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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

INJURY RISK TO THE UPPER EXTREMITY RESULTING FROM BEHIND SHIELD BLUNT TRAUMA

de Lange, Julia January 2023 (has links)
Ballistic shields are supported by a user’s arm, placing the upper extremity at close proximity to the back-face of the shield. Although ballistic shields must pass a protective standard that outlines projectile (bullet) penetration; there is no standard that stipulates the amount of acceptable deformation when ballistic shields stop or deflect projectiles. There are no injury criteria developed for the high-rate, short duration and focal loading that is typical of shield back-face deformation from these events. In this research, an anthropomorphic test device (ATD) was modified to allow for additional instrumentation capable of measuring these loads. It was then used in a ballistic testing facility to quantify loading at the hand, wrist, forearm, and elbow. A lightweight projectile was created that matched the shape and stiffness of the deforming ballistic shield and impacts within 5% of the peak force measured in the ballistic testing facility were applied with it to post-mortem human subjects (PMHS) until failure. Eight 50th percentile male PMHS pairs were segmented at the mid-humerus and impacted to failure to determine the fracture threshold of the hand, wrist, forearm, and elbow, confirmed by x-ray imaging. The peak force required to generate fracture varied significantly among anatomical location, indicating boundary conditions influence failure threshold. Further, these injury criteria were substantially different than previously reported criteria for other loading events (e.g., automotive), highlighting the importance of developing injury criteria specific for the intended application. An existing finite element human body model designed for automotive impacts was also assessed for its applicability to predict injury in these high-rate loading scenarios, and performed well for peak force, but not for the force-time curve shape. This is the first study of its kind to assess injury risk resulting from shield behind armour blunt trauma, and results from this work will inform a protective standard to assess ballistic shields. / Thesis / Doctor of Philosophy (PhD) / Ballistic shields used by defence personnel are designed to stop incoming bullets by deflecting or absorbing them. In the process, the back-face of the shield undergoes a rapid deformation that can potentially cause an upper extremity injury to users, an injury mechanism termed behind shield blunt trauma. This work aimed to quantify the injury risk that this mechanism poses at four locations along the upper extremity: the hand, wrist, forearm, and elbow. This was conducted by modifying and employing a crash test dummy upper extremity and measuring loads applied to the upper extremity in a ballistic testing range. Assessment of whether these loads caused injury was conducted using cadaveric specimens and testing them to failure. An existing finite element human body model was also assessed for its applicability to predict injury in these high-rate loading scenarios. Results from this work will inform a protective standard to assess ballistic shields.
32

Efficient multiple hypothesis track processing of boost-phase ballistic missiles using IMPULSE©-generated threat models

Rakdham, Bert 09 1900 (has links)
In this thesis, a multiple hypotheses tracking (MHT) algorithm is developed to successfully track multiple ballistic missiles within the boost phase. The success of previous work on the MHT algorithm and its application in other scientific fields enables this study to realize an efficient form of the algorithm and examine its feasibility in tracking multiple crossing ballistic missiles even though various accelerations due to staging are present. A framework is developed for the MHT, which includes a linear assignment problem approach used to search the measurement-to-contact association matrix for the set of exact N-best feasible hypotheses. To test the new MHT, an event in which multiple ballistic missiles have been launched and threaten the North American continent is considered. To aid in the interception and destruction of the threat far from their intended targets, the research focuses on the boost-phase portion of the missile flight. The near-simultaneous attacks are detected by a network of radar sensors positioned near the missile launch sites. Each sensor provides position reports or track files for the MHT routine to process. To quantify the performance of the algorithm, data from the National Air and Space Intelligence Center's IMPULSE ICBM model is used and demonstrates the feasibility of this approach. This is especially significant to the U.S. Missile Defense Agency since the IMPULSE model represents the cognizant analyst's accurate representation of the ballistic threats in a realistic environment. The results show that this new algorithm works exceptionally well in a realistic environment where complex interactions of missile staging, non-linear thrust profiles and sensor noise can significantly degrade the track algorithm performance especially in multiple target scenarios.
33

Kriminalistická balistika / Forensic ballistics

Votava, Milan January 2011 (has links)
- 1 - 9. Abstract Forensic ballistics The goal of this thesis is to initiate readers into the branch of criminalistic or forensic ballistics and to its basic terminology. It is not possible to compile this theme at full length, there is no sufficient space for it, therefore I offer professional minimum of criminalistic ballistics. The fundamental purpose of my thesis is to afford the complex view of problems of modern forensic ballistics. The thesis is composed of introduction, six chapters, conclusion and supplements. Introduction defines short acquaintance with theme and with reasons why I decided on the subject of criminalistic ballistics. The following chapter "Historic development of fire arms" features history of weapons or fire arms. The subchapter "Historical development of forensic ballistics" includes the development of the branch abroad and in the territory of late Czechoslovakia too, including the well-known case of manslaughter of countess Windischgrätz. The chapter "Conception of forensic ballistics and its signification" illustrates basic division of criminalistic ballistics, then illustrates objects of investigation and occurrence of ballistics clues. The chapter named "Categories of object in ballistics investigation" is divided into three subchapters and readers can learn basic dividing of...
34

Viability of Bismuth as a Green Substitute for Lead in Jacketed .357 Magnum Revolver Bullets

Jenkins, Joel A. 11 March 2015 (has links)
In seeking to develop environmentally friendly lead-free non-toxic bullets, the research ballistically evaluated the performance of copper-jacketed handgun bullets containing a pure bismuth core. The lead was first removed from 140 grain HornadyTM XTP® bullets of 38 caliber (.357 diameter) by melting. The empty jackets were then refilled with pure bismuth, including the forming of a correctly sized hollow-point cavity. Due to the lower density of bismuth as compared to lead, the bismuth-cored bullets consistently weighed 125 gains. Conveniently this allowed direct comparison to commercially available 125 grain HornadyTM XTP® lead-cored bullets of 38 caliber. Both bismuth-cored and lead-cored versions of the 125 grain bullets had identical nose dimensions and jacket material, the only dimensional difference being the bullet length below the cannelure. Shooting took place at an outdoor range using a 357 Magnum RugerTM SP101® revolver with 3" barrel as the test weapon. FBI protocols were followed when firing through clothing, wallboard, plywood, steel plates and laminated glass. Wound paths and bullets were captured in ballistic gelatin, with data collected for velocity, penetration, expansion, and weight retention. Bismuth compared favorably with lead in all but the laminated glass test, where it under penetrated due to jacket separation.
35

Microstructure and mechanical properties of glass-ceramics from the MgO-Al₂O₃-SiO₂ system for ballistic protection / Microstructure et propriétés mécaniques des vitrocéramiques du système mgo-Al₂o₃-SiO₂ pour la protection balistique

Gallo, Leonardo Sant'ana- 26 September 2016 (has links)
Afin d'examiner les effets de la cristallisation sur certaines propriétés mécaniques, l'évolution du module de Young (E), du module de cisaillement (G) et du coefficient de Poisson, ainsi que la séquence des phases cristallines formées au cours d'un traitement thermique en deux étapes ont été accompagnées sur un verre baptisé 75-25, du système MgO-Al2O3-SiO2 (MAS), en utilisant TiO2 comme le principal agent de nucléation. L'évolution de la dureté et de la résistance à la rupture a aussi été examinée. La diffractométrie de Rayons X à haute température a révélé, après cristallisation, la présence de spinelle (MgO.Al2O3) rutile (TiO2), karooite (MgO.2TiO2), sillimanite (Al2O3.SiO2) et la saphirine (4MgO.5Al2O3.2SiO2). Les modules élastiques et de cisaillement des vitrocéramiques (VC) se sont montré environ 20% plus élevés que ceux du verre précurseur. Les valeurs de dureté obtenues sont proches de 10 GPa et KIC proche de 1,2 MPa.m1/2. Dans le but de fabriquer des VCs transparentes et incolores, de nouvelles formulations, dénommées ZT1B4, 75-25/ZT et 75-25/25TI, avec des teneurs en TiO2 réduites et des teneurs en ZrO2 plus élevées, ont été proposées et cristallisées. La formulation ZT1B4 a produit une VC transparente avec une dureté maximale de 8GPa et une ténacité à la fracture (TF) à peu près 40% plus élevée que celle du verre de base. Les formulations 75-25 ZT et 75-25/25Ti ont produit des VC transparentes avec des valeurs de dureté allant jusqu'à 9GPa et une ténacité à la fracture jusqu'à 35% plus élevée que celle du verre de base. Une série de verres ont été fondus en utilisant Ag métallique, au lieu de ZrO2 et TiO2, en tant qu'agent de nucléation. Les traitements thermiques appliqués ont produit des VCs non-homogènes, qui perdent la forme en raison des températures de cristallisation élevées. Ces nouveaux verres précurseurs ont donc été écartés. La transmittance dans la région de l'ultraviolet et visible a été mesurée dans les échantillons de verre et VCs de formulation 75-25, 75-25 / ZT et 75-25 / 25TI. La formulation 75-25 / ZT a présenté la plus haute transmittance soit à l'état vitreux ou en forme de vitrocéramique. En conclusion, parmi les nouvelles compositions, la formulation 75-25 / ZT est la plus adéquate pour une utilisation en tant que protection balistique, lorsque la transparence à la lumière visible est nécessaire. / In situ experiments were conducted on a glass dubbed 75-25, of the MgO-Al2O3-SiO2 (MAS) system, using TiO2 as the main nucleating agent, in order to examine the evolution of Young’s modulus (E), shear modulus (G) and Poisson's ratio, and the sequence of the crystalline phases formed during a double-stage heat treatment. The effects of crystallization on hardness and fracture toughness were also examined. High temperature X-ray diffraction experiments revealed the presence of spinel (MgO.Al2O3), rutile (TiO2), karooite (MgO.2TiO2), sillimanite (Al2O3.SiO2) and sapphirine (4MgO.5Al2O3.2SiO2) after crystallization. The elastic and shear moduli of the glass-ceramics (GC) were approximately 20% larger than those of the parent glass. Hardness values were close to 10 GPa and KIC close to 1.2 MPa.m1/2. Aiming to obtain transparent and colorless GC, new formulations, dubbed ZT1B4, 75-25/ZT and 75-25/25Ti, with lower titania content and higher zirconia content, were proposed and crystallized. Formulation ZT1B4 yielded a transparent GC with hardness of up to 8 GPa and an indentation fracture toughness (IFT) about 40% higher than that of the parent glass. Formulations 75-25/ZT and 75-25/25Ti yielded transparent GC with hardness values of up to 9 GPa and an IFT up to 35% higher than that of the parent glass. A series of glasses were also melted using metallic Ag as nucleating agent instead of ZrO2 and TiO2. The applied heat treatments generated non-homogeneous GC, which became warped due to the high crystallization temperatures. These new precursor glasses were therefore discarded. Transmittance in the ultraviolet to visible range was measured in the glass and GC samples of formulations 75-25, 75-25/ZT and 75-25/25Ti. Formulation 75-25/ZT presented the highest transmittance in both glass and GC states. It was concluded that among the new compositions, formulation 75-25/ZT is the most suitable one for use as ballistic protection when transparency to visible light is required.
36

Effets vulnérants des armes à feu réglementaires : sept siècles de balistique lésionnelle / Wound effects of infantry weapons

Laforge, Vincent 18 May 2018 (has links)
Comment quelques grammes de plomb propulsés par quelques grammes de poudre peuvent-ils avoir raison, à distance, du plus robuste des soudards ? Pourquoi le même projectile peut-il tuer l’un et épargner l’autre ? Depuis le XVe siècle, ces questions effraient le combattant, intriguent le chirurgien et agitent la communauté scientifique.Croisant données historiques, comptes rendus médico-légaux et expérimentation scientifique, cette étude tente de répondre à ces interrogations pluriséculaires. Les sources consultées reposent principalement sur les écrits chirurgicaux, mais explorent également les ouvrages traitant d’armes, de munitions et de tactique, partant du principe que tous ces facteurs jouent un rôle dans ce drame parfois définitif qu’est la rencontre tumultueuse entre un projectile et la cible particulière que constitue l’organisme humain. Les réponses apportées sont contrastées et souvent contradictoires : à ceux qui estiment qu’une plaie par projectile d’arme à feu est une plaie comme les autres répondent ceux qui considèrent que le mécanisme qui l’a produit doit être pris en compte dans l’étude de ces effets et dans la décision thérapeutique. Ce travail expose, au travers de ces polémiques, l’extrême diversité des effets vulnérants des armes à feu, aucun traumatisme balistique n’étant strictement superposable à un autre. Ce caractère non reproductible, en dehors de l’expérimentation scientifique, exclut toute conclusion formelle et définitive quant aux effets des projectiles d’armes à feu. Être touché par une balle reste une aventure individuelle aux conséquences imprévisibles. / How can a few grams of lead expelled with a few grams of powder remotely take out the toughest boor? Why can the same projectile kill one and spare the other? Since the 15th century, these questions frighten the fighter, intrigue the surgeon and stir the scientific community.Crossing historic data, medicolegal reports and scientific experiments, this study tries to answer these centuries-long questions. The consulted sources are mostly based on surgical writing but also explore books dealing with weapons, ammunition, tactics, given all these factors interneve in this, something definitive, drama that is the tumultuous encounter between a projectile and the particular target that the human body is. The results are mixed and often contradictory, opposing those who think a projectile-induced wound is a common wound and those who consider the igniting mechanism has to be taken into account to study and treat its effects efficiently. This work shows, apart from these polemics, the great diversity of firearms wounding effects, no ballistic trauma being strictly comparable to another. This non-reproductible specificity, aside from scientific experiments, rules out any formal and definitive answer regarding the effects of firearms projectiles. Being shot with a bullet remains an individual adventure with unpredictable consequences.
37

Internal Ballistic Design Optimization Of A Solid Rocket Motor

Acik, Sevda 01 June 2010 (has links) (PDF)
Design process of a solid rocket motor with the objective of meeting certain mission requirements can be specified as a search for a best set of design parameters within the overall design constraints. In order to ensure that the best possible design amongst all achievable designs is being achieved, optimization is required during the design process. In this thesis, an optimization tool for internal ballistic design of solid rocket motors was developed. A direct search method Complex algorithm is used in this study. The optimization algorithm changes the grain geometric parameters and nozzle throat diameter within the specified bounds, finally achieving the optimum results. Optimization tool developed in this study involves geometric modeling of the propellant grain, burnback analysis, a 0-dimensional ballistic performance prediction analysis of rocket motor and the mathematical optimization algorithm. The code developed is verified against pretested rocket motor performance.
38

Surface Properties of Advanced Materials and Their Applications in Ballistics

Yun, Huisung 16 December 2013 (has links)
This thesis research investigates the surface properties and performances of gold nanoparticles, microarc oxidation coating, and epitaxial nano-twinned copper film. The research aims to understand the critical behavior of material surfaces in order to facilitate design and development of new materials for tribological applications. The research will focus on improving of the gun barrel performances. Experimental approaches will be used for combining analysis with basic thermal energy transfer principles. Results obtained here will be used for developing new materials to be used in facilitating gun barrels. Experimental approach includes scanning calorimetry-thremogravimetric analysis, tribological testing, and potentiodynamic polarization. The fundamental understanding obtained here will be beneficial for the gun barrel design, manufacturing, and military technologies followed by the results of experiments with different three types of materials. The results of this research showed that the coatings with microarc oxidation and nano-twinned structure improved wear resistance from the tribological examinations and size of AuNPs affected their thermal behaviors measured by differential scanning calorimetry and thermogravimetric analysis method.
39

An acoustic countermeasure to supercavitating torpedoes

Cameron, Peter J. K. 12 June 2009 (has links)
Supercavitating torpedoes pose new threats to submarines, surface ships, and shore targets whose current countermeasures are inadequate against this technology. These torpedoes have the advantage over their predecessors and companion weapons of dramatically increased speed, which reduces the reaction time available for deploying a countermeasure heightening the threat to their intended target. Proliferation of supercavitating torpedoes has motivated research on countermeasures against them as well as on the fluid phenomenon which makes them possible. The goal of this research was to investigate an envisaged countermeasure; an acoustic field capable of slowing or diverting the weapon by disrupting the cavitation envelope. The research focused on the interactions between high-level sound signals and a supercavity produced by a small free-flying projectile. In order to conduct this study it was necessary to achieve three preliminary accomplishments involving the design of: 1) experimental apparatus that allowed for the study of a small-scale supercavitating projectile in the laboratory environment; 2) apparatus and software for measuring and recording information about projectile dynamics and supercavity geometry; and 3) an acoustic array and power source capable of focusing the desired sound signal in the path of the supercavitating object. Positive results have been found which show that the accuracy of a supercavitating projectile can indeed be adversely affected by the sound signal. This research concludes with results that indicate that it is acoustic cavitation in the medium surrounding the supercavity that is responsible for the reduced accuracy. A hypothesis has been presented addressing the means by which the acoustic cavitation could cause this effect. Additionally, corrugations on the cavity/water interface imposed by the pressure signal have been observed and characterized.
40

Hemodynamic, respiratory and neurophysiological reactions after high-velocity behind armor blunt trauma /

Gryth, Dan, January 2007 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

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