Gun System Research Articles

The Turreted Gun System Technology Integrated To The Helmet Mounted Display System

This research aims to emphasize the operational importance of avionics subsystems integrated into helicopters, primarily used for assault purposes, such as the Helmet Mounted Display System (HMDS) and Turreted Gun Systems. It addresses the functional capabilities of HMDS in target detection and aiming, as well as the defense and engagement capabilities of Turreted Gun Systems against various threats. The focus of the research is on evaluating the parametric data, such as the dispersion of the Turreted Gun Systems and the targeting performance values of the HMDS, during their use together. It also assesses the transmission of this data through a Kalman filter before being sent to the Turreted Gun Systems to mitigate platform-induced disruptive factors. The findings help us understand the profound impact of technological advancements in helicopter avionics systems on operational effectiveness. Additionally, this study sheds light on the impact of dispersion values on hit performance during usage. It is assessed that the proposed method in this study will result in more stable data, and that controlling the Turreted Gun Systems with this stable data can enhance hit performance. The study can be further developed by examining subsystems with different performance characteristics and filtering methods.

Ballistic impact performance of aramid fabrics impregnated with single‐phase shear thickening fluids STFs and SiC additive multi‐phase shear thickening fluids

AbstractThis study presents STF/Fabric composite configurations by impregnating single‐phase shear thickening fluids (S‐STF) and multi‐phase shear thickening fluids (M‐STF) into aramid fabrics. S‐STFs were first prepared at different concentrations by weight (25%, 40%, 55%, and 65%). In addition, M‐STFs were produced by adding silicon carbide (SiC) additive to S‐STFs. As a result of the impregnation of the produced STFs on Aramid fabrics, 30‐layer composite samples were prepared. To determine the ballistic performance of the produced samples, tests were carried out with a single‐stage gas gun system. The shots were performed at an average velocity of 670 m/s. Ballistic tests show that STF‐impregnated fabric samples have better ballistic performance compared to fabric without STF. The STF65/Aramid sample is notable for a 238% increase in energy absorption. In addition, the STF40SiC10/Aramid composite sample produced with M‐STF was found to absorb 18.7% more energy compared to the STF40/Aramid sample. It has been confirmed that keeping the weight ratio of the additive at an optimum level will contribute to ballistic performance. These results contributed to determining the optimum concentration amount for STF/Aramid composites at high speed.Highlights S‐STF and SiC additive M‐STFs were produced. STFs were impregnated into 30‐layer Aramid fabrics. Ballistics tests were performed on S‐STF/Aramid and M‐STF/Aramid composite samples with a single‐stage gas gun system. The effects of S‐STF and M‐STF on ballistic performance were investigated. The addition of STF enhanced ballistic performance by increasing energy absorption.

Mechanical properties and impact behavior of frozen clay: Insights from static mechanical tests, fly-plate tests, and split-Hopkinson pressure bar analysis

The presence of frozen clay as a natural protective material makes it a crucial layer of defense against potential impacts in various engineering projects. Studying the strength and deformation characteristics of frozen clay is, therefore, particularly important. In this study, static mechanical tests, the Hopkinson impact test, and fly-plate tests were conducted on frozen clay to identify its mechanical properties under an impact load. The uniaxial compression strength, flexural strength, and elastic modulus displayed a linear increase with the change in temperature. The fractal dimension was used to describe the failure characteristics of frozen clay, yielding values ranging from 1.5691 to 1.8785. At the same temperature, the fractal dimension exhibited a strain rate effect as the strain rate increased. A light gas gun system was then used to conduct fly-plate tests on frozen clay at varying temperatures (−3, −20 °C, and ordinary temperature). The impact process was meticulously analyzed, considering factors such as shock wave velocity, particle velocity behind the shock wave, impact pressure, and volume strain. Moreover, our investigation plotted the D–u (volume strain–particle velocity) and P–μ shock (impact pressure–shock wave velocity) adiabatic curves. Notably, we observed that samples with a higher initial strength exhibited an increased resistance to compression under an identical initial density and moisture content, resulting in a discernible leftward shift of the P–μ curve. The results provide a theoretical basis and technical support for similar projects in the future.

A study on motion characteristics of the forced vibration of a floating body in two-degree-of-freedom machine gun system with impact and momentum offset

Floating technology is an emerging firearm recoil reduction technique. Firearms utilizing this technology differ significantly from traditional firearm systems, featuring distinctive characteristics of a two-degree-of-freedom system. This paper presents a novel model for this floating principle machine gun, incorporating a bi-directional buffer spring. The model is established and validated against experimental results. The experiment reveals both the floating body and the automaton body exhibit quasi-harmonic motion with some randomness. An observed impact and momentum offset between the floating body and the automaton body show an offset efficiency of 29%. The stiffness of the two springs is thoroughly analyzed regarding its influence on the floating characteristics, especially the backward ending state of the bi-direction floating body, offset efficiency, and triggering consistency. Increasing the stiffness of the bi-direction floating spring raises the bi-direction floating body’s motion frequency, resulting in a delayed phase at triggering time. Likewise, augmenting the automaton spring stiffness increases its motion frequency and advances the bi-direction floating body’s phase at triggering time. These adjustments affect the relative phase between the bi-direction floating body and the automaton body, thus impacting the backward ending state, offset efficiency, and consistency.

Experimental and numerical study on projectile impact damage of EBC-SiC/SiC

The ingested particles or debris will cause high-speed & low-energy impact to the hot end components of aeroengine. Few literature focus on the projectile impact of SiC/SiC with Environmental Barrier Coating(EBC). The impact of 2 mm projectile was specially studied for Si/Yb2Si2O7/Yb2SiO5-SiC/SiC. Gas gun system was used to conduct impact testing at the speed of 3 m/s∼353m/s. The optical microscope, Scanning Electronic Microscope(SEM), micro CT were used to observe the impact and tension after impact(TAI) damage. For TAI, Digital Image Correlation (DIC) was used to conduct the full-field strain detection around the impact point. Meanwhile, the Smoothed Particle Hydrodynamics (SPH) methodology was programmed in C++ and developed to simulate SiC/SiC impact problem by introducing modified Hashin-Rotem criteria, extending interface method to 3D and adding GPU accelerated algorithm. The results indicate that threshold velocities of EBC huge peeling and SiC/SiC penetration are different, TAI residual strength also has extinct threshold at the velocity of 246 m/s with 37.1% declining extent, and the impact pit depth of SPH simulation is in good agreement with the experiment.

Experimental research on crush response and impact energy absorption of dual-material biomimetic honeycomb structures

This article proposes a soft/hard dual-material honeycomb structure. The quasi-static and dynamic crush modes and crashworthiness of six groups of honeycombs were studied by using universal testing machine and multi-purpose impact gun system. Experimental results indicate that under quasi-static conditions, dual-material honeycombs exhibit similar crush modes, while single-material honeycombs have regular and progressive folding modes. Under dynamic impact, single-material honeycombs will collapse overall along cracks, while dual-material honeycombs exhibit layer-by-layer collapse and negative Poisson’s ratio phenomena. The dual-material structures exhibit the best crashworthiness. The bionic corrugation and dual-material design show excellent synergy in enhancing the energy-absorbing performance of the structure.

Combined biolistic and cell penetrating peptide delivery for the development of scalable intradermal DNA vaccines

Physical-based gene delivery via biolistic methods (such as the Helios gene gun) involve precipitation of nucleic acids onto microparticles and direct transfection through cell membranes of exposed tissue (e.g. skin) by high velocity acceleration. The glycosaminoglycan (GAG)-binding enhanced transduction (GET) system exploits novel fusion peptides consisting of cell-binding, nucleic acid condensing, and cell-penetrating domains, which enable enhanced transfection across multiple cell types. In this study, we combined chemical (GET) and physical (gene gun) DNA delivery systems, and hypothesized the combination would generate enhanced distribution and effective uptake in cells not initially transfected by biolistic penetration. Physicochemical characterization, optimization of bullet contents and transfection experiments in vitro in cell monolayers and engineered tissue demonstrated these formulations transfected efficiently, including DC2.4 dendritic cells. We incorporated these formulations into a biolistic format for gene gun by forming fireable dry bullets obtained via lyophilization (freeze drying). This system is simple and with enhanced scalability compared to conventional methods to generate bullets. Flushed GET bullet contents retained their ability to mediate transfection (17-fold greater and 13-fold greater reporter gene expression than standard spermidine bullets in the absence and presence of serum, respectively). Fired GET bullets in vitro (in cells and collagen gels) and in vivo (mice) showed increased reporter gene transfection compared to untreated controls, whilst maintaining cell viability in vitro and having no obvious toxicity in vivo. Lastly, a SARS-CoV-2 plasmid DNA vaccine with spike (S) protein-receptor binding domain (S-RBD) was delivered by gene gun using GET bullets. Specific T cell and antibody responses comparable to the conventional system were generated. The non-physical and physical combination of GET‑gold-DNA carriers using gene gun shows potential as an alternative DNA delivery method that is scalable for mass deployable vaccination and intradermal gene delivery.

Study on impact resistance of sandwich glass based on CT scan-3D reconstruction

Utilizing the light gas gun system, impact tests on sandwich glass specimens with various structural configurations were performed at high-speed, medium-speed, and low-speed to evaluate the impact resistance of polyvinyl butyral (PVB) sandwich glass. An impact damage test method that incorporates stress data and three-dimensional fracture data was proposed in conjunction with the CT scan-3D reconstruction technique. The experimental findings demonstrated that as glass thickness grew, sandwich glass’ rigidity increased noticeably, and impact resistance of sandwich glass was significantly improved. On the other hand, under the action of elastic deformation energy absorption and horizontal cohesion of the PVB interlayer, the thicker interlayer could consume and disperse more impact energy, making the veins radially distributed and reducing the flying of debris. The conclusion that thin glass-thick interlayer could equivalently replace thick glass-thin interlayer to a certain extent was obtained. The study offers crucial technological backing for sandwich glass’s industrial applicability.

Dynamic engraving characteristics of nylon belt under different charge conditions

Abstract In the present study, a 105 mm short tube gun system was designed to conduct the firing experiments under low charge conditions, which could precisely obtain the projectile displacement data and projectile base pressure data during the engraving process. Besides, a 3-dimensional dynamic engraving FEM-SPH model was established by coupling the internal ballistic process to much authentic investigate the engraving characteristics of the projectile, which were verified and compared through the experiment. On this premise, the influence mechanism and engraving features of the nylon belt were numerically calculated under higher charge conditions. The comparison between the experimental recovery belt and the numerical calculation results shows that the damage to the front of the nylon belt is axial compression wear, while the damage to the back of the nylon belt is circumferential shear wear. The direction of force exerted by the slope chamber and the projectile body on the belt was inconsistent, causing a bulge in the middle of the nylon belt. The more rapid the average boosting rate, the stronger the instantaneous impact on the nylon belt, the larger the stress and the strain damage on the nylon belt, the higher the pressure at the end of the engraving process and the greater the maximum engraving resistance. When the average boosting rate increased from 2.7 MPa⋅ms−1 to 33.0 MPa⋅ms−1, the engraving time was shortened by 73.9%, while the maximum engraving resistance increased by 78.2%.

Comparative Analysis Of A Multi-Layered Weapon System For City Air Defense In The Modern Warfare

In the era of modern warfare, urban defense is a very important aspect to maintain the security and stability of a country. Because modern war is a non-military war in which developed countries and foreign countries try to destroy a country through ideological, political, social, cultural and security defense. To protect the territory with effective air defense, it takes a strong and sophisticated defense resources with a reliable range of surveillance and agility to destroy any effort that threatens the security and sovereignty of the country. To achieve the objective of building a more efficient air defense system and functioning alongside other air defense platforms, new ideas and thinking are needed for program planning and the requirements of medium-range missile systems when building an air defense system. The research method used in this research is descriptive qualitative through a literature study. In the literature review, it is necessary to conduct a thorough search to ensure that the literature sources used are truly relevant to the research topic and a comparative analysis approach is used. In the realm of analyzing layered weapon systems, such as Hisar O, Hisar A, Korkut Gun System, Iron Dome, and NASAMS, it becomes imperative to delve into the comparative analysis and interpret the implications of their similarities and differences. Hisar O, a sophisticated air defense system, showcases advanced capabilities designed to counter aerial threats. Its cutting-edge technology and robust infrastructure provide a formidable defense mechanism. On the other hand, Hisar A, another component of the layered defense, excels in short-range air defense, ensuring effective protection against low-altitude aerial targets. Korkut Gun System, presents a unique blend of artillery and air defense capabilities. Its adaptable nature allows it to provide ground forces with enhanced protection against a wide range of threats. Iron Dome system has gained international recognition for its exceptional performance in countering short-range rocket threats. This innovative system incorporates advanced tracking and interception technologies, enabling it to neutralize incoming projectiles with a high success rate. NASAMS (Nationals Advanced Surface-to-Air Missile System) stands out as a versatile air defense solution. Its state-of-the-art radar and missile technologies ensure reliable protection against a variety of airborne threats, including aircraft, helicopters, and unmanned aerial vehicles (UAVs). Now, let's delve into the implications of these comparative analyses for Indonesia. By understanding the strengths and weaknesses of each system, Indonesian defense strategists can make informed decisions regarding their defense capabilities. This analysis assists in identifying potential gaps in the country's air defense network and formulating strategies to address them effectively. In conclusion, through a comparative analysis of layered weapon systems such as Hisar O, Hisar A, Korkut Gun System, Iron Dome, and NASAMS, we gain valuable insights into their capabilities and implications. evaluating differences and similarities, can help Indonesian defense planners make informed decisions to strengthen city air defense systems in the modern warfare.

The fluid-structure interaction response of composite auxetic re-entrant honeycomb structures to underwater impact

In this paper, the effects of the gradient form, peak pressure and decaying time on the fluid-structure interaction of composite auxetic re-entrant honeycomb structures was experimentally and numerically investigated. The specimens for this experiment were manufactured by hot-press molding method. The acrylic transparent tube was utilized to accommodate water medium, pistons and specimen during experiment. The exponential decaying shock wave was simulated by accelerating the fly plate to impact the piston based on the one-stage light gas gun system. The incident velocity of the fly plate and process of the fluid-structure interaction response were monitored by high frame rate camera. In addition, the velocity of the shock wave in water was measured by transducers installed at different measuring points. The voltage signal of the dynamic overpressure collected by transducers was amplified by the charge amplifier and recorded by the oscilloscope. On the other hand, finite element software Abaqus/Explicit was applied to simulate the cavitation process of water domain and dynamic response of specimens. The experimental results and numerical results were in good agreement. The results indicated that the increase of the thickness of the fly plate had a certain effect on the propagation velocity of the shock wave, and the increase of the peak pressure would make the cavitation generation position close to the fluid-structure interface and make the cavitation duration longer. And the average structure which has a minimum transformation of 8.12 mm shows better underwater impact resistance than the gradient structure.

Development of an impact based pyroshock test setup using finite element and response surface methods

In this study, a simulation and test-based procedure is created and applied to develop mechanical pyroshock test setup. In order to build an effective design, preliminary input parameters are defined with finite element simulations. The agreement between impact simulations and experimental data was achieved for resonant plate, metallic anvil plate and gun system. The obtained Shock Response Spectrum (SRS) curves are not well fitted to explicit finite element simulations for nonmetallic anvil plate materials, such as felt, which also have significant contribution to results. Therefore, further improvement is established by using test-based Response Surface Method (RSM). After validating the relationship statistically, response optimizer was used to find the best combination of design parameters to achieve target SRS curve. Finally, the prediction was checked experimentally to show the effectiveness of the developed methodology.

Delamination Behavior of CFRP Laminated Plates under the Combination of Tensile Preloading and Impact Loading.

When subjected to impact loading, aircraft composite structures are usually in a specific preloading condition (such as tension and compression). In this study, ballistic tests were conducted using a high-speed gas gun system to investigate the effect of biaxial in-plane tensile preload on the delamination of CFRP laminates during high-speed impact. These tests covered central and near-edge locations for both unloaded and preloaded targets, with the test speeds including 50 m/s, 70 m/s, and 90 m/s. The delamination areas, when impacting the center location under 1000 με, show a 14.2~36.7% decrease. However, the cases when impacting the near-edge location show no more than a 19.3% decrease, and even more delamination areas were observed. In addition, in order to enhance the understanding of experimental phenomena, numerical simulations were conducted using the ABAQUS/Explicit solver, combined with the user subroutine VUMAT with modified Hou criteria. The experimental and simulation results were in good agreement, and the maximum error was approximately 12.9%. The results showed that not only the preloading value but also the impact velocity have significant influences on the delamination behavior of preloaded CFRP laminated plates. Combining detailed discussions, the biaxial tensile preload enhanced the resistance to out-of-plane displacement and caused laminate interface stiffness degradation. By analyzing the influence of the preloading value and impact velocity on competing mechanisms between the stress-stiffening effect and interface stiffness degradation effect, the complex delamination behaviors of laminates under various preloading degrees and impact velocities at different impact locations were reasonably explained.

Effect of incorporating Lode angle into fracture criterion on predicting ballistic resistance of 6061-T651 aluminum alloy plates with different thicknesses struck by blunt projectiles

According to existing research, in addition to the second deviatoric stress invariant, Lode angle parameter (hereinafter abbreviated as Lode angle), which is related to the third deviatoric stress invariant, is also required to be taken into account when studying plastic flow and failure of metal materials. In order to study the effect of incorporating Lode angle into fracture criterion on predicting ballistic resistance of 6061-T651 aluminum alloy plates, a one-stage gas gun system was used to conduct ballistic tests of 6061-T651 aluminum alloy plates with different thicknesses when struck by the blunt projectile with a diameter of 12.66 mm and a mass of 34.0 g. Meanwhile, Abaqus/Explicit finite element software with user-defined material subroutine (VUMAT) was used to establish corresponding finite element models. Under the same constitutive model, numerical simulations were carried out by using Lode independent MJC fracture criterion and Lode dependent WMJC fracture criterion. It is found that when using MJC fracture criterion, not only the ductility of material is overestimated in low stress triaxiality state, resulting in significantly higher predicted ballistic limits; but also the predicted material fracture strain in high stress triaxiality state is negative, sometimes causing irrational predictions. Therefore, some modifications to MJC fracture criterion are needed to reasonably predict the impact process. By contrast, the predicted results of Lode dependent WMJC fracture criterion are more consistent with experiments. Besides, as the thickness of the target increases, the ballistic limit shows an “S” shaped growth trend. Overall, for ballistic tests of targets with different thicknesses, WMJC criterion has a better predictive effect than MJC criterion, indicating the importance of incorporating Lode angle into fracture criteria.

A Study of the Dynamic Mechanical Properties of Q460D Steel

The dynamic mechanical properties of Q460D steel were studied to facilitate an assessment of the impact resistance of building structures. In the present work, material performance tests of Q460D steel at different temperatures, strain rates, and stress states were conducted. Using a hybrid experimental–numerical approach, a modified Johnson–Cook (JC) constitutive relation, a modified Johnson–Cook (JC) fracture criterion, and a lode-dependent fracture criterion were calibrated. To validate the calibration, Taylor impact tests of Q460D steel rods onto rigid target plates were carried out in a one-stage light-gas gun system. Mushrooming, tensile splitting, and petalling failure modes were obtained as the impact velocity was increased from 191.6 to 422.1 m/s. A three-dimensional finite element model was built for the Taylor impact tests, and FE simulations were run using the material models calibrated. It was found that the FE simulations using the lode-dependent fracture criterion were reasonable in terms of the failure modes of the Taylor rods. In contrast, the fracture behavior of the Taylor rods was significantly underestimated using the lode-independent JC fracture criterion. Finally, the effect of anisotropy, strain rate sensitivity and yield plateau on the Taylor impact FE predictions were explored and discussed.

ZK61m magnesium alloy plate thickness effect on the impact characteristics of blunt projectiles experimental and numerical simulation studies

To study the impact resistance of ZK61m magnesium alloy plate, firstly, impact experiments were conducted on magnesium alloy plates of different thicknesses using a one-stage gas gun system to obtain the ballistic limit velocity (BLV) and failure mode of the target plate. In addition, the velocity of the punch plug was analyzed by the squeeze chisel block velocity model. Finally, the corresponding numerical simulations were carried out using the Lode parameter-independent MJC fracture criterion and the Lode parameter-dependent MMC fracture criterion, and the influence mechanism of the Lode parameter on the numerical simulation results was analyzed. The results show that under the impact of the blunt projectile, different thicknesses of target plates mainly occur shear plug failure, the BLV first tends to flatten and then increases sharply with the increase of its thickness. Besides, in the same velocity interval, the plugging velocity decreases with the increase of the target plate thickness; the Lode parameter has an obvious influence on the simulation results, which the MMC fracture criterion is more consistent with the experimental results. However, with the increase of the target plate thickness, both MMC and MJC fracture criteria show the phenomenon of overestimation of the material ductility.

A planning strategy for sprinkler-based variable rate irrigation

Automated variable rate irrigation (VRI) is one of the frontiers for sustainable water use in agriculture. In this paper, we describe a planning procedure for self-propelled rain gun sprinklers, a type of equipment largely used in irrigation of open field crops thanks to its relatively low cost and easy deployment in multiple sites. The sprinkler is commanded by an information system which acquires data from remote sensors (satellite), processes vegetation indices and spatial maps describing the water need of the crop, and computes a VRI prescription map for a specific field, i.e. the water quantity to be supplied to each field sub-area. The VRI prescription map is used to compute the motion commands for a rain gun system pulled by a hose reel. The procedure is based on a sprinkler model, has been validated by simulation, and is fully automated. Experiments have shown the precision in water distribution achievable with software-controlled sprinklers and effective planning strategies.

Normal and oblique ballistic impact damage behaviour of functionally graded plates: Experimental and numerical

The present study discusses experimental and numerical investigations on the dynamic response of functionally graded plates subjected to normal and oblique ballistic impact. Functionally graded plates were produced in a step-wise manner with powder metallurgy method using powder stacking-hot pressing technique. An experimental configuration was developed where projectiles impact functionally graded plates with three different compositions at impact angles of 0°, 15°, 30°, 45°, and 60°. Ballistic tests of functionally graded plates were carried out with a single-stage gas gun system using fragment simulating projectile (FSP) at velocities of approximately 610 m/s. The effect of the material composition and obliquity on damage and deformation of functionally graded plates was studied by varying the Al 6061 and SiC volumetric ratios to metal-rich (n = 0.1), linear (n = 1.0), and ceramic-rich (n = 10.0). Finite element analyses of functionally graded plates were performed with ANSYS Ls-Dyna explicit solver by employing the Mori Tanaka method to determine local material properties in the graded region and the TTO model to define elasto-plastic material behavior. The normal and oblique ballistic tests of functionally graded plates were compared with the values predicted from the finite element model in terms of damage, deformation, and fracture mechanisms. According to both numerical and experimental studies, the impact angle and material composition were found to be significant influences on damage and deformation of functionally graded plates. Given the complexity of the modeling of the ballistic impact events, the numerical models developed to predict the penetration depth and failure mechanism of plates in the ballistic impact tests showed a good agreement for n = 0.1 and n = 1.0 material compositions due to their metal-rich compositions.

Design and Research of Missile launcher Drive System for Anti-aircraft Gun and Missile Weapon System

Aiming at the problems of large size and weight of electric cylinder, low efficiency and large pressure fluctuation of centralized hydraulic drive system, a drive system of anti-aircraft gun and missile weapon system based on electro-hydrostatic actuator is designed. The working principle of the hydraulic system of electro-hydrostatic actuator is discussed, its components are selected and designed, the micro cartridge hydraulic control check valve is designed and the electro-hydrostatic actuator is analyzed and integrated structure is designed;The simulation model is established by AMEsim software. The simulation results show that the electro-hydrostatic actuator can move the missile driving device to the highest position within 2s, meet the working requirements, and have certain guiding significance for the research and development of missile launcher driving.

Effect of Lode angle and projectile diameter on the ballistic resistance of 6061-T651 aluminum alloy plates struck by hemispherical nosed projectile

Aluminum alloy has been gradually applied to the field of armor protection because of its excellent material properties. The research on its ballistic resistance has important theoretical and engineering application value. In order to study the ballistic resistance of 6061-T651 aluminum alloy plate, the impact tests of 6061-T651 aluminum alloy plate against hemispherical nosed projectile with a diameter of 12.66 mm were carried out with a light gas gun system and the ballistic limit velocity and failure mode of the target plate were obtained. Subsequently, the numerical simulations corresponding to the tests were carried out by using the Lode dependent and independent fracture criteria, and the effect mechanism of the Lode angle on the numerical simulation results were analyzed. Finally, the effect of projectile diameter on the ballistic resistance of the target plate was analyzed by the expansion of numerical simulation. The research results show that the numerical simulation will be quite different from the test results if the effect of the Lode angle on the material fracture strain is not considered. As the diameter of the projectile increases, the armor-piercing efficiency of the hemispherical nosed projectile is improved since the energy dissipation mechanism of the target plate gradually changes from ductile hole enlargement to shear plugging.