Metallic Projectile Research Articles

A Droplet Generator Using Piezoelectric Ceramics to Impact Metallic Pellets.

Metal micro-droplet ejection technology has attracted attention for its potential applications in the rapid prototyping of micro-metal parts and microelectronic packaging. The current micro-droplet ejection device developed based on this technology faces challenges such as the requirement of a micro-oxygen ejection environment, a complex feeding structure, and high costs. Therefore, a drop-on-demand droplet generator for metallic pellets with impact feed ejection is designed in this paper. This device has a simple and compact structure, does not require a high-cost heat source, and can perform drop-on-demand ejection of metallic pellets in an atmospheric environment. A micro-channel feeding method based on piezoelectric ceramic actuator drives is proposed. A rigid dynamics metallic pellet flight trajectory model is established to analyze the relationships between the driving voltage and the flight trajectory of the pellets. With the help of Fluent to simulate and analyze the melting and ejection processes of the pellets inside the nozzle, the changes in the variable parameters of the flow field in the process of the melting and flight of a single molten drop are studied. The droplet generator produces stable droplets with a 500 µs pulse width and 1100 mm/s initial velocity of the projectile. The simulation results show that a single projectile has to go through three stages including feeding, melting, and ejecting, which take 39.5 ms, 7.85 ms, and 17.65 ms. The total simulation time is 65.0 ms. It is expected that the injection frequency of the metal projectile droplet-generating device will reach 15 Hz.

Management of gunshot injury to the abdominal aorta and inferior vena cava: a case report of a combat patient wounded in the Russo-Ukrainian war

BackgroundRusso-Ukrainian war is associated with severe traumas, including injuries to the major vessels. Penetrating aortic injury remains one of the most difficult injuries; the mortality rate is 90–100% in case of gunshot wounds, associated with frequent lethal outcomes due to uncontrolled bleeding. Of the three main abdominal veins, the inferior vena cava (IVC) is the most frequently damaged, which is required quick and appropriate surgical decisions to be made. Little is known about the management of gunshot injuries to such major vessels as the aorta and IVC. It is also worth mentioning about the importance to share our practical experience from the ongoing war for better understanding and future considerations by war surgeons of the vascular trauma management. The aim of the study was to demonstrate the specific features of the diagnosis and management of a gunshot shrapnel blind penetrating wound to the abdomen with injury to the aortic bifurcation level and the infrarenal section of the inferior vena cava.Case presentationA 44-year-old male soldier of the Armed Forces of Ukraine received a gunshot injury to the abdomen from a mortars’ explosive shelling. The patient was evacuated to the Forward Surgical Team (Role 1) and received primary surgical treatment within one hour after the injury according to the “golden hour” principle. Then, evacuated was performed to the Role 3 hospital in Kharkiv. At the Role 3 hospital, the patient underwent second-look surgery as well as damage control surgery. At revision, no active bleeding was observed, and the surgical pads (packed previously by the Forward Surgical Team) were removed. Further revision showed a metal projectile within the aortic wall at the level of aortic bifurcation and wall defects were also detected for inferior vena cava. This metal projectile was removed by using the multifunctional surgical magnetic tool followed by suturing of the aortic wall defect as well as defects of the inferior vena cava.ConclusionsApplication of Damage Control Surgery is a useful approach in the management of severe vascular injury as well as useful to stop abdominal contamination by intestinal contents. The application of a surgical magnetic tool for the searching and removal of ferromagnetic foreign bodies reduces operative trauma and reduces the time for identification of foreign bodies.

A novel case of tracheal injury secondary to gunshot trauma in a white rhinoceros (Ceratotherium simum).

To describe a case of tracheal injury secondary to gunshot trauma in a rhinoceros. 5-year-old female white rhinoceros (Ceratotherium simum). The rhinoceros was found alive with an apparent bullet entry wound cranial to the left shoulder. The rhinoceros was agitated and had bilateral epistaxis and increased respiratory noise. Immobilization of the animal facilitated closer examination and initiation of medical therapy. Radiographs obtained of the neck region at this first examination were nondiagnostic. Subsequent immobilization events allowed for further diagnostics and treatment. Initial treatment included a broad-spectrum antibiotic and a corticosteroid. Five days following the injury, the rhinoceros was considered stable, and the animal was immobilized to investigate the cause of the epistaxis and respiratory signs. Tracheoscopy revealed a full-thickness penetrating wound in the mid to caudal region of the trachea, and the surface of a metallic projectile was viewed within the wound. Medical treatment was continued and the rhinoceros was managed conservatively. At 14 days, radiographs of the neck made with a more powerful unit revealed tissue emphysema dorsal to the trachea. A subsequent tracheoscopy 54 days after injury revealed a granulated wound. Follow-up at 4 years after injury determined that the rhinoceros was reported to be behaving normally and had successfully calved. Gunshot wounds associated with poaching are a prevalent problem in rhinoceros in Africa. Although more aggressive therapy including surgery may likely be considered in zoo or domestic animals, limited conservative treatment was successful in this wild-managed rhinoceros.

Enhanced structural damage behavior of liquid-filled tank by reactive material projectile impact

A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles (RMPs) impacting liquid-filled tanks, and the corresponding hydrodynamic ram (HRAM) was studied in detail. PTFE/Al/W RMPs with steel-like and aluminum-like densities were prepared by a pressing/sintering process. The projectiles impacted a liquid-filled steel tank with front aluminum panel at approximately 1250 m/s. The corresponding cavity evolution characteristics and HRAM pressure were recorded by high-speed camera and pressure acquisition system, and further compared to those of steel and aluminum projectiles. Significantly different from the conical cavity formed by the inert metal projectile, the cavity formed by the RMP appeared as an ellipsoid with a conical front. The RMPs were demonstrated to enhance the radial growth velocity of cavity, the global HRAM pressure amplitude and the front panel damage, indicating the enhanced HRAM and structural damage behavior. Furthermore, combining the impact-induced fragmentation and deflagration characteristics, the cavity evolution of RMPs under the combined effect of kinetic energy impact and chemical energy release was analyzed. The mechanism of enhanced HRAM pressure induced by the RMPs was further revealed based on the theoretical model of the initial impact wave and the impulse analysis. Finally, the linear correlation between the deformation-thickness ratio and the non-dimensional impulse for the front panel was obtained and analyzed. It was determined that the enhanced near-field impulse induced by the RMPs was the dominant reason for the enhanced structural damage behavior.

Case of gunshot injury to the liver by a hand-made modified sniper bullet: organ-preserving surgical management with damage control tactics and transpapillary biliary decompression

Combat penetrating gunshot injuries are frequently associated with damage to the liver. A bile leak and an external biliary fistula (EBF) are typical complications. Biliary decompression is commonly applied for the management of EBF. Furthermore, there is insufficient data available regarding the characteristics of combat trauma and its management in the context of ongoing hybrid warfare in East Ukraine.
 A 23­year­old male was admitted with a thoracoabdominal penetrating gunshot wound (GSW) that was caused by a high­energy multiple metal projectile (a fragmented sniper bullet). Damage control tactics was applied at all 4 levels of military medical care. Endoscopic retrograde cholangiopancreatography (ERCP), endoscopic sphincterotomy, and placement of a biliary stent were used for evaluation and biliary decompression. Stent occlusion was treated with stent replacement and scheduled ERCP. Partial EBF was diagnosed based on the primary wound defect of the liver and was closed without surgical intervention on the 34th day after injury. Acute cholecystitis was associated with ERCP and was managed with cholecystostomy.
 The combination of operative and nonoperative techniques for the management of the combat GSW to the liver is effective, along with the application of damage control tactics. Scheduled ERCP is effective for the management of EBF, so liver resection can be avoided. The transpapillary intervention with stent placement was successfully used for biliary decompression. Early post­traumatic stent occlusion can be diagnosed and effectively managed by scheduled ERCP as well as stent replacement with a large­diameter stent inserted as close as possible to the site of bile leak.

Microscopic impactor debris at Kamil Crater (Egypt): The origin of the Fe-Ni oxide spherules

Kamil crater (Egypt) is a natural laboratory for the study of processes and products associated with the impacts of small iron projectiles on the Earth’s crust. In particular, because of the distinctive composition of the impactor (an ungrouped Ni-rich ataxite) and the target (Cretaceous sandstones and minor wackes) it offers a unique opportunity to study impactor–target physical–chemical interactions. Continuing the study of impact melt ejecta, we investigated the mineralogy and geochemistry of 25 Fe-Ni spherules - representative of a suite of 135 - recovered from the soil around the crater. Samples were collected during our 2010 geophysical expedition and investigated by combining scanning electron microscope imaging, electron probe microanalyzer and Raman spectroscopy analyses. Spherules range in size from 100 to 500 µm and show a variety of dendritic textures and mineral compositions dominated by Fe-Ni oxides of the wüstite – bunsenite and magnetite – trevorite series or Fe-Ni metal. All these features indicate quenching of high temperature (1600–1500 °C) oxide or metal liquid droplets under varying oxidizing conditions. A geochemical affinity with the iron impactor recorded by the Fe, Co, Ni ratios in the constituent phases (average Ni/Co element ratio of 25.1 ± 7.6; average Ni/(Ni + Fe) molar ratio of 0.21 ± 0.13), combined with target contamination (i.e., the ubiquitous occurrence of Si and Al from trace to minor amounts), document their origin as impact melt spherules formed through the physical and chemical interaction between metal projectile and silicate target melts and air. We propose a petrogenetic model that envisions formation as liquid droplet residues of immiscible projectile in a mixed silicate melt and their subsequent separation as individual spherules by stripping during hypervelocity ejection. We also argue that this model applies to all impact events produced by small iron projectiles and that such individual Fe-Ni oxide and metal spherules should be common impact products, despite little documentation in the literature. Our detailed mineralogical and geochemical characterization will facilitate their distinction from other, similar spherules of different origin (cosmic spherules, ablation spherules) often encountered in the geologic record.

Molecular Dynamics Analysis of Damage Process of fcc Metal Multilayer And Monolayer Structures by HVI

Hypervelocity impact (HVI), up to 14,000 m/s, of metallic projectile on Al or Ni multilayer composite structure or monolayer structure are simulated by molecular dynamics (MD) method. The translational kinetic energy of the projectile causes the formation of heat and the deformation of solid bodies. Damage, deformation and phase transformation of the solid bodies are analyzed from the mesoscopic viewpoint. The space distribution of physical quantities in the both structures are visualized by CG movie in collision process.

High Speed Projectile Sensor: Design, Development and System Engineering

Chronography is a muzzle velocity and position sensor for a small metallic projectile (bullet) used for the military training purpose. We report on design, development, and performance testing of a conductor-insulator-conductor (CIC) sensory panel integrated with chronograph hardware and portable bullet speedometer. The established system is capable of dual recharging by alternating current mains as well as by battery support. The sensory mechanism is based on a short circuit voltage pulse developed while onset passage of the bullet from the screens. The pulse time is suitably registered, transferred, and communicated to a data storage unit interfaced to a multiport readout using the developed hardware. The whole sensor circuitry was, initially, simulated followed by optimization and final assembly of the hardware. Moreover, measured read out is taken onto a handheld speedometer with a capability to connect to personnel computer/laptop or cell phone using a state-of-the-art wireless fidelity communication interface. Three-dimensional printing technology was used to package the integrated sensor, after finalizing isometric engineering drawings. Details of fabrication, integration, and performance evaluation is demonstrated. System is real time, portable, power, and cost effective. Sensor is capable to measure the muzzle velocity ~1000 m/s more than 98% accuracy when compared with a standard doppler radar and an acoustic sensor. Details are presented.

Энергоемкость тканевых материалов при ударном нагружении

Space orbital stations operations support consists an adoption of meaningful measures to protect space station against impacts of space debris and meteoroids. This goal can be reached by using multilayered protection shields that are made with the fabric material layers. Shields designing and modeling requires specific characteristics that define energy absorbed volume by the fabric destruction under impact. The paper describes the methodology and experimental determination method for absorbed energy volume results by using multilayer fabrics of orbital manned stations shielding constructions under distributed impulse loading caused by the space debris impacts. The energy absorbed volume by the multilayer fabrics is obtained from the experiments by analysis of specimen and flat metal projectile impact. Projectile was accelerated by the air gas gun. The obtained experimental determination results of energy absorbed volume in pressure range up to 1,5 GPa are given. Using the model of fabric as a porous material its energy absorption volume dependence in pressure range up to 10 GPa and compared with experimental data. It is shown that for materials with high porosity absorbed energy volume against pressure dependence is close to linear. Corresponding asymptotic dependence for materials with high porosity under the high pressure is obtained.

Effect of fiber architecture on the impact resistance of composite panels subjected to metallic projectile

Experiments using a single-stage gas gun were conducted to evaluate the resistance of three types of composite panels to high-velocity impacts from metallic projectiles: panels reinforced with unidirectional tape or formed from plain-woven fabric or two-dimensionally braided fabric. The critical penetration velocity, deformation, and failure morphologies were examined by virtue of high-speed photography, 3D digital image correlation technology and non-destructive testing methods. In addition, a normalized quantity was introduced to assess the energy absorption capacity of the panels. Laminates stacked by angle-ply unidirectional tapes contained impacts at higher velocities than other panels, and the energy absorption capacities of the plain-woven and braided composite panels are comparable. The results provide insights into the impact failure behavior of composite panels and can aid in the selection of materials for aeroengine casings.

A comparison study on the impact failure behavior of laminate and woven composites with consideration of strain rate effect and impact attitude

The anisotropy and heterogeneity of carbon fiber–reinforced polymer (CFRP) composites contribute to their complex failure characteristics, posing challenges for predicting their impact failure behavior. In this study, high-fidelity finite element models are established to predict the performance of laminated and woven composite panels impacted by a metallic projectile, with consideration of strain-rate effect and impact attitudes. The numerical models are experimentally validated and are applied to investigate the impact resistance of both composites under various impact conditions. The results indicate that the maximum ratio of delamination of laminated panel is about 0.4, which is greater than 0.2 of the woven panel. Woven panels can better withstand impact damage, while laminates are more prone to delamination under high-speed impacts loads.

Crater shape as a possible record of the impact environment of metallic bodies: Effects of temperature, impact velocity and impactor density

Metallic bodies that were the cores of differentiated bodies are sources of iron meteorites and are considered to have formed early in the terrestrial planet region before migrating to the main asteroid belt. Surface temperatures and mutual collision velocities differ between the terrestrial planet region and the main asteroid belt. To investigate the dependence of crater shape on temperature, velocity and impactor density, we conducted impact experiments on room- and low-temperature iron meteorite and iron alloy targets (carbon steel SS400 and iron‑nickel alloy) with velocities of 0.8–7 km s−1. The projectiles were rock cylinders and metal spheres and cylinders. Oblique impact experiments were also conducted using stainless steel projectiles and SS400 steel targets which produced more prominent radial patterns downrange at room temperature than at low temperature. Crater diameters and depths were measured and compiled using non-dimensional parameter sets based on the π-group crater scaling relations. Two-dimensional numerical simulations were conducted using iSALE-2D code with the Johnson–Cook strength model. Both experimental and numerical results showed that the crater depth and diameter decreased with decreasing temperature, which strengthened the target, and with decreasing impact velocity. The decreasing tendency was more prominent for depth than for diameter, i.e., the depth/diameter ratio was smaller for the low temperature and low velocity conditions. The depth/diameter ratios of craters formed by rock projectiles were shallower than those of craters formed by metallic projectiles. Our results imply that the frequency distribution of the depth/diameter ratio for craters on the surface of metallic bodies may be used as a probe of the past impact environment of metallic bodies.

Design of Simulated Magnetic Gun

STM32F103 single-chip microcomputer is used as the control unit of the simulated electromagnetic squint. The single-chip microcomputer is used to control the function of launching shell and steering gear angle, and the steering gear is used to control the launching angle and direction of the electromagnetic squint. In the design of electromagnetic gun, coaxial coil gun is used as the main part, and two batteries are used as the energy supply device. Then the electromagnetic relay connected with the single-chip microcontroller controls the cycle charging. Firstly, 12V DC power is input into the circuit by the DC stabilized voltage power supply. After the current enters into the circuit, it is divided into two branches. One branch flows through the boosting circuit of electromagnetic relay to charge the thyristor capacitor. With the switch off, the instantaneous discharge of the capacitor generates an inverter magnetic field in the coil, which pushes the metal projectile out at a high speed. What the electromagnetic relay does is to boost the voltage. What the thyristor capacitor needs is high voltage current charging. Another branch supplies 5V DC power to the steering gear through the step-down electromagnetic relay to support the rotation of the steering gear. The system obtains the target position through openmv, and STM32 uses PWM wave to control the rotation angle and direction of the steering gear.

Modeling and Simulation Techniques Used in High Strain Rate Projectile Impact

A series of computational models and simulations were conducted for determining the dynamic responses of a solid metal projectile impacting a target under a prescribed high strain rate loading scenario in three-dimensional space. The focus of this study was placed on two different modeling techniques within finite element analysis available in the Abaqus software suite. The first analysis technique relied heavily on more traditional Lagrangian analysis methods utilizing a fixed mesh, while still taking advantage of the finite difference integration present under the explicit analysis approach. A symmetry reduced model using the Lagrangian coordinate system was also developed for comparison in physical and computational performance. The second analysis technique relied on a mixed model that still made use of some Lagrangian modeling, but included smoothed particle hydrodynamics techniques as well, which are mesh free. The inclusion of the smoothed particle hydrodynamics was intended to address some of the known issues in Lagrangian analysis under high displacement and deformation. A comparison of the models was first performed against experimental results as a validation of the models, then the models were compared against each other based on closeness to experimentation and computational performance.

Ballistic Penetration Analysis of Soft Laminated Composites Using Sublaminate Mesoscale Modeling

Ballistic impact mitigation requires the development of protective armor applications from composite material systems with good energy absorption and penetration resistance against threats, e.g., metallic projectiles. In this aim, high-strength and high-stiffness soft fibrous composite materials (such as ultra-high molecular weight polyethylene—UHMWPE) are often used. The high specific strength feature is one of the main reasons for using these soft composite systems in ballistic impact applications. In the present investigation, experimental and computational finite element (FE) studies were carried out to investigate the ballistic behaviors of these soft layered composite targets. To this end, a new FE multi-scale analysis framework for ballistic simulations is offered. The proposed analysis presents a new meso-scale sublaminate material model, which is applied to Dyneema® cross-ply laminate in order to predict its behavior under ballistic impact. The sublaminate model is implemented within an explicit dynamic FE code to simulate the continuum response in each element. The sublaminate model assumes a through-thickness periodic stacking of repeated cross-ply configuration. In addition, a cohesive layer is introduced in the sublaminate model in order to simulate the delamination effect leading to the subsequent degradation and deletion of the elements. This new approach eliminates the widely used costly computational approach of using explicit cohesive elements installed at pre-specified potential delamination paths between the layers. Furthermore, in-plane damage modes (such as fiber tensile, and out-of-plane shearing) are also accounted for by employing failure criteria and strain-softening. The obtained quantitative results of ballistic impact simulations show good correlation when compared to a relatively wide range of experiments. Moreover, the simulations include evidence of capturing the main energy absorption mechanisms under high-velocity impact. The proposed modeling approach can be used as a useful armor design tool.

Test on the linear induction launcher with a new type of 3-phase helical coil

Different from the classical coaxial coils, a new type of asynchronous linear motor with helical 3-phase helical coil been brought forward in this paper. It has simple structures and produces peculiar travelling magnetic waves along the axis, which lead to the metal projectile is subjected invariable axial driving forces and rotary torques at the same time. It has a very useful property of this kind of winding, which is applied as a linear asynchronous launcher’s primary section. The high speed rotating projectile has stable flying attitude in moving direction because of the gyroscopic effect. The basic electromagnetic problems of the motor were discussed in this paper. An experimental model was build and tested to verify the principle results mentioned above at last.

Impact penetration through spacecraft honeycomb panels analytical, numerical and experimental study

Abstract Sandwich panels owing its high bending stiffness and low density are widely used in space and aerospace industry [1].Sandwich panel consists of two thin face sheet separated by the core material. Core geometry and material properties determine the strength and stiffness of the sandwich panel. In the aerospace industry, foam and metal cores are used. Honeycomb core is widely used in the satellite. In this paper, the impact resistance of metallic honeycomb is studied analytically. Analytical formulation discusses the resistance force,energy dissipation and damage in the metallic honeycomb. Analytical formulation discusses the perforation velocity of the projectile as function cell size and a wall thickness of honeycomb. The quasi-static test was done on various size of the honeycomb to study penetration and perforation by a spherical projectile. Analytical Formulation was compared with the impact experimental on metallic honeycomb by Goldsmith et al. [3], A.Alavi Nia et al. [4] and H.Zhao et al.[5]. Full 3D F.E model of the metallic honeycomb and projectile was developed in Abaqus 6.14 . Material and Geometric Nonlinearity has been modeled for the metallic honeycomb in the explicit simulation. Continuum damage modeling technique is used to compare the analytical, experimental and numerical results

Lung Injuries on Computerized Tomography Due to Pellet Gun

Pellet gun used by law enforcement agencies have the potential to cause grevious or life threatening injuries as metallic projectiles fired at high speeds from pellet gun have potential to damage air containing organs like lungs which occupy a large portion of chest cavity and lie in close approximation to chest wall. Thoracic injury overall is the third most common cause of trauma following injury to the head and extremities.
 Objective. The objective of this study was to evaluate lung pellet gun injuries in patients of a conflict zone by a so called non-lethal weapon.
 Methods. The study was conducted in post graduate department of Radiodiagnosis and Imaging, Government Medical College, Srinagar Jammu and Kashmir. Our study was performed between the 6th January 2019 to the 22th May 2019. A total of 40 patients with pellet injuries were taken up for study.
 Inclusion criteria were patients with pellet gun injuries without any immediate life threatening injury like head injury; patients willing to be part of study. Radiographs of all the patients were studied. Whenever there was suspicion of severe injury, CT scan was done. We obtained thin-section axial CT scans (0.625– 1.25 mm) with multiplanar reformation with an interval of 3-5 mm.
 Results. All of the patients were males with most of patients in age group of 20 to 30 years.
 About 14 patients out of 40 had lung injuries. The most common pattern of lung injury was pneumothorax followed by pulmonary hemorrhage.
 In conclusion, a so called non-lethal pellet gun used by law enforcement agencies has the potential to cause lung injuries which can sometimes be lethal to life especially when fired from short distance.

Meloxicam to treat post-surgical pain of hemilaminectomy to remove a metal projectile in a cat: Case report

Acute spinal cord injuries are common in veterinary. Three factors can measured the severity of spinal cord injury: time (duration of compression), degree of compression, and especially compression force. Diagnosis can be made by radiography. Treatment with corticosteroids are contraindicated after six hours of spinal cord trauma. Nonsteroidal anti-inflammatory drugs such as meloxicam are recommended due to neuroprotective effect. The objective of this case report is to describe a spinal cord trauma in female cat, short hair, six months of age, treated with meloxicam, a nonsteroidal anti-inflammatory. Pacient got in Veterinary Clinic of the Anhanguera College in Dourados – MS, with paraplegia of the pelvic limbs, without response to the cutaneous panniculus test by L2, absence of bilateral proprioception in the pelvic limbs, absence of deep pain reflexes, decreased urethral and anal sphincter reflexes. Thoracolumbar spine radiographic exam shows the presence of a metal projectile in spinal cord between first and second lumbar vertebrae. Blood tests demonstrated a normocytic normochromic anemia and moderate leukocytosis. Patient was referred for a left dorsolateral hemilaminectomy to removal the metal projectile and spinal decompression. Postoperatively recovered well and pacient started to perform physiotherapy sessions.

Crater Formation on High-Velocity Collision of a Metallic Projectile with Polymethylmethacrylate Targets

The possibility of using targets made of polymethylmethacrylate for determining the velocity of metallic projectiles is considered. Results of experimental investigations of the interaction of single spherical steel particles of diameter 2.5 mm with polymethylmethacrylate targets in the velocity range 0.94–2.4 km/s are presented. The acceleration of particles is achieved with the aid of a light-gas magnetoplasma launcher. A semiempirical dependence of the depth of penetration of steel projectiles into a polymethylmethacrylate target on the collision velocity has been obtained.