Low Velocity Projectiles Research Articles

Ballistic projectiles removal in head and neck region

ABSTRACT Injuries caused by firearm projectiles in the head and neck region generally imply severe morbidity and mortality, representing an important public health problem. These injuries can be classified as: penetrating, perforating and avulsive, and the latter is the most worrisome, because they are caused by high-velocity projectiles. Low-velocity projectiles commonly cause penetrating injuries, sometimes remaining lodged in tissues, and their removal may or may not be indicated, depending on factors such as location and severity of the lesion. This paper presents the report of three clinical cases that address injuries caused by low-velocity firearm projectiles, in which they had the indication of this artifact removal, addressing the pre, trans and post-surgery procedures. And we point out that full tactical, technical and theoretical domains are required from the Oral-Maxillofacial Surgeons for being successful in the planning and success in the treatment of these lesions.

Experimental study on anti-penetration mechanism of bolted composite protective structure with limited span under impact of low-velocity projectile

In order to study the influence of the bolt joint mode on low-velocity projectiles penetrating the composite protective structure, two bolt joint models which connect the composite target to the fixed frame were designed, the ballistic test of the bolted composite protective structure with limited span was carried out, and the bearing and failure characteristics of the bolted region, as well as the energy dissipation of each part of the structure, were analyzed. The results show that in the condition of low-velocity impact, there are three failure modes for the bolted composite protective structure subjected to projectile penetration, including failure of the impact point of the composite target, failure of protective structure connecting components and failure of the holes in the bolted region of the composite target; the failure mode of bolt holes in the bolted region has a great influence on the protection performance, and the allowable value of the bearing capacity of the bolted region depends on the sum of the minimum failure load in the failure modes and the friction force; shear-out failure occurring in the bolt holes in the bolted region exerts the greatest effect on ballistic performance, which should be avoided; When simultaneous failure occurs in the bolted region and the free deformation region of the composite protective structure, the energy absorption per unit surface density of the composite protective structure reaches the maximum, which can give full play to its anti-penetration efficiency.

Impacted waves in granular media: A laboratory scale asteroids experiment

Asteroids and small bodies of the Solar System can be considered as agglomerates of irregular boulders, therefore cataloged as granular media. Ejections of particles and dust, resulting in a cometary-type plume, can result from impacts on their surface generating waves within these bodies and potentially causing modifications in the rocks distribution. Since no asteroid seismicity data are available, we propose a laboratory scale experiment of impact-induced seismic waves in granular media. Our study focuses on the influence of static compression mimicking pressure variations induced by self-gravity on the asteroid interior. A cubic box (50 x50 x50 cm) filled with different natural and artificial granular matter is impacted with low velocity projectiles (40 to 200 m/s). An array of accelerometers records the resulting wavefield while the box is compressed to understand its dependence with the monitored internal pressure. This study is relevant to understand how asteroids reacts to kinetic energy, as is will be tested at real scale during the Asteroid Impact and Deflection Assessment mission (2022).

Comparison of porcine organs and commonly used ballistic simulants when subjected to impact from steel spheres fired at supersonic velocities

Firearm injuries are common in the world today, in both military and civilian settings. Research into the effects different ammunition has on the human body has been conducted using tissue simulants such as Ballistics Ordnance Gelatine. Previous research has found that with low velocity projectiles, the tissue simulants only represent a selected few organs, as the human body and its organs/tissues are not homogeneous. The aim of this research was to determine which ballistic simulants best represent the abdomen and thorax, for the purposes of anatomical modelling. A mounted firearm was used to fire specially made ammunition containing a sabot and steel spherical projectile at medium (∼500m/s) and high (∼900m/s) velocities. Test specimens of 50mm cube porcine tissues (lung, liver, kidney and heart) and ballistics simulants (20% and 10% Ballistics Gelatine and Clear Gel) were shot at and the energy loss determined using Doppler radar, optical infra-red sighting screens and high speed video. This study determined that the conclusions drawn from studies in these tissue simulants may not be an accurate representation of what occurs in human tissues and that different impact velocities produce differing results. New simulants are required to better represent the energy loss of a projectile through the organs of the abdomen and thorax and the results of this study may guide this development. Further experiments will be required to determine different concentrations of gelatine and their accuracy at representing the heterogeneous nature organs of the human body.

An empirical equation between track radii and melting temperatures and its consequences for insulators irradiated by swift heavy ions

A universal function Θ(r) describes the empirical relationship between track radii Re and melting temperatures Tm without involving any other materials parameters. The precise form of the function Θ(r) is derived. Track radii Re for mica and NiFe2O4 are calculated from the experimental data of TeO2 and Y3Fe5O12 by using only the Tm values and Θ(r). The good agreement of the calculated values with the data for low and high velocity projectiles confirm the validity of Θ(r) in a broad range of the electronic stopping power Se. Consequences for the damage cross-section velocity effect are discussed. Equations are derived from Θ(r) for the track evolution Re2-Se and the threshold value of Se for track formation which agree with the basic equations of the analytical thermal spike model.

Bioarchaeological Investigation of Possible Gunshot Wounds in 18th Century Human Skeletons from Korea

Notwithstanding the relative abundance of bioarchaeological evidence of pre-20th century gunshot wounds discovered at European and American archaeological sites, similar findings in East Asian countries have been very rare. In this study, we report evidence of possible gunshot wounds sustained by two individuals buried in Joseon tombs of Korea. The shapes of the trauma seemed to indicate low-velocity projectiles, most likely musket balls. To our knowledge, this is the first bioarchaeological report specifically concerning possible gunshot-wound evidence in East Asian skeletons recovered from archaeological fields. Copyright (c) 2011 John Wiley & Sons, Ltd. Language: en

Asymmetric impacts of near-Earth asteroids on the Moon

Recent lunar crater studies have revealed an asymmetric distribution of rayed craters on the lunar surface. The asymmetry is related to the synchronous rotation of the Moon: there is a higher density of rayed craters on the leading hemisphere compared with the trailing hemisphere. Rayed craters represent generally the youngest impacts. The purpose of this paper is to test the hypotheses that (i) the population of Near-Earth asteroids (NEAs) is the source of the impactors that have made the rayed craters, and (ii) that impacts by this projectile population account quantitatively for the observed asymmetry. We carried out numerical simulations of the orbital evolution of a large number of test particles representing NEAs in order to determine directly their impact flux on the Moon. The simulations were done in two stages. In the first stage we obtained encounter statistics of NEAs on the Earth's activity sphere. In the second stage we calculated the direct impact flux of the encountering particles on the surface of the Moon; the latter calculations were confined within the activity sphere of the Earth. A steady-state synthetic population of NEAs was generated from a debiased orbital distribution of the known NEAs. We find that the near-Earth asteroids do have an asymmetry in their impact flux on the Moon: apex-to-antapex ratio of 1.32 +/- 0.01. However, the observed rayed crater distribution's asymmetry is significantly more pronounced: apex-to-antapex ratio of 1.65 +/- 0.16. Our results suggest the existence of an undetected population of slower (low impact velocity) projectiles, such as a population of objects nearly coorbiting with Earth; more observational study of young lunar craters is needed to secure this conclusion.

Penetrating injury to cervical spine from a nail gun

Though modern civilian neurosurgical practice frequently encounters unusual penetrating injuries of cranium and spine; penetrating nail injuries to neck are very rarely described. We describe the case of a 24 year old male who suffered such an injury from a nail gun. The history, radiological studies and treatment are presented. Mechanism of injury seems to share characteristics of low velocity projectiles. We discuss the management of this unusual case reviewing the current literature on penetrating neck injuries caused by similar objects.

Teeth in the brain: An unusual presentation of penetrating head injury

Penetrating injuries other than gunshot wounds or low-velocity wounds to the head are extremely rare. We report the case of a 19 year old male who sustained a penetrating craniocerebral trauma following a road traffic accident. Mechanism of injury seems to share characteristics of low velocity projectiles. We discuss the management of this unusual case reviewing the current literature on craniocerebral injuries caused by similar objects.

Static and dynamic finite element analysis of honeycomb sandwich structures

The extensive use of honeycomb sandwich structures has led to the need to understand and analyze their low velocity impact response. Commercially available finite element software provides a possible analysis tool for this type of problem, but the validity of their material properties models for honeycomb materials must be investigated. Three different problems that focus on the effect of differences in honeycomb material properties on static and dynamic response are presented and discussed. The first problem considered is a linear elastic static analysis of honeycomb sandwich beams. The second is a nonlinear elastic-plastic analysis of a circular honeycomb sandwich plate. The final problem is a dynamic analysis of circular honeycomb sandwich plates impacted by low velocity projectiles. Results are obtained using the ABAQUS final element code and compared against experimental results. The comparison indicates that currently available material properties models for honeycomb materials can be used to obtain a good approximation of the behavior of honeycomb sandwich structures under static and dynamic loading conditions.

Dynamic Analysis of Penetrating Trauma

Whereas considerable literature exists on the wounding mechanics of high velocity projectiles in the military domain, there is a paucity of such data from projectiles routinely encountered in the civilian population in the United States. This study was undertaken to develop a methodology and to determine the dynamics of penetrating trauma secondary to low velocity projectiles (200-300 m/sec). To demonstrate the feasibility of the methodology and the experimental protocol, two markedly different projectiles were chosen in the study. Two projectiles were discharged into a human tissue simulant; one projectile was smooth and the other was of the expansion type. High-speed video photographic analysis and synchronized trigger techniques were used to describe the path of the projectile during its travel within the simulant. The temporal transient and residual profiles demonstrating the "wound involvement" were computed. Results indicated a stark contrast between the two cases. There was a ratio of approximately three-to-one in the maximum wound involvement due to penetration. Transient wave oscillations during penetration and perforation of the projectile from the tissue simulant demonstrated significant differences in amplitudes and time durations. In addition, the residual wound involvement profiles indicated differences in the injury potential. This study has provided an experimental methodology to delineate the temporal dynamic behavior of penetrating projectiles. To fully quantify and differentiate the dynamic differences in the temporal behaviors of the numerous available projectiles (with various combinations in design, type of equipment, and discharge), further research in this area is clearly necessary. The present protocol lends itself to be used to systematically analyze all these behaviors. Quantified data may assist clinical personnel in the management of penetrating trauma.

Theory and Practice of Projectile's Penetration in Soils

Experimental studies of soil penetration by low-velocity projectiles stimulated the development of theoretical modeling of the phenomena. We developed a model of vertical penetration of granular soils verified by known experiments and dimensional analysis. The experimental results showed nonmonotonic dependence between projectile deceleration and depth of penetration. Net resistant force was found to be a complicated function of variable deceleration and depth. This force was defined not only with pure dynamic and static components, but also with a mixed component important for interpretation of experimental results. Theoretical analysis of nonmonotonic variation of resistance with depth permits evaluation of static properties of noncohesive material using dynamic characteristics of projectile penetration. An understanding of physical processes governing projectile's deceleration was acquired. Velocity and acceleration are obtained as functions of initial velocity, depth of penetration, and media properties. We show two conditions when peaks of acceleration are observed. The initial peak is due to dynamic characteristics, and the second peak is due to static characteristics of penetration.

Atomic Collision Experiments Utilizing Low-Velocity, Highly-Charged Ion Beams

Intense beams of highly-stripped ions are now routinely produced at low velocities using the Brookhaven dual MP-tandems in a unique four-stage accel/decel mode. This mode of operation combines three stages of acceleration, stripping at high energy, and one stage of deceleration to near-zero velocity. To date, experiments have used 10-100 nA beams of bare and few-electron heavy ions at energies as low as 0.2 MeV/amu, and upgrades of the facility should push the lower limit below 0.1 MeV/amu. Recent experiments, such as measurements of charge transfer and x-ray production for S6-16+ on He and Ar at 6-20 MeV and P(b) measurements for MO x-rays produced in Cl16+ + Ar collisions at 20, 10 and 5 MeV have demonstrated the usefulness of highly-stripped, low-velocity projectiles. These experiments and a few possibilities for future experiments are discussed.

Analysis of electronic stopping cross sections of organic molecules

The experimental values of electronic stopping cross sections of Li projectiles measured in many organic substances are analyzed with regard to the influence of bonding on the stopping cross section. The invalidity of Bragg's rule, especially for low-velocity projectiles, demands a concept for the analysis which goes beyond simply dividing molecular stopping cross sections into the atomic stopping cross sections of the constituents. Two different approaches are discussed. In the first one, the organic molecule is decomposed into characteristic molecular groups and their corresponding contributions to the molecular stopping cross sections are derived by using only symmetry arguments. The influence of bonding is already included in these values and the problematic atomic stopping cross sections are thus avoided. The second approach, which is more restricted, treats the various bonds in a molecule separately with respect to their specific contributions to the molecular stopping cross section. The results obtained with both procedures are tested by using these values to calculate stopping cross sections of more complex organic compounds. The comparison with measured values shows excellent agreement.

Experimental study of multiple interior impacts

In this paper, experiments involving interior impacts on soft, lead targets are described. The term “interior impact” refers to the impact of a projectile at the bottom of a predrilled hole in the target. It is known that impact of low-velocity projectiles into such soft targets results in plastic flow and cavities similar to those obtained in high-velocity impact of hard targets. Therefore, comparatively simple rifle-propelled projectile impacts on soft targets may yield useful information for high-speed hard-target impacts.