflected overpressure on rigid walls under close-range explosions, which can provide a reference for the distribution and data analysis of shock wave overpressure in small equivalent near-ground experiments.
Study on Damage Characteristics of Non-equimolar High Entropy Alloy under High-Speed Impact Conditionsalloy
Authors: Wang Z X , Xu L Z , Zheng H L , Li X T , Liu A B , Wang J B , Li Z K , Du Z H
Published: December 2024

To analyze the damage characteristics of high-entropy alloys (HEAs) under the coupling of kinetic and chemical energy, we conducted tests on fragment penetration through spaced target A combination of experimental and theoretical analyses was employed to study the damage characteristics and mechanisms of HEAs. The results indicate that, with an increase in impact velocity, the damage area caused by the fragments on both steel and aluminum targets gradually expands, and the energy release process becomes more prolonged. In the study of the damaging effects of HEA fragments on fuel tanks under high-speed impact conditions, the chemical energy of the HEA fragments is released, forming a wide-ranging high-temperature deflagration field, which rapidly ignites upon contact with oil-gas mixtures, resulting in large-area combustion. This, in turn, ignites the remaining kerosene inside the fuel tanks and elucidates the mechanism of fuel tank damage by HEA fragments. The findings demonstrate that the non-equimolar ratio Zr42Ti15Nb20Ta20Al3 (at.%) high-entropy alloy possesses not only excellent penetration capabilities but also superior impact energy release potential, making it a promising candidate for use as an energetic structural material (ESM).
Research on Velocity Test of Fragment Group of Gradient Scattering Preformed Fragment Warhead
Authors: Liu Guifeng , Xu Yuxin , Li Qingze
Published: December 2024

In order to obtain the velocity of the fragment group of gradient scattering preformed fragment warhead, the radial scattering field of the fragments was photographed by the laser high-speed CCD camera system, and the velocities of all the fragments in the image after filtering the explosion firelight were obtained. The velocity of the preformed fragments shows a continuous gradient distribution from 77.9 m/s to 424.2 m/s, which was consistent with the theoretical calculation results. This indicates that the test technology is feasible and provides a new method for the velocity test of the fragment group.
The comparative study on the anti-penetration performance of high-strength material and normal-strength concrete based on experiments and simulation
Authors: Si Xuena , Liu Rongqiang , Yu Rui , Liu Ji’an , Wang Zhiyi
Published: December 2024

To comparatively study the penetration resistance characteristics of typical robust targets including superhard granite rock, C130 ultra-high strength concrete, and C40 normal-strength concrete, dynamic penetration comparative experiments and simulation were conducted, and the remarkable difference in penetration mechanisms between dense rocks and concrete was revealed. Cause of similar quasi-rigid penetration mechanism and similar damage behavior of target observed in experiments, the penetration resistance equivalent relationship between C130 concrete and C40 concrete was established by simulation based on the principle of energy consumption similarity. Despite with similar strength grade, the penetration mechanism transforming from quasi-rigid penetration in C130 high-strength concrete to complete fragmentation penetration in granite rock was observed, indicating that it is impractical to conduct equivalent evaluations of the anti-intrusion capabilities of granite using high-strength concrete of the same strength grade. These research findings can provide technical support for the efficient destruction and equivalent evaluation of ultra-hard targets.
Effect of charge structure on the stability of charge penetration
Authors: Liu Peng , Cheng Fang , Zhou Yang , Shen Jiaqi , Zhong Qianhui , Ren Yunyan
Published: December 2024

When the penetrating warhead penetrates the target, the internal charge is subjected to extremely high overload and impact loads. If the load intensity and duration meet the detonation conditions, the warhead may experience early detonation, compromising both the penetration effect and safety. To study the influence of charge structure on penetration stability, a specific warhead was used as a model reference, and finite element simulation software was employed to numerically simulate the penetration of concrete targets by the warhead. The results showed that stress concentration occurred at the warhead head during the penetration process, with the maximum stress exceeding the critical detonation stress of the charge, indicating a possibility of early detonation. To improve penetration stability while maintaining the original damage performance, different models of penetration warheads with various charge structures were constructed to analyze the influence of baffle position and number on charge stress. The results show that the loading structure with added partitions can effectively reduce the stress on the charge during penetration. The optimal effect is achieved when the partition is located at 1/2 of the interior of the projectile, with a maximum pressure of 3.75 GPa, which is 44.36% lower than that of the structure without partitions, thereby improving the penetration stability of the projectile.
Influence of Venting Factors on the pressure-relief effect of Ammunition Shell
Authors: Zhang Haijun , Yu Wanqian , Guo Shang
Published: December 2024

Mitigation techniques are effective measures for reducing the reaction level of ammunition under accidental stimulation. The key to the design of a mitigation structure is ensuring the effectiveness of pressure relief to avoid the conversion of combustion to detonation. Venting is one of the main mitigation techniques. In this paper, we design experiments and simulation calculations to research the effects of the pressure relief rate, such as the pressure increase rate, vent area and position. The relationship be-tween the pressure-relief coefficient and these factors is obtained, which can provide guidance for the design of mitigation structures in ammunition…
Study on predicting the stability of penetrating projectile charges via machine learning methods
Authors: Cheng Wei , Lu Xiaoyu , Wang Xiaoming , Li Weibing , Xie Zhentao , Zhang Jianan
Published: December 2024

Due to the limitations of current theoretical research, numerical simulation, and experimental analysis for predicting the stability of penetrating projectile charge, in this work, we propose a method to predict the stability of charges by using machine learning methods. Three models are selected, including Support Vector Machine (SVM), Random Forest (RF), and Extreme Gradient Boosting Tree (XGBoost). A practical sample dataset with inputs of the charge type, temperature and speed, and outputs of whether the charge is stabilized or not is constructed to train the model. The results indicate that using machine learning methods to predict the stability of charges is a feasible research direction.
The influence of digging holes inside the shell on the firing strength of armor piercing shells
Authors: Li Meng , Pan Xuchao , Hao Yu , Du Wei , Jiao Junjie , Fang Zhong , He Yong
Published: December 2024

The filling of active materials in the internal openings of armor piercing bullets can improve their destructive ability. In order to study the firing strength of armor piercing bullets after opening the holes, this paper takes 30mm armor piercing bullets as the research object, changes the opening aperture of the armor piercing bullets, and establishes a theoretical model of stress changes in the dangerous section of the bullet under different excavation radii based on the Brink method. Then, the finite element simulation software LS-DYNA is used to simulate and analyze the firing strength of armor piercing bullets, and compare it with the theoretical model. The results indicate that the aperture of the armor piercing bullet has a significant impact on the stress of the dangerous section. In the cylindrical part of the front section of the armor piercing bullet, the Brink method is basically consistent with the simulation calculation results; When the center opening of the 30mm armor piercing bullet cylinder is filled with active material with a density of 2.6g/cm3, the maximum opening radius is 6.8mm while ensuring the launch strength. This article has certain significance for the development of small caliber armor piercing bullets.
Structural response analysis of tungsten-steel composite warheads with different geometries under three typical transverse loads based on the rigid-perfectly plasticity
Authors: Ming Ke , Gang Zhou , Yutao Hu , Kang Li , Hang Yao , Haocheng Tian , Xian Li , Weihua Qi
Published: December 2024

Heavy metals such as tungsten were demonstrated helpful in increasing warheads’ penetrating ability, and used in practical warhead designs. Until recently, a relatively practical analytical method based on the rigid-perfectly plastic theory was proposed. This paper used this method to analyse the structural response of different heavy metal-involved designs under different transverse loads. The results show that the yield functions of warheads with tungsten in different geometries show a two-peak structure, and the critical section does not essentially appear at the first peak, but also might be at the second one, and even jump from one to the other. Besides, bonding strength plays a positive role in improving the impact resistance of the warhead. It should be noted that the tungsten part might do harm to the bearing capacity of the warhead, and attention should be paid to balance the penetrating and bearing ability. More practically, careful design of the inertia distribution along the axis might counteract the negative effect of the tungsten part on the structural integrity.
Effect of supercavity and shell casing on underwater energy release characteristics of armor-piercing-explosion supercavitating projectile charge
Authors: Hanxin Gong , Kui Tang , Jinxiang Wang , Yiming Ma , Xulong Hao
Published: December 2024

The Armor-Piercing Explosive Supercavitating Projectile (APESP) integrates explosion and armor-piercing effects, introducing a novel approach to underwater munitions. The energy release characteristic of the APESP charge underwater may differ from traditional underwater explosions due to the presence of the supercavity and shell casing. In order to investigate the effects of the supercavity and shell casing on this energy release characteristics, a finite element model of APESP charge underwater explosions is established. The deformation of the target is examined to evaluate the effects of the supercavity and shell casing. The mechanisms of these factors are further analysed theoretically. The results indicate that plastic deformation under the explosion of the APESP charge is primarily completed during the shock wave phase. Both the supercavity and shell casing influence the final deformation of the target by affecting the shock wave intensity, and the supercavity having a more significant impact. The pressure of the initial shock wave transmitted to the external medium of the charge is the highest when the charge is encased by a shell casing, and is the lowest when the charge is inside a supercavity. As the shock wave transmits through interfaces, it is amplified at the air-water interface and attenuated at both the shell-water and shell-air interfaces, with the greatest attenuation at the shell-air interface. Additionally, the presence of the shell casing reduces shock wave intensity but extends the duration of its action, thereby increasing the shock wave impulse.
Simulation Study on Adjustable Structural Shaped Charge Water Jet Forming and Penetrating Improvised Explosive Devices
Authors: Shuai Ma , Hao Xue , Chenxi Bian , Zhiyu Ma , Zhou Yang , Xinyi Shi , Xuke Lan , Guangyan Huang
Published: December 2024

To address the need for rapid and safe disposal of improvised explosive devices during bomb disposal operations, a method utilizing a structurally adjustable shaped water jet for the destruction of improvised explosive devices is proposed. Finite element analysis software AUTODYN is employed to develop a simulation model to study the formation process of the shaped water jet. To further explore the influence of structural parameters of the shaped charge on the jet head velocity and effective jet length, an orthogonal optimization design method is utilized. The water thickness and cone angle of the water-filled liner are selected as key structural parameters for numerical simulation, aiming to obtain the optimal parameter combination for the shaped charge structure. Based on this optimal shaped charge structure, a simulation model for the penetration of improvised explosive devices by the shaped water jet is established. Theoretical analysis and simulation results indicate that a reasonably designed shaped charge structure can generate a water jet capable of safely neutralizing improvised explosive devices without detonating the explosives.
Damage and failure mechanism of bioinspired helical layered structure under low velocity impact
Authors: Zhang Xingyuan , Sun Xin , Dong Yongxiang
Published: December 2024

Inspired by natural organisms, this paper employs carbon fiber epoxy resin composite thin layers to prepare a bioinspired helical layered structural material with excellent strength and toughness by imitating the internal helical layered structural of the mantis shrimp’s rods. The deformation failure and energy absorption characteristics of this material under low velocity impact loads were studied. It shows that, the helical layered structure samples with different interlayer angles exhibit complex intralayer and interlayer stress distributions during the deformation and failure processes, which significantly affect load transfer efficiency. As the interlayer helix angle changes, these intralayer and interlayer stress distributions will vary significantly, which may lead to complex failure modes such as fiber breakage, matrix cracking, fiber-matrix debonding, and delamination, and furthermore have a substantial impact on the material’s impact resistance and energy absorption. These results provide positive guidance for the internal structure design and performance optimization of lightweight, high-strength, and high-toughness materials.
Effects of density and water-entry angle on variations of the maximum impact acceleration of the projectile in water-entry process
Authors: Han Xiangdong , Wang Xiquan , Sun Yanxin , Chen Junbiao , Li Junzhi , Feng Huiyong
Published: December 2024

Projectile water-entry experiments under the working medium with different densities and various water entry angles were performed. Under the temperature of 30°C, mass fraction of lithium bromide solution was changed to obtain various densities. The mass fraction was 1%, 2%, and 3%. The water-entry angles were 25°, 27.5°, and 30°. Real-time variation of the impact acceleration was got by acceleration transducer. Via the analysis, the maximum impact accelerations under all conditions were obtained. Results indicated that with the increase of density, the maximum impact acceleration grew gradually. The maximum impact acceleration increased steadily with the growing of water-entry angle. Variation degree of the maximum impact acceleration indicated that effects of density were more significant than that of water entry angle.
Thermal management design and optimization of the pulse inductor for electromagnetic launch under continuous discharge condition
Authors: Ma Fuqiang , Wang Feng , Wang Sheng , Li Xianglin , Li Yuan
Published: December 2024

As the key component of electromagnetic launch (EML) system, insulation packaging structure and the existence of internal resistance leads to the continuous temperature rise of the pulse inductor under the continuous discharge condition, which greatly reduces the reliability and safety of the EML. This paper takes the solenoid pulse inductor as the research object and proposes a thermal management scheme that using hollow conductor to wind the coil and pumping coolant into the coil. And an optimization design method with flow resistance and thermal resistance as the objectives is proposed. By establishing coupling analysis model, it is demonstrated that the scheme can meet the temperature control requirements of solenoid inductor under continuous pulse discharge conditions. To improve the environmental applicability of thermal management scheme, the feasibility of glycol-deionized water solution as an alternative coolant at low temperature is proposed and demonstrated. The research are of great significance for promoting the engineering application process of EML.
Design and Experiment of Electromagnetic Pulse Protection Circuit for RF Front End
Authors: Jiang Dan , Li Liuhe , Su Yun , Wang Yajie , Jin Zhaoxin , Lu Hongmin
Published: December 2024

This paper introduces the structure and working principle of electromagnetic pulse protection circuit in VHF frequency band in detail. Based on this, a protection circuit with multilevel filtering and transient suppression function is designed. The filter function of the device is realized through a five-order coaxial filter, while the transient suppression feature is accomplished using TVS devices. In order to guarantee the power capacity, the input and output ports of the circuit use N-type connector. Due to good design, the operating bandwidth of the protection circuit exceeds 1.3GHz and the insertion loss is less than 0.5dB. The protective performance of this device was tested by sub-nanosecond solid-state pulse source. The experimental results show that the peak power of electromagnetic protection circuit is greater than 700kW, the suppression capacity is more than 33dB, and the response time is better than 1.4ns.