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A key aspect of understanding the impact of ballistic projectiles on a target is understandingthe dependence of the hole diameter and residual velocity on parameters like initial velocity,mass of the projectile, the geometry of the projectile, and thickness of the target plate.Ideally, simulation tools can be used to study this concept. Physical testing can be expensiveand slow, and it is often difficult to visualize what happens in an experiment. However, in simulation, these models can contain errors or may not account for relevantphysics, so one needs to be cautious with the results. We determined the hole diameterand residual velocity for projectile impact on steel and concrete plates. These results werecalculated by conducting simulations and independently from empirical formulas found inthe literature. The comparison reveals the accuracy of different formulas. The study reveals notable discrepancies between empirical formulas and numerical simula-tions for residual velocity in concrete, Furthermore in the case of steel the empirical formulas agrees more with numerical simulation. These formulas offer limited general applicabilityand only provide rough approximations. However, they align more closely with simulationsin predicting residual velocity, despite a small margin of error. Certain formulas, like theThor formula at an initial speed of 2000 m/s and considering the angle are notably morereliable, suggesting their potential use as affordable alternatives to numerical simulations.

A key aspect of understanding the impact of ballistic projectiles on a target is understandingthe dependence of the hole diameter and residual velocity on parameters like initial velocity,mass of the projectile, the geometry of the projectile, and thickness of the target plate.Ideally, simulation tools can be used to study this concept. Physical testing can be expensiveand slow, and it is often difficult to visualize what happens in an experiment. However, in simulation, these models can contain errors or may not account for relevantphysics, so one needs to be cautious with the results. We determined the hole diameterand residual velocity for projectile impact on steel and concrete plates. These results werecalculated by conducting simulations and independently from empirical formulas found inthe literature. The comparison reveals the accuracy of different formulas. The study reveals notable discrepancies between empirical formulas and numerical simula-tions for residual velocity in concrete, Furthermore in the case of steel the empirical formulas agrees more with numerical simulation. These formulas offer limited general applicabilityand only provide rough approximations. However, they align more closely with simulationsin predicting residual velocity, despite a small margin of error. Certain formulas, like theThor formula at an initial speed of 2000 m/s and considering the angle are notably morereliable, suggesting their potential use as affordable alternatives to numerical simulations.

A detailed mapping of volcanic ballistic projectiles emplaced in a defined area, represents the starting point to derive preparatory data in hazard and risk studies of ballistics phenomena. Considering as case study the 3rd July 2019 paroxysmal eruption occurred at Stromboli volcano, we map and analyse at very high spatial resolution (8 cm) the distribution of the ballistic spatter clasts emplaced on the E flank of the volcano. The resulting map identifies and reproduces as geospatial polygon elements 152,228 spatter clasts with areal dimensions from 0.03 to 4.23 m2. Dispersed on 0.407 km2, the spatters cover an area of 29,000 m2 corresponding to an erupted products volume from 2.3 to 7.0 × 103 m3, calculated here for the first time. Spatial analyses indicate that the area mostly affected by the clasts emplacement is between N67.5 and N135 directions, identifying a preferential deposition between N112.50 and N123.75 directions. The clasts size distribution rapidly decreases with the size increase, highlighting a nearly constant ratio small/large clasts regardless the distance from the vent. Finally, additional investigations reveal that clasts dispersion parameters decrease progressively with the distance from the vent only along one direction (N67.5), highlighting how the morphology influences the deposition and remobilisation of mapped ballistics.

An internal ballistics reconstruction technique is applied to the data gathered experimentally on two different hybrid rocket engines. In particular, this numerical method allows to obtain the evolution of the spatially averaged regression rate and the internal port diameter of the solid fuel grain over the burning time. The inputs of the algorithm are the oxidizer mass flow rate and combustion chamber pressure, as well as the total fuel mass consumption. A preliminary assessment of the technique is carried out in this paper applying it to the test data gathered on the H2O2/HDPE HYCAT engine of ONERA, and to the experimental data of the ULB-HRM N2O/HDPE engine of Université Libre de Bruxelles. The different engines operating conditions and oxidizer selection provide a larger dataset for the validation of the technique robustness and reliability of the results., info:eu-repo/semantics/nonPublished

Military ground vehicles require protection against ballistic threats encountered in the battlefield. Traditionally used armour steel dramatically increases the weight of a vehicle, decreasing its mobility and hampering its capability of carrying payload. The development of new material and protection concepts, namely non-metallic armours, that function as the main structural element of the vehicle hull aims to optimise this relationship between protection and manoeuvrability, mainly through weight reduction. In this work, the ballistic impact response of multi-layered non-metallic targets under the impact of high-speed armour-piercing projectiles is studied by experimental and analytical methods. The residual velocity of the projectile, the failure modes and the energy absorption of different target configurations composed of aluminium oxide, E-glass or carbon fibre-reinforced polymer composite and aluminium plates are analysed. The results show that ceramic/composite target configurations containing aluminium interlayers have better anti-penetration capability against 12.7x99mm APM2 (hardened steel core) and 7.62x51mm AP8 (tungsten carbide core) projectiles, and E-glass outperforms carbon fibre in composite backings. An energy-based terminal ballistics model is built by combining two analytical models from literature and modifying them based on experimental observations as a cost-effective, simple modern approach to forecast the ballistic performance of ceramic-faced composite-backed targets. Model verification proves challenging due to incorrect formulation, lack of detail in the algorithm and insufficient input data provided by the authors. The ceramic plate submodel is verified, and projectile and ceramic damage mechanisms contribute the most to the projectile kinetic energy dissipation. There are significant disagreements between experimental and analytical results, mainly deriving from incorrect input values of projectile and ceramic material properties. The, Aerospace Engineering

A detailed mapping of volcanic ballistic projectiles emplaced in a defined area, represents the starting point to derive preparatory data in hazard and risk studies of ballistics phenomena. Considering as case study the 3rd July 2019 paroxysmal eruption occurred at Stromboli volcano, we map and analyse at very high spatial resolution (8 cm) the distribution of the ballistic spatter clasts emplaced on the E flank of the volcano. The resulting map identifies and reproduces as geospatial polygon elements 152,228 spatter clasts with areal dimensions from 0.03 to 4.23 m2. Dispersed on 0.407 km2, the spatters cover an area of 29,000 m2 corresponding to an erupted products volume from 2.3 to 7.0 × 103 m3, calculated here for the first time. Spatial analyses indicate that the area mostly affected by the clasts emplacement is between N67.5 and N135 directions, identifying a preferential deposition between N112.50 and N123.75 directions. The clasts size distribution rapidly decreases with the size increase, highlighting a nearly constant ratio small/large clasts regardless the distance from the vent. Finally, additional investigations reveal that clasts dispersion parameters decrease progressively with the distance from the vent only along one direction (N67.5), highlighting how the morphology influences the deposition and remobilisation of mapped ballistics.

A detailed mapping of volcanic ballistic projectiles emplaced in a defined area, represents the starting point to derive preparatory data in hazard and risk studies of ballistics phenomena. Considering as case study the 3rd July 2019 paroxysmal eruption occurred at Stromboli volcano, we map and analyse at very high spatial resolution (8 cm) the distribution of the ballistic spatter clasts emplaced on the E flank of the volcano. The resulting map identifies and reproduces as geospatial polygon elements 152,228 spatter clasts with areal dimensions from 0.03 to 4.23 m2. Dispersed on 0.407 km2, the spatters cover an area of 29,000 m2 corresponding to an erupted products volume from 2.3 to 7.0 × 103 m3, calculated here for the first time. Spatial analyses indicate that the area mostly affected by the clasts emplacement is between N67.5 and N135 directions, identifying a preferential deposition between N112.50 and N123.75 directions. The clasts size distribution rapidly decreases with the size increase, highlighting a nearly constant ratio small/large clasts regardless the distance from the vent. Finally, additional investigations reveal that clasts dispersion parameters decrease progressively with the distance from the vent only along one direction (N67.5), highlighting how the morphology influences the deposition and remobilisation of mapped ballistics.

The ballistics field is known by the presence of several complex phenomena such as muzzles and flying projectiles flow fields. Consequently, numerical simulations are commonly used to model these complicated flows. However, the validation process of these codes has proven to be problematic due to the lack of experimental quantitative data. In this context, the present paper describes the application of the Background Oriented Schlieren technique (BOS) as a quantitative investigation tool in the ballistics field. We illustrate that BOS can accurately capture the main characteristics of the studied configurations: Firstly, we discuss the visualization and the density field reconstruction around a Bullet Simulated Projectile BSP flying at supersonic velocities and a sniper projectile flying at supersonic and transonic velocities. We demonstrate that these fields are in satisfactory agreement with the results of Taylor and Maccoll’s equation and numerical simulation. Then, the findings of the BOS visualization of the precursors and the propellant flow fields are presented. To this end, the salient features accurately captured by the BOS technique such as vortex rings, shock bottles, Mach, and blast wave are described both qualitatively and in terms of density profiles. Two improved approaches that are essential to the aforementioned analysis are proposed: the first is related to density field reconstruction based on Abel inversion and the second approach is a phase separation procedure., SCOPUS: cp.p, info:eu-repo/semantics/published

In the context of intermediate ballistics, a thorough understanding of the muzzle flow is necessary to optimize the design of muzzle devices and long-range projectiles. However, due to the harsh environment, the extremely short duration, and the transient evolution of the intermediate ballistics phase, both experimental and flow modeling efforts are hampered by the lack of quantitative experimental data. In this study, a Particle Imaging Velocimetry (PIV) experimental set-up is implemented to quantitatively investigate the muzzle flow based on its velocity. This tool has the advantage of obtaining a non-intrusive and whole-field diagnostic, both qualitatively and quantitatively. The first part of the study explains that PIV is suitable for measuring the velocity fields of the muzzle flow. This was achieved by using the naturally present particles in the gas as tracers. We demonstrate that the raw PIV images revealed that the structure of this flow is composed of two regions. The first region is located within the under-expanded jet and consists of spatially dispersed particles. The second region, downstream of the Mach disk, is formed by large structures. We show that cross-correlation and particle tracking velocimetry (PTV) algorithms can determine the flow velocity in both regions. In the second part, we present a quantitative description of the muzzle flow issued from the launch of a subsonic .300 Blackout projectile. The results show that these gases reach a maximum centerline velocity of more than 900 m/s inside the shock bottle. At the barrel exit plane, the gases start to discharge with a velocity close to that of the projectile’s launch velocity, accelerating it. In the third part, we present a detailed comparison between the aforementioned flow and the flow resulting from the launch of a supersonic projectile. Differences and similarities are pronounced and explained. The presented set-up and the description of the whole flow field velocity would serve as v, info:eu-repo/semantics/published

The ballistics field is known by the presence of several complex phenomena such as muzzle and flying projectiles flow fields. Consequently, numerical simulations are commonly used to model these complicated flows. However, the validation process of these codes has proven to be problematic due to the lack of experimental quantitative data. In this context, the present paper describes the application of the Background Oriented Schlieren technique (BOS) as a quantitative investigation tool in the ballistics field. We illustrate that BOS can accurately capturethe main characteristics of the studied configurations: Firstly, we discuss the visualization and the density field reconstruction around a sniper projectile flying at supersonic and transonic velocities. We demonstrate that these fields are in satisfactory agreement with numerical simulation. Then, the findings of the BOS visualization of the precursors and the propellant flow fields are presented. To this end, the salient features accurately captured by the BOS technique such as vortex rings, shock bottles, Mach disk, and blast wave are described both qualitatively and in terms of density profiles. Two improved approaches that are essential to the aforementioned analysis are proposed: the first is related to density field reconstruction based on Abel inversion and the second approach is a phase separation procedure., info:eu-repo/semantics/published

Gracie R Baum,1 Jaxon T Baum,2 Dan Hayward,2 Brendan J MacKay1 1Department of Orthopedic Hand Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA; 2School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USACorrespondence: Brendan J MacKay, Department of Orthopedic Hand Surgery, Texas Tech University Health Sciences Center, 808 Joliet Ave Suite 310, Lubbock, TX, 79415, USA, Tel +1 806 743 4600, Email brendan.j.mackay@ttuhsc.eduAbstract: As the epidemic of gunshot injuries and firearm fatalities continues to proliferate in the United States, knowledge regarding gunshot wound (GSW) injury and management is increasingly relevant to health-care providers. Unfortunately, existing guidelines are largely outdated, written in a time that high-velocity weapons and deforming bullets were chiefly restricted to military use. Advances in firearm technology and increased accessibility of military grade firearms to civilians has exacerbated the nature of domestic GSW injury and complicated clinical decision-making, as these weapons are associated with increased tissue damage and often result in retained bullets. Currently, there is a lack of literature addressing recent advances in the field of projectile-related trauma, specifically injuries with retained bullets. This review aims to aggregate the available yet dispersed findings regarding ballistics, GSW etiology, and treatment, particularly for cases involving retained projectiles.Keywords: ballistics, gunshot injuries, retained bullets, orthopedic surgery, trauma

This study has investigated the conceptual feasibility of a rocket propelled kinetic energy penetrator (KEP), designed for the handheld recoilless rifle Carl-Gustaf® 84 mm calibre system, from an exterior ballistics perspective. The methodology is based upon evaluating the aerodynamic properties of different conceptual design proposals through CFD-simulations and then performing trajectory analysis to assess their exterior ballistic performance. In particular, the main focus has been to optimize the stability, velocity and spin rate of the KEP. The results of the study indicates that the final chosen KEP design retains, from an aerodynamic perspective, longitudinal stability for Mach numbers up to 4.5, regardless if the rocket motor is ignited or not. Furthermore, if using NK1384 propellant, the final chosen design in the study is, according to the calculations, able to achieve a maximum velocity of 0.7⋅v_ref and retain a minimum velocity of 0.628⋅v_ref in the horizontal range of [0.318⋅x_ref,0.648⋅x_ref] measured from the shooter. In addition, the angular spin velocity achieves a maximum value of 15.5 Hz, satisfying the performance limitation of the rocket motor which only functions properly for frequencies up to 30 Hz, while simultaneously providing a sufficiently considered spin rate in order to average possible thrust and mass deviations of the KEP. The results also show that if using ammonium dinitramide (ADN) propellant, the KEP is able to achieve a maximum velocity of 0.786⋅v_ref, retain a minimum velocity of 0.628⋅v_ref in the horizontal range of [0.28⋅x_ref,0.98⋅x_ref] and achieve a maximum spin rate of 17.5 Hz., Den här studien har på ett konceptuellt plan undersökt om det är möjligt att konstruera en raketdriven kinetisk energi-pil (KE-pil), designad för det rekylfria Carl-Gustaf® 84 mm granatgeväret. Studiens metod grundade sig i att undersöka olika konceptuella designförslag och utvärdera deras aerodynamiska egenskaper genom CFD-simulationer för att sedan genomföra bansimuleringar och bedöma deras ytterballistiska prestanda. Framför allt fokuserades det på att optimera KE-pilens stabilitet, hastighet och rollvinkelfrekvens. Resultaten från studien indikerar att det ur ett aerodynamiskt perspektiv är möjligt att statiskt stabilisera KE-pilen för Machtal upp till 4.5, oavsett om raketmotorn är antänd eller ej. Vidare, vid implementering av NK1384-krut lyder prestandaspecifikationerna enligt följande för studiens slutgiltiga designförslag enligt genomförda beräkningar. Den maximalt uppnådda hastigheten är 0.7⋅v_ref och en minimumhastighet om 0.628⋅v_ref kan upprätthållas inom det horisontella intervallet [0.318⋅x_ref,0.648⋅x_ref ] räknat ifrån skytten. Vidare uppnås en maximal rollvinkelfrekvens på 15.5 Hz, vilket tillfredsställer raketmotorns prestandabegränsning om en maximal rollvinkelfrekvens på 30 Hz, samtidigt som detta är en god frekvens för att utjämna eventuella avvikelser från raketmotors avsedda massflödesriktning tillika avsedd massdistribution hos KE-pilen. Om krutet i stället byts ut till ammoniumdinitramid (ADN) kan en maximal hastighet om 0.786⋅v_ref uppnås, en minimumhastighet om 0.628⋅v_ref kan upprätthållas inom intervallet [0.28⋅x_ref,0.98⋅x_ref ] och den maximala rollfrekvensen är 17.5 Hz.

This study has investigated the conceptual feasibility of a rocket propelled kinetic energy penetrator (KEP), designed for the handheld recoilless rifle Carl-Gustaf® 84 mm calibre system, from an exterior ballistics perspective. The methodology is based upon evaluating the aerodynamic properties of different conceptual design proposals through CFD-simulations and then performing trajectory analysis to assess their exterior ballistic performance. In particular, the main focus has been to optimize the stability, velocity and spin rate of the KEP. The results of the study indicates that the final chosen KEP design retains, from an aerodynamic perspective, longitudinal stability for Mach numbers up to 4.5, regardless if the rocket motor is ignited or not. Furthermore, if using NK1384 propellant, the final chosen design in the study is, according to the calculations, able to achieve a maximum velocity of 0.7⋅v_ref and retain a minimum velocity of 0.628⋅v_ref in the horizontal range of [0.318⋅x_ref,0.648⋅x_ref] measured from the shooter. In addition, the angular spin velocity achieves a maximum value of 15.5 Hz, satisfying the performance limitation of the rocket motor which only functions properly for frequencies up to 30 Hz, while simultaneously providing a sufficiently considered spin rate in order to average possible thrust and mass deviations of the KEP. The results also show that if using ammonium dinitramide (ADN) propellant, the KEP is able to achieve a maximum velocity of 0.786⋅v_ref, retain a minimum velocity of 0.628⋅v_ref in the horizontal range of [0.28⋅x_ref,0.98⋅x_ref] and achieve a maximum spin rate of 17.5 Hz., Den här studien har på ett konceptuellt plan undersökt om det är möjligt att konstruera en raketdriven kinetisk energi-pil (KE-pil), designad för det rekylfria Carl-Gustaf® 84 mm granatgeväret. Studiens metod grundade sig i att undersöka olika konceptuella designförslag och utvärdera deras aerodynamiska egenskaper genom CFD-simulationer för att sedan genomföra bansimuleringar och bedöma deras ytterballistiska prestanda. Framför allt fokuserades det på att optimera KE-pilens stabilitet, hastighet och rollvinkelfrekvens. Resultaten från studien indikerar att det ur ett aerodynamiskt perspektiv är möjligt att statiskt stabilisera KE-pilen för Machtal upp till 4.5, oavsett om raketmotorn är antänd eller ej. Vidare, vid implementering av NK1384-krut lyder prestandaspecifikationerna enligt följande för studiens slutgiltiga designförslag enligt genomförda beräkningar. Den maximalt uppnådda hastigheten är 0.7⋅v_ref och en minimumhastighet om 0.628⋅v_ref kan upprätthållas inom det horisontella intervallet [0.318⋅x_ref,0.648⋅x_ref ] räknat ifrån skytten. Vidare uppnås en maximal rollvinkelfrekvens på 15.5 Hz, vilket tillfredsställer raketmotorns prestandabegränsning om en maximal rollvinkelfrekvens på 30 Hz, samtidigt som detta är en god frekvens för att utjämna eventuella avvikelser från raketmotors avsedda massflödesriktning tillika avsedd massdistribution hos KE-pilen. Om krutet i stället byts ut till ammoniumdinitramid (ADN) kan en maximal hastighet om 0.786⋅v_ref uppnås, en minimumhastighet om 0.628⋅v_ref kan upprätthållas inom intervallet [0.28⋅x_ref,0.98⋅x_ref ] och den maximala rollfrekvensen är 17.5 Hz.

Gracie R Baum,1 Jaxon T Baum,2 Dan Hayward,2 Brendan J MacKay1 1Department of Orthopedic Hand Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA; 2School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USACorrespondence: Brendan J MacKay, Department of Orthopedic Hand Surgery, Texas Tech University Health Sciences Center, 808 Joliet Ave Suite 310, Lubbock, TX, 79415, USA, Tel +1 806 743 4600, Email brendan.j.mackay@ttuhsc.eduAbstract: As the epidemic of gunshot injuries and firearm fatalities continues to proliferate in the United States, knowledge regarding gunshot wound (GSW) injury and management is increasingly relevant to health-care providers. Unfortunately, existing guidelines are largely outdated, written in a time that high-velocity weapons and deforming bullets were chiefly restricted to military use. Advances in firearm technology and increased accessibility of military grade firearms to civilians has exacerbated the nature of domestic GSW injury and complicated clinical decision-making, as these weapons are associated with increased tissue damage and often result in retained bullets. Currently, there is a lack of literature addressing recent advances in the field of projectile-related trauma, specifically injuries with retained bullets. This review aims to aggregate the available yet dispersed findings regarding ballistics, GSW etiology, and treatment, particularly for cases involving retained projectiles.Keywords: ballistics, gunshot injuries, retained bullets, orthopedic surgery, trauma

Most recent style-transfer techniques based on generative architectures are able to obtain synthetic multimedia contents, or commonly called deepfakes, with almost no artifacts. Researchers already demonstrated that synthetic images contain patterns that can determine not only if it is a deepfake but also the generative architecture employed to create the image data itself. These traces can be exploited to study problems that have never been addressed in the context of deepfakes. To this aim, in this paper a first approach to investigate the image ballistics on deepfake images subject to style-transfer manipulations is proposed. Specifically, this paper describes a study on detecting how many times a digital image has been processed by a generative architecture for style transfer. Moreover, in order to address and study accurately forensic ballistics on deepfake images, some mathematical properties of style-transfer operations were investigated.

En lättgaskanon är en typ av kanon som används vid experiment där mycket snabba förlopp är av intresse, till exempel hypersonisk strömning och höghastighetskollisioner. Kanontypen når betydligt högre hastigheter än en konventionell kanon då projektilen accelereras genom eldröret av en gas med låg molekylmassa som vätgas eller helium istället för krutgaser. Denna lättgas komprimeras först till högt tryck och temperatur i pumptuben av en kolv som accelererats av en krutladdning. Pumptuben är ett rör anslutet till eldröret som initialt är frånskild av ett membran. För kanonen kan en mängd olika parametrar varieras och hur dessa ska väljas för att en viss mynningshastighet ska nås är inte självklart. Vid FOI har val av parametrar historiskt gjorts baserat på erfarenhet och genom experiment vilket kan vara tidsödslande. Syftet med examensarbetet var därför att simulera kanonen och undersöka hur olika parametrar påverkar dess prestanda. Forskningsfrågor som skulle besvaras var hur olika parametrar påverkar projektilens mynningshastighet och vilket utav två eldrörsalternativ som är bäst lämpat för en viss projektilvikt. Det innerballistiska förloppet i kanonen har simulerats för olika parameterkombinationer med ett program utvecklat specifikt för lättgaskanoner vid NASA:s Ames Research Center och modellen har i viss mån kunnat jämföras mot experimentell data. Resultatet av simuleringarna är att mängden lättgas och krut båda har stor inverkan på mynningshastigheten och att högre kolvvikt jämnar ut trycktoppar som uppstår till följd av stötar i gasen. Att ändra membranets öppningstryck ger ingen förbättring av kanonprestandan för den undersökta projektilvikten och utav de två eldrören som undersökts är det med större kaliber mer lämpligt för de aktuella experimenten., A light gas gun is a type of gun which is used for experiments when high velocity phenomena are of interest, such as hypersonic flow and high-velocity impacts. The gun type can reach much higher velocities than a conventional gun as the projectile is accelerated down the barrel by a gas with low molecular mass such as hydrogen or helium instead of combustion gasses. This light gas is first compressed to high pressure and temperature in the pump tube with a piston which is accelerated with a propellant charge. The pump tube is connected to the barrel but initially separated from it with a membrane. A vast array of parameters can be varied on the gun in order to achieve a target muzzle velocity and their selection is not trivial. Historically parameters have been selected at FOI through experience and experiments which can be tedious. The purpose of this thesis was to simulate the gun and investigate how various parameters influence its performance. The research questions to be answered was how the parameters influence the muzzle velocity of the projectile and which of two barrels is the most suitable for a given projectile weight. The internal ballistics of the gun was simulated for various combinations of parameters using a program specifically developed for light gas guns at NASA's Ames Research Center and the model has to some extent been compared to experimental data. The result of the simulations shows that the amount of light gas and the propellant charge have a significant effect of the achieved velocity and that the weight of the piston has a reducing effect on the pressure peaks caused by shockwaves in the gas. Changing the opening pressure of the membrane does not improve gun performance for the investigated projectile weight and of the two barrels investigated the one with larger calibre is better suited for the experiments of interest.

En lättgaskanon är en typ av kanon som används vid experiment där mycket snabba förlopp är av intresse, till exempel hypersonisk strömning och höghastighetskollisioner. Kanontypen når betydligt högre hastigheter än en konventionell kanon då projektilen accelereras genom eldröret av en gas med låg molekylmassa som vätgas eller helium istället för krutgaser. Denna lättgas komprimeras först till högt tryck och temperatur i pumptuben av en kolv som accelererats av en krutladdning. Pumptuben är ett rör anslutet till eldröret som initialt är frånskild av ett membran. För kanonen kan en mängd olika parametrar varieras och hur dessa ska väljas för att en viss mynningshastighet ska nås är inte självklart. Vid FOI har val av parametrar historiskt gjorts baserat på erfarenhet och genom experiment vilket kan vara tidsödslande. Syftet med examensarbetet var därför att simulera kanonen och undersöka hur olika parametrar påverkar dess prestanda. Forskningsfrågor som skulle besvaras var hur olika parametrar påverkar projektilens mynningshastighet och vilket utav två eldrörsalternativ som är bäst lämpat för en viss projektilvikt. Det innerballistiska förloppet i kanonen har simulerats för olika parameterkombinationer med ett program utvecklat specifikt för lättgaskanoner vid NASA:s Ames Research Center och modellen har i viss mån kunnat jämföras mot experimentell data. Resultatet av simuleringarna är att mängden lättgas och krut båda har stor inverkan på mynningshastigheten och att högre kolvvikt jämnar ut trycktoppar som uppstår till följd av stötar i gasen. Att ändra membranets öppningstryck ger ingen förbättring av kanonprestandan för den undersökta projektilvikten och utav de två eldrören som undersökts är det med större kaliber mer lämpligt för de aktuella experimenten., A light gas gun is a type of gun which is used for experiments when high velocity phenomena are of interest, such as hypersonic flow and high-velocity impacts. The gun type can reach much higher velocities than a conventional gun as the projectile is accelerated down the barrel by a gas with low molecular mass such as hydrogen or helium instead of combustion gasses. This light gas is first compressed to high pressure and temperature in the pump tube with a piston which is accelerated with a propellant charge. The pump tube is connected to the barrel but initially separated from it with a membrane. A vast array of parameters can be varied on the gun in order to achieve a target muzzle velocity and their selection is not trivial. Historically parameters have been selected at FOI through experience and experiments which can be tedious. The purpose of this thesis was to simulate the gun and investigate how various parameters influence its performance. The research questions to be answered was how the parameters influence the muzzle velocity of the projectile and which of two barrels is the most suitable for a given projectile weight. The internal ballistics of the gun was simulated for various combinations of parameters using a program specifically developed for light gas guns at NASA's Ames Research Center and the model has to some extent been compared to experimental data. The result of the simulations shows that the amount of light gas and the propellant charge have a significant effect of the achieved velocity and that the weight of the piston has a reducing effect on the pressure peaks caused by shockwaves in the gas. Changing the opening pressure of the membrane does not improve gun performance for the investigated projectile weight and of the two barrels investigated the one with larger calibre is better suited for the experiments of interest.

The ability to accurately model the operation of a solid rocket motor before undergoing multiple firing tests is essential. The analysis of the internal ballistics of a solid rocket motor results in a depiction of the flow properties inside the chamber, and thus, the overall motor performance. Therefore, enhancing the internal ballistics prediction capabilities reduces the design and testing costs while increasing reliability. The present dissertation is the outcome of an extensive process of work and research driven by a great personal interest in Rocket Propulsion and Aerospace Engineering. The project was born with the purpose of developing a computer software capable of simulating the internal aerodynamics of a solid rocket motor, by means of a one-dimensional discretization, allowing to model the behaviour of three-dimensional propellant geometries. As a result, S2P2-ODIB has been developed. It is a C++ written software, designed and built in Qt Creator, which is capable of simulating the internal behaviour of a given solid rocket motor. It has been developed in a way that allows it to be expanded or merged into a larger computer application. S2P2-ODIB features both a quasi steady and an unsteady algorithm, which have been enhanced by implementing several models capable of predicting erosive combustion phenomena. This document gathers the theoretical framework, the numerical discretization, an insight into the data structure, the validation and results and, lastly, two application examples.

The dose delivered to the planning target volume by proton beams is highly conformal, sparing organs at risk and normal tissues. New treatment planning systems adapted to spot scanning techniques have been recently proposed to simultaneously optimize several fields and thus improve dose delivery. In this paper, we investigate a new optimization framework based on a genetic algorithm approach. This tool is intended to make it possible to explore new schemes of treatment delivery, possibly with future enhanced technologies. The optimization framework is designed to be versatile and to account for many degrees of freedom, without any {\it a priori} technological constraint. To test the behavior of our algorithm, we propose in this paper, as an example, to optimize beam fluences, target points and irradiation directions at the same time. The proposed optimization routine takes typically into account several thousands of spots of fixed size. The evolution is carried out by the three standard genetic operators: mutation, crossover and selection. The figure-of-merit (or fitness) is based on an objective function relative to the dose prescription to the tumor and to the limits set for organs at risk and normal tissues. Fluence optimization is carried out via a specific scheme based on a plain gradient with analytical solution. Several specific genetic algorithm issues are addressed: (i) the mutation rate is tuned to balance the search and selection forces, (ii) the initial population is selected using a bootstrap technique and (iii) to scale down the computation time, dose calculations are carried out with a fast analytical ray tracing method and are multi-threaded. In this paper implementation issues of the optimization framework are thoroughly described. The behavior of the proposed genetic algorithm is illustrated in both elementary and clinically-realistic test cases., Comment: 18 pages, 4 figures

In solid rocket motors, the absence of combustion controllability and the large amount of financial resources involved in full-scale firing tests, increase the importance of numerical simulations in order to asses stringent mission thrust requirements and evaluate the influence of thrust chamber phenomena affecting the grain combustion. Among those phenomena, grain local defects (propellant casting inclusions and debondings), combustion heat accumulation involving pressure peaks (Friedman Curl effect), and case-insulating thermal protection material ablation affect thrust prediction in terms of not negligible deviations with respect to the nominal expected trace. Most of the recent models have proposed a simplified treatment to the problem using empirical corrective functions, with the disadvantages of not fully understanding the physical dynamics and thus of not obtaining predictive results for different configurations of solid rocket motors in a boundary conditions-varied scenario. This work is aimed to introduce different mathematical approaches to model, analyze, and predict the abovementioned phenomena, presenting a detailed physical interpretation based on existing SRMs configurations. Internal ballistics predictions are obtained with an in-house simulation software, where the adoption of a dynamic three-dimensional triangular mesh together with advanced computer graphics methods, allows the previous target to be reached. Numerical procedures are explained in detail. Simulation results are carried out and discussed based on experimental data.

In solid rocket motors, the absence of combustion controllability and the large amount of financial resources involved in full-scale firing tests, increase the importance of numerical simulations in order to asses stringent mission thrust requirements and evaluate the influence of thrust chamber phenomena affecting the grain combustion. Among those phenomena, grain local defects (propellant casting inclusions and debondings), combustion heat accumulation involving pressure peaks (Friedman Curl effect), and case-insulating thermal protection material ablation affect thrust prediction in terms of not negligible deviations with respect to the nominal expected trace. Most of the recent models have proposed a simplified treatment to the problem using empirical corrective functions, with the disadvantages of not fully understanding the physical dynamics and thus of not obtaining predictive results for different configurations of solid rocket motors in a boundary conditions-varied scenario. This work is aimed to introduce different mathematical approaches to model, analyze, and predict the abovementioned phenomena, presenting a detailed physical interpretation based on existing SRMs configurations. Internal ballistics predictions are obtained with an in-house simulation software, where the adoption of a dynamic three-dimensional triangular mesh together with advanced computer graphics methods, allows the previous target to be reached. Numerical procedures are explained in detail. Simulation results are carried out and discussed based on experimental data.

Interior ballistics are the events in a gun system that determines the performance of any gun design. In order to efficiently design any gun system the internal ballistics should be understood to minimize energy losses and correctly define design parameters. The goal of this computational model is to develop a ballistics model to aid in gun design. A computational analysis of the dynamics events aids in the design of the gun system by providing output information such as pressure, velocity, charge burnout, and projectile distance versus time profiles. By applying the chemical and physical parameters of the propellant, gun breech geometry, projectile mass and gun barrel parameters, one can iterate through design parameters in an attempt to improve gun performance. There will be several computational models describing the main program being a lumped parameter internal ballistics analysis. The muzzle velocity of the model has been validated with empirical testing to at least one gun system and being applied to other gun systems for further validation on different designs. The validation of the muzzle velocity and breech pressure will build confidence in the model and allow for the model to be further developed into a more user friendly program.

Interior ballistics are the events in a gun system that determines the performance of any gun design. In order to efficiently design any gun system the internal ballistics should be understood to minimize energy losses and correctly define design parameters. The goal of this computational model is to develop a ballistics model to aid in gun design. A computational analysis of the dynamics events aids in the design of the gun system by providing output information such as pressure, velocity, charge burnout, and projectile distance versus time profiles. By applying the chemical and physical parameters of the propellant, gun breech geometry, projectile mass and gun barrel parameters, one can iterate through design parameters in an attempt to improve gun performance. There will be several computational models describing the main program being a lumped parameter internal ballistics analysis. The muzzle velocity of the model has been validated with empirical testing to at least one gun system and being applied to other gun systems for further validation on different designs. The validation of the muzzle velocity and breech pressure will build confidence in the model and allow for the model to be further developed into a more user friendly program.

Compared to computed tomography (CT), magnetic resonance imaging (MRI) provides superior visualization of the soft tissue. Recently, the first 7 Tesla (7 T) MRI scanner was approved for clinical use, which will facilitate access to these ultra-high-field MRI scanners for noninvasive examinations and scientific studies on decedents. 7 T MRI has the potential to provide a higher signal-to-noise ratio (SNR), a characteristic that can be directly exploited to improve image quality and invest in attempts to increase resolution. Therefore, evaluating the diagnostic potential of 7 T MRI for forensic purposes, such as assessments of fatal gunshot wounds, was deemed essential. In this article, we present radiologic findings obtained for craniocerebral gunshot wounds in three decedents. The decedents were submitted to MRI examinations using a 7 T MRI scanner that has been approved for clinical use and a clinical 3 T MRI scanner for comparison. We focused on detecting tiny injuries beyond the wound tract caused by temporary cavitation, such as microbleeds. Additionally, 7 T T2-weighted MRI highlighted a dark (hypo intense) zone beyond the permanent wound tract, which was attributed to increased amounts of paramagnetic blood components in damaged tissue. Microbleeds were also detected adjacent to the wound tract in the white matter on 7 T MRI. Based on the findings of radiologic assessments, the advantages and disadvantages of postmortem 7 T MRI compared to 3 T MRI are discussed with regard to investigations of craniocerebral gunshot wounds as well as the potential role of 7 T MRI in the future of forensic science.

In practical forensic casework, backspatter recovered from shooters' hands can be an indicator of self-inflicted gunshot wounds to the head. In such cases, backspatter retrieved from inside the barrel indicates that the weapon found at the death scene was involved in causing the injury to the head. However, systematic research on the aspects conditioning presence, amount and specific patterns of backspatter is lacking so far. Herein, a new concept of backspatter investigation is presented, comprising staining technique, weapon and target medium: the ‘triple contrast method' was developed, tested and is introduced for experimental backspatter analysis. First, mixtures of various proportions of acrylic paint for optical detection, barium sulphate for radiocontrast imaging in computed tomography and fresh human blood for PCR-based DNA profiling were generated (triple mixture) and tested for DNA quantification and short tandem repeat (STR) typing success. All tested mixtures yielded sufficient DNA that produced full STR profiles suitable for forensic identification. Then, for backspatter analysis, sealed foil bags containing the triple mixture were attached to plastic bottles filled with 10% ballistic gelatine and covered by a 2-3-mm layer of silicone. To simulate backspatter, close contact shots were fired at these models. Endoscopy of the barrel inside revealed coloured backspatter containing typable DNA and radiographic imaging showed a contrasted bullet path in the gelatine. Cross sections of the gelatine core exhibited cracks and fissures stained by the acrylic paint facilitating wound ballistic analysis.

в данной статье рассматривается один из вариантов основной задачи внешней баллистики в условиях интервальной недетерминированности параметров. Предполагается, что начальные данные заданы неточно, т.е. их возможные значения принадлежат к некоторому интервалу. Разработан алгоритм решения поставленной задачи в рамках интервального анализа и получены оценки ширины интервального решения., this article describes one of options of the main objective of external ballistics under the interval non-determination of parameters. It is supposed that initial data has been set inaccurately, i.e. their possible values belong to some interval. The algorithm of the solution of an objective within the interval analysis has been developed. The evaluation of the interval decision width has been obtained.

У роботі розглядається динаміка руху кулі у повітрі, випущеної із снайперської гвинтівки Драгунова. Вважається, що на неї діють сила лобового опору повітря, вага кулі та сила, спричинена дією бічного вітру. Сила лобового опору повітря залежить від коефіцієнта аеродинамічності, площі поперечного перерізу кулі, густини і швидкості звуку в повітрі, швидкості супутнього або зустрічного вітру, швидкості кулі та двох безрозмірних коефіцієнтів, які мають різні значення при надзвуковій і дозвуковій швидкостях кулі. Величина сили, обумовленої дією бічного вітру, пропорційна максимальній площі повздовжнього перерізу кулі, густині повітря та різниці швидкостей вітру і бічного зміщення кулі, яка піднесена до певного ступеня. Між теоретичними та експериментальними результатами кінематичних параметрів кулі досягнута незначна розбіжність. Однак при дії бічного вітру є значні розбіжності, якщо координата точки обнуління траєкторії понад 700 метрів. Проведенням теоретичної перевірки експериментальних значень встановлено, що на окремих ділянках руху кулі значення середньої швидкості її бічного зміщення суперечить законам механіки., В роботе рассматривается динамика движения пули в воздухе, выпущенной из снайперской винтовки Драгунова. Считается, что на нее действуют сила лобового сопротивления воздуха, вес пули и сила бокового ветра. Сила лобового сопротивления зависит от коэффициента аэродинамичности, площади поперечного сечения пули, удельной массы и скорости звука в воздухе, скорости сопутствующего или встречного ветра, скорости пули и двух безразмерных коэффициентов, которые имеют различные значения при надзвуковой и дозвуковой скоростях. Сила бокового ветра пропорциональна максимальной площади продольного сечения пули, удельной массе воздуха, разнице скоростей ветра и бокового смещения пули, которая вознесена к определенной степени. Между теоретическими и экспериментальными результатами кинематических параметров пули имеется незначительное расхождение. Но при учете бокового ветра имеется значительное расхождение, если координата точки обнуления траектории более 700 метров. Проведением теоретической проверки экспериментальных значений установлено, что на отдельных участках движения пули значения средней скорости ее бокового смещения противоречат законам механики., In the paper the author investigate the dynamics of the movement of the bullet of the cartridge LPS in the air released from the sniper rifle Dragunov. The main influence on the bullet movement in the air has the force of the frontal air resistance, the bullet’s mass and the force caused by the action of the counter wind on the bullet. It is assumed that the force of the frontal air resistance depends on the factor described the aerodynamics properties of the bullet, the cross-section of the bullet, the density of the air and the sound velocity in the air , the velocity of the accompanying or opposite wind and the bullet’s velocity. In addition, its functional relationship contain two dimensionless coefficients that have different values in supersonic and subsonic velocity of the bullet and are determined using the results of experimental studies. The action of the accompanying or opposite wind affects the value of the force of the frontal air resistance of the bullet’s movement and is taken into account through the corresponding force expression. There is a slight difference between the theoretical and experimental results of the kinematic parameters of the bullet. The value of the force caused by the action of the crosswind is proportional to the maximum area of the longitudinal section of the bullet, the air density, and the difference of the wind velocities and cross drift of the bullet, which is elevated to a certain degree. The values of the coefficient of proportionality and degree depend on the nature of the air movement – laminar or turbulent. Analyzing the results of theoretical calculations, we can state that the velocity of the cross drift of the bullet is constantly increasing; the value of the cross drift of the bullet increases according to the nonlinear law. In addition, there are significant differences between the results of theoretical and experimental studies, if the coordinate of the point of zeroing of the trajectory is greater than 700 meter

Accurate predictions of volcanological phenomena, such as the trajectory of blocks accelerated by volcanic explo-sions, require quantitative skills training. Large outdoor experiments can be useful to convey concepts of volcanicprocesses to students in an exciting way. Beyond the fun aspects, these experiments provide an opportunity toengage with the physics of projectile flight and help promote mathematical learning within the Earth Sciences.We present a quantitative framework required to interpret ballistic trajectories and the outdoor experiment knowncommonly as “trashcano”, taking a step-by-step approach to the physics of this problem, and deriving a rangeof mathematical solutions involving different levels of complexity. Our solutions are consistent with the predic-tions from established computer programs for volcanic ballistic trajectory modelling, but we additionally providea nested set of simplified solutions, useful for a range of teaching scenarios as well as downloadable simulateddatasets for use where the full experiment may not be possible.

В статті розглянуто питання наявних можливостей вимірювання прискорення сили ваги за допомогою абсолютних балістичних гравіметрів, вдосконалення системи автоматизації обробки інформації та можливість подальшого створення системи відеоспостереження за процесом отримання результатів, що повинно усунути похибки та забезпечити максимальну точність вимірювання, In paper the question of existing possibilities of measuring of an acceleration due to gravity by means of terrain clearance ballistics gravimeters is observed, development of system of automation of machining of the information and possibility of the further making of system of video observation behind process of receptionof effects that should eliminate lapses and provides the maximum accuracy of measurings

A method for calculating the trajectories of guided, non-axisymmetric, hypervelocity projectiles is developed. The method is based on the equations of motion for a rigid body with an internal skid weight and roll wheel, combined with a tabulated set of ballistic coefficients used to specify the aerodynamic forces and moments on the body. The ballistic coefficients can in principle come from experiments or computational fluid dynamics (CFD) calculations. CFD calculations are carried out for a standard bullet (0.308 168 grain Sierra International) in order to characterize the accuracy given various mesh sizes. The ballistics model is applied to a standard rifle shot in order to demonstrate the epicyclic pitch and yaw behavior. It is then applied to a smart bullet that utilizes a preliminary autopilot algorithm., The original document contains color images. Prepared in collaboration with Dynamics Research Corp., Andover, MA.

Lumped-parameter interior ballistics (IB) codes have had limited success in simulating the IB of mortars due to the complex nature of the firing event. Only near the end of the firing event does the mortar conform to the conventional ballistics model for which lumped-parameter codes were designed. Modified lumped-parameter models are capable of simulating some key mortar variables. There are significant pressure waves developed in mortars, which are due in part to the nonuniform discharge of combustion products from the flashtube. The mortar IB cycle is not only time dependant but is also very spatially complex. These pressure waves cannot be adequately represented in a one-dimensional IB model. Plans to modify the Army?s two- or three-dimensional IB code ARL-NGEN3 for mortar simulations are discussed. However, conventional NGEN modeling approaches cannot capture the nonuniform discharge of combustion products from the flashtube as shown in experiments. An improvement in gas generation tables and work on a two-phase turbulence model of a primer and black powder pellets with a velocity profile based on the one-dimensional turbulence modeling approach are presented. Plans for coupling this primer model to the ARL-NGEN3 code for mortars are discussed., The original document contains color images.

There are many models of ballistics trajectories. The high-resolution 6-degree-of-freedom (6-DOF) models require many computations and a small time increment. The modified point mass models ignore the spinning of the round to reduce the computational requirements. Selecting a model to use for ballistics estimation or tracking requires tradeoffs between system accuracy and computation expense. The purpose of this report is to present reduced state models (simpler than the 6-DOF model) that can be used to model the trajectories using an extended Kalman filter. These filters can be used to enhance the performance of smart munitions., The original document contains color images.

Detta examensarbete är en utvecklings- och evalueringsprocess av en numeriskt löst ytterballistik modell för ett eldledningssystem utvecklat av SAAB Technologies. Den befintliga ballistik modell som används av eldledningssystemet idag är linjäriserad vilket simplifierar problemet att nå upp till de hårda realtidskrav som finns, dock på grund av de approximationer och simplifieringar knutna till linjäriseringen finns det utrymme för förbättringar i termer av beräkningsnoggrannhet. Ökande krav på systemnivå prestanda tillsammans med initiala utredningar motiverade en undersökning av en numeriskt löst ytterballistik i termer av prestanda relativt den befintliga linjäriserade ytterballistik modellen. Examensarbetet har fokuserat på hela processen från första koncept av en numeriskt löst ytterballistik modell ända till implementering på eldledningssystemet. Arbetet är grundat i ett teoretiskt ramverk i huvudsak inriktat på ballistikteori. Konceptet som har tagits fram använder en olinjär ytterballistikmodell baserad på en befintlig modell beskriven i teori och löses med hjälp av en fjärde ordningens Runge-Kutta integrator. En iterativ metod liknande en diskret kontrollstruktur används för att finna initial- och ändvärden till ballistikmodellen och en adaptiv steglängdsalgoritm används som klarar av att upprätthålla realtidskraven. Parametrisering av modellen gjordes mot eldledningstabeller från ammunitionstillverkare och den resulterande beräkningsnoggrannheten visade sig vara förbättrad relativt den befintliga linjära ytterballistik modellen. Slutsatserna av projektet är att en numeriskt löst olinjär ytterballistik är möjlig trots de hårda realtidskrav som finns på systemet samt kan förbättra systemnivå prestanda, speciellt för långa avstånd. Dock på grund av att konceptet ökar komplexiteten av ballistik mjukvaran samt komplicerar parametriseringen så avråds SAAB från att använda denna lösning såvida systemnivåprestandan inte anses ett problem., This Masters Thesis is a development and evaluation process of a numerically solved nonlinear external ballistics model for a direct Fire Control System developed by SAAB Technologies. The currently used external ballistics model is linearized which significantly simplifies the task of meeting hard real-time constraints on the system but due to the approximations and simplifications tied to the linearization of the external ballistics there exists room for improvements in terms of calculation accuracy. Increasing demands on system level performance together with initial investigations on the Fire Control System concluded that there was interest for an evaluation of a numerical solution in terms of calculation accuracy and processing load. The project focuses on the process from concept development of a numerical external ballistics solution all the way to actual implementation on the targeted Fire Control System. The work is founded on a theoretic frame of reference on primarily external ballistics theory. The concept that has been developed uses a nonlinear external ballistics model based on an existing Modified Point Mass Trajectory Model (MPMTM) described in the theoretic frame of reference and is solved using a fourth order Runge-Kutta integrator. An iterative method similar to that of a discrete time control loop is used to find boundary values of the ballistics model satisfying hard real-time constraints on the system. Parameterization of the external ballistics model was carried out using firing-tables provided from the projectile manufacturer and the resulting calculation accuracy was improved relative the existing linearized solution. The conclusion of the project is that a numerical solution is possible despite the hard real-time constraints on the system and can increase the system level performance, particularly so for long range trajectories. However because the solution increases the complexity of the ballistics calculation software and complicates the

Detta examensarbete är en utvecklings- och evalueringsprocess av en numeriskt löst ytterballistik modell för ett eldledningssystem utvecklat av SAAB Technologies. Den befintliga ballistik modell som används av eldledningssystemet idag är linjäriserad vilket simplifierar problemet att nå upp till de hårda realtidskrav som finns, dock på grund av de approximationer och simplifieringar knutna till linjäriseringen finns det utrymme för förbättringar i termer av beräkningsnoggrannhet. Ökande krav på systemnivå prestanda tillsammans med initiala utredningar motiverade en undersökning av en numeriskt löst ytterballistik i termer av prestanda relativt den befintliga linjäriserade ytterballistik modellen. Examensarbetet har fokuserat på hela processen från första koncept av en numeriskt löst ytterballistik modell ända till implementering på eldledningssystemet. Arbetet är grundat i ett teoretiskt ramverk i huvudsak inriktat på ballistikteori. Konceptet som har tagits fram använder en olinjär ytterballistikmodell baserad på en befintlig modell beskriven i teori och löses med hjälp av en fjärde ordningens Runge-Kutta integrator. En iterativ metod liknande en diskret kontrollstruktur används för att finna initial- och ändvärden till ballistikmodellen och en adaptiv steglängdsalgoritm används som klarar av att upprätthålla realtidskraven. Parametrisering av modellen gjordes mot eldledningstabeller från ammunitionstillverkare och den resulterande beräkningsnoggrannheten visade sig vara förbättrad relativt den befintliga linjära ytterballistik modellen. Slutsatserna av projektet är att en numeriskt löst olinjär ytterballistik är möjlig trots de hårda realtidskrav som finns på systemet samt kan förbättra systemnivå prestanda, speciellt för långa avstånd. Dock på grund av att konceptet ökar komplexiteten av ballistik mjukvaran samt komplicerar parametriseringen så avråds SAAB från att använda denna lösning såvida systemnivåprestandan inte anses ett problem., This Masters Thesis is a development and evaluation process of a numerically solved nonlinear external ballistics model for a direct Fire Control System developed by SAAB Technologies. The currently used external ballistics model is linearized which significantly simplifies the task of meeting hard real-time constraints on the system but due to the approximations and simplifications tied to the linearization of the external ballistics there exists room for improvements in terms of calculation accuracy. Increasing demands on system level performance together with initial investigations on the Fire Control System concluded that there was interest for an evaluation of a numerical solution in terms of calculation accuracy and processing load. The project focuses on the process from concept development of a numerical external ballistics solution all the way to actual implementation on the targeted Fire Control System. The work is founded on a theoretic frame of reference on primarily external ballistics theory. The concept that has been developed uses a nonlinear external ballistics model based on an existing Modified Point Mass Trajectory Model (MPMTM) described in the theoretic frame of reference and is solved using a fourth order Runge-Kutta integrator. An iterative method similar to that of a discrete time control loop is used to find boundary values of the ballistics model satisfying hard real-time constraints on the system. Parameterization of the external ballistics model was carried out using firing-tables provided from the projectile manufacturer and the resulting calculation accuracy was improved relative the existing linearized solution. The conclusion of the project is that a numerical solution is possible despite the hard real-time constraints on the system and can increase the system level performance, particularly so for long range trajectories. However because the solution increases the complexity of the ballistics calculation software and complicates the

This paper describes the internal, external, and terminal ballistics of the 30-06 rifle cartridge. With cartridge case capacity of 68-70 grains of water and operating pressures up to 60,000 psi, the 30-06 launches 110-220 grain bullets with muzzle velocities between 3400 fps and 2400 fps, respectively. Low-drag bullets are available which make the 30-06 an effective and capable choice for target and anti-personnel use out to 1000 yards, but longer range applications are challenging due to the sonic transition. With an appropriate bullet choice, the 30-06 penetrates a variety of commonly encountered barriers. It also penetrates soft body armors and can deliver significant wounding effects even when stopped by hard body armor. At shorter ranges, wounding effects in human and deer-sized living targets are impressive and yield rapid incapacitation., The original document contains color images.

The US Army Research Laboratory (ARL) is currently conducts tests on anti-ballistic armor for military uses. This research is concerned with determining the limit velocity (vL.) of different target penetrator combinations. The limit velocity is the highest velocity a penetrator can have without penetrating the targe. Unfortunately, penetration processes are highly complex and an effective first principles derivation of vL has not been discovered. Estimation of vL is therefore done empirically. Furthermore, ballistics tests can be very expensive, resulting in a small size sample with which to perform statistical data analysis. There are two ballistics testing methods commonly used to estimate vL. The Jonas Lambert method involves measuring the residual velocity of the projectile after perforation. The bisection method or V 50 simply evaluates the perforation without residual velocity. The second method is significantly less expensive. Simulation is used to model both of the common ballistics testing methods as well as several new approaches to ballistics testing. The results are evaluated and compared for statistical significance and accuracy. This work suggests that the bissection method is more accurate when sample size is small. This discovery could provide considerable cost savings to ballistics testing at ARL., Published in Proceedings of the 13th Annual U.S. Army Research Laboratory/United States Military Academy Technical Symposium, p72-95, 2005. Prepared in collaboration with the U.S. Army Aviation School, Fort Rucker, AL, and the Department of Mathematical Sciences, United States Military Academy, West Point, NY.

This report documents the theory and use of the BOOM computer program. BOOM is an exterior ballistics simulation program specifically designed to predict atmospheric flight of smart projectiles. The software contains a projectile dynamic model coupled to an open structure flight control system. The code can be run on PC, Unix, or Mac systems., The original document contains color images.

The state-of-the-art interior ballistics (IB) code for the Army, ARL-NGEN3, is being used to predict the interior ballistics behavior of next-generation gun charges, which include densely-packed solid propellants. Recently, the results from ARL-NGEN3 code simulations were linked to structural dynamics codes in order to predict the in-bore behavior of the projectile afterbody. In the current paper results are presented from recent efforts to bring together the capabilities of ARL-NGEN3 and two of the prominent structural mechanics codes, DYNA3D and EPIC. Results from simulations of a test case show the effectiveness of this approach., See also ADM001736, Proceedings of the Army Science Conference (24th) held in Orlando, FL on 29 Nov-2 Dec 2004. Prepared in cooperation with Army High Performance Computing Research Center (AHPCRC). The original document contains color images.

The efficiency of traditional ballistics imaging system is heavily dependent upon the expertise and experience of end-user. An intelligent ballistics imaging system is highly demanded to address this issues. This paper presents a novel ballistics imaging system which achieves traditional functions and many new features including line-scan image module, characteristics extraction module and intelligent image processing module. Benefit from these features, the system can identify firearm more efficiently and effectively.

Since the traditional ballistics imaging system is dependent upon the expertise and experience of end-user, an intelligent ballistics imaging system is highly demanded to overcome the drawbacks of traditional techniques. This paper aims to develop a novel ballistics imaging system so as to combine the traditional functions with new features such as the line-scan image module, the characteristics extraction module, and the intelligent image processing module. With the help of these features, the new system can identify firearm more efficiently and effectively than the traditional techniques.

Since the traditional ballistics imaging system is dependent upon the expertise and experience of end-user, an intelligent ballistics imaging system is highly demanded to overcome the drawbacks of traditional techniques. This paper aims to develop a novel ballistics imaging system so as to combine the traditional functions with new features such as the line-scan image module, the characteristics extraction module, and the intelligent image processing module. With the help of these features, the new system can identify firearm more efficiently and effectively than the traditional techniques.

There is significant experimental evidence that burning particles of various chemical compositions and sizes are ejected from gun primers and that these particles interact with the propellant grains during main charge ignition. This explicit ignition phenomenon is thought to be incompatible with the implicit treatment of primer function used in conventional interior ballistics codes and models. Generally, the primer efflux is treated as a hot gas that evolves from a specified region in the model's representation of the gun chamber. Essentially, an igniter table is derived from experimental means and by careful calibration of the interior ballistics simulation using gun firing data. With the advent of multidimensional, multiphase interior ballistics codes that employ coupled Eulerian-Lagrangian schemes to explicitly treat both the gas and solid phase, a primer model that is commensurate with the availability of such an interior ballistics model is developed. A further development in the formulation of a primer model that is compatible with the ARL-NGEN3 code and small-caliber weapons is described herein. The model is based on the One-Dimensional Turbulence modeling approach. Integration of the primer model with the ARL-NGEN3 code is shown. Preliminary simulated results comparing primers with particles and primers without particles provide key insights into the early initiation phase of small-caliber ammunition., The original document contains color images.

Ballistics firearm identification based on image processing is of paramount importance in criminal investigation. The efficiency of traditional ballistics imaging system is heavily dependent upon the expertise and experience of end-user. An intelligent ballistics imaging system is highly demanded to address this issues. The segmentation of cartridge case object from the original image is a key step to subsequent process. It is very difficult to segment cartridge case from the original image using traditional threshold based methods due to the shadows or unlimited environments to acquire image. In this paper, we proposed a novel approach based upon the colour invariant and geometrical shape of objects. The experimental results show the proposed method can precisely segment the objects in various images such as heavy shadow, low contrast, uneven illumination etc.

In preparation to the SALTO JIP (Safe Arctic Logistics, Transport & Operations) work was done towards developing an improved model for icing due to sea spray at the bow of a ship. The so-called SHIPICE model may be used in a probabilistic risk-based approach and consists of two main segments: 1. Probabilistic modeling of spray water volumes and the break-up in droplets rising above the freeboard, and 2. Modeling the ballistic and thermodynamic processes of these droplets when falling and freezing to the ship. The present paper deals with the second phase of the SHIPICE model. The modeling of marine spray shows that spray is a phenomenon with sharply increasing volumes with speed and sea state. Furthermore, the droplet size of spray rising above the freeboard has a distinctive effect on the distribution of the spray volume landing on deck. The thermodynamic freezing model takes into account intermittent wetting and run-off, and depends also on the droplet size distribution due to in-flight cooling of the droplets when falling to the ship. The results from the model seem realistic when computed icing growth is compared with two measured icing events reported in literature. The development of SHIPICE will allow users to dimension pre-cautions to the area and time of operation. Additionally, it will provide an improved basis for regulations and guidelines (e.g. ISO TC 67 SC8). For ship owners, it will help evaluate the susceptibility of their ship to marine spray icing., Offshore Engineering

In preparation to the SALTO JIP (Safe Arctic Logistics, Transport & Operations) work was done towards developing an improved model for icing due to sea spray at the bow of a ship. The so-called SHIPICE model may be used in a probabilistic risk-based approach and consists of two main segments: 1. Probabilistic modeling of spray water volumes and the break-up in droplets rising above the freeboard, and 2. Modeling the ballistic and thermodynamic processes of these droplets when falling and freezing to the ship. The present paper deals with the second phase of the SHIPICE model. The modeling of marine spray shows that spray is a phenomenon with sharply increasing volumes with speed and sea state. Furthermore, the droplet size of spray rising above the freeboard has a distinctive effect on the distribution of the spray volume landing on deck. The thermodynamic freezing model takes into account intermittent wetting and run-off, and depends also on the droplet size distribution due to in-flight cooling of the droplets when falling to the ship. The results from the model seem realistic when computed icing growth is compared with two measured icing events reported in literature. The development of SHIPICE will allow users to dimension pre-cautions to the area and time of operation. Additionally, it will provide an improved basis for regulations and guidelines (e.g. ISO TC 67 SC8). For ship owners, it will help evaluate the susceptibility of their ship to marine spray icing., Offshore Engineering

Image Forensics has already achieved great results for the source camera identification task on images. Standard approaches for data coming from Social Network Platforms cannot be applied due to different processes involved (e.g., scaling, compression, etc.). Over 1 billion images are shared each day on the Internet and obtaining information about their history from the moment they were acquired could be exploited for investigation purposes. In this paper, a classification engine for the reconstruction of the history of an image, is presented. Specifically, exploiting K-NN and decision trees classifiers and a-priori knowledge acquired through image analysis, we propose an automatic approach that can understand which Social Network Platform has processed an image and the software application used to perform the image upload. The engine makes use of proper alterations introduced by each platform as features. Results, in terms of global accuracy on a dataset of 2720 images, confirm the effectiveness of the proposed strategy., Comment: 6 pages, 1 figure