The exploding foil initiator (EFI) is a high voltage detonator used to initiate explosions. It is designed to improvesafety standards by lowering the risk of accidental detonation and in doing so allows for in-line integration in, forexample, weapon systems that minimizes their complexity and thus reduces the number of possible failures. It ishighly reliable in terms of timing and avoids that functionality of the detonator deteriorates over time, which has beena problem in earlier designs of detonators. This thesis aims to develop an understanding of each part of the initiationprocess by means of computer simulations. The proportions of the electrically conducting bridge is varied in order tofind relations that optimize the design. Success depends on the simulated pressure generated inside a hexanitrostilbene(HNS) primer.The results showed that increasing the dimensions of the bridge greatly affects the pressure produced in the primer,but its proportions were still important. Unfortunately the simulations of the electrical explosion and the accelerationof the flyer suffered from convergence issues that rendered the flyer’s velocity graphs incomplete. But even with theseshortcomings, thanks to empirical data from earlier studies that analysed EFI prototypes, it was possible to makepredictions about the success of various set ups. The information gathered in this thesis should serve as a foundationfor future development of computer models of the EFI technology that will aid the production of prototypes that meetthe specific requirements.i / Den explosiva folieinitieraren (EFI) är en högspänningsdetonator som används för att initiera explosiva förlopp. Denär designad för att förbättra säkerheten genom att sänka risken för oavsiktlig detonering och till följd av detta möjligörför in-line integrering i, till exempel, vapensystem. Detta minimerar komplexiteten av sådanna system och sänker antaletmöjliga fel som kan uppstå. Denna teknolgi är högst pålitlig när det gäller timing och undviker att detonatorns funktionförsämras över tid, vilket har varit ett problem i tidigare konstruktioner av detonatorer. Denna avhandling syftar tillatt utveckla en förståelse för varje del av initieringsprocessen genom datorsimuleringar. Proportionerna av den elektrisktledande bryggan varierades för att hitta relationer som optimerar designen. Framgången beror på det simulerade trycketsom genereras inuti en primer av det explosiva materialet hexanitrostilben (HNS).Resultaten visade att ökade dimensioner på bryggan kraftigt påverkar trycket som produceras i primern, men dessproportioner var fortfarande viktiga. Tyvärr led simuleringarna av den elektriska explosionen och accelerationen avflyern av konvergensproblem som gjorde att flyerns hastighetsgrafer blev ofullständiga. Men även med dessa brister,tack vare empiriska data från tidigare studier som analyserade EFI-prototyper, var det möjligt att göra förutsägelserom framgången för olika uppsättningar. Informationen som samlats in i denna avhandling bör tjäna som en grund förframtida utveckling av dator modeller av EFI-teknologi som kommer att underlätta produktionen av prototyper somuppfyller specifika krav.ii

Increasing insensitivity demands on designing and producing munitions necessitates utilizing primarily insensitive initiation trains specifically in missile systems. Exploding Foil Initiator (EFI) is a high voltage detonator that is used as the initiation elementof rocket motor and warhead initiation trains of modern insensitive missile systems. In this thesis, EFI prototypes are designed and manufactured with the knowledge gained from detailed literature studies. An experimental setup is constructed including firing and testing means for EFI prototypes. That experimental setup is capable of firing EFI prototypes from 500 volts to 3000 volts voltage range. Besides, it allows measuring electrical characteristics like current and voltage traces and average velocity of the flyer plates of these prototypes.Using EFI prototypes,detonation tests of HNS &ndash / IV and PBXN &ndash / 5 explosive pellets are carried out.Function times and detonation outputs of the prototypesare measured with the same experimental setup. A numerical study which predicts electrical performance of EFI prototypes and impact characteristics of flyer plates are carried out. Numerical code is validated with the experimental results.

This study was directed at the pyrotechnic time delay compositions that are used in detonator assemblies. The objectives were to: --Investigate effective alternatives for the barium and lead-based oxidants currently used, maintaining the use of silicon as fuel --Develop easy to use, realistic measurement techniques for burn rates and shock tube ignitability --Determine the variables that affect burn rate, and --Evaluate alternative processing routes to facilitate intimate mixing of the component powders. Lead chromate and copper antimonite were found to be suitable oxidants for silicon in time delay compositions. They were ignitable by shock tubing, a relatively weak ignition source. The measured burn speeds for these systems showed a bimodal dependence on stoichiometry. Measured burn rates varied between 6-28 mm/s. Lead chromate is potentially a suitable alternative to the oxidant currently used in the medium burn rate commercial composition. It burns faster than copper antimonite. The latter is potentially a suitable replacement oxidant for the slow and medium compositions. Antimony trioxide-based compositions exhibited unreliable performance with respect to ignition with shock tubing. The addition of aluminium powder or fumed silica was found to reduce the burn rate. Increasing the silicon particle size (<3,5<font face="symbol">m</font>m) also decreased the burn speed for copper antimonite and lead chromate compositions. Addition of fumed silica improved the flow properties of the lead chromate, copper antimonite and antimony trioxide powders allowing for easier mixing. The silicon powder was found to react violently with water in alkaline solutions. This makes particle dispersion in a wet-mixing process problematic. / Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2006. / Chemical Engineering / unrestricted

In this master´s thesis is after first part, which is study explosions and detonators work, solutions to technology of production case of delay. First is anatomize technology of construction where is solve the form of stock and material from which the case of delay should be produce. Next capitol is about the ways of production of this part. The output of the thesis is complete production processes at all levels of detonators and selection of machine according to technical and economical aspects.

Les systèmes pyrotechniques sont des éléments clés pour la réussite de la mise en orbite des satellites. Ils permettent de réaliser des fonctions vitales pour la phase de vol d'un lanceur spatial comme l'allumage des moteurs, la séparation d'étages ou la neutralisation. L'actionnement de ces systèmes pyrotechniques nécessite différents effets pyrotechniques comme la génération d'une flamme, d'une grande quantité de gaz et une onde de choc. Ces travaux de thèse interviennent à la suite d'une précédente thèse sur la conception d'un initiateur intelligent et sécurisés permettant de générer une flamme et une grande quantité de gaz mais pas une onde de choc, indispensable dans la réalisation de certaines fonctions pyrotechniques comme la séparation d'étages ou la neutralisation. L'initiateur est piloté par commandes numériques, il dispose d'un stockage local d'énergie, d'une barrière de sécurité mécanique, et d'un PyroMEMS permettant de convertir un signal électrique en un signal pyrotechnique. Cet initiateur est conçu pour remplacer les systèmes pyrotechniques actuellement utilisés sur Ariane 5 car ils sont lourds, encombrants, ils contiennent une grande quantité de substance pyrotechnique augmentant les coûts de fabrication et de stockage, pour finir, les détonateurs et les lignes de transmissions contiennent du plomb dont l'obsolescence est programmé par la réglementation Européenne REACh. L'objectif de ces travaux de thèse est de concevoir et de développer la fonction détonation à partir d'un PyroMEMS contenant moins de 50 µg de nanothermite Al / CuO dans un volume inférieur à 0,83 cm3. Après l'étude des méthodes d'amorçage d'explosif secondaire et de l'état de l'art des détonateurs existant, nous avons conçu une architecture fonctionnant sur la propulsion d'un projectile créant une onde de choc par impact. Le développement de cette fonction détonation a permis d'étudier le comportement de différentes nanothermites (Al / CuO, Al / Bi2O3, Al / MoO3 et Al / PTFE) dans l'optique de propulser le projectile. Un modèle de balistique intérieure est développé avec la combustion de nanothermite Al / Bi2O3 dopé avec du PTFE permettant de conclure qu'il n'est pas possible d'utiliser des nanothermites pour amorcer par impact un explosif secondaire tel que le RDX. Un système de propulsion basé sur la combustion du RDX initié par nanothermite est alors développé avec une étude de l'influence des paramètres dimensionnels. La réalisation d'un démonstrateur final qui permet d'amorcer en détonation du RDX démontre la faisabilité d'un tel dispositif et permet de valider des choix de conception. / Pyrotechnic systems are the keys for satellite launching on orbit. Those systems are used for engines ignition, stage separation and self-destruction. To activate those functions, different kinds of initiators are used to generate a flame, pressure from gas expansion and a shock wave. This work involved following a previous thesis on the design of a smart and safe initiator able to generate a flame and pressure form gas expansion but not a shock wave which is essential in achieving certain functions on launcher as stage separation or neutralization. The initiator is controlled by digital controls, it contain local energy source, a mechanical safety barrier and a PyroMEMS for electro-pyrotechnical conversion. This initiator is design to replace Ariane 5 current pyrotechnic systems because they are heavy, bulky, they contain a large amount of pyrotechnic substance increasing the cost of manufacturing and storage. Also detonators and transmission lines contain lead banned by the European REACh. The goal of these thesis works is to design the detonator function from the flame generated by the PyroMEMS containing 50 µg of Al / CuO nanothermite in a volume less than 0,83 cm3 without primary explosive. After the study of secondary explosive priming methods and the state of art of existing detonators, we designed an architecture running on propelling a projectile creating a shock wave through impact. The development of this detonation function was used to study the behavior of different nanothermites (Al / CuO, Al / Bi2O3, Al / MoO3 and Al / PTFE) with a view to propel the projectile. An interior ballistic model is developed with the combustion nanothermite Al / Bi2O3 doped with PTFE to conclude that it is not possible to use nanothermites to ignite in detonation by impact, by a shock to Detonation Transition) a secondary explosive such as RDX. A propulsion system based on the combustion of RDX initiated by nanothermite is then developed with a study of the influence of dimensional parameters. Achieving a final demonstrator allows to ignite in detonation RDX demonstrates the feasibility of such a device and to validate design choices.