<p>Shaped charges are a well established type of projectile, subjected to a lot of research ever since emerging as a viable technology in the 1940s. The penetration achieved by shaped charges decreases with increased standoff distance. This is often attributed to the shaped charge jet losing its coherence. The Swedish Defence Research Agency however, noted no such loss of coherence in its experiments. An alternative explanation to the decrease of penetration was instead proposed. The object of this thesis was to investigate this proposed theory. To this end, the hydrocode Autodyn was used, modelling the impact of a high-velocity projectile into a generic target and analysing the resulting behaviour of the target. Several setups were used and several parameters were considered when evaluating the results. The conclusion of this thesis is that the alternative explanation offered is not supported by the observed behaviour of the target in the computer model.</p>

Shaped charges are a well established type of projectile, subjected to a lot of research ever since emerging as a viable technology in the 1940s. The penetration achieved by shaped charges decreases with increased standoff distance. This is often attributed to the shaped charge jet losing its coherence. The Swedish Defence Research Agency however, noted no such loss of coherence in its experiments. An alternative explanation to the decrease of penetration was instead proposed. The object of this thesis was to investigate this proposed theory. To this end, the hydrocode Autodyn was used, modelling the impact of a high-velocity projectile into a generic target and analysing the resulting behaviour of the target. Several setups were used and several parameters were considered when evaluating the results. The conclusion of this thesis is that the alternative explanation offered is not supported by the observed behaviour of the target in the computer model.

In addition to its various military applications, shaped charges have been used in oil industry as an oil well perforator (OWP) to connect oil and gas to their reservoirs. The collapse of the liner material under the explosive load produces a hypervelocity jet capable of achieving a deep penetration tunnel into the rock formation. The achieved penetration depends on the OWP design, which includes the geometry and the material of the explosive and the liner as well as the initiation mode and the casing of the shaped charge. The main purpose of this research is to assess the performance of OWP with different design aspects in terms of its penetration depth into concrete material.This research employed the Autodyn finite difference code to model the behaviour of OWPs in the stages of liner collapse, jet formation and jet penetration. The design parameters of OWPs were studied quantitatively to identify the effect of each individual parameter on the jet characteristics and the jet penetration depth into concrete material according to the API-RP43 standard test configuration. In order to validate the Autodyn jetting analysis, this research compared the jetting simulation results of copper OWP liners with those obtained from flash x-ray measurements while the numerical jet penetration into the laminated concrete target was validated experimentally by the static firing of OWPs. Above-mentioned experiments were designed and performed in this project.The validated hydrocode was implemented in this research to study the effects of the concrete target strength, the liner material and the liner shape on the jet penetration depth into concrete targets.For the target strength, the traditional virtual origin (VO) penetration model was modified to include a strength reduction term based on Johnson’s damage number and the effect of the underground confinement pressure using Drucker-Prager model. The VO analytical model is also implemented in the liner material study to account for the jet density reduction phenomena and its induced reduction of jet penetration capability. The jets obtained from machined copper and zirconium liners and from copper-tungsten powder liner all exhibited the density reduction phenomena. The modified VO model considers the non-uniform distribution of jet density based on the jet profile analysis using Autodyn and the experimental soft recovery for some tested liners. The results lead to a modified VO penetration model including the non-uniform jet density effect.For zirconium liner material, numerical and analytical studies were conducted for different flow velocities and different collapse angles in order to determine the boundaries between the jetting and non-jetting phases and whether a coherent or a non-coherent jet will form. This study indicated that the suggested four different liner shapes (i.e. the conical, the biconical, the hemispherical and the bell) will produce coherent jet when the zirconium is used as OWP liner.The validated Autodyn hydrocode is also used in this thesis to calculate the velocity difference between two neighbouring zirconium jet fragments. The velocity difference is related directly to the breakup time of an OWP jet, and thus, it is calculated for a range of zirconium liners with different liner wall thicknesses. The calculated values of velocity difference gave a clear insight for the breakup time formulae for zirconium jet in terms of the liner thickness and the charge diameter.

HEAT-grenades are wing-stabilized grenades using shaped charge technology. Theshaped charge is a method, producing a jet-beam, with the use of a copper linerin which the aim is to focus the detonation energy to be able to penetrate armourand structures. This jet-beam is only eective under a rotational frequency of 15Hz, any frequency above this and the produced jet-beam loses its eciency and willnot be able to penetrate its target. One approach to minimize the inner body'srotation is by using bearings. By the use of ball bearings the intention is to with-hold transferring the angular momentum from the outer rotating body to the innercylinder body. This thesis have been analysing how much rotation the warhead haveacquired from the outer rotation of the grenade divided in an acceleration phase anda ying phase. During the acceleration phase the rotation of the warhead is reach-ing a frequency of 0.35 Hz. Proposals are presented for improving and lowering therotational speeds for future studies.

Shaped charges are explosive devices with a high penetration capability and are used for both civilian and military purposes. In civilian applications shaped charge devices are used in demolition works, oil drilling and mining. In the military applications, shaped charges are used against different kinds of armors, primarily as anti-tank devices. This thesis work involves the modeling and simulation of shaped charge devices, with the focus being on anti-tank warhead design. Both numerical simulation and analytical calculation methods are used to predict shaped charge performance / in the aspects of jet formation, breakup and penetration. The results are compared within themselves and with the data available in the literature. AUTODYN software is used for the numerical simulations. Different solver and modeling alternatives of AUTODYN are evaluated for jet formation and penetration problems. AUTODYN&rsquo / s Euler solver is used to understand how the jet formation is affected by the mesh size and shape and the presence of air as the surrounding medium. Jetting option in the AUTODYN-Euler simulations are used to simulate jet formation as an alternative to simulations performed using AUTODYN&rsquo / s Euler solver. In the jetting option liner elements are modeled as Lagrangian shell elements, rather than Eulerian elements. Analytical codes are written to study the jet formation, breakup and penetration processes. Many alternative formulas that can be used in the analytical calculations are listed and discussed. Parameters of these formulas are varied to investigate their effects on the results. Necessary constants for the analytical formulas are obtained using the results of AUTODYN simulations.

The objective of this study is to investigate the detrimental effects of a flexible linear shaped charge (FLSC) to variable thickness back and constant thickness front plates due to varying backspace distance. A FLSC is used to cut both metallic and non-metallic material, quickly and efficiently. It is flexible and may be formed to produce cuts of many configurations, thereby making it particularly useful where more conventional cutting techniques are difficult to employ. While performing its function, the FLSC gives some damage to the back due to the high transient pressure and fragmentation effects. In order to decrease this damage, a steel plate is placed behind the FLSC. In this work, a numerical analysis is carried out by using Autodyn Hydrocode for the investigation of the extent of the plastic deformation of the back as well as front plates for varying backspace distance of the steel plate having different thicknesses. The numerical results are then compared with the experimental findings. The flexibility property of the FLSC is not used in this study. Only the straight segment of FLSC is used.

The shaped charges on the market today ranges from about 20 to 200 mm in diameter but there is a need of smaller sizes for example in applications where a small projectile with a high speed is needed or to equip or take out drones with. The objective of this thesis work was to develop a miniaturized shaped charge with dimensions smaller than those available today and preferably with a diameter down to 10 mm. The project was conducted at Karlstad University in collaboration with Saab Dynamics AB. The process used during this project was to start with a feasibility study to obtain information about the limits on dimensions in order to investigate how small dimensions can be used for the casing and liner with respect to manufacturability. The feasibility study was conducted by studying academic literature, contacting companies with expertise within the field of manufacturing. A previously used shaped charge was used as a starting point and the dimensions was scaled in accordance with the objective. The influence of the design parameters was examined using the γSPH module in IMPETUS Afea. The liner material used was restricted to oxygen-free high thermal conductivity copper and different materials for the casing was tested. Two material selections for the casing were made with the aid of Granta Edupack. It has been concluded that it is possible to manufacture a miniaturized shaped charge with dimensions down to about ten mm. Both a design for a jet forming shaped charge and an explosively formed penetrator was developed during the project. The resulting projectile for the explosively formed penetrator had a velocity of 2450 m/s, a total length of 7.3 mm and 3.5 mm in diameter, and the jet forming shaped charge had a jet tip velocity of 7060 m/s and was able to penetrate 38-mm into an AISI 4340 steel target according to the models used in IMPETUS Afea. A prototype was planned but due to cost restrictions, it is left as future work. / Riktad sprängverkan (RSV)-laddningarna som finns på marknaden idag sträcker sig från ungefär 20 till 200 mm i diameter. Det finns dock ett behov för storlekar mindre än detta, till exempel i tillämpningar där en liten projektil med hög fart krävs, alternativt att utrusta eller sänka drönare med. Målet med detta examensarbete var att utveckla en miniatyriserad RSV-laddning med dimensioner mindre än vad som finns tillgängligt idag och helst med en diameter neråt tio mm. Projektet utfördes på Karlstads universitet i samarbete med Saab Dynamics AB. Processen som användes under detta projekt gick ut på att börja med en förstudie for att erhålla information om gränserna för mått för att undersöka hur små dimensioner som kan användas för höljet och linern med avseende på tillverkningsbarhet. Förstudien genomfördes genom att studera akademisk litteratur och kontakta företag med expertis inom tillverkningsområdet. En tidigare använd RSV-laddning användes som startpunkt och dimensionerna justerades i enlighet med målet. Påverkan av parametrar på prestanda undersöktes genom att använda γSPH modulen i IMPETUS Afea. Det använda materialet för linern begränsades till OFHC koppar och olika material för höljet testades. Två materialval gjordes för höljet med hjälp av Granta Edupack. Slutsatsen som kan dras utifrån arbetet är att det är möjligt att tillverka miniatyriserade RSV-laddningar med dimensioner neråt tio mm. Både en design för en strålbildande RSV-laddning och en projektilbildande RSV-laddning utvecklades under projektet. Den resulterande projektilen för den projektilbilande RSV-laddningen hade en fart på 2450 m/s, en längd av totalt 7.3 mm och 3.5 mm i diameter och den strålbildande RSV-laddningen hade en spetsfart på 7060 km/s och kunde penetrera 38 mm AISI 4340 stål enligt modellen som användes i IMPETUS Afea. En prototyp planerades men på grund av kostnadsrestriktioner lämnades det som framtida arbete.

This thesis developed a linear shaped charge (LSC) separation mechanism capable of severing the interstage skin for first stage separation of the Ares I launch vehicle. The derived LSC design solution was found using available data on Explosive Technology’s Jetcord LSC and from National Aeronautics and Space Administration (NASA) Marshall Space Flight Center’s (MSFC) desired characteristics. Mechanism components are designed after Minuteman III’s separation mechanism for first stage separation and NASA MSFC’s desired characteristics. Mechanism severance is verified through the use of the numerical method capability smoothed particle hydrodynamics that the hydrocode Autodyn offers. Three simulations are conducted to determine feasibility: the first of only the LSC exploding, to numerically validate the explosion process; the second of the LSC penetrating the target, to numerically validate the penetration process and failure mechanisms; and the last of the entire mechanism, to obtain information about the explosion, penetration, failure, and debris generated.

Vid röjning av RSV-ammunition saknas idag adekvat beslutstöd för att dimensionera skadebegränsande åtgärder mot jetstrålens verkan. I uppsatsen vidareutvecklas en beräkningsmodell som författaren tidigare föreslagit. Syftet är att skapa ett verktyg som kan införas i ammunitionsröjningsverksamheten. Fullskaliga skjutförsök har genomförts för att klarlägga inverkan av förhållanden som är typiska vid ammunitionsröjning; en skyddskonstruktion byggd av sandsäckar och med ett långt detonationsavstånd till röjningsobjektet. Försöksresultatet visar att den grundläggande hydrodynamiska penetrationsteorin inte är användbar för dessa förhållanden. Vidare ger sandsäckskonstruktionen signifikant bättre skydd mot jetstrålen än en homogen grusbädd. Genom störningsanalys har känsligheten hos de enskilda parametrarna i beräkningsmodellen för verksamhetstypiska fel utretts. Härefter har Monte Carlo-simulering använts för att analysera den sammanlagda inverkan som dessa fel kan ge. Resultatet har legat till grund för att bestämma modellens säkerhetsmarginal. Militär nytta innebär att modellen skall kunna tillämpas fältmässigt, med korta tidsförhållanden och utan tillgång till avancerade beräkningshjälpmedel. Detta har lett fram till att ett enkelt diagram inkluderats i det kompletta dimensioneringsverktyget. Verktyget föreslås införas i regelverk och utbildningssystem för att avhjälpa den brist som råder idag. / During the clearance of shaped charge ammunition, explosive ordnance disposal (EOD) personnel lack adequate means for the design of protective measures against the jet. In this thesis a calculation model, previously suggested by the author, is developed further. The aim is to create a tool that can be applied to EOD operations. Full-scale experiments have been conducted to clarify the effects of conditions that are typical for EOD operations: protective measures built from sandbags with a long standoff distance to the ordnance. The results indicate that the hydrodynamic penetration theory is not suitable for these conditions. Furthermore, a sandbag construction provides significantly better protection against the jet than a homogeneous gravel construction. By disturbance analysis, the sensitivity of the individual parameters in the model is studied for typical errors. Subsequently, Monte Carlo simulation has been used to analyse the effect these errors can cause. The simulation results have then been the used to determine the model´s margin of safety. Military utility implies that it should be possible to use the model under field conditions, with limited time frames and without access to advanced calculating means. This has resulted in a simple diagram included in the comprehensive design tool. It is proposed that the tool is implemented in regulations and curricula in order to remedy today’s lack of decision support.

<p>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.</p> / <p>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.</p>