Global ETD Search

71	Rozpoznávání markantních rysů na nábojnicích / Recognition of Unique Features on Weapon Cartridges Siblík, Jan January 2010 (has links) Subject of this thesis is design and implementation of an algorithm, capable of distinct feature based comparision of two weapon cartridge casing images. In the first section it looks into the issue of fi- rearms with special emphasis on ballistic traces. In following parts it presents design and imple- mentation of scanning unit for acquisition of such images and their processing and design and excuti- on of the comparation algorithm. In the conclusion there is an evaluation of goals achieved and possi- bilities for further development.
72	Experimental assessment of proximal-lateral edge grinding on haft damage using replicated Clovis points Werner, Angelia N. 26 April 2017 (has links) No description available. Archaeology Experiments archaeology experiments experimental archaeology paleoindians paleo indians Clovis Clovis culture lithics lithic technology projectile points Eren Laboratory ballistics grinding abrading dulling lateral edges basal grinding prehistoric
73	Model for risk evaluation for fragment debris after a grenade detonation / Modell för riskbedömning av splitter från en granatdetonation Lund, Gustav January 2021 (has links) Accidents when using or storing explosives can lead to a large number of casualties and injuries. Hence, it is of vital importance, in all countries, to know the risk and act responsibly when working with explosives. A model for evaluating the risk for fragment-induced injuries from grenade detonation is created starting from experimental data of three different types of grenades. The grenades differ in shape, type of explosives and design. The experiments were conducted shooting the grenades on a wooden target and the fragments from the grenade detonation were collected by witness packages. The witness packages have a layered structure of aluminum plates and polystyrene foam. The collected fragments are weighted and the number of perforated plates for each fragment are counted. From the number of perforated plates the impact velocities of the fragments are calculated and ballistics is then used to obtain the initial velocity of the fragments. Fragmentation is regarded as a stochastic event and a distribution will more correctly describe the variation in shapes and sizes of the fragments. All data obtained in the experiment are evaluated and used to create distributions describing the fragmentation of the grenades. The fragmentized objects are accelerated by the detonation and will, under the influence of the medium, decreases their velocities. The velocity of the fragmentized objects are compared to criterions for skin perforations developed in the 20th century. According to a risk assessments manual, develop by the Swedish defense research agency (FOI), the risk of severe injury can be regarded as acceptable when it occurs one in a million detonations. The distance where only one fragment in one million detonations has the ability to perforate bare skin, according to the injury criterions, is calculated using the developed model. For the three tested grenades the distance at which the injury is acceptable (safety distance) did vary between 55 m and 240 m. The variation in safety distances is assumed to be due to design variation between the three grenades and also dependent on the model for injury criteria that was used. / Det är för alla länder viktigt att veta riskerna med de sprängmedel och ammunition som förvaras och används av deras försvarsmakter. Olyckor som kan uppstå vid förvaring och användning av dessa vapen kan leda till omfattade skador på personer i omgivningen. En modell för att beräkna riskerna för skador från fragmenterade föremål från en detonation har skapats från experiment med tre olika typer av granater. De tre granaterna varierar i form, typ av sprängmedel samt den övergripande designen. Experimenten genomfördes genom skjuta de olika granaterna mot ett mål i trä, fragmenten som skapades vid detonationen fångades sedan upp av vittnespaket. Vittnespaket har en struktur bestående av flera lager aluminiumplåtar och frigolit. Fragment som fångats av dessa paket vägs och från antalet perforerade plåtar räknas. Från antalet perforerade plåtar kan anslagshastigheten för fragmentet beräknas, ballistik används sedan för att beräkna den initiala hastigheten för fragmentet. Från den data som erhållits av experimentet skapas en fördelning av möjliga massor och en för möjliga hastigheter för fragmenten. Fördelningarna används för att beskriva problemet, då fragmentering anses vara en stokastisk process. Fragment som accelererats av detonationen kommer bromsas genom att dessa interagerar med mediet de färdas i. Hastigheten som fragmenten har vid olika distanser från detonationen jämförs med villkor för hudperforering som utvecklats under 1900-talet. Enligt en riskmatris utvecklad av Totalförsvarets forskningsinstitut FOI, anses risken för alvarlig skada vara accepterat om skadan inte uppstår oftare än en gång på en miljon fall. Avståndet där endast ett fragment per en miljon detonerade granater har en hastighet tillräckligt hög för att perforera hud beräknas av modellen. För de testade granaterna varierade detta avstånd mellan 55 och 240 m. Skillnaden i avstånd tros bero på skillnader i granaternas är designade, samt vilket villkor för hudperforering som används. Risk evaluation Ballistic limit of skin Lewis model Greenbook External ballistics Riskbedömning Ballistisk gräns för hud Lewismodellen Greenbookmodellen Ytterballistik Physical Sciences Fysik
74	Exterior ballistics analysis for rocket propelled KE-penetrator - A conceptual simulation study within fluid mechanics and flight mechanics / Ytterballistik för raketdriven KE-pil – En konceptuell studie inom strömnings- och flygmekanik Wegberg, Emil January 2022 (has links) 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. Exterior ballistics fluid mechanics high-speed aerodynamics CFD RANS conceptual design Ytterballistik strömningsmekanik höghastighetsaerodynamik CFD RANS konceptuell design Aerospace Engineering Rymd- och flygteknik
75	Prédiction des lésions pulmonaires lors d’un impact balistique non pénétrant / Prediction of lung injuries during ballistic blunt thoracic trauma Prat, Nicolas 30 November 2011 (has links) Les impacts non transfixiants sur les gilets pare-balles sont responsables de lésions non pénétrantes potentiellement létales, regroupées sous le terme d’effets arrière (Behind Armor Blunt Trauma : BABT). De telles lésions fermées se retrouvent également lors d’impacts thoraciques de projectiles d’Armes à Létalité Réduite cinétiques (ALRc). Afin d’améliorer le pouvoir protecteur des protections balistiques et de mieux maitriser le pouvoir vulnérant des ALRc, il est nécessaire de définir un critère lésionnel permettant de prédire l’importance des lésions en cas de traumatisme thoracique fermé de type balistique. Ce critère se doit d’être bien corrélé à la gravité du traumatisme, et de pouvoir être facilement transposable à l’ensemble des systèmes d’évaluation des protections balistiques et des ALRc. La gravité du traumatisme a été définie ici par le volume de la contusion pulmonaire. L’utilisation de cette valeur nécessitait le recours au modèle animal. Or, nous avons démontré que le thorax du modèle porcin n’offrait pas le même comportement biomécanique lors de l’impact que le thorax de l’adulte jeune. Nous avons donc développé un critère, l’impulsion de pression intrathoracique maximale (PImax), basé sur la mesure de la pression intrathoracique lors de l’impact, et donc indépendant du comportement biomécanique de la paroi thoracique vis-à-vis de ses effets sur le poumon. Ce critère très bien corrélé avec le volume de la contusion pulmonaire, quelque soit le type d’impact thoracique balistique (ALRc ou BABT), a l’avantage de pouvoir être transposable aux autres moyens d’évaluations balistiques tels que les modèles numériques ou mécaniques de thorax, afin de s’affranchir de l’expérimentation animale / When non-penetrating, impacts on bulletproof jackets can lead to potentially lethal blunt injuries known as behind armor blunt trauma (BABT). Impacts of less lethal kinetic weapons (LLKW) can also lead to such injuries. To both improve the protection capabilities of the BPJ and better comprehend the ounding potential of the LLKW, we need to design a wounding criterion to predict the injury severity of ballistic blunt thoracic trauma. In one hand, this criterion has to be well correlated with the severity of the injuries, and in the other hand, it has to be easily used with all the LLKW and BPJ assessment systems in use. First, we defined the pulmonary contusion volume as the severity of the injuries. Studying the pulmonary contusion involves the use of animal experiments. But we demonstrated that the biomechanics of the chest wall are different in animals and young adults. Then, we developed the maximum pressure impulse criterion (PImax). As it is based on the intrathoracic pressure measure during the blunt impact, it is independent from the chest wall behavior. This criterion can be used with the other assessment tools as the numerical simulation mechanical chest surrogates. This can help to reduce the use of animal experiments, which is more and more expensive, heavy and questionable on the ethical aspect Balistique lésionnelle Traumatisme thoracique fermé Contusion pulmonaire Gilet pare-balles Effets arrière Arme à létalité réduite Wound ballistics Blunt thoracic trauma Lung contusion Bulletproof jacket Behind armor blunt trauma Less lethal weapon 612.24
76	The use of firearm evidence in the investigation of murder Tshishonga, Mpho 02 1900 (has links) In this dissertation, the researcher wants to establish the use of firearm evidence in the investigation of the crime of murder. Firearm evidence can be of significance to the investigators during murder investigations. To determine the importance of this evidence the researcher has formulated the following research questions to address the research problem:  What is the role of forensic science in the investigation of crimes?  How can firearm evidence be used in the investigation of murder? An empirical research design and qualitative research approach were used for this dissertation. International and national literature sources were consulted and the researcher conducted semi-structured interviews with the investigators from Akasia SAPS, crime scene experts from the Pretoria North LCRC and ballistics experts from the Forensic Science Laboratory in Silverton, Pretoria. The role of forensic science and the use of firearm evidence in the investigation of murder were established. Recommendations have been made for further research on aspects highlighted by the findings. / Police Practice / M. Tech. (Forensic Investigations) Crime scene Firearm Locard principle Murder Physical evidence 363.2595230968 Forensic ballistics -- South Africa Evidence, Criminal -- South Africa Murder -- Investigation -- South Africa Criminal investigation -- South Africa Firearms and crime -- South Africa
77	Bradford Non-Lethal Weapons Research Project (BNLWRP). Research Report 1. Lewer, N. January 1997 (has links) yes / The NLW database illustrates the extensive and eclectic literature regarding NLWs which covers the last few decades. It currently contains over 250 entries. It is important to have access not only to the more recent material, but also to earlier sources since many of the general debates and controversies have already been rehearsed, and lessons learnt from them are still relevant today. Yet, it is also vital to follow new developments of NLWs closely because rapidly changing technology is producing weapons whose implications for integration into military and civil police forces have yet to be clearly defined and understood. Of particular interest are not only NLW applications for war fighting, but opportunities for deployment in peace enforcement and peace keeping missions. These technologies span many bases including: psycho-chemicals; unmanned weapons platforms and delivery systems; biogenetics; acoustic and microwave weapons; biological and chemical weapons; laser systems; kinetic energy ballistics; dual purpose (lethal/non-lethal) weapons; and, sprays and foams which inhibit movement. The database will keep up to date on these developments and future reports will highlight new issues and debates surrounding them. With these rapid technological advances come a series of associated dangers and concerns including: the ethics of use; implications for weapons control and disarmament treaties; military doctrine; public accountability and guidelines; dangers of misuse and proliferation; and, research and development strategies. Using the database, and drawing from military and non-military sources, this report will select the main current issues and debates within the non-lethal community. Bearing in mind that many operations undertaken by military forces are now more akin to policing actions (such as peace support operations) there are lessons to be learnt by military units from civil police experience. There still remains a tension between perceived benign and malign intent both in NLW operational use and non-lethal research and development. Non lethal weapons War Peace enforcement Peace keeping missions Kinetic energy ballistics Microwave weapons Acoustic weapons Biogenetics Unmanned weapons platforms Psycho-chemicals Laser systems Dual purpose (lethal/non-lethal) weapons Sprays and foams
78	Caractérisation et modélisation du comportement lors de l'allumage de poudres propulsives à vulnérabilité réduite en balistique intérieure / Experimental characterization and numerical modeling of the ignition of low vulnerability gun propellants in interior ballistics Boulnois, Christophe 30 May 2012 (has links) Les poudres propulsives pour armes sont des matériaux énergétiques dont la combustion permet l’accélération de projectiles jusqu’à des vitesses importantes. Ces matériaux énergétiques sensibles peuvent être soumis à de fortes contraintes (chocs, impacts et incendies) lors de leur utilisation. Le remplacement de certaines substances entrant dans leur formulation permet de diminuer leur vulnérabilité. En conséquence, ces poudres propulsives présentent une dynamique d’allumage différente. Ce travail de recherches est consacré à l’allumage des poudres propulsives pour armes et se présente en quatre chapitres. Un état de l’art sur le sujet est réalisé. Il porte en particulier sur la phénoménologie de l’allumage, la caractérisation de poudres propulsives, et la modélisation de l’allumage. Deux poudres propulsives sont expérimentalement analysées par thermogravimétrie, calorimétrie et spectrométrie de masse. Cette analyse permet de caractériser les différentes étapes cinétiques de la dégradation thermique de ces poudres propulsives. Un code de modélisation biphasique 2D est développé pour servir de support à la comparaison de modèles d’allumage. Le modèle implémenté décrit la chambre de combustion du canon dans les premières phases du coup de canon, lorsque le lit de poudre propulsive est compacté et que les gaz issus du dispositif pyrotechnique d’allumage le parcourent. Un modèle d’allumage est développé à partir des résultats expérimentaux obtenus au deuxième chapitre. Le code de calcul précédemment évoqué permet de comparer l’influence de différents modèles sur la propagation de l’allumage. / Gun Propellants are energetic materials whose combustion can accelerate projectiles to high speeds. These sensitive energetic materials can be subjected to high stresses (shocks, impacts and fires), potentially able to ignite them. The modification of their chemical formulation reduces such vulnerability. Consequently, these propellants have different ignition dynamics. This work focuses on the ignition of gun propellants and comes in four chapters. A state of the art on the subject is firstly made. It focuses on the phenomenology of the ignition and on energetic materials experimental characterization, and modeling of their ignition. Two gun propellants are experimentally analyzed by thermogravimetry, calorimetry and mass spectrometry. This analysis allows characterizing the various stages of the degradation kinetics of these propellants. A 2D biphasic modeling code was developed to provide support for the comparison of ignition models. It describes the combustion chamber in the early stages of the gun firing, when the propellant bed is compacted and the gases from the pyrotechnic igniter are flowing through it. An ignition model is developed from the experimental data obtained in the second chapter. The previously mentioned modeling code allows comparing the influence of different ignition models on the spreading speed of the ignition signal through the packed bed of propellant. Matériaux énergétiques Poudres propulsives Balistique intérieure Allumage Analyse thermique Thermogravimétrie Calorimétrie Spectrométrie Analyse cinétique Ecoulement réactif Pyrotechnie Vulnérabilité réduite Modélisation biphasique Energetic materials Propellants Interior ballistics Firing Thermal analysis Thermogravimetry Calorimetry Spectrometry Kinetic analysis Reactive flow Pyrotechnics Low vulnerability Biphasic modeling
79	Nano-particles In Multi-scale Composites And Ballistic Applications Gibson, Jason 01 January 2013 (has links) Carbon nanotubes, graphene and nano sized core shell rubber particles have all been extensively researched for their capability to improve mechanical properties of thermoset resins. However, there has been a lack of research on their evaluation for energy absorption in high velocity impact scenarios, and the fundamental mechanics of their failure mechanisms during highly dynamic stress transfer through the matrix. This fundamental research is essential for laying the foundation for improvement in ballistic performance in composite armor. In hard armor applications, energy absorption is largely accomplished through delamination between plies of the composite laminate. This energy absorption is accomplished through two mechanisms. The first being the elongation of the fiber reinforcement contained in the resin matrix, and the second is the propagation of the crack in between the discreet fabric plies. This research aims to fundamentally study the energy absorption characteristics of various nano-particles as reinforcements in thermoset resin for high velocity impact applications. Multiple morphologies will be evaluated through use of platelet, tubular and spherical shaped nano-particles. Evaluations of the effect on stress transfer through the matrix due to the combination of nano sized and micro scale particles of milled fiber is conducted. Three different nano-particles are utilized, specifically, multi-walled carbon nanotubes, graphene, and core shell rubber particles. The difference in surface area, aspect ratio and molecular structure between the tube, platelet and spherical nano-particles causes energy absorption through different failure mechanisms. This changes the impact performance of composite panels enhanced with the nanoparticle fillers. Composite panels made through the use of dispersing the various nano-particles iv in a non-contact planetary mixer, are evaluated through various dynamic and static testing, including unnotched cantilever beam impact, mixed mode fracture toughness, split-Hopkinson bar, and ballistic V50 testing. The unnotched cantilever beam testing showed that the addition of milled fiber degraded the impact resistance of the samples. Addition of graphene nano platelets unilaterally degraded impact resistance through the unnotched cantilever beam testing. 1.5% loading of MWCNT showed the greatest increase in impact resistance, with a 43% increase over baseline. Determining the critical load for mixed mode interlaminar shear testing can be difficult for composite panels that bend without breaking. An iterative technique of optimizing the coefficient of determination, R2 , in linear regression is developed for objectively determining the point of non-linearity for critical load. This allows for a mathematical method of determination; thereby eliminating any subjective decision of choosing where the data becomes non-linear. The core shell rubber nano particles showed the greatest strain energy release rate with an exponential improvement over the baseline results. Synergistic effects between nano and micro sized particles in the resin matrix during transfer of the stress wave were created and evaluated. Loadings of 1% milled carbon fiber enhanced the V50 ballistic performance of both carbon nanotube and core shell rubber particles in the resin matrix. However, the addition of milled carbon fiber degrades the impact resistance of all nano-particle enhanced resin matrices. Therefore, benefits gained from the addition of microsized particles in combination with nano-sized particles, are only seen in high energy impact scenarios with micro second durations. v Loadings of 1% core shell rubber particles and 1% milled carbon fiber have an improvement of 8% in V50 ballistic performance over the baseline epoxy sample for 44 mag single wad cutter gas check projectiles. Loadings of 1% multi-walled carbon nanotubes with 1% milled carbon fiber have an improvement of 7.3% in V50 ballistic performance over the baseline epoxy sample. The failure mechanism of the various nano-particle enhanced resin matrices during the ballistic event is discussed through the use of scanning electron microscope images and Raman spectroscopy of the panels after failure. The Raman spectroscopy data shows a Raman shift for the fibers that had an enhancement in the V50 performance through the use of nano-particles. The Raman band for Kevlar® centered at 1,649 cm-1 stemming from the stretching of the C==O bond of the fiber shows to be more sensitive to the residual axial strain, while the Raman band centered at 1,611 cm-1 stemming from the C-C phenyl ring is minimally affected for the CSR enhanced panels due to the failure mechanism of the CSR particles during crack propagation. Nanotubes graphene ballistics composite armor composites energy absorption raman spectroscopy kevlar split hopkinson bar unnotched cantilever beam impact v50 mixed mode interlaminar shear astm d6671 astm d4812 mil std 662f nanocomposite carbon nanotubes mwcnt core shell rubber crack propagation impact resistance energy release rate Engineering Mechanical Engineering
80	Untersuchung der Geschosswirkung in der sehr frühen Phase unter besonderer Berücksichtigung der Hochgeschwindigkeitsmunition / Study of bullet effects at a very early stage with special consideration of high-speed ammunition Siegmund, Bernward 13 November 2006 (has links) No description available. 610 Medizin, Gesundheit Medicine Ausschuss ballistische Gelatine ballistisches Pendel Druckwelle Druckverlauf Energieabsorption Energieverlust Einschuss Energieabgabe Fragmentation Frangible Training Ammution Gewehr Geschwindigkeit Geschosse gerichtliche Medizin Glasfaserhydrophon Geometrie Hochgeschwindigkeit Hochgeschwindigkeitskamera Hochgeschwindigkeitsmunition Jagdunfälle Kaliber Kavitation Kaliber Militär Munition Projektil Reflexion Rechtsmedizin Schallgeschwindigkeit Schussverletzungen Schusswaffen Schusswirkung Schusswunden temporäre Zielhöhle Tötungsdelikt Vollmantelmunition Wechselwirkung Wundballistik Zugwelle Zielballistik Zielpulsation ammunition ballistic gelatine ballistic pendulum bullet bullet hole calibre cavitation energy absorption energy emission firearm forensic medicine fragmentation frangible training ammunition full metal ammunition geometry glass fibre hydrophone gunshot wound high speed high speed camera homicide hunting accident interaction loss of energy medial jurisdiction military pressure progression projectiles rejects reflection rifle shot effect shock wave speed speed of sound suction waves target ballistics target pulsation temporary target cave wound ballistics 44.72 MED 590: Rechtsmedizin

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