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1
Dykes, John William. "Projectile linear theory for aerodynamically asymmetric projectiles." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42828.
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Currently, there are few analytical tools within the ballistics community to aid
in the design and performance evaluation of aerodynamically asymmetric projectiles.
The scope of this thesis is to (1) create analytical tools that are capable of quantifying
aerodynamically asymmetric projectile performance, (2) demonstrate the ability of
these models to accurately account for aerodynamic asymmetries, and (3) gain insight
into the flight mechanics of several aerodynamically asymmetric projectiles. First, a
six-degree-of-freedom (6 DOF) flight dynamic model, which uses a point-force lifting-surface
aerodynamic model, was developed to replicate flight characteristics observed
from measured results of common projectiles. A quasi-linear flight dynamic model
was then created using the machinery of Projectile Linear Theory (PLT). From this,
flight dynamic stability models were developed for linear time-invariant (LTI) and
linear time-periodic (LTP) systems. Dynamic simulation and stability trade studies
were then conducted on asymmetric variants of 4-finned, 3-finned, 2-finned, and hybrid
projectile configurations. First, stability of symmetric projectiles are validated
and show that the classical and extended PLT model yielded identical results. Results show that aerodynamic asymmetries can sometimes cause
instabilities and other times cause significant increase in dynamic mode damping and
increase/decrease in mode frequency. Partially asymmetric (single plane) configurations
were shown to cause epicyclic instabilities as the asymmetries became severe,
while fully asymmetric (two plane) can grow unstable in either the epicyclic modes or
the roll/yaw mode. Another significant result showed that the LTP stability model
is able to capture aerodynamic lifting-surface periodic affects to evaluate dynamic
stability requirements for asymmetric projectiles.
2
Myrtroeen, Ole Joergen. "Negatively buoyant fluid projectiles." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9212.
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An experimental study concerning the rise height and morphology of a negatively buoyant fluid projectile, produced when a finite volume of saline solution is forced vertically upwards into a quiescent and uniform fresh water environment, is presented. Unlike the much studied continuous injection of high Reynolds number negatively buoyant fluid giving rise to a turbulent fountain, the behaviour of a finite volume negatively buoyant release remains, until now, unstudied. The work presented herein is based on the development of an experimental set up and methodology specifically tailored to the study of the negatively buoyant projectile. We commence by identifying the two source parameters governing the behaviour of the negatively buoyant projectile; namely the source Froude number FrD, expressing the ratio of source momentum to source buoyancy, and the aspect ratio of release L/D. relating the length L of the column of saline solution dispensed to the nozzle diameter D. In doing so, we note the link to turbulent fountains (continuous negatively buoyant releases) whose behaviour is governed solely by FrD and to vortex rings (finite volume neutrally buoyant releases), whose behaviour is governed solely by L/D. Based on its differing rise height behaviour and morphology of release (for varying FrD and L/D), we classified the negatively buoyant projectile into one of three regimes: the weak-fountain regime, where the rise height behaviour of the negatively buoyant projectile adhered to very weak fountain predictions; the vorticity-development regime, where the development of an internal vortical structure within the head of the negatively buoyant projectile inhibited its vertical propagation; and the forced-release regime, where the rise height behaviour of the negatively buoyant release adhered, under certain source conditions, to forced fountain predictions. This adherence of the rise height behaviour of negatively buoyant projectiles to fountain rise height predictions led to a study of the source conditions (in terms of FrD and L/D), separating finite volume behaviour (negatively buoyant projectile) from continuous behaviour (fountain), at least in terms of initial fountain rise heights. This study led to a classification of the FrD and L/D vales marking the transition from finite volume behaviour to continuous behaviour for negatively buoyant releases, linking our work on the negatively buoyant projectile to existing fountain literature. Finally, we studied the time dependent volume of the head of the negatively buoyant projectile as it propagated, and identified two stages: a growth stage and a decay stage. We established that the volume of the head of the negatively buoyant projectile is subject to an absolute limit. This finding compares favourably with the absolute limit on the volume of fluid contained within a neutrally buoyant vortex ring (the formation number), as detailed in vortex ring literature. On comparing our findings on the negatively buoyant projectile to those on vortex rings, we developed a new method for estimating the formation number of negatively buoyant projectiles (possibly also for vortex rings), determined the dependence of the formation number on FrD, and linked our work on the negatively buoyant projectile to the existing literature on vortex rings.
3
Salles-Le, Gac Danielle. "Cohérence et limites projectiles." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37601005b.
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4
Polat, Mehmet. "Tracking Of Subsequently Fired Projectiles." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614426/index.pdf.
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In conventional tracking algorithms the targets are usually considered as point source objects. However, in realistic scenarios the point source assumption is often not suitable and
estimating the states of an object extension characterized by a collectively moving ballistic object group (cluster) becomes a very critical and relevant problem which has applications in the defense area. Recently, a Bayesian approach to extended object tracking using random matrices has been proposed. Within this approach, ellipsoidal object extensions are
modeled by random matrices and treated as additional state variables to be estimated. In this work we propose to use a slightly modified version of this new approach that simultaneously estimates the ellipsoidal shape and the kinematics of a group of ballistic targets. Target group that is tracked consists of subsequent projectiles. We use JPDAF framework together with the new approach to emphasize the pros and cons of both approaches. The methods are demonstrated and evaluated in detail by making various simulations.
5
Sommerville, R. "Mid-course guidance for artillery projectiles." Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338034.
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6
PETRELLESE, JOSEPH JR. "Modified Instrumentation for Torsional Impulse Projectiles." International Foundation for Telemetering, 1990. http://hdl.handle.net/10150/613440.
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International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, NevadaThe demand for test projectiles instrumented for gathering in-bore torsional impulse data has been steadily increasing. A test projectile consists of a telemeter, 12 accelerometers, and the remaining necessary hardware. Cost, availability, and survivability of commercial accelerometers being used have become a major concern. In-house testing of a new source and different technology accelerometer show a cost benefit, higher availability and a much higher survivability rate. This paper outlines the recent progress of qualifying a new source and different technology accelerometer, which leads to a modification of the current Torsional Impulse test projectile, along with potential developments to insure a more cost effective, available, and reliable test projectile to be used in future torsional impulse tests.
7
PEREIRA, CARLOS M. "INSTRUMENTATION OF TRIBOELECTRIC EFFECTS ON PROJECTILES." International Foundation for Telemetering, 1990. http://hdl.handle.net/10150/613458.
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International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, NevadaTriboelectric phenomena occurs when static electricity accumulates on the surfaces of flying projectiles due to friction of air contaminants on the aerodynamic projectile surfaces. The sequence of events that create this phenomena indicate that as the projectile flies through the denser atmosphere, electric charges are transferred from the surface of the flying projectiles to the dust as a result of the collision with the atmospheric air stream. In the development of highly static sensitive electronic circuitry used in timing and fuzing, the need to know how the charge builds up has warranted the investigation of the triboelectric affects during flight. This paper will discuss the method of instrumentation used, the pre-flight test results obtained during dynamic wind tunnel tests, and the instrumentation system used to perform the triboelectric measurements.
8
Saygin, Oktay. "An Effectiveness Evaluation Method For Airburst Projectiles." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613202/index.pdf.
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Airburst projectiles increase the effectiveness of air defense, by forming clouds of small pellets. In this work, in order to evaluate the effectiveness of airburst projectiles, Single Shot Kill Probability (SSKP) is computed at different burst distances by using three lethality functions defined from different measures of effectiveness. These different measures are target coverage, number of sub-projectile hits on the target and kinetic energy of sub-projectiles after burst. Computations are carried out for two different sub-projectile distribution patterns, namely circular and ring patterns. In this work, for the determination of miss distance, a Monte Carlo simulation is implemented, which uses Modified Point Mass Model (MPMM) trajectory equations. According to the results obtained two different distribution patterns are compared in terms of effectiveness and optimum burst distance of each distribution pattern is determined at different ranges.
9
Verreault, Jimmy. "Initiation of gaseous detonation by conical projectiles." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107822.
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Initiation and stabilization of detonation by hypersonic conical projectiles launched into combustible gas mixtures is investigated. This phenomenon must be understood for the design and optimization of specific hypersonic propulsion devices, such as the oblique detonation wave engine and the ram accelerator. The criteria for detonation initiation by a projectile is also related to fundamental aspects of detonation research, such as the requirement for direct initiation of a detonation by a blast wave. Experimental results of this problem also offer useful references for validation of numerical and theoretical modeling.Projectiles with cone half angles varying from 15° to 60° were launched into stoichiometric mixtures of hydrogen/oxygen with 70% argon dilution at initial pressures between 10 and 200 kPa. The projectiles were launched from a combustion-driven gas gun at velocities up to 2.2 km/s (corresponding to 133% of the Chapman Jouguet velocity). Pictures of the flowfields generated by the projectiles were taken via Schlieren photography.Five combustion regimes were observed about the projectile ranging from prompt and delayed oblique detonation wave formation, combustion instabilities, a wave splitting, and an inert shock wave. Two types of transition from the prompt oblique detonation wave regime to the inert shock regime were observed. The first (the delayed oblique detonation wave regime) showed an inert shock attached to the tip of the projectile followed by a sharp kink at the onset of an oblique detonation wave; this regime occurred by decreasing the cone angle at high mixture pressures. The second (the combustion instabilities regime) exhibited large density gradients due to combustion ignition and quenching phenomena; this regime occurred by decreasing the mixture pressure at large cone angles.A number of theoretical models were considered to predict critical conditions for the initiation of oblique detonations. The Lee-Vasiljev model agreed qualitatively well with the experimental results for relatively blunt projectiles (cone half-angle larger than 35°) and low mixture pressures (lower than 100 kPa). The trend of the critical Damköhler number calculated along the projectile cone surface was similar to that of the experimental results for slender cones (cone half-angles lower 35°) and high mixture pressures (higher than 100 kPa). Steady 2D simulations of reacting flows over finite wedges using the method of characteristics with a one-step Arrhenius chemical reaction model reproduced the three regimes observed for direct initiation of a detonation: the subcritical, critical and supercritical regimes. It is shown that in order for a 2D wedge to be equivalent to the problem of blast initiation of a detonation (which is the essence of the Lee-Vasiljev model), the Mach number normal to the oblique shock needs to be greater than 50 and the wedge angle has to be smaller than 30°. Simulations of reacting flows over semi-infinite wedges and cones were validated with CFD results. Excellent agreement was reached between the angle of overdriven oblique detonations obtained from the simulations and those from a polar analysis. For wedge or cone angles equal or lower than the minimum angle for which an oblique detonation is attached (according to the polar analysis), a Chapman-Jouguet oblique detonation was initiated. In the conical configuration, the curvature around the cone axis allowed an oblique detonation to be self-sustained at an angle less than without the curvature effect. At larger activation energies, the initiation process of an oblique detonation wave at the tip of a semi-infinite wedge or cone was identified. Unsteady 2D computational simulations were also conducted and showed the cellular structure of an oblique detonation wave. Instabilities in the form of transverse shock waves along the oblique detonation front arise for large activation energies.Cette étude a pour objet l'initiation et la stabilisation d'une onde de détonation par un projectile conique hypersonique projeté dans un milieux combustible gazeux. On retrouve ce phénomène dans certains propulseurs hypersoniques, comme le moteur à onde de détonation oblique et le ram accelerator. Le critère pour l'initiation d'une détonation par un projectile est relié à des aspects fondamentaux de la recherche en détonique, tel que les conditions nécessaires pour l'initation directe d'une détonation par une forte onde de choc. Les résultats expérimentaux de ce problème offrent aussi d'utiles références pour la validation d'études numériques et théoriques. Des projectiles conique dont le demi-angle varie de 15° à 60° ont été lancés dans des mélanges stoechiométriques d'hydrogène et d'oxygène avec une dilution d'argon à 70% à des pressions initiales de 10 à 200 kPa. Les projectiles ont été accélérés par un canon qui produit la propulsion à partir de la combustion gazeuse de mélanges stoechiométriques composées d'hydrogène et d'oxygène à des pressions initiales élevées. Des vitesses de l'ordre de 2.2 km/s ont été atteintes, correspondant à 133% de la vitesse Chapman Jouguet. Des photographies de l'écoulement autour des projectiles ont été prises avec un système Schlieren. Cinq régimes de combustion ont été observés autour des projectiles: formation d'une onde de détonation oblique prompte et retardée, instabilités de combustion, séparation d'ondes, et onde de choc inerte. Deux types de transition entre les régimes de détonation oblique prompte et de choc inerte on été observés. La première (qui concerne le régime onde de détonation retardée) a produit une onde de choc inerte attachée au nez du projectile suivie d'une augmentation abrupte de l'angle de choc au passage à la détonation oblique. Cette transition a eu lieu en diminuant l'angle de cône à de hautes pression de mélange. La deuxième (qui concerne le régime instabilités de combustion) a révélé la présence de forts gradients de densité causés par des phénomènes d'allumage et d'extinction du mélange combustible. Cette transition a été observée en diminuant la pression de mélange à des angles de cône élevés. Quelques modèles théoriques ont été considérés afin de prédire les conditions critiques pour l'initiation de détonations obliques. Le modèle de Lee-Vasiljev s'est avéré en accord qualitatif avec les résultats expérimentaux pour des projectiles relativement émoussés (des demi-angles de cône plus grand que 35°) et de basses pressions de mélanges (plus petit que 100 kPa). La tendance du nombre de Damköhler critique calculé sur la surface du cône s'est avéré similaire à celle des résultats expérimentaux pour des projectiles élancés (des demi-anges de cône plus petit que 35°) et des pressions de mélanges élevées (plus grand que 100 kPa). Des simulations 2D en mode permanent d'écoulements réactifs autour de dièdres finis en utilisant la méthode des caractéristiques avec une réaction chimique de forme Arrhenius ont reproduis les trois régimes observés dans les études d'initiation directe de détonations: les régimes sous-critique, critique et sur-critique. Il est démontré qu'un dièdre est équivalent au problème d'initiation directe d'une détonation si le nombre de Mach normal au choc oblique est supérieur à 50 et si l'angle du dièdre est inférieur à 30°. Des simulations d'écoulements réactifs autour de dièdres et de cônes semi-infinis ont été validés avec des résultats numériques. Un excellent accord a été observé entre l'angle d'une détonation oblique forte obtenu des simulations et celui dérivé d'une analyse des polaires. Pour un angle de dièdre ou de cône égal ou inférieur à l'angle minimal pour lequel une détonation oblique est attachée, une détonation oblique Chapman-Jouguet a été initiée. Pour une configuration conique, la courbure autour de l'axe du cône a permis une détonation oblique d'être non supportée à un angle inférieur à celui sans l'effet de courbure.
10
Zhou, Gang. "Penetration of fastener projectiles into construction materials." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6313/.
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The normal impact, penetration of both projectile and fastener into soils, rocks, and concrete at low velocities has been investigated using theoretical, experimental, and numerical approaches under axisymmetric conditions. The projectile penetration theory is developed on the basis of the existing cylindrical cavity expansion theory with target materials approximated by compressible locking behaviour in a hydrostatic state and elastic-plastic, linear strain- hardening behaviour in a shear state. This theory is one-dimensional with respect to wave propagation in a radial direction. Impact penetration experiments have been performed using a cartridge-operated tool firing the steel fasteners into sandstone and concrete targets. The associated pull-out problem has also been studied. Damage to both fastener and target caused by the impact penetration is assessed using an optical microscope. Finite element programs have been employed to investigate the penetration process of the projectile, and eventually to simulate the process of fastener penetration. The dependency of the penetration process on impact velocity, projectile nose shape, projectile-target interfacial friction, and target material properties have been studied for a variety of impact conditions. Comparisons of results obtained from all three approaches are made for cases in which data are available. Agreements reached are reasonably good.
11
Locklear, Jay Edward. "Secondary ion emission under keV carbon cluster bombardment." Diss., Texas A&M University, 2006. http://hdl.handle.net/1969.1/4273.
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Secondary ion mass spectrometry (SIMS) is a surface analysis technique capable of providing isotopic and molecular information. SIMS uses keV projectiles to impinge upon a sample resulting in secondary ion emission from nanometric dimensions. It is well documented that secondary ion emission is enhanced using cluster projectiles compared to atomic projectiles. Previous studies of enhanced secondary ion yields with cluster projectiles have led to the present study dealing with the scope of C60 as a projectile for SIMS. The secondary ion yields (i.e., the number of secondary ions detected per projectile impact) from impacts of 10-26 keV C24H12+, C60+, gramicidin S+ and C60F40+ projectiles were examined to compare the effectiveness of the projectiles. The [M-H]- secondary ion yields from several organic samples varied inversely with the molecular weight. Multiple ion emission decreases monotonically as a function of the number of secondary ions emitted per impact and varies with impact energy such that higher energies produce more multiple ion emission. The emission of CN- from biological samples as a function of carbon-based projectile characteristics was examined to explore the possibility of using CN- as a molecular identifier. CN- emission was found to be the product of both direct and recombination/rearrangement emission. Re-emitted projectile atoms in the form F- were found under C60F40+ bombardment. Two forms of re-emitted F- were found: One form in which F atoms retained a portion of the initial kinetic energy, and a second in which the F atoms deposited most of the initial kinetic energy into the surface before being ejected. The [M-H]- secondary ion yield of gramicidin S was increased ~ 15 times by embedding the analyte in a matrix of sinapic acid. These results show the optimum carbon based projectile for a given sample is dependent upon the signal to be monitored from the surface. The results also show CN- has potential as a molecular identifier. Additionally, the detection of re-emitted F- confirms prior predictions of re-emitted projectile atoms.
12
Cakir, Tanju. "Resistance Of Alumina Ceramics To Kinetic Energy Projectiles." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/4/1260450/index.pdf.
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The objective of this study is to investigate the penetration and perforation resistance of alumina ceramics against kinetic energy projectiles. There are several different mechanisms by which a target can fail when it is subjected to impact of a projectile and these may occur singly or in combinations of two or more. The presence of large number of penetration and failure mechanisms makes the investigation of the perforation very difficult. Because of this difficulty, the analytical investigations of penetration and perforation processes usually assume one type of failure mechanism. One of these analytical investigations is reviewed and it is seen that this analytical model is capable of predicting after impact parameters reasonably accurately. A parallel investigation of this problem is also been carried out numerically by using
Autodyn hydrocodes. Numerical study is capable of simulating the main changes in ceramic/steel composite target during penetration process of kinetic energy projectile. Results of analytical and numerical investigations are parallel to each other. A set of experiments was carried out for checking the results of analytical and numerical calculations with the experimental data.
13
Bell, M. C. "Numerical investigation of pin-control for supersonic projectiles." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546010.
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Chew, Gilbert. "Projectile nose heating in the Ram accelerator /." Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/9957.
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Seidel, Kristoffer. "Asymmetries and Their Impact on Explosively Formed Projectiles Performance." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297798.
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Shaped Charges (SC) are explosives which are set up to concentrate the energy of an explosive to deform a thin metal cover, so called liner into either a jet of particles or a solid projectile, the latter one is refered to an Explosively Formed Projectile or EFP. The purpose of this project is to map out the effect of different asymmetries in different parts of the EFP. Several asymmetries are investigated such as cavities in the explosive, offset positions of the point of detonation as well as an array of errors concerning the liner. Using ANSYS Space Claim for modelling and IMPETUS for simulating the combustion of the explosive and deformation of the liner. By analyzing the velocity of the projectile in both the direction it is pointed in and in the direction of the asymmetry a mapping of how potential production errors effect its performance. The following is some of the most interesting results acquired: There is close to no difference having the detonation point further in, there is however a crucial difference in performance for the remaining asymmetries. Rust gives an asymmetrically deformed projectile, although rust on the inside perimeter of the liner gives better results than having the rust on the outside perimeter it still gives a close to useless projectile because of its form. Skewed detonation seems to give approximately 1 m/s velocity per 0.5mm of distance from the central axis. Although the simulations run here only gave a miss of around a decimeter the rotational velocity of the projectiles is what is most worrying. When it comes to cavities in the HE there is a clear pattern of the effects getting worse the closer to the liner the bubbles are. The Offset detonation shows most rotation.
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Wilson, Michael J. "Nonlinear projectile attitude estimation with magnetometers and angular rate sensors." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 37 p, 2006. http://proquest.umi.com/pqdweb?did=1163250861&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Wilson, Michael J. "Projectile navigation and the application to magnetometers." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 87 p, 2007. http://proquest.umi.com/pqdweb?did=1397912991&sid=15&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Smith, Michael Willet. "Barrel wear reduction in rail guns : an investigation of silver paste liquid-metal interface." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FSmith%5FMichael.pdf.
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Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2002.Thesis advisor(s): William B. Maier II, Donald Snyder, Richard Harkins. Includes bibliographical references (p. 45-46). Also available online.
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Zeidler, Mickael. "Application des techniques de contrôle des écoulements au pilotage des projectiles : contrôle fluidique d’un projectile gyrostabilisé de 155 mm par effet Coanda." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10057/document.
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Afin d'améliorer les performances des systèmes d'armes, les industriels de l'armement envisagent la mise en service de projectiles intégrant une capacité de correction de trajectoires. Le principal objectif consiste à proposer de nouveaux dispositifs de correction permettant de réduire l'erreur de dispersion de l'engin. Dans le cadre de projectiles aérostabilisés, le contrôle de leurs trajectoires est assuré à l'aide de surfaces portantes, technologie éprouvée depuis de nombreuses décennies. Néanmoins, le contrôle de la trajectoire d'un projectile gyrostabilisé s'avère plus délicat. En effet, les conditions extérieures de ce dernier varient du régime haut subsonique au régime supersonique. Le dispositif de contrôle doit par conséquent être adapté à tous les régimes de vol. De plus, une vitesse de rotation est inculquée au projectile afin de le stabiliser au cours de son vol. Cette rotation représente une énorme contrainte puisque le dispositif doit agir dans une direction azimutale donnée afin de générer une déviation significative. Il doit en plus être facilement implémentable et conserver un coût raisonnable. Ces travaux se proposent par conséquent d'évaluer un dispositif de contrôle prometteur et adapté aux contraintes décrites précédemment : l'effet Coanda. Des simulations RANS et URANS ont été initialement réalisées afin d'évaluer les efforts aérodynamiques générés par cet effet. Des simulations de mécanique du vol ont ensuite été conduites afin de déterminer les déviations engendrables par ce dispositif. Une simulation des grandes échelles d'une configuration simplifiée contrôlée par effet Coanda est finalement proposée afin d'améliorer notre compréhension des mécanismes physiques induits par l'utilisation d'un tel dispositifIn order to increase weapons performances, manufacturers consider to produce projectiles incorporating a trajectory correction capability. The main goal is also to reduce the projectile scattering error. For aero-stabilized munitions, the control of the projectile path is carried out via airfoil surfaces, technologies mastered for decades. However, the control of a spin-stabilized projectiles is much more complex. Indeed, the flight conditions of a 155 mm spin-stabilized projectile range from high subsonic to supersonic velocities so the control device has to be adapted to all flight regimes. Moreover, the projectile has to spin to insure its stability during the flight. Then, the control devices have to be actuated at the projectile spin rate to create a significant deviation. These devices need to be low-cost and easily installed in the projectile too. This work also focuses on a promising fluidic control adapted to the previous constraints: the Coanda effect. RANS and URANS computations are performed to evaluate the aerodynamic forces generated by the Coanda effect for respectively a spinning and a non-spinning projectile. Then, 6-dof flight mechanics simulations are realized to assess the downrange and crossrange deviation of the controlled projectile. Finally, a large-eddy simulation of a simplified geometry has been conducted in order to improve our understanding of the physical mechanisms induced by the control device
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Truscott, Tadd Trevor. "Cavity dynamics of water entry for spheres and ballistic projectiles." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50584.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references.
The free surface impact of solid objects has been investigated for well over a century. This canonical problem has many facets that may be studied: object geometry, surface treatment, and diameter; impact speed and angle; and fluid viscosity and surface tension. The problem is further enriched with the consideration of varying mass ratios and rotational velocities. This thesis uses advanced high-speed imaging and visualization techniques to discover underlying physics and further our understanding of these phenomena through improvements to analytical solutions describing criterion such as cavity formation, depth of deep seal, and trajectory for all impact parameters studied. The topic is extended to the impact of high-speed projectiles or bullets. Through experimentation the trajectory, cavity size, and forces acting on the projectiles are elucidated. Experimentation coupled with improvements to an existing cavitation model lead to an improved bullet design that forms a narrower cavity and achieves higher speeds. Industrial applications include ship slamming, extreme waves and weather on oil platforms, sprayed adhesives, paint aerosols and ink jet printing. In the field of naval hydrodynamics there is particular interest as these problems relate to the study of the water entry of mines and bullets, and the underwater launching of torpedos and missiles. Physical insight can also be applied to sports performance research relating to the water entry of athletes, reducing drag of swimmers near the free surface, decreasing cavity formation for divers, and the entry and exit of oars in rowing.
(cont.) This thesis examines the effect of several key parameters on the water entry physics of spheres at relatively low Froude numbers including: hydrophobic vs. hydrophilic surfaces, mass ratio and rotational velocity. Physical models that predict the depth of deep seal and the effect of dynamic and static wetting angle on cavity formation will be discussed. Theories are derived from physical parameters witnessed through high-speed video image sequences using advanced image processing techniques. New phenomena have been witnessed via these techniques including a wedge of fluid that crosses the cavity in the case of transverse rotational velocity. Furthermore, the images reveal the forces acting on the sphere through the entire trajectory, which adds valuable information for future theoretical models. The discussion continues with the water entry of bullets, which produce water vapor cavities large enough to engulf the projectile (i.e. supercavitation). The effects of speed, geometry and angle of attack on the formation of the subsurface cavity are analyzed through an improved physical model and full scale experimentation. The analytical model is then used to improve the design of projectile geometry to allow for more efficient travel inside the cavity and experimentally validated.
by Tadd Trevor Truscott.
Ph.D.
21
Parisé, Nicolas. "Prédiction des effets aérothermiques sur des projectiles et missiles hypersoniques." Mémoire, Université de Sherbrooke, 2002. http://savoirs.usherbrooke.ca/handle/11143/1211.
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Vu l'importance des effets aérothermiques pour le vol en régime hypersonique, un outil analytique et numérique a été élaboré afin de permettre une meilleure compréhension de ces effets lors du processus de conception de projectiles et missiles. Un des objectifs majeurs de ce projet était de fournir un outil rapide qui permet d'évaluer les phénomènes complexes d'échauffement aérodynamique causés par des interactions choc-choc. Le travail a donc été divisé en trois thèmes majeurs: (i) le calcul de l'écoulement externe non-visqueux autour de projectiles en vol, (ii) le calcul des zones d'interaction choc-choc et (iii) l'évaluation des taux de transfert de chaleur aux parois du véhicule et le calcul d'ablation de composantes. La première partie du travail visait à prédire la configuration d'ondes de choc ainsi que les propriétés du fluide autour de véhicules hypersoniques. La deuxième partie du travail consistait à se servir de la position des ondes de choc, obtenue avec le code Euler, afin de calculer les effets d'interaction choc-choc."--Résumé abrégé par UMI.
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Ryken, Marv, Rick Davis, and Scott R. Kujiraoka. "DESIGN OF A GPS/TELEMETRY ANTENNA FOR SMALL DIAMETER PROJECTILES." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/608282.
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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaIn the past, airplanes, target drones, pods, and large missiles have been instrumented with telemetry, flight termination and beacon tracking antennas to assess performance. With the emerging use of the Global Positioning System (GPS) for tracking purposes, GPS is also included as part of the instrumentation package. This paper addresses the design of a conformal wraparound antenna system to cover the telemetry and GPS L1 frequencies for a small (2.75 inch) diameter airborne projectile. A filter is also integrated into the antenna system to isolate the transmitted telemetry signal from the received GPS signal. This integration is necessary due to the lack of space in the small diameter projectile. Performance characteristics of the prototype antenna system are also presented.
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Ma, Ying. "Ballistic strength of multi-layer fabrics against fragment simulating projectiles." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35067.
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Doctor of PhilosophyDepartment of Mechanical and Nuclear Engineering
Youqi Wang
Ballistic performance of textile fabric is affected by numerous elements, such as fabric architecture, material property, and projectile characteristics. Near fiber-level microstructures of soft body armor composed of multi-layer Kevlar KM-2 fabrics are generated for numerical simulation. The modified digital element approach (DEA) is applied to determine the ballistic limit of textile fabrics against fragment simulating projectiles (FSP). Different from other numerical models, the DEA takes a considerable amount of fiber-level detail into consideration and models the fabric at filament-level. In this approach, fabric is an assembly of yarns weaved and relaxed into pre-arranged pattern; yarn is simulated as a bundle of digital fibers. When the number of digital fibers per yarn reaches the number of actual fibers per yarn, fiber-level simulation is achieved. The DEA model successfully simulates real scale multi-layer fabric impacted by spherical projectile and accurately predicted fabric displacement and failure mechanism. It was assumed that the digital fiber is fully flexible and its bending rigidity is negligible. Shear force was thus neglected. However, for projectiles with sharp edge(s), such as FSP, due to resultant shear force, fabric failure starts where it interacts with projectile edge. As a result, the numerical results derived from the previous DEA overestimated the impact strength of fabrics against projectiles with shape edges. Therefore, shear force and fiber bending rigidity must be considered. In the modified DEA approach, numerical tests are employed to determine the effective bending rigidity of digital fiber. A combined tension-shear failure model is then incorporated into the DEA in order to calculate the shear force applied to fibers. The 3-D microscope is applied to measure the radius of FSP along the edge. The surface of the FSP is meshed into triangle elements. A unique algorithm is developed and employed to search contacts between textile fabric and projectile of arbitrary shape. In this research, first, an overview of ballistic impact analysis is discussed; the previous DEA model used in simulating ballistic impact and penetration process is presented. Second, the modified DEA approach used in simulating arbitrary shape projectile perforation process is established and verified. The method of searching and calculating contacts between textile fabric and solid body projectile is explained. The convergence and accuracy of digital element mesh are investigated statistically using tension-shear failure model. Third, fabric shear force and fiber bending rigidity are investigated using tension-shear failure model. The effective digital fiber area moment of inertia is numerically determined. Fourth, standard ballistic tests of real scale multi-layer Kevlar KM2 fabrics are simulated using FSP. Numerical results are compared to high-resolution experimental test data. The modified DEA is validated.
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Stoumbos, Tom James G. "Impact response of composite structures to rigid and flexible projectiles." Diss., This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-06062008-170607/.
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Parisé, Nicolas. "Prédiction des effets aérothermiques sur des projectiles et missiles hypersoniques." Sherbrooke : Université de Sherbrooke, 2003.
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Hoyle, Alastair Richard. "Investigation of flat capacitor discharge electromagnetic launchers." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/17677.
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In this thesis, studies of flat or pancake type electromagnetic launcher systems are described. The studies involved the development of several numerical models, and are supported throughout by experimental investigation. The models were based on a coaxial filamentary division technique, and the results they provided were compared with those from a commercial electromagnetic finite element modelling package. They were used to investigate some of the many possible launcher structures and power supply arrangements, as part of a wide-ranging parametric study. The aim of this thesis was to gain an insight into the factors that affect the performance of the launchers. Several different techniques were implemented to reduce the computation time. Practical experimentation provided a clear demonstration of the launcher technology, and supplied valuable model validation data. To aid the experimental work new projectile speed and yaw measurement systems were developed, and these were supported by results from a high-speed camera. A novel dual projectile launcher was tested, and was shown to improve the launch efficiency and to operate at higher energies, due to the reduction in drive coil recoil. Projectile deformation was investigated in both solid discs and flat annular projectiles.
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Pechier, Marc. "Prévisions numériques de l'effet Magnus pour des configurations de munitions." Poitiers, 1999. http://www.theses.fr/1999POIT2308.
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Les projectiles sont generalement animes d'un mouvement de rotation ; il contribue a la maitrise du tir, en gommant les eventuels defauts de geometrie (cas des projectiles fleches), et en augmentant la stabilite gyroscopique (cas des projectiles gyrostabilises). Malheureusement, la conjugaison de l'incidence et de la rotation genere un effort lateral, appele force de magnus, et le moment de lacet induit peut affecter significativement la stabilite dynamique du projectile. La maitrise de la trajectoire n'est alors plus assuree. Cette these est une etude numerique et experimentale du phenomene. Un premier algorithme a ete realise pour traiter les geometries de revolution ; un effort experimental parallele a valide avec succes les developpements. En incidence et rotation, la presence d'ailettes rompt le caractere axisymetrique precedent. L'integration de mouvements du maillage a conduit a la definition d'un schema instationnaire original, a meme de predire l'ecoulement turbulent autour de projectiles empennes en rotation. Les coefficients statiques et dynamiques, qui gouvernent le comportement en vol, s'obtiennent dorenavant d'une maniere tres simple, en imposant les bons mouvements de maillage. Les objectifs sont d'expliquer les origines diverses du phenomene, de meme que dresser une liste, non exhaustive, des parametres d'influence sur l'effet magnus, pour participer a terme au design des formes geometriques les moins sensibles.
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Bukowski, Edward, Michael Don, David Grzybowski, and Thomas Harkins. "An On-Board Instrumentation System for High-Rate Medium Caliber Projectiles." International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596432.
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ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NVThe U.S. Army Research Laboratory developed an on-board telemetry instrumentation system to obtain measurements of the in-flight dynamics of medium caliber projectiles. The small size, high launch acceleration, and extremely high spin rates of these projectiles created many design challenges. Particularly challenging were the high spin rates, necessitating the development of a data compression scheme for solar sensors. Flight tests successfully captured data for spin rates exceeding 1000 Hertz (1 kHz).
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Libsig, Michel. "Contrôle d'écoulements en vue d'un pilotage alternatif pour les projectiles d'artillerie." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2022/document.
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Afin d'atteindre leur cible, les projectiles guidés d'artillerie nécessitent d'être dotés d'un dispositif de pilotage. Des surfaces de contrôle déployables et orientables sont donc nécessaires. Toutefois, le montage de gouvernes ajustables sur une ogive est une tâche mécaniquement ardue. En effet, lors du tir effectué par canon, l'équipement de bord subit une accélération significative, ce qui implique que des liaisons mécaniques particulièrement robustes doivent être conçues entre les ailettes et le corps. Cette technologie est bien maîtrisée lorsqu'elle est employée sur des projectiles de gros calibre, mais devient bien plus compliquée quand elle doit être adaptée pour être intégrée dans des petits ou moyens calibres. Néanmoins, dans des conditions de vol supersonique, des ondes de choc qui interagissent avec des surfaces solides sont susceptibles de considérablement modifier la distribution de pression. Ce principe a permis d'imaginer une méthode alternative de pilotage de projectiles supersoniques en exploitant des ondes de choc générées au moyen de petites perturbations créées à partir d'un micro-actionneur de forme cylindrique, aussi appelé micro-plot. Comme les forces de portance exercée sur un corps sont essentiellement dues à une pression appliquée sur de grandes surfaces, il a été choisi de se baser sur une configuration stabilisée par empennage. En vue de simplifier l'étude, le travail a été effectué sur un projectile académique de référence bien connu appelé le Basic Finner.Des expériences ont tout d'abord été effectuées dans la soufflerie supersonique de l'ISL sur une plaque plane comportant un plot et deux ailettes verticales. Ces mesures ont permis de valider la capacité de simulations numériques stationnaires RANS à prédire à la fois la distribution pariétale de la pression que génère un tel actionneur et le champ de vitesse de l'écoulement dans son voisinage. Les distributions de pression et de vitesse ont été mesurées en utilisant des méthodes optiques appelés Pressure Sensitive Paints (PSP) et Particle Image Velocimetry (PIV) afin d'être comparés avec les résultats de la CFD. Une étude paramétrique a ensuite été menée en se basant exclusivement sur ces simulations RANS. Ces calculs ont permis de déterminer l'emplacement optimal pour lequel le plot est le plus efficace sur toute l'enveloppe de vol du projectile. A partir de cette position optimale, deux configurations spécifiques ne générant aucun moment de roulis ont été étudiées numériquement et comparés en termes d'efficacité. En utilisant les coefficients aérodynamiques résultants de ce travail, des simulations de trajectoires à 6 degrés de liberté (6-DOF) ont été réalisées avec le code de BALCO (OTAN). Celles-ci ont permis de déterminer la déviation potentielle qui peut être obtenue sur une des deux configurations retenues en employant un tel micro-actionneur. Ces simulations 6-DOF ainsi que l'effet de du plot sur le projectile ont enfin été validés lors d'une campagne d'essai en vol libre qui a eu lieu sur le champ de tir de l'ISLIn order to reach their target, guided artillery projectiles need some steering capability. Folding and adjustable control surfaces are thus necessary. However, mounting adjustable rudders on a shell is a difficult task, mechanically speaking. Indeed, during the gun launch, the onboard equipment undergoes significant acceleration so that robust mechanical joints have to be designed between the rudders and the body. This technique performs very well on large-caliber projectiles, but becomes more complicated when it has to be embedded in small- or medium-caliber ones. Nevertheless, under supersonic flight conditions, shock waves interacting with solid surfaces are likely to strongly modify the pressure distribution. This principle made it possible to imagine a way of steering small-caliber vehicles using shock waves generated by means of small disturbances created by a cylindrical-shaped micro-actuator, also called micro-pin. As lift forces exerted on a body are mainly due to the pressure applied to large surfaces, a finned configuration has been chosen. To simplify the study, the work has been conducted on the Basic Finner, a well known academic reference projectile.Experiments were first performed in the ISL supersonic wind tunnel on a flat plate on which a pin and two vertical projectile-like fins were mounted in order to validate the capability of steady RANS numerical simulations to predict both the pressure footprint of such an actuator and the flow velocity in its vicinity. Pressure and velocity distributions have been measured by using optical methods called Pressure-Sensitive Paint (PSP) and Particle Image Velocimetry (PIV) in order to be compared with the calculation results. A parametric study was then conducted with these RANS simulations so that the optimum location for which the pin is the most effective over the complete flight envelope of the projectile could be determined. Using this optimum position two specific no-roll momentum configurations were studied numerically and compared in terms of effectiveness. By using the aerodynamic coefficients resulting from this work, 6-Degree-Of-Freedom (6-DOF) trajectory simulations were performed with the NATO BALCO code on one of these configurations in order to determine the potential deviation which can be obtained with such an actuator. These 6-DOF simulations as well as the pin effect on the projectile could finally be validated during a free-flight campaign that took place at the ISL open-range testing site
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Jarskär, Erik. "Improving Microwave Oven Safety in Truck Cabins : Preventing Projectiles on Crash/Brake." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67247.
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Large trucks may have an integrated microwave oven, or a driver may add oneas a standalone solution, to allow heating food during long-haul transports. If a crash occurs with an item inside the oven, it may thrust against the door with such force that it opens from the inside. The goal of this thesis work is to develop a concept for a universally applicable solution that prevents flying parts from within the oven on a crash, as that presents a safety hazard for anyone inside the cabin. The thesis work was conducted according to a stage gate process, which included four phases: Context, Ideation, Concept Development, and Concept Design. It includes interviews, company visits, literature searches, design methodology, concept comparisons and computer aided design. The thesis work concludes with three concepts, all of which are locking solutions that are applied externally onto a microwave oven. They include a bolt latch, a solenoid lock, and a bolt latch integrated with the oven’s door button. All solutions traverse the transition area between door and panel.
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Roberts, Pauline. "Impact ignition of explosives." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318324.
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Schmitt, Anne-Gabrielle. "Evaluation des forces exercées sur des projectiles accélérés par un lanceur électromagnétique à rails." Mulhouse, 1998. http://www.theses.fr/1998MULH0492.
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L'évaluation des forces de propulsion exercées sur des projectiles accélérés par un lanceur électromagnétique à rails a été entreprise afin de déterminer les conditions qui permettent de distribuer ces forces de manière optimale le long du projectile. Le principal but de cette étude est d'éviter la déformation des projectiles, qui résulte de contraintes mécaniques locales trop élevées. Le travail a consisté à élaborer de nouveaux sabots, adaptés aux spécificités des lanceurs à rails. Ceux-ci présentent un avantage considérable sur les lanceurs à poudre car ils permettent de contrôler l'application des forces de propulsion : ils offrent la possibilité de les répartir le long du projectile, en les appliquant, par l'intermédiaire de plusieurs points d'injection du courant, en différents endroits. Ces sabots sont donc constitués de plusieurs ponts de courant dont les caractéristiques ont été déterminées de sorte que la force appliquée en chaque point le long du projectile soit égale. Il a été constaté que l'égalité des forces est obtenue pour une répartition de courant telle qu'il soit plus important à l'avant qu'à l'arrière du projectile. Les paramètres qui influencent la répartition du courant ont été évalués. Il s'agit : ○ du nombre de ponts de courant ○ de leur géométrie (forme et écartement) ○ des caractéristiques électriques du matériau qui les compose (résistivité des ponts, qui dépend de la température, et profondeur de peau) ○ de la qualité du contact électrique entre les rails et les ponts de courant. L'étude a été menée, à l'aide de simulations numériques 3D par la méthode des éléments finis, ainsi que par expérimentation, sur plusieurs projectiles, équipés de deux ou de quatre ponts de courant. En particulier, des résultats concluants ont été obtenus pour un projectile équipé de quatre ponts de courant, et constitué de la combinaison de matériaux suivante (de l'arrière vers l'avant du projectile) : ○ titane ○ matériau de conductivité 4. 106 S/m (par exemple un cupro-aluminium) ○ molybdène ○ alliage cuivre-cadmium (Cu99/Cd1).
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Li, Guojing. "Development of a wireless instrumented projectile for impact testing based on elastic wave reduction." Diss., Connect to online resource - MSU authorized users, 2008.
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Skamangas, Emmanuel Epaminondas. "New Optimal-Control-Based Techniques for Midcourse Guidance of Gun-Launched Guided Projectiles." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/102752.
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The following is an exploration into the optimal guidance and control of gun-launched guided projectiles. Unlike their early counterparts, modern-day gun-launched projectiles are capable of considerable accuracy. This ability is enabled through the use of control surfaces, such as fins or wings, which allow the projectile to maneuver towards a target. These aerodynamic features are part of a control system which lets the projectile achieve some effect at the target. With the advent of very high velocity guns, such as the Navy's electromagnetic railgun, these systems are a necessary part of the projectile design. This research focuses on a control scheme that uses the projectile's angle of attack as the single control in the development of an optimal control methodology that maximizes impact velocity, which is directly related to the amount of damage in icted on the target. This novel approach, which utilizes a reference trajectory as a seed for an iterative optimization scheme, results in an optimal control history for a projectile. The investigation is geared towards examining how poor an approximation of the true optimal solution that reference trajectory can be and still lead to the determination of an optimal control history. Several different types of trajectories are examined for their applicability as a reference trajectory. Although the use of aerodynamic control surfaces enables control of the projectile, there is a potential down side. With steady development of guns with longer ranges and higher launch velocities, it becomes increasingly likely that a projectile will y into a region of the atmosphere (and beyond) in which there is not sufficient air ow over the control surfaces to maintain projectile control. This research is extended to include a minimum dynamic pressure constraint in the problem; the imposition of such a constraint is not examined in the literature. Several methods of adding the constraint are discussed and a number of cases with varying dynamic pressure limits are evaluated. As a result of this research, a robust methodology exists to quickly obtain an optimal control history, with or without constraints, based on a rough reference trajectory as input. This methodology finds its applicability not only for gun-launched weapons, but also for missiles and hypersonic vehicles.Doctor of Philosophy
As the name implies, optimal control problems involve determining a control history for a system that optimizes some aspect of the system's behavior. In aerospace applications, optimal control problems often involve finding a control history that minimizes time of ight, uses the least amount of fuel, maximizes final velocity, or meets some constraint imposed by the designer or user. For very simple problems, this optimal control history can be analytically derived; for more practical problems, such as the ones considered here, numerical methods are required to determine a solution. This research focuses on the optimal control problem of a gun-launched guided projectile. Guided projectiles have the potential to be significantly more accurate than their unguided counterparts; this improvement is achieved through the use of a control mechanism. For this research, the projectile is modeled using a single control approach, namely using the angle of attack as the only control for the projectile. The angle of attack is the angle formed between the direction the projectile is pointing and the direction it is moving (i.e., between the main body axis and the velocity vector of the projectile). An approach is then developed to determine an optimal angle of attack history that maximizes the projectile's final impact velocity. While this problem has been extensively examined by other researchers, the current approach results in the analytical determination of the costate estimates that eliminates the need to iterate on their solutions. Subsequently, a minimum dynamic pressure constraint is added to the problem. While extensive investigation has been conducted in the examination of a maximum dynamic pressure constraint for aerospace applications, the imposition of a minimum represents a novel body of work. For an aerodynamically controlled projectile, (i.e., one controlled with movable surfaces that interact with the air stream), dropping below a minimum dynamic pressure may result in loss of sufficient control. As such, developing a control history that accommodates this constraint and prevents the loss of aerodynamic control is critical to the ongoing development of very long range, gun-launched guided projectiles. This new methodology is applied with the minimum dynamic pressure constraint imposed and the resulting optimal control histories are then examined. In addition, the possibility of implementing other constraints is also discussed.
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Dietrich, Franck. "Simulation numérique du couplage entre la mécanique du vol et l'aérodynamique des projectiles." Poitiers, 2003. http://www.theses.fr/2003POIT2319.
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L'étude du comportement en vol des projectiles met en œuvre des modèles de plus en plus réalistes prenant en compte la complexité multi-physique des phénomènes. L'objectif des travaux présentés est de sélectionner les méthodes numériques les mieux adaptées à la simulation numérique des phénomènes couplés d'aérodynamique et de mécanique du vol des projectiles " flèche " et gyrostabilisé. Pour cela, l'ensemble des méthodes existantes dans chacune des deux disciplines a été tout d'abord étudié en tenant compte des exigences du problème couplé. Puis, ces dernières ont été modifiées et adaptées pour permettre le couplage. Finalement, les codes d'aérodynamique et de mécanique du vol ont été regroupés dans une architecture distribuée et validés sur des cas simples et complexes. Les mouvements à 6 degrés de liberté ont été simulés à partir de modèles d'aérodynamique empiriques, semi-empiriques et numériques. Globalement, les résultats de simulations sont en bon accord avec les données expérimentales de trajectoires réelles. Ces simulations ont souligné l'intérêt d'une méthodologie faisant appel à plusieurs modèles simultanémentThe study of projectile motion requires the development of realistic models taking into account complex multi-physic phenomena. The aim of this study is to propose efficient numerical models to simulate flight mechanics and aerodynamics coupling for body-tail and spinning projectiles. First, existing methods in both domains are studied and coupling induced problems are addressed. These methods are then modified and adapted in order to allow the coupling between fligth mechanics and aerodynamics. The aerodynamics and flight mechanics codes are coupled using distributed architecture before beeing validated on different cases of growing complexity. Futhermore, the 6 degree of freedom motions are simulated using empirical, semi-empirical and numerical aerodynamic solvers. The coupling computational results compare favourably with the available experimental flight data. These simulations show the interest of the coupling calculations methodology based on several different aerodynamic models
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Hung, Patrick Shepherd J. E. "Algorithms for reaction mechanism reduction and numerical simulation of detonations initiated by projectiles /." Diss., Pasadena, Calif. : California Institute of Technology, 2003. http://resolver.caltech.edu/CaltechETD:etd-05302003-142744.
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Heddadj, Settie. "Aéroélasticité des corps de grand allongement en régime supersonique." Orléans, 2001. http://www.theses.fr/2001ORLE2032.
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Le comportement en vol des corps de grand allongement peut être le siège de phénomènes aéroélastiques rédhibitoires, du fait du caractère déstabilisant du couplage entre l'écoulement et la structure mécanique oscillante. Les problèmes aéroélastiques sont couramment étudiés en aéronautique, mais notre cas d'étude présente des particularités, qui imposent la définition d'une nouvelle approche. La spécificité du problème, par rapport à ce qui peut être fait en aéronautique, tient au régime de l'écoulement, ainsi qu'à la configuration géométrique et mécanique du corps. Le but de cette étude est de déterminer l'influence de l'aéroélasticité sur la précision et la dispersion des tirs. Elle s'appuie sur une modélisation mécanique de la flexion par deux corps rigides, reliés par le biais d'une liaison rotule élastique (qui transmet les couples). Les équations du mouvement du projectile flexible sont alors écrites, selon un formalisme de Lagrange, puis linéarisées. Le système linéaire obtenu est alors exploité numériquement de deux manières. La première est une étude modale, qui permet de discuter a priori la stabilité, mais impose de travailler à coefficients constants. La seconde consiste en la résolution implicite des équations. Enfin, dans une dernière étape de validation, des essais de tir ont été réalisés à l'Institut Saint Louis, institut de recherche franco-allemand pour la Défense.
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Lundberg, Patrik. "Interface Defeat and Penetration: Two Modes of Interaction between Metallic Projectiles and Ceramic Targets." Doctoral thesis, Uppsala University, Department of Engineering Sciences, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4641.
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Ceramics constitute an important group of low-density armour materials. Their high intrinsic strength makes it possible to design ceramic armour systems capable of defeating projectiles directly on the ceramic surface. This capability, named interface defeat, signifies that the projectile material is forced to flow radially outwards on the surface of the ceramic without penetrating significantly.
This thesis presents impact experiments between long-rod projectiles and ceramic targets. The projectile/target interaction was studied using flash X-ray technique. Transition velocities (the impact velocity at which interface defeat can no longer be maintained and penetration starts) were estimated for different combinations of metallic projectiles and ceramic targets and compared to critical velocities estimated on a theoretical basis. Replica scaling experiments were also performed in order to investigate the possible influence of scale.
All ceramic materials tested showed a distinct transition from interface defeat to penetration. Experiments with different silicon carbides showed that the transition velocity correlated better with the fracture toughness than with the hardness of the ceramic materials. For conical projectiles, penetration occurred along a conical surface crack and at a lower transition velocity than that observed for cylindrical projectiles. Experiments with unconfined alumina targets in different scales showed only a slight increase in dimensionless final penetration with length scale.
A unique transition velocity seems to exist for each combination of projectile, target material and target configuration. This velocity was found to depend on both the strength (hardness) and the brittleness (fracture toughness) of the ceramic. The lower transition velocity of conical projectiles compared with cylindrical ones is mainly due to the radially expanding load and the penetration of projectile material into surface cracks. The results of the experiments in different scales indicate that replica scaling is valid for penetration in ceramics.
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Tran, Huu Dung. "Traumatismes oculaires par projectiles et réparation du dommage corporel : à propos de 50 cas." Bordeaux 2, 1996. http://www.theses.fr/1996BOR2M165.
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Laforge, Vincent. "Effets vulnérants des armes à feu réglementaires : sept siècles de balistique lésionnelle." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0117.
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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 imprévisiblesHow 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
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Youch, Daniel F. "Efficient calculation of earth penetrating projectile trajectories." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Sep%5FYouch.pdf.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, September 2006.Thesis Advisor(s): Joshua Gordis. "September 2006." Includes bibliographical references (p. 101). Also available in print.
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Milla, Peinado Manuel. "Modélisation et validation expérimentale du canal de transmission radio sol-projectile pour la conception d'un transceiver numérique." Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2326.
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Cette thèse résume trois années de travail dans le domaine de la caractérisation large bande du canal radio pour des applications projectiles. L’instrumentation des projectiles évolue avec la miniaturisation de l’électronique et l’accroissement constant de ses performances. L’échange de données par liaison sans fil bi-directionnelle entre le projectile et lastation de base doit s’effectuer aussi efficacement que possible. Afin de répondre à cette exigence, il est fondamental d’optimiser chaque élément de la chaîne de communication. Le canal, qui est le support où la propagation des ondes radio prend place, est l’un des éléments à modéliser.Dans le but de caractériser le canal radio pour ces applications, cette thèse a été structurée en cinq chapitres: dans les premier et deuxième chapitres, le contexte général de la thèse est présenté, introduisant le cadre de la thèse et donnant les éléments nécessaires pour comprendre le reste du manuscrit. Au chapitre trois, nous abordons le problème du développement des briques nécessaires pour caractériser le canal de propagation. Une des contributions de cette thèse est la définition d’un ensemble de procédures pour effectuer une modélisation de canal. Au chapitre quatre et cinq, nous présentons nos résultats. Alors qu’au chapitre quatre une étude préliminaire du canal est effectuée, une caractérisation complète est donnée au chapitre cinq. Les chapitres se terminent par la présentation d’un modèle de canal dédié aux simulations de communications numériques afin d’améliorer la liaison avec le projectile. Dans une dernière étape, les conclusions et les questions ouvertes sont détailléesThis thesis summarizes three years of work in the field of wideband characterization of the radio channel in projectile applications. The popularization of the miniaturized electronics has allowed the instrumentation of projectiles. The information gathered by the onboard sensors needs to be sent from the projectile to the base station as efficiently as possible by means of bi-directional communication links. In order to fulfill this requirement, it is fundamental to optimize every element in the communication chain. The channel, which is the medium where the radio wave propagation takes places, is one of the elements to be modeled. With the purpose of characterizing the radio channel in projectile applications, this thesis has been structured in five chapters: in chapter one and two, the general context of the thesis is presented, introducing the reader to this topic and giving the necessary elements to understand the rest of the manuscript. In chapter three, we address the problem of developing the necessary elements in order to characterize the propagation channel. The first contribution of this thesis is found here in the form of a set of procedures to perform channel modeling. In chapter four and five, we present our results. While chapter in chapter four a preliminary study of the channel is performed, in chapter five a complete characterization is given. The chapters ends with the presentation of the second contribution of this thesis, i.e.a channel model to be used in simulations in order to improve the projectile communication link. In a last stage, the conclusions and open questions are detailed
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Taflin, David E. "Numerical simulation of unsteady hypersonic chemically reacting flow /." Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/9967.
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Marroquin, Salvador Michael Deivi. "Hypervelocity Impact of Spherical Aluminum 2017-T4 Projectiles on Aluminum 6061-T6 Multi-Layered Sheets." Thesis, Mississippi State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10642662.
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With the growing threat of orbital debris impacts to space structures, the development of space shielding concepts has been a critical research topic. In this study, numerical simulations of the hypervelocity impact response of stacked aluminum 6061-T6 sheets were performed to assess the effects of layering on penetration resistance. This work was initially motivated by set of experimental tests where a stack of four aluminum sheets of equal thickness was observed to have a higher hypervelocity ballistic resistance than a monolithic aluminum sheet with the same total thickness. A set of smoothed particle hydrodynamic simulations predicted a 40% increase in the ballistic limit for a 6-layer target compared to a monolithic sheet. In addition, the effect of variable sheet thickness and sheet ordering on the impact resistance was investigated, while still maintaining a constant overall thickness. A set of thin layers in front of a thick layer generally lead to a higher predicted ballistic limit than the inverse configuration. This work demonstrates an increase in the performance of advanced space shielding structures associated with multi-layering. This suggests that it may be possible to dramatically improve the performance of such structures by tailoring the material properties, interfaces, and layering concepts.
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Renström, René. "Impact of Metallic Projectiles on a Ceramic Target Surface : Transition Between Interface Defeat and Penetration." Doctoral thesis, Uppsala universitet, Hållfasthetslära, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7264.
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The purpose of this thesis is to gain understanding of the load on flat target surfaces produced by projectile impact. Models are proposed from which upper and lower bounds can be derived for the transition be-tween interface defeat and normal penetration. It is shown that the dominating contribution to the normal load is generally provided by the hydrodynamic pressure due to the effect of inertia. In addition it is shown that the contributions from yield strength and compressibility are also significant. For a cylindrical tungsten alloy projectile at an impact velocity representative of to-day’s ordnance velocities, the contributions to the load intensity on the axis of symmetry from yield strength and compressibility are shown to be 15% and 3.4%, respectively, of that of inertia. Impact tests have shown that for conical projectiles transition from interface defeat to penetration occurs at a significantly lower impact velocity than for cylindrical projectiles. In order to better understand the influence of projectile shape, a conical projectile in axi-symmetric impact is studied by use of an analytical model for self-similar flow, and the results obtained are compared to results of numerical simula-tions. It is shown how the maximum load intensity, and the position of the maximum, depends on the apex angle. For an apex angle of 90º, the maximum load intensity is found to be almost three times that pro-duced by a cylindrical projectile with the same impact velocity. This maximum occurs well off the axis of symmetry and is 20% larger than the load intensity at this axis. Both the self-similar model and the nu-merical simulations show that the contribution to the load intensity from compressibility is positive below and negative above an apex angle of around 80º. The contribution of yield strength to the load in-tensity at centre of impact depends only weakly on the apex angle and is therefore similar to that of a cylindrical projectile.
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Laverty, Stephen Michael. "Experimental hydrodynamics of spherical projectiles impacting on a free surface using high speed imaging techniques." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33566.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2005.Includes bibliographical references (leaves 78-80).
This thesis looks at the hydrodynamics of spherical projectiles impacting the free surface using a unique experimental WebLab facility. Experiments were performed to determine the force impact coefficients of spheres and then compare obtained results to theories developed by Von-Karman [ 19] and Wagner [20]. It was found that experimental results matched a generalized Wagner approach developed by Touvia Miloh [12]. A critical impact speed for splash formation was determined before which no splash cavity would form. The cone angle formed behind an impacting object was also studied. The cone angle was found to be a function of depth and impact speed over the range of impact velocities tested. Steel spheres ranging in diameter from 0.64 cm (1/4 in) to 5.08 cm (2 in) were used at impact speeds from 0 to 6.9 m/s. Standard billiard balls of diameter 5.72 cm (2.25 in) were also used in this study. As part of this project, the WebLab facility was constructed. iMarine WebLab is an interactive teaching tool used to educate students in various aspects of marine hydrodynamics and experimental fluid mechanics.
by Stephen Michael Laverty, Jr.
S.M.
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Simon, Franck. "Simulations numériques hybrides RANS/LES de l'aérodynamique des projectiles et application au contrôle des écoulements." Lille 1, 2007. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2007/50376-2007-95.pdf.
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La modernisation des techniques de combat et les avancées technologiques en matière d'armement ont conduit l'armée à accroître ses exigences concernant les vecteurs militaires. Dans ce contexte, deux objectifs en particulier sont transmis aux industriels : l'accroissement de la manoeuvrabilité et la réduction de la dispersion à l'impact. Le contrôle des écoulements parait être un bon candidat, bien que très ambitieux, pour répondre à cette attente. Ce travail de thèse vise à simuler numériquement les phénomènes aérodynamiques rencontrés en vol sur des projectiles gyrostabilisés et à évaluer des dispositifs de contrôle qui permettraient d'améliorer les performances ou de disposer d'une certaine manoeuvrabilité. Dans un premier temps, une étude bibliographique sur le contrôle des écoulements est réalisée afin de mieux appréhender les avantages et contraintes de tels systèmes en vue de leur application aux projectiles. La seconde partie est consacrée à la compréhension de la physique du vol des projectiles à travers l'utilisation de simulations hybrides instationnaires de type RANS/LES pour une large gamme de conditions de vol. Une description fine de ces phénomènes aérodynamiques en régime compressible et à haut nombre de Reynolds est proposée, en se concentrant sur l'analyse du champ turbulent et des fortes instationnarités présentes au sein des écoulements massivement décollés. La dernière partie de l'étude propose des concepts de contrôle et évalue leur performance, que ce soit en terme de réduction de l'effort Magnus ou d'amélioration de la manoeuvrabilité.
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Pavlov, Aleksey D. "Improvement of Electromagnetic Railgun Barrel Performance and Lifetime by Method of Interfaces and Augmented Projectiles." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/986.
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Several methods of increasing railgun barrel performance and lifetime are investigated. These include two different barrel-projectile interface coatings: a solid graphite coating and a liquid eutectic indium-gallium alloy coating. These coatings are characterized and their usability in a railgun application is evaluated. A new type of projectile, in which the electrical conductivity varies as a function of position in order to condition current flow, is proposed and simulated with FEA software. The graphite coating was found to measurably reduce the forces of friction inside the bore but was so thin that it did not improve contact. The added contact resistance of the graphite was measured and gauged to not be problematic on larger scale railguns. The liquid metal was found to greatly improve contact and not introduce extra resistance but its hazardous nature and tremendous cost detracted from its usability. The simulated resistivity augmented projectiles were able to mitigate harmful current build-up on the back of a projectile using different conductivity gradients. Within the range of conductivity of aluminum alloys no simulated gradient was able to fully level the current density, however, once the range was expanded to include the lower conductivity of titanium, nearly uniform current density was achieved.
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Robertson, Edward Angus. "An analysis of the aerodynamics of a fiber optic mortar projectile." Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/50082.
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In December of 1987 tests were conducted in the Virginia Tech Stability Wind Tunnel on a full-scale model of a fiber optic mortar projectile. The desired model configurations were sting-mounted on the Stability Tunnel STO-1 strain gauge balance. The sting was mounted on a streamlined vertical pylon which provided remote rotation in both pitch and yaw while maintaining the center of the balance along the tunnel centerline. The model inputs included the six-component force and moment data in body coordinates and the pressure data from the five pressure taps located within the model. The tunnel inputs were the static temperature, static pressure, and dynamic pressure. The angle of attack and yaw angle were input manually by the tunnel operator. The data analysis for the preliminary test program was intended to define the aerodynamic qualities of various components and configurations to aid in the redesign of the projectile.Master of Science
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Petersson, Jimmy. "Finkalibriga projektiler, RSV och penetrerande stridsvagnsminor : vad krävs av ett ballistiskt skydd för att undvika penetration från dessa stridsdelar?" Thesis, Swedish National Defence College, Swedish National Defence College, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-827.
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Detta arbete syftar till att undersöka vilket konventionellt ballistiskt skydd som krävs för att undvika penetration från finkalibriga projektiler, RSV-stridsdelar samt penetrerande stridsvagnsmina. Arbetet tar sitt ursprung i en handbok utgiven av FMV där stridsdelar som kan förekomma i Afghanistan behandlas. Handboken anger data och prestanda för dessa stridsdelar och det är därifrån arbetet tar uppgifter om genomslagsförmåga för stridsdelen. Skyddsprinciper och verkansprinciper för stridsdelar hämtas i huvudsak från rapporter utgivna av FOI samt från litteratur utgiven av FHS. Arbetets beskrivande delar inleds med en redogörelse för homogena ballistiska skyddsmaterial av metall samt keramer. Därefter beskrivs verkans principer för finkalibriga projektiler, strålbildande RSV, projektilbildande RSV samt penetrerande stridsvagnsminor. Arbetet fortgår med en beskrivning av en finkalibrig projektil med kaliber 7,62*54R mm, hot av typen RPG-7 med tillhörande ammunition samt stridsvagnsmina TMK-2. Avslutningsvis presenteras resultat på vilket ballistiskt skydd som krävs för att skydda sig mot dessa stridsdelar samt en diskussion kring resultatet och alternativa lösningar på problemet. Det presenteras även några förslag på ny forskning inom området verkan och skydd.
This essay aims to investigate which conventional ballistic protection required preventing penetrationof small-caliber projectiles, shaped charged warheads and anti-tank mine. The essay takes its originin a handbook published by the Swedish Defense Material Administration, (FMV), where the warheads that can occur in Afghanistan are presented. The handbook present data of the warheads and it is from here information regarding the warheads penetration capabilities is taken. Effect principles and protection principles of the warheads are primarily gathered from reports published bythe FOI and from literature published by the National Defense College of Sweden, (FHS). The essays descriptional parts begin with an explanation of homogeneous ballistic protection materials fabricated in metal and ceramics. It then continues with a description of effect principles of small caliber projectiles, shaped charge projectiles, explosively formed projectiles and anti-tank mines. The essay then continues with a description of a small caliber projectile with caliber 7.62*54R mm, threats of RPG-7 type with its ammunition and the anti-tank mine TMK-2. In the end of the essay, results are presented according to the ballistic protection required to protect against the presented warheads, and a discussion of the result and alternative solutions to the problem.