Design of an Impact Test for Estimating the Deformation Energies of Projectiles in Wound Ballistics Studies (original) (raw)
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Wound ballistics: Theory and practice
Annals of Emergency Medicine, 1984
Ballistics is the study of the natural laws governing projectile missiles and their predictable performances, and wound ballistics is the study of a missile's effect on living tissue. A knowledge of these topics is essential to determine the extent and type of injury from a missile. The type of missile can often be determined by radiography. The caliber can be measured directly if the bullet is close to the x-ray plate and the x-ray tube is at least six feet from the film. Changing these distances can result in a maximum magnification of the bullet image of 20%, and the exact amount can be calculated using a formula provided. Definitions of ballistic and wound ballistic terms are provided, as are examples of wound ballistics in application. [Ordog GJ,
Firearm-related injuries are caused by a wide variety of weapons and projectiles. The kinetic energy of the penetrating projectile defines its ability to disrupt and displace tissue, whereas the actual tissue damage is determined by the mode of energy release during the projectile–tissue interaction and the particular characteristics of the tissues and organs involved. Certain projectile factors, namely shape, construction, and stability, greatly influence the rate of energy transfer to the tissues along the wound track. Two zones of tissue damage can be identified, the permanent cavity created by the passage of the bullet and a potential area of contused tissue surrounding it, produced mainly by temporary cavitation which is a manifestation of effective high-energy transfer to tissue. Due to the complex nature of these injuries, wound assessment and the type and extent of treatment required should be based on an understanding of the various mechanisms contributing to tissue damage.
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This study aims to investigate the penetration of a projectile into a surrogate human tissue numerically, using Finite Element (FE) simulation. 20% Balistic Gelatin material (BG) is simulated with an elasto-plastic hydrodynamic constitutive law, and then impacted by steel spheres at different velocities. The results from the FE simulations are compared with existing experimental data and other analytical equations from the literature. To our knowledge, this is the first study to investigate a projectile penetration by numerical simulation, and then compare the results with analytical and experimental data from previous studies. This developed model gives encouraging results for further investigations of penetrating impact of projectile in the human body.
Research on the Dynamic Response Properties of Nonlethal Projectiles for Injury Risk Assessment
ACS Omega, 2022
Based on the models already on the market, we have manufactured six types of nonlethal projectiles. We have made convex heads out of polyurethane foam (PUR) filled with mineral fillers like alumina (Al 2 O 3) and montmorillonite (MMT). We chose a suitable holder for nonlethal projectiles. Also, we made a custom industrial model and used CAD modeling in SolidWorks to simulate the deformation of the nonlethal projectiles. The polymeric nonlethal projectile holders were then 3Dprinted. We performed a dynamic mechanical analysis (DMA) and discussed the results. Likewise, we conducted ballistic impact experiments on nonlethal projectiles (XM1006) and nonlethal projectiles manufactured that were evaluated using a rigid wall and a pneumatic launcher. Furthermore, we looked at cell structure, the spread of the mean pore diameter, and the particle size distributions of the mineral fillers using scanning electron microscopy (SEM). We evaluated and discussed injury risks from nonlethal impacts. Data on nonlethal projectile lethality and safe impact speed are collected. This study explains how lab studies and real-world practice coexist through nonlethal projectile properties.
Human Effects Assessment of 40-mm Nonlethal Impact Munitions
Human Factors and Mechanical Engineering for Defense and Safety
An extensive human effects study was conducted on 40MM nonlethal impact munitions having two different projectile nose configurations: a compliant sponge nose, and a frangible foam nose carrying a powder payload. The study included initial characterization of the rounds using the Blunt Criterion (BC). Injury risk assessment was done using two previously validated surrogates; blunt impact assessment utilized the 3-Rib Ballistic Impact Dummy (3RBID), and penetrating trauma assessment utilized a biomechanical surrogate consisting of ordnance gelatin and a specific combination of layers to simulate skin and underlying soft tissue. Production impact munitions were manufactured to produce a range of energy levels on impact by adjusting the propellant charge in the smokeless propulsion system, resulting in different projectile muzzle velocities. Twenty-three impacts were performed on a biomechanical surrogate at kinetic energy levels in the range of 148-257 J to generate Viscous Criterion (VCmax) levels for injury assessment. The production configurations of the sponge and frangible-nose munitions were compared to the acceptable values for blunt trauma (VCmax ≤ 0.8). Thirty-nine impacts were done on a penetration surrogate at kinetic energy levels in the range of 170-305 J, and the impact energies corresponding to penetrations were identified and compared to the production configurations for these munitions and to the expected energy density values for a 50% risk of penetration for specific areas of the body.
International Journal of Legal Medicine, 2010
By measuring the total crack lengths (TCL) along a gunshot wound channel simulated in ordnance gelatine, one can calculate the energy transferred by a projectile to the surrounding tissue along its course. Visual quantitative TCL analysis of cut slices in ordnance gelatine blocks is unreliable due to the poor visibility of cracks and the likely introduction of secondary cracks resulting from slicing. Furthermore, gelatine TCL patterns are difficult to preserve because of the deterioration of the internal structures of gelatine with age and the tendency of gelatine to decompose. By contrast, using computed tomography (CT) software for TCL analysis in gelatine, cracks on 1-cm thick slices can be easily detected, measured and preserved. In this, experiment CT TCL analyses were applied to gunshots fired into gelatine blocks by three different ammunition types (9-mm Luger full metal jacket, .44 Remington Magnum semi-jacketed hollow point and 7.62×51 RWS Cone-Point). The resulting TCL curves reflected the three projectiles' capacity to transfer energy to the surrounding tissue very accurately and showed clearly the typical energy transfer differences. We believe that CT is a useful tool in evaluating gunshot wound profiles using the TCL method and is indeed superior to conventional methods applying physical slicing of the gelatine.