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This thesis work is dedicated towards finding a feasible test rig design, which can expose small components, produced by SAAB, to a variety of accelerations under different conditions. A literature study is conducted with the objective of gathering information regarding high acceleration testing, where relevant components, designs and calculation methods are presented. A series of concepts are presented and evaluated against a requirement specification, the first concept iteration concerns the method of acceleration whereas the second and the third concept iterations concerns the design of the test rig on different levels of detail. The third concept evaluation is strengthened by several calculations, which indicates the feasibility of the concept in some manner. One concept achieved the highest score in the third concept evaluation and as such is presented as the best suited concept for further development., Denna avhandling är dedikerad till framtagningen av en möjlig design för en provningsrigg, som kan utsätta små komponenter, som produceras av SAAB, för flera olika accelerationer under olika förhållanden. En litteraturstudie genomförs med syftet att samla information om provning under höga accelerationer, där relevanta komponenter, designer och beräkningsmetoder presenteras. En serie koncept presenteras och utvärderas med hjälp av en kravspecifikation. Den första konceptiterationen berör metoden för acceleration, medan den andra och den tredje konceptiterationen berör designen av provningsriggen. Den tredje koncept utvärderingen stärks av flera beräkningar, som indikerar konceptets lämplighet ur något perspektiv. Ett koncept uppnådde högst poäng i den tredje koncept utvärderingen och presenteras därav som det bäst lämpade konceptet för vidare utveckling.

This thesis work is dedicated towards finding a feasible test rig design, which can expose small components, produced by SAAB, to a variety of accelerations under different conditions. A literature study is conducted with the objective of gathering information regarding high acceleration testing, where relevant components, designs and calculation methods are presented. A series of concepts are presented and evaluated against a requirement specification, the first concept iteration concerns the method of acceleration whereas the second and the third concept iterations concerns the design of the test rig on different levels of detail. The third concept evaluation is strengthened by several calculations, which indicates the feasibility of the concept in some manner. One concept achieved the highest score in the third concept evaluation and as such is presented as the best suited concept for further development., Denna avhandling är dedikerad till framtagningen av en möjlig design för en provningsrigg, som kan utsätta små komponenter, som produceras av SAAB, för flera olika accelerationer under olika förhållanden. En litteraturstudie genomförs med syftet att samla information om provning under höga accelerationer, där relevanta komponenter, designer och beräkningsmetoder presenteras. En serie koncept presenteras och utvärderas med hjälp av en kravspecifikation. Den första konceptiterationen berör metoden för acceleration, medan den andra och den tredje konceptiterationen berör designen av provningsriggen. Den tredje koncept utvärderingen stärks av flera beräkningar, som indikerar konceptets lämplighet ur något perspektiv. Ett koncept uppnådde högst poäng i den tredje koncept utvärderingen och presenteras därav som det bäst lämpade konceptet för vidare utveckling.

Aluminum alloy AA 7075 majorly consists of Zinc and Magnesium, and it has been known as an alloy with high strength and ability to be heat treated. In regard to that, AA 7075 alloy was investigated to determine its application in military vehicles that require high protection and great mobility capabilities. The addition of Al_2O_3 can be done to improve the mechanical properties of the material such as hardness and impact toughness that is related to the protective ability of the material. This research was conducted to determine the effect of adding nano Al2O3 and heat treatment o n the ballistic resistance of composite plates. The composites were fabricated by the squeeze casting method followed by heat treatment of T6 at 470 °C for two hours, water quench, and artificial aging at 120 °C for one hour. The reinforcement of nano Al_2O_3 is added to the melted aluminum alloy when the fabrication process takes place as much as 0.1, 0.2, 0.3 wt%. Furthermore, the composite plate was tested by ballistic testing Type II and III according to NIJ standard. Other characterizations were also car ried out on the samples such as microstructural observations and hardness testing. The results of the characterization have found that all samples have protective ability in Type II ballistic testing but do not have protective ability in Type III ballistic testing. The addition of reinforcing particles affects the value of the hardness of composite material. Heat treatment increases the hardness value, impacts toughness value, and penetration trace in ballistic testing which has a direct relationship to microstructural changes that occur during the heat treatment process.

Low-density armour often uses ceramic materials, as their high compressive strength and relatively low weight make the material ideal for moving in the field. The ballistic protection works by redirecting the plastic flow of the projectile radially, which reduces penetration. The main drawback of using ceramics is their brittle behaviour, causing rapid crack propagation. When subjected to ballistic impacts, the ceramic fails catastrophically by spalling and cracking. The fracture behaviour is essential to model correctly to predict the effectiveness of armor systems. In this experiment, a notched specimen was used to investigate mode I fracture. The setup is similar to an open edge on impact experiment where the fracture propagation is initiated by the impact of a projectile fired by an air pressure gun. To avoid spallation, the projectile velocities were kept low to only initiate crack development from bending. For velocities below 15 m/s, a single crack develops across the specimen. For higher velocities between 15-75 m/s, the behaviour is different for short and long projectiles. For short projectiles, a straight crack develops before bifurcating when the projectile and ceramic lose contact. For longer projectiles, the crack bifurcates at the initiation. It forms a pointed ellipse up to the point when the projectile and ceramic lose contact, at which point it behaves the same as for shorter projectiles. Simulations were conducted using LS-Dyna and Impetus AFEA with four different material models. Two different fracture formulations were also used. Erosion was used in LS-Dyna, while erosion and node-splitting were used in Impetus AFEA. Simulations in both LS-Dyna and Impetus AFEA could reproduce experimental results. Simulations show that bifurcation highly depends on the materials' tensile strength. The transition from straight to bifurcating cracks emerges in a small velocity range, allowing for the possibility of calibrating the simulations to experiments. A po, Komplexa skydd använder sig ofta av keramiska material då keramer har stark kompressionsstyrka och relativt låg vikt, vilket gör dem idealiska för att röra sig i fält. Ballistiskt skygg verkar genom att omdirigera projektilens plastiska flöde radiellt, vilket reducerar risk för penetration. Största nackdelen med keramiska material är deras spröda beteende. På grund av materialets tidsberoende beteende är materialegenskaperna svåra att bestämma. När materialet utsätts för ballistisk belastning orsakar det ofta katastrofartad sprickbildning. Sprickbeteendet är därför ett viktigt fenomen att bestämma för att förutsäga effektiviteten hos skyddsmaterialet. I detta experiment används en uppställning med ett skårad provkropp för att studera sprickutvecklingen av mod I sprickor. Uppställningen har likheter med kant anslags experiment där sprickutbredningen initieras med hjälp en cylindrisk projektil. För att begränsa brottbeteendet till mod I använder sig uppställningen av låga projektilhastigheter mellan 15 och 75 m/s för att initiera sprickor genom böjning. För hastigheter under 15 m/s utvecklades endast raka sprickor som propagerade över hela provkroppen. För hastigheter mellan 15 och 75 m/s skiljer sig beteendet mellan långa och korta projektiler. För korta projektiler delar sig sprickan när projektilen studsar mot provkroppen. För långa projektiler delar sig sprickan i två redan vid initiering och bildar en spolform upp till den punkt då projektilen tappar kontakt med provkroppen varefter beteendet mellan kort och lång projektil är likartat. Simuleringar utfördes med LS-Dyna och Impetus AFEA med fyra olika materialmodeller. Två olika brottformuleringar användes. Erosion användes i LS-Dyna, medan erosion och node-splitting användes i Impetus AFEA. Simuleringar i både LS-Dyna och Impetus AFEA kunde återskapa de experimentella resultaten. Simuleringarna visar att delningen av sprickan vid avlastning i hög grad beror på materialens draghållfasthet. Övergången från rak spri

Aluminum alloy AA 7075 majorly consists of Zinc and Magnesium, and it has been known as an alloy with high strength and ability to be heat treated. In regard to that, AA 7075 alloy was investigated to determine its application in military vehicles that require high protection and great mobility capabilities. The addition of Al_2O_3 can be done to improve the mechanical properties of the material such as hardness and impact toughness that is related to the protective ability of the material. This research was conducted to determine the effect of adding nano Al2O3 and heat treatment o n the ballistic resistance of composite plates. The composites were fabricated by the squeeze casting method followed by heat treatment of T6 at 470 °C for two hours, water quench, and artificial aging at 120 °C for one hour. The reinforcement of nano Al_2O_3 is added to the melted aluminum alloy when the fabrication process takes place as much as 0.1, 0.2, 0.3 wt%. Furthermore, the composite plate was tested by ballistic testing Type II and III according to NIJ standard. Other characterizations were also car ried out on the samples such as microstructural observations and hardness testing. The results of the characterization have found that all samples have protective ability in Type II ballistic testing but do not have protective ability in Type III ballistic testing. The addition of reinforcing particles affects the value of the hardness of composite material. Heat treatment increases the hardness value, impacts toughness value, and penetration trace in ballistic testing which has a direct relationship to microstructural changes that occur during the heat treatment process.

Low-density armour often uses ceramic materials, as their high compressive strength and relatively low weight make the material ideal for moving in the field. The ballistic protection works by redirecting the plastic flow of the projectile radially, which reduces penetration. The main drawback of using ceramics is their brittle behaviour, causing rapid crack propagation. When subjected to ballistic impacts, the ceramic fails catastrophically by spalling and cracking. The fracture behaviour is essential to model correctly to predict the effectiveness of armor systems. In this experiment, a notched specimen was used to investigate mode I fracture. The setup is similar to an open edge on impact experiment where the fracture propagation is initiated by the impact of a projectile fired by an air pressure gun. To avoid spallation, the projectile velocities were kept low to only initiate crack development from bending. For velocities below 15 m/s, a single crack develops across the specimen. For higher velocities between 15-75 m/s, the behaviour is different for short and long projectiles. For short projectiles, a straight crack develops before bifurcating when the projectile and ceramic lose contact. For longer projectiles, the crack bifurcates at the initiation. It forms a pointed ellipse up to the point when the projectile and ceramic lose contact, at which point it behaves the same as for shorter projectiles. Simulations were conducted using LS-Dyna and Impetus AFEA with four different material models. Two different fracture formulations were also used. Erosion was used in LS-Dyna, while erosion and node-splitting were used in Impetus AFEA. Simulations in both LS-Dyna and Impetus AFEA could reproduce experimental results. Simulations show that bifurcation highly depends on the materials' tensile strength. The transition from straight to bifurcating cracks emerges in a small velocity range, allowing for the possibility of calibrating the simulations to experiments. A po, Komplexa skydd använder sig ofta av keramiska material då keramer har stark kompressionsstyrka och relativt låg vikt, vilket gör dem idealiska för att röra sig i fält. Ballistiskt skygg verkar genom att omdirigera projektilens plastiska flöde radiellt, vilket reducerar risk för penetration. Största nackdelen med keramiska material är deras spröda beteende. På grund av materialets tidsberoende beteende är materialegenskaperna svåra att bestämma. När materialet utsätts för ballistisk belastning orsakar det ofta katastrofartad sprickbildning. Sprickbeteendet är därför ett viktigt fenomen att bestämma för att förutsäga effektiviteten hos skyddsmaterialet. I detta experiment används en uppställning med ett skårad provkropp för att studera sprickutvecklingen av mod I sprickor. Uppställningen har likheter med kant anslags experiment där sprickutbredningen initieras med hjälp en cylindrisk projektil. För att begränsa brottbeteendet till mod I använder sig uppställningen av låga projektilhastigheter mellan 15 och 75 m/s för att initiera sprickor genom böjning. För hastigheter under 15 m/s utvecklades endast raka sprickor som propagerade över hela provkroppen. För hastigheter mellan 15 och 75 m/s skiljer sig beteendet mellan långa och korta projektiler. För korta projektiler delar sig sprickan när projektilen studsar mot provkroppen. För långa projektiler delar sig sprickan i två redan vid initiering och bildar en spolform upp till den punkt då projektilen tappar kontakt med provkroppen varefter beteendet mellan kort och lång projektil är likartat. Simuleringar utfördes med LS-Dyna och Impetus AFEA med fyra olika materialmodeller. Två olika brottformuleringar användes. Erosion användes i LS-Dyna, medan erosion och node-splitting användes i Impetus AFEA. Simuleringar i både LS-Dyna och Impetus AFEA kunde återskapa de experimentella resultaten. Simuleringarna visar att delningen av sprickan vid avlastning i hög grad beror på materialens draghållfasthet. Övergången från rak spri

The ballistics field is known by the presence of several complex phenomena such as muzzle and flying projectiles flow fields. Consequently, numerical simulations are commonly used to model these complicated flows. However, the validation process of these codes has proven to be problematic due to the lack of experimental quantitative data. In this context, the present paper describes the application of the Background Oriented Schlieren technique (BOS) as a quantitative investigation tool in the ballistics field. We illustrate that BOS can accurately capturethe main characteristics of the studied configurations: Firstly, we discuss the visualization and the density field reconstruction around a sniper projectile flying at supersonic and transonic velocities. We demonstrate that these fields are in satisfactory agreement with numerical simulation. Then, the findings of the BOS visualization of the precursors and the propellant flow fields are presented. To this end, the salient features accurately captured by the BOS technique such as vortex rings, shock bottles, Mach disk, and blast wave are described both qualitatively and in terms of density profiles. Two improved approaches that are essential to the aforementioned analysis are proposed: the first is related to density field reconstruction based on Abel inversion and the second approach is a phase separation procedure., info:eu-repo/semantics/published

Polybenzoxazole fibers (PBO, commercially trademarked as Zylon) were once used as an alternative to ultra-high molecular weight polyethylene (UHMWPE) fibers in body armor systems. PBO fibers exhibit a high Young’s modulus, excellent thermal stability, and tensile strength (nearly twice that of Kevlar), but the physical properties severely degrade when exposed to water. Hydrophobic polymer coatings were applied to PBO fibers and studied for moisture resistance, coating durability, and ballistic performance. Instron tensile testing and a V50 assessment utilizing a light gas gun and 9.525 mm spherical chromium-steel projectiles were conducted on four different textile armor systems, including uncoated PBO weave, uncoated PBO weave exposed to water, polymer-coated PBO weave, and polymer-coated PBO weave exposed to water. Using load cells to measure uni-axial forces, combined with digital image correlation enabling measurement of both in-plane and out-of-plane fiber deflection, stress-strain measurements of the four different textile armor systems were measured and compared. Flex Seal liquid coating proved to be the most effective waterproof coating in terms of consistent hydrophobic performance, flexibility, and ease of application; however, further research is required to refine coating methods as well as collect additional data for the performance of PBO under dynamic loads., http://archive.org/details/effectsofhydroph1094566605, Lieutenant, United States Navy, Approved for public release. distribution is unlimited

En este trabajo se estudian las protecciones balísticas ligeras con las que se podrían hacer un prototipo de casco capaz de detener balas de rifle de forma segura. La protección balística de la cabeza a través de los cascos presenta un nivel inferior con respecto a la protección disponible para el resto del cuerpo, a pesar de la gran importancia. Esto es debido a las importantes limitaciones de peso que puede soportar, así como a la fragilidad del cráneo y cerebro, siendo una barrera infranqueable que ha causado que los cascos usados por la policía y los ejércitos de todo el mundo solo sean capaces a de detener de manera segura balas de pistola. Las balas de rifles tienen mucha más capacidad de penetración y este tipo de amenaza es cada día más común debido a los cambios que se producen en los diversos teatros de operaciones., In this work, the light weight ballistic protections are studied in order to mature a prototype helmet capable of stopping rifle bullets. The ballistic protection of the head through the helmets is lower than the protection available for the rest of the body, despite the great importance for the survival of the user. This is due to the significant weight limitations the head and neck can withstand, as well as the fragility of the skull and brain. This has been an impassable barrier that has caused the helmets worn by police and armies around the world to only be able to safely stop pistol bullets. Rifle bullets are much more dangerous; and this type of threat is becoming more common due to the changes taking place in the various theatres of operations. This makes a thorough study of the problem necessary to improve the safety and security of users.

The present study exposes an analysis of the suspension system technical state evaluation for civil vehicles that have been subject to armouring processes. Such evaluation is performed through a mechanised revision established by state regulation and is based on the method defined by EuSAMA. The development of this analysis focuses on establishing the existing relation between the ballistic resistance integrated to a vehicle and the dynamic effect exercised for the modification of its mass, according to two reliability/safety driving measurement criteria: (i) tyre-road adhesion index and (ii) tyre excitation phase angle. The study proposes new elements to the current procedure established to evaluate the suspension of civil armoured cars considering the two measurement criteria, which can be acquired by a standard commercial suspension tester machine. Copyright © 2013 Inderscience Enterprises Ltd.

Магістерська дисертація: 100 сторінок, 4 розділи, 37 таблиць, 30 рисунків, 2 додатки, 32 джерела. Актуальність. Навчання стрільбі дуже важливе для військових, а також потрібне спортсменам і мисливцям. Водночас, проведення навчальних стрільб може бути доволі дорогим, шкодить навколишньому середовищу і іноді небезпечне. Тож доволі перспективною є розробка віртуальних тирів, що дозволяють відпрацювати навички на початкових етапах навчання. Таким чином, доцільним буде дослідити семантичну модель таких систем, щоб у подальшому ефективніше підходити до їхньої розробки. Зв'язок роботи з науковими програмами, планами, темами. Робота виконувалась на кафедрі автоматизованих систем обробки інформації та управління Національного технічного університету України «Київський політехнічний інститут ім. Ігоря Сікорського» в рамках теми «Розробка методів розпізнавання образів» (№ ДР 0117U0009100). Мета дослідження — створення додаткових можливостей для навчання техніці стрільби, збільшення доступності такого навчання. Завдання дослідження: — розробка моделі даних системи; — розробка математичної моделі системи; — розробка архітектури програмного забезпечення; — розробка програмної системи за прийнятими рішеннями. Об’єкт дослідження — віртуальний симулятор тиру. Предмет дослідження — семантичне моделювання віртуального симулятора тиру. Наукова новизна отриманих результатів — розроблено систему, що поєднує у собі розрахунок руху снаряду за методом Сіачі і визначення положення об’єкту на зображенні з використанням алгоритму визначення відрізків віртуальної прямої. Публікації. Н.О. Абрашина, 2020, “КОНЦЕПТ СИСТЕМИ ВІРТУАЛЬНОГО ТИРУ НА ОСНОВІ ВІДЕО-ВВОДУ”, п’ятнадцята міжнародна науково-практична конференція “Математичне та імітаційне моделювання систем МОДС 2020”, Україна, м. Чернігів, 29 червня — 01 липня, стр. 196-198. Абрашина Н.О, Баклан І.В., 2020, “СЕМАНТИЧНЕ МОДЕЛЮВАННЯ ВІРТУАЛЬНОГО СТИМУЛЯТОРА ТИРУ”, V Всеукраїнська науково- практична конференція молодих вчених та студентів “Інфор, Master's dissertation: 100 pages, 4 sections, 37 tables, 30 figures, 2 appendices, 32 sources. Topicality. Shooting training is very important for the military, as well as for athletes and hunters. At the same time, training shootings can be quite expensive, harmful to the environment and sometimes dangerous. Therefore, the development of virtual shooting ranges is quite promising, allowing to practice skills in the initial stages of learning. Thus, it will be expedient to investigate the semantic model of such systems in order to approach their development more effectively in the future. Connection of work with scientific programs, plans, themes. The work was performed at the Department of Automated Information Processing and Control Systems of the National Technical University of Ukraine "Kyiv Polytechnic Institute. Igor Sikorsky ”in the framework of the topic“ Development of image recognition methods ”(№ DR 0117U0009100). The purpose of the study is to create additional opportunities for training in shooting techniques, increase the availability of such training. Objectives of the study: — development of a system data model; — development of a mathematical model of the system; — software architecture development; — development of a software system based on the decisions made. The object of research is a virtual shooting range simulator. The subject of research is semantic modeling of a virtual shooting simulator. Scientific novelty of the obtained results - a system has been developed that combines the calculation of the projectile motion by the Siachi method and determining the position of the object in the image using the algorithm for determining the segments of the virtual line. Publications. Nadiia Abrashina, 2020, “CONCEPT OF VIRTUAL SHOOTING SYSTEM BASED ON VIDEO INPUT”, Fifteenth International Scientific and Practical Conference “Mathematical and Simulation Modeling of MODS 2020 Systems”, Ukraine, Chernihiv, June 29, 1969 - June 29. 198. Nadiia Abrashina

Este proyecto se centra en el diseño conceptual de una baliza automática para uso en puertos deportivos. A partir del estado del arte se ha constatado que el mercado actual es inexistente, así pues, partiendo de cero, se han creado dos posibles conceptos. Estos conceptos incluyen un diseño del sistema mecánico, electrónico y de telecomunicaciones. Dicha embarcación de servicios tendrá la función de baliza, la cual estará dentro de puerto y se encargará de ir a buscar embarcaciones y guiarlas hasta su amarre. Todo esto de forma automática. Con tal de realizar un diseño conceptual, primero se estudiará las opciones que presenta el mercado, para posteriormente presentar dos alternativas que puedan cumplir las funciones deseadas. Con la ayuda del programa de diseño asistido Solidworks 2018 se presentan las soluciones conceptuales de ambas propuestas. Para el análisis de la embarcación, a partir del planteamiento de las ecuaciones matemáticas y físicas se realiza una simulación de su funcionamiento. Esta simulación va acompañada de una hoja de cálculo que simula el controlador PID incorporado. Todo esto con el fin de tomar la decisión de cuál de las dos propuestas es la más adecuada para este proyecto y su fin.

Este proyecto se centra en el diseño conceptual de una baliza automática para uso en puertos deportivos. A partir del estado del arte se ha constatado que el mercado actual es inexistente, así pues, partiendo de cero, se han creado dos posibles conceptos. Estos conceptos incluyen un diseño del sistema mecánico, electrónico y de telecomunicaciones. Dicha embarcación de servicios tendrá la función de baliza, la cual estará dentro de puerto y se encargará de ir a buscar embarcaciones y guiarlas hasta su amarre. Todo esto de forma automática. Con tal de realizar un diseño conceptual, primero se estudiará las opciones que presenta el mercado, para posteriormente presentar dos alternativas que puedan cumplir las funciones deseadas. Con la ayuda del programa de diseño asistido Solidworks 2018 se presentan las soluciones conceptuales de ambas propuestas. Para el análisis de la embarcación, a partir del planteamiento de las ecuaciones matemáticas y físicas se realiza una simulación de su funcionamiento. Esta simulación va acompañada de una hoja de cálculo que simula el controlador PID incorporado. Todo esto con el fin de tomar la decisión de cuál de las dos propuestas es la más adecuada para este proyecto y su fin.

We report on experimental study of quantum conductivity corrections for two-dimensional electron gas in GaAs/InGaAs/GaAs single and double quantum wells in a wide temperature range (1.8–100)K. We perform a comparison of our experimental data for the longitudinal conductivity in zero magnetic field to the theory of interaction-induced corrections to the transport coefficients. In the temperature range from 10 K up to (45–60)K, which covers the ballistic interaction regimes for our samples, rather a good agreement between the theory and our experimental results has been found. © 2019 Elsevier B.V.

During flight, aerospace structures are often exposed to high velocity impacts with both hard and soft or deformable objects. These objects include metal pieces or fragments, stone debris, birds, hailstones, and tyre rubber. Therefore, in the design of aerospace structures, engineers are required to implement composite structures that are able to withstand this type of impact. This thesis aims at developing a novel hybrid composite material based on kenaf fibre and x-ray films and at analysing the obtained materials with regard to their mechanical properties, as well as high velocity impact and compression after impact behaviour, with a view to determining their potential to compete with existing high velocity impact resistant materials, which are presently used to fabricate the insert plates of bulletproof vests. The kenaf fibre used to reinforce the composites was treated with NaOH solution, and, for comparison purposes, composites were prepared with both treated and untreated kenaf fibre. Similarly, the x-ray films were punctured to improve adhesion between the layers and composites were fabricated with both punctured and unpunctured x-ray films. The materials were fabricated using the conventional hand lay-up method, with 7 layers arranged according to different configurations. The optimum configuration was then chosen – judging by the mechanical characteristics obtained – and improved. The new configuration was then used to fabricate a series of samples to be tested with regard to their behaviour to high velocity impact. A single stage gas gun was used for the tests, and the analysed variables were the pressure of the gas gun – which influences the velocity of the bullets – and the type of the bullets. The bullet types used were: blunt or flat bullets, hemispherical bullets and conical or chisel-pointed bullets. The pressure for the gas gun was varied as follows: 20 bar, 30 bar, 40 bar and 50 bar. The tests revealed that the hemispherical bullets penetrated the

During flight, aerospace structures are often exposed to high velocity impacts with both hard and soft or deformable objects. These objects include metal pieces or fragments, stone debris, birds, hailstones, and tyre rubber. Therefore, in the design of aerospace structures, engineers are required to implement composite structures that are able to withstand this type of impact. This thesis aims at developing a novel hybrid composite material based on kenaf fibre and x-ray films and at analysing the obtained materials with regard to their mechanical properties, as well as high velocity impact and compression after impact behaviour, with a view to determining their potential to compete with existing high velocity impact resistant materials, which are presently used to fabricate the insert plates of bulletproof vests. The kenaf fibre used to reinforce the composites was treated with NaOH solution, and, for comparison purposes, composites were prepared with both treated and untreated kenaf fibre. Similarly, the x-ray films were punctured to improve adhesion between the layers and composites were fabricated with both punctured and unpunctured x-ray films. The materials were fabricated using the conventional hand lay-up method, with 7 layers arranged according to different configurations. The optimum configuration was then chosen – judging by the mechanical characteristics obtained – and improved. The new configuration was then used to fabricate a series of samples to be tested with regard to their behaviour to high velocity impact. A single stage gas gun was used for the tests, and the analysed variables were the pressure of the gas gun – which influences the velocity of the bullets – and the type of the bullets. The bullet types used were: blunt or flat bullets, hemispherical bullets and conical or chisel-pointed bullets. The pressure for the gas gun was varied as follows: 20 bar, 30 bar, 40 bar and 50 bar. The tests revealed that the hemispherical bullets penetrated the

Empirical data suggests that ceramic spheres can serve as front face systems for armor applications, which can improve performance over current monolithic plate design by providing multi-hit fracture resistance and lower costs. Ballistic test results of ceramics composed of AD90, AD995 and sapphire (AL2O3) are presented alongside hydro code simulation results. In addition to chemical differences, impact performance between geometric differences is also examined. Performance calculations include (as a function of time) projectile velocity, deceleration, force applied and work applied to the projectile. Shockwave propagation through sapphire targets is observed to be consistent with published sound speeds and is in agreement with hydro code. We found that 1/2" spheres are shown to perform better than 1/2" right circular cylinders. AD90 is shown to perform better under ballistic test conditions than AD995, indicating the feasibility of a low-cost, ceramic sphere–based front facing armor system., http://archive.org/details/effectsofballist1094559559, Captain, United States Marine Corps, Approved for public release; distribution is unlimited.

Printing techniques are constantly being improved following the development of computer technology. In recent years we are witnesses of a useful printing of objects in three dimensions in industry, medicine, arts and other fields. Also, this technology can be abused to make weapons in an improvised ballistic laboratory. The question is, if such a weapon is used to commit crime (murder, attempted murder, grievous bodily harm, causing general danger, etc.) how can one examine traces of the ammunition or parts of the ammunition fired from the weapon. This way of producing weapons is an illegal act and a global threat, so it is vital to consider how to prevent abuse of this technology and opportunities of forensic investigations of ammunition fired from such a weapon if it is used for committing a crime., Štamparska tehnika se konstantno usavršava prateći razvoj kompjuterske tehnologije i poslednjih godi-na svedoci smo korisnog štampanja predmeta u tri dimenzije u industriji, medicini, umetnosti i dr. Takođe, ovu tehnologiju moguće je i zloupotrebiti i napraviti oružje u improvizovanoj balističkoj laboratoriji. Postavlja se pitanje, ukoliko se ovakvo oružje upotrebi za izvršenje nekog krivičnog dela (ubistvo, pokušaj ubistva, nanošenje teških telesnih povreda, izazivanje opšte opasnosti i sl.), na koji način se mogu ispitati tragovi na municiji koja je ispaljena iz ovakvog oružja i na njenim delovima. Ovakav način izrade oružja je nelegalan čin i kao takav predstavlja globalnu opasnost, te je razmatrana prevencija zloupotrebe ove tenologije, ali i mogućnosti kriminalističko-tehničkih ispitivanja tragova na municiji ispaljenoj iz ovakvog oružja ako već dođe do izvršenja krivičnog dela tim oružjem.

Este trabajo se basa en la simulación numérica de impactos balísticos sobre un modelo de elementos finitos compuesto por un casco de combate y una cabeza humana. El objetivo del trabajo es evaluar la respuesta de un casco de combate de aramida y de los tejidos vivos de la cabeza humana ante diferentes condiciones de impacto balístico. Para simular el impacto se emplea un módulo de cálculo explícito con integración directa y se obtiene la respuesta cinemática de los cuerpos involucrados y la energía absorbida por éstos, así como otros parámetros ingenieriles. El modelo numérico de cabeza humana se obtiene a partir de la segmentación de imagen médica, y se valida mediante la recreación de ensayos experimentales obtenidos de la literatura. De esta manera es posible aportar sugerencias para el diseño y la metodología de aceptación de los cascos de combate actuales de manera que garanticen una protección y unas prestaciones requeridas.

Este trabajo se basa en la simulación numérica de impactos balísticos sobre un modelo de elementos finitos compuesto por un casco de combate y una cabeza humana. El objetivo del trabajo es evaluar la respuesta de un casco de combate de aramida y de los tejidos vivos de la cabeza humana ante diferentes condiciones de impacto balístico. Para simular el impacto se emplea un módulo de cálculo explícito con integración directa y se obtiene la respuesta cinemática de los cuerpos involucrados y la energía absorbida por éstos, así como otros parámetros ingenieriles. El modelo numérico de cabeza humana se obtiene a partir de la segmentación de imagen médica, y se valida mediante la recreación de ensayos experimentales obtenidos de la literatura. De esta manera es posible aportar sugerencias para el diseño y la metodología de aceptación de los cascos de combate actuales de manera que garanticen una protección y unas prestaciones requeridas.

Este trabajo se basa en la simulación numérica de impactos balísticos sobre un modelo de elementos finitos compuesto por un casco de combate y una cabeza humana. El objetivo del trabajo es evaluar la respuesta de un casco de combate de aramida y de los tejidos vivos de la cabeza humana ante diferentes condiciones de impacto balístico. Para simular el impacto se emplea un módulo de cálculo explícito con integración directa y se obtiene la respuesta cinemática de los cuerpos involucrados y la energía absorbida por éstos, así como otros parámetros ingenieriles. El modelo numérico de cabeza humana se obtiene a partir de la segmentación de imagen médica, y se valida mediante la recreación de ensayos experimentales obtenidos de la literatura. De esta manera es posible aportar sugerencias para el diseño y la metodología de aceptación de los cascos de combate actuales de manera que garanticen una protección y unas prestaciones requeridas.

Este trabajo se basa en la simulación numérica de impactos balísticos sobre un modelo de elementos finitos compuesto por un casco de combate y una cabeza humana. El objetivo del trabajo es evaluar la respuesta de un casco de combate de aramida y de los tejidos vivos de la cabeza humana ante diferentes condiciones de impacto balístico. Para simular el impacto se emplea un módulo de cálculo explícito con integración directa y se obtiene la respuesta cinemática de los cuerpos involucrados y la energía absorbida por éstos, así como otros parámetros ingenieriles. El modelo numérico de cabeza humana se obtiene a partir de la segmentación de imagen médica, y se valida mediante la recreación de ensayos experimentales obtenidos de la literatura. De esta manera es posible aportar sugerencias para el diseño y la metodología de aceptación de los cascos de combate actuales de manera que garanticen una protección y unas prestaciones requeridas.

Printing techniques are constantly being improved following the development of computer technology. In recent years we are witnesses of a useful printing of objects in three dimensions in industry, medicine, arts and other fields. Also, this technology can be abused to make weapons in an improvised ballistic laboratory. The question is, if such a weapon is used to commit crime (murder, attempted murder, grievous bodily harm, causing general danger, etc.) how can one examine traces of the ammunition or parts of the ammunition fired from the weapon. This way of producing weapons is an illegal act and a global threat, so it is vital to consider how to prevent abuse of this technology and opportunities of forensic investigations of ammunition fired from such a weapon if it is used for committing a crime., Štamparska tehnika se konstantno usavršava prateći razvoj kompjuterske tehnologije i poslednjih godi-na svedoci smo korisnog štampanja predmeta u tri dimenzije u industriji, medicini, umetnosti i dr. Takođe, ovu tehnologiju moguće je i zloupotrebiti i napraviti oružje u improvizovanoj balističkoj laboratoriji. Postavlja se pitanje, ukoliko se ovakvo oružje upotrebi za izvršenje nekog krivičnog dela (ubistvo, pokušaj ubistva, nanošenje teških telesnih povreda, izazivanje opšte opasnosti i sl.), na koji način se mogu ispitati tragovi na municiji koja je ispaljena iz ovakvog oružja i na njenim delovima. Ovakav način izrade oružja je nelegalan čin i kao takav predstavlja globalnu opasnost, te je razmatrana prevencija zloupotrebe ove tenologije, ali i mogućnosti kriminalističko-tehničkih ispitivanja tragova na municiji ispaljenoj iz ovakvog oružja ako već dođe do izvršenja krivičnog dela tim oružjem.

We realize nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot-like resonances are probed by in situ transport measurements at various temperatures. The energies of the resonances are determined by the size of the constrictions, which can be controlled precisely using STM lithography. The temperature and size dependence of the measured conductances are in quantitative agreement with tight-binding calculations. The fact that these interference effects are visible even at room temperature makes the reported devices attractive as building blocks for future carbon based electronics. © 2016 American Physical Society.

Soft-matrix ballistic laminates (such as those composed of fibres of Ultra High Molecular-Weight Polyethylene, e.g. Dyneema® HB26 and Spectra Shield) find extensive use as catching type armour systems. The relationship between the lay-up of these laminates with respect to the observed failure mechanisms has not been empirically investigated in the open literature, and is the subject of this work. Lay-ups are characterised by two parameters: (i) sequencing (or interply lay-up angle) θ¯ and (ii) in-plane anisotropy β, and can be mapped on to θ¯-β space. Four geometries that lie at the extrema of this parameter space are designed, built and tested. Testing is through ball bearing impact on circular clamped plates. The anisotropy (β) is coupled to the macroscopic response of the plates, while sequencing (θ¯) is coupled to the microscopic response. Penetration velocity is strongly affected by pull-out at the boundary, and in the present study this is shown to account for two-thirds of the ballistic resistance. The results have implications for validation testing on scaled samples, predictive modelling and simulation, and armour design., QC 20160126. QC 20160205

The impact response of an ultrahigh molecular weight polyethylene (UHMWPE) fiber reinforced polymer matrix composite laminate has been investigated. The laminate encapsulated an aluminum alloy sandwich panel whose corrugated core was filled with prismatic alumina inserts. The laminate encased hybrid core target could sustain ceramic prism base impacts by a spherical, 12.7 mm diameter steel projectile with velocities in excess of 2.7 km s-1. This was 150% higher than the ballistic limit of an equal areal density, similarly encapsulated aluminum plate target. By contrast, when the projectile impacted a hybrid core target at the apex of a ceramic prism insert, failure of the UHMWPE laminate on the rear face occurred at a lower impact velocity. High-speed imaging, three-dimensional digital image correlation and x-ray tomography measurements are used to show that upon impact the projectile and the ceramic insert fragment. These fragments then load the UHMWPE laminate on the rear face with a significantly reduced pressure compared to the impact pressure of the projectile on the front surface of the target. The loading area on the inner surface of the rear laminate was highest for a prism base impact and lowest for a prism apex impact. The inability to penetrate the rear laminate of the base impacted samples is consistent with the recent identification of an impact pressure controlled mechanism of progressive penetration in this class of laminate.

The PELE ammunition is characterized by a low-density filling material surrounded by a high-density brittle jacket material. An analytical model describing the fragmentation of this ammunition behind a target plate is presented. This model assumes uniaxial strain in the filling and uses the RankingeHugoniot relations to calculate the material state. In addition, shock and rarefaction wave interactions at the target free surface and the filling/target interface are accounted for, as well as the radial rarefaction originating from the jacket outer surface. This allows the calculation of the pressure evolution in the filling and the radial acceleration of the jacket at any axial position along the projectile. This model aims at improving previously published analytical models where the acoustic wave approximation was used and the wave interactions were neglected. Experimental results (Paulus and Schirm, 2006) are used to validate the analytical model for different target materials (aluminum and steel), target thicknesses (3 mm and 8 mm), filling materials (polyethylene and aluminum) and impact velocities (900 m/s to 3000 m/s). A qualitative comparison based on X-ray photographs reveals similar features between the model and the experiments, such as smaller and lighter fragments with a greater radial velocity at the front of the projectile compared to the fragment characteristics at the back of the projectile. A quantitative comparison based on the maximum radial velocity of the fragments shows on average a 20% difference between the analytical and experimental results for all impact conditions considered. Despite this difference, the analytical trend follows more closely the experimental one compared to the acoustic approximation especially at high impact velocities. In addition, the acoustic approximation fails to reproduce the jacket fragmentation pattern since the fragmentation length of the jacket is significantly under-predicted. A numerical simulation is also pre

In this thesis, the plausibility of developing a portable light-weight artillery computer has been investigated. The main goal of the project has been to replace the traditional methods that the Swedish Armed Forces are using today to find firing solutions for their mortar, the GRK m/84. A computational core has been written in Java that simulates the trajectory of a shell using the model in NATO's STANAG 4355. The developed system finds firing solutions by using shooting methods and the multi-dimensional Newton Raphson's method. A Graphical User Interface (GUI) tailored to mobile computers has been designed in Android. The computational core along with the GUI has been installed on a rugged hand held computer and the whole unit has been tested at Markstridsskolan (MSS). The tests showed that the computational core delivers firing solutions that coincide very well with the actual firing solutions needed to hit the desired target.

The use of combat helmets has greatly reduced penetrating injuries and saved lives of many soldiers. However, behind helmet blunt trauma (BHBT) has emerged as a serious injury type experienced by soldiers in battlefields. BHBT results from nonpenetrating ballistic impacts and is often associated with helmet back face deformation (BFD). In the current study, a finite element-based computational model is developed for simulating the ballistic performance of the Advanced Combat Helmet (ACH), which is validated against the experimental data obtained at the Army Research Laboratory. Both the maximum value and time history of the BFD are considered, unlike existing studies focusing on the maximum BFD only. The simulation results show that the maximum BFD, the time history of the BFD, and the shape and size of the effective area of the helmet shell agree fairly well with the experimental findings. In addition, it is found that ballistic impacts on the helmet at different locations and in different directions result in different BFD values. The largest BFD value is obtained for a frontal impact, which is followed by that for a crown impact and then by that for a lateral impact. Also, the BFD value is seen to decrease as the oblique impact angle decreases. Furthermore, helmets of four different sizes - extra large, large, medium, and small - are simulated and compared. It is shown that at the same bullet impact velocity the small-size helmet has the largest BFD, which is followed by the medium-size helmet, then by the large-size helmet, and finally by the extra large-size helmet. Moreover, ballistic impact simulations are performed for an ACH placed on a ballistic dummy head form embedded with clay as specified in the current ACH testing standard by using the validated helmet model. It is observed that the BFD values as recorded by the clay in the head form are in good agreement with the experimental data., QC 20151130

The use of combat helmets has greatly reduced penetrating injuries and saved lives of many soldiers. However, behind helmet blunt trauma (BHBT) has emerged as a serious injury type experienced by soldiers in battlefields. BHBT results from nonpenetrating ballistic impacts and is often associated with helmet back face deformation (BFD). In the current study, a finite element-based computational model is developed for simulating the ballistic performance of the Advanced Combat Helmet (ACH), which is validated against the experimental data obtained at the Army Research Laboratory. Both the maximum value and time history of the BFD are considered, unlike existing studies focusing on the maximum BFD only. The simulation results show that the maximum BFD, the time history of the BFD, and the shape and size of the effective area of the helmet shell agree fairly well with the experimental findings. In addition, it is found that ballistic impacts on the helmet at different locations and in different directions result in different BFD values. The largest BFD value is obtained for a frontal impact, which is followed by that for a crown impact and then by that for a lateral impact. Also, the BFD value is seen to decrease as the oblique impact angle decreases. Furthermore, helmets of four different sizes - extra large, large, medium, and small - are simulated and compared. It is shown that at the same bullet impact velocity the small-size helmet has the largest BFD, which is followed by the medium-size helmet, then by the large-size helmet, and finally by the extra large-size helmet. Moreover, ballistic impact simulations are performed for an ACH placed on a ballistic dummy head form embedded with clay as specified in the current ACH testing standard by using the validated helmet model. It is observed that the BFD values as recorded by the clay in the head form are in good agreement with the experimental data., QC 20151130

The use of combat helmets has greatly reduced penetrating injuries and saved lives of many soldiers. However, behind helmet blunt trauma (BHBT) has emerged as a serious injury type experienced by soldiers in battlefields. BHBT results from nonpenetrating ballistic impacts and is often associated with helmet back face deformation (BFD). In the current study, a finite element-based computational model is developed for simulating the ballistic performance of the Advanced Combat Helmet (ACH), which is validated against the experimental data obtained at the Army Research Laboratory. Both the maximum value and time history of the BFD are considered, unlike existing studies focusing on the maximum BFD only. The simulation results show that the maximum BFD, the time history of the BFD, and the shape and size of the effective area of the helmet shell agree fairly well with the experimental findings. In addition, it is found that ballistic impacts on the helmet at different locations and in different directions result in different BFD values. The largest BFD value is obtained for a frontal impact, which is followed by that for a crown impact and then by that for a lateral impact. Also, the BFD value is seen to decrease as the oblique impact angle decreases. Furthermore, helmets of four different sizes - extra large, large, medium, and small - are simulated and compared. It is shown that at the same bullet impact velocity the small-size helmet has the largest BFD, which is followed by the medium-size helmet, then by the large-size helmet, and finally by the extra large-size helmet. Moreover, ballistic impact simulations are performed for an ACH placed on a ballistic dummy head form embedded with clay as specified in the current ACH testing standard by using the validated helmet model. It is observed that the BFD values as recorded by the clay in the head form are in good agreement with the experimental data., QC 20151130

In this thesis, the plausibility of developing a portable light-weight artillery computer has been investigated. The main goal of the project has been to replace the traditional methods that the Swedish Armed Forces are using today to find firing solutions for their mortar, the GRK m/84. A computational core has been written in Java that simulates the trajectory of a shell using the model in NATO's STANAG 4355. The developed system finds firing solutions by using shooting methods and the multi-dimensional Newton Raphson's method. A Graphical User Interface (GUI) tailored to mobile computers has been designed in Android. The computational core along with the GUI has been installed on a rugged hand held computer and the whole unit has been tested at Markstridsskolan (MSS). The tests showed that the computational core delivers firing solutions that coincide very well with the actual firing solutions needed to hit the desired target.

The use of combat helmets has greatly reduced penetrating injuries and saved lives of many soldiers. However, behind helmet blunt trauma (BHBT) has emerged as a serious injury type experienced by soldiers in battlefields. BHBT results from nonpenetrating ballistic impacts and is often associated with helmet back face deformation (BFD). In the current study, a finite element-based computational model is developed for simulating the ballistic performance of the Advanced Combat Helmet (ACH), which is validated against the experimental data obtained at the Army Research Laboratory. Both the maximum value and time history of the BFD are considered, unlike existing studies focusing on the maximum BFD only. The simulation results show that the maximum BFD, the time history of the BFD, and the shape and size of the effective area of the helmet shell agree fairly well with the experimental findings. In addition, it is found that ballistic impacts on the helmet at different locations and in different directions result in different BFD values. The largest BFD value is obtained for a frontal impact, which is followed by that for a crown impact and then by that for a lateral impact. Also, the BFD value is seen to decrease as the oblique impact angle decreases. Furthermore, helmets of four different sizes - extra large, large, medium, and small - are simulated and compared. It is shown that at the same bullet impact velocity the small-size helmet has the largest BFD, which is followed by the medium-size helmet, then by the large-size helmet, and finally by the extra large-size helmet. Moreover, ballistic impact simulations are performed for an ACH placed on a ballistic dummy head form embedded with clay as specified in the current ACH testing standard by using the validated helmet model. It is observed that the BFD values as recorded by the clay in the head form are in good agreement with the experimental data., QC 20151130

The use of combat helmets has greatly reduced penetrating injuries and saved lives of many soldiers. However, behind helmet blunt trauma (BHBT) has emerged as a serious injury type experienced by soldiers in battlefields. BHBT results from nonpenetrating ballistic impacts and is often associated with helmet back face deformation (BFD). In the current study, a finite element-based computational model is developed for simulating the ballistic performance of the Advanced Combat Helmet (ACH), which is validated against the experimental data obtained at the Army Research Laboratory. Both the maximum value and time history of the BFD are considered, unlike existing studies focusing on the maximum BFD only. The simulation results show that the maximum BFD, the time history of the BFD, and the shape and size of the effective area of the helmet shell agree fairly well with the experimental findings. In addition, it is found that ballistic impacts on the helmet at different locations and in different directions result in different BFD values. The largest BFD value is obtained for a frontal impact, which is followed by that for a crown impact and then by that for a lateral impact. Also, the BFD value is seen to decrease as the oblique impact angle decreases. Furthermore, helmets of four different sizes - extra large, large, medium, and small - are simulated and compared. It is shown that at the same bullet impact velocity the small-size helmet has the largest BFD, which is followed by the medium-size helmet, then by the large-size helmet, and finally by the extra large-size helmet. Moreover, ballistic impact simulations are performed for an ACH placed on a ballistic dummy head form embedded with clay as specified in the current ACH testing standard by using the validated helmet model. It is observed that the BFD values as recorded by the clay in the head form are in good agreement with the experimental data., QC 20151130

This report details a 2012-13 study, performed by the Natick Soldier Research, Development and Engineering Center, to examine the effects of wearing soft body armor and fighting loads on Soldier performance, mobility, and postural control. In addition to wearing body armor for protection against fragmentation or ballistic threats, Soldiers are encumbered with a fighting load that typically includes a weapon, helmet, ammunition, fighting load carrier and other essentials. Recently, the Army issued guidance on levels of body armor that can be worn during tactical operations. While increased levels of armor increase in ballistic protection of Soldiers, they also increase the weight carried. Previous research has shown that heavy loads from back packs diminish Soldier performance and mobility; however, little research has examined body armor and fighting load alone. Therefore, the main purpose of this evaluation was to examine how increases in body armor protection levels with a fighting load impacted Soldiers performance, mobility and postural control. Mobility and postural control were also examined without a fighting load. Results indicate that it is the addition of the fighting load that decreases mobility and postural control, while only large increases in body armor protection levels decrease performance. Further research on body armor protection levels with a fighting load is recommended to examine more challenging and unconstrained mobility and agility task, in the presence of cognitive performance tasks., The original document contains color images. Prepared in collaboration with Oak Ridge Institute for Science and Education, Belcamp, MD.

Ceramics are often employed as a hard strike face in composite armor systems. The ceramic serves to break up and erode the penetrator while the back plate absorbs the kinetic energy of the remaining penetrator material. In this program, soda lime glass was used as a surrogate for ceramic to investigate how the strike face geometry affects composite back plate delamination. Understanding how the strike face design influences damage in the armor is an important consideration for multihit requirements. The test specimens were composed of a soda lime float -glass strike face that was adhered to an S-2 glass composite back plate using a transparent adhesive. A 0.30- cal. fragment-simulating projectile was used to ballistically interrogate the specimens, thereby introducing areas of delamination in the backing plate. The inherent translucency of the test specimen allowed for capture of dynamic delamination images with high-speed photography. The projected delamination area was quantified using commercially available digital image analysis software. The effects of glass thickness, geometry, and hit location were studied. It was found that an increase in the strike face diameter resulted in an increase in delamination area and an increase in delamination growth velocity. It was also found that projectile impacts at seam locations between 2 tiles result in more delamination than projectile impacts on the tile center or triple point of the strike faces. These are significant results because they run counter to some of the commonly held beliefs in the armor community., The original document contains color images.

Cost imposition strategies focus on eliciting an adversary response that creates a hardship differential favoring the initiating nation. There is new interest in cost-imposing strategies as the most beneficial element of the competitive spectrum. If applied against China, cost-imposing strategies can succeed when based on correct predictions of Chinese responses and accurate accounting for the monetary and other security costs involved. In the air domain, competition involving China's ballistic and cruise missiles, surface-to-air missiles (SAM), and fighters offers the United States different degrees of advantage and hardship. Defense decision makers will find that cost imposition is not a panacea. They should understand the concept beyond its current level of misuse both for the disproportionate advantage it offers and for the liability it poses when used against America. To institutionalize the practice, the Department of Defense (DOD) should revive the competitive strategies structure and methods developed in the 1980s. Implementation will require overcoming institutional resistance, short time horizons, and significant fiscal constraints., Published in Strategic Studies Quarterly p26-59 Spring 2015.

The US Army Research Laboratory conducted an initial study to characterize the material properties and armor performance of low-density ceramic composite tiles manufactured by the Ukrainian National Academy of Science, under a US Army International Technology Center contract. These ceramic formulations were compared with standard armor-grade boron carbide and silicon carbide tiles versus the 12.7-mm armor-piercing APM2 projectile.

Ballistic Research Laboratory Computer-Aided Design (BRL CAD) is a solid modeling system used by the Army for ballistics analysis. US Army Research Laboratory (ARL) target describers use the BRL CAD Geometry Difference (GDiff) tool to determine the differences between their target models. GDiff is currently a command-line-only utility lacking a graphical user interface (GUI). To improve the usability of the tool and to increase target describers productivity, a GUI for the tool is being created. Various differencing-type GUIs were researched to create an initial GUI design. Several possible designs were sketched and then made, and an initial design concept was reviewed by ARL target describers who provided feedback that improved the GUI design. A final sketch of the GUI was then created. The GUI is being implemented using the Tcl/Tk tookit in the form of an extension to Archer, which is a GUI for BRL CAD itself. Previous plug-ins for Archer are being examined to determine how to best implement the new GUI that is being written and tested., The original document contains color images.

The goal of this project was to develop a W-based amorphous-crystalline composite for penetrator applications. The composite was to have high strength, toughness, abrasion resistance, tailorable density, and a propensity for shear localization. Our year 3 tasks, as laid out in the project proposal, were to: 1) Consolidate amorphous or nanocrystalline powder blends 2) Mechanical testing 3) Ballistic testing, The original document contains color images.

A computational study was performed as an initial evaluation of the Lagrangian marker method recently implemented in the CTH shock physics code. A set of Taylor impact experiments served as the basis of this initial evaluation of the method. Numerical simulations of Taylor impact were performed with the CTH marker method, and the final shapes of the impacting cylinders were compared to experimental results. Additional CTH simulations were performed using the legacy Eulerian solver to isolate the influence of the CTH solver on the computational results. Finally, a set of Arbitrary Lagrangian-Eulerian (ALE) finite element simulations was performed for further comparison. The study revealed that the Lagrangian marker method reproduces the Taylor impact results with a degree of fidelity on par with the CTH legacy Eulerian and ALE methods. This study provides a critical first step toward the application of the CTH Lagrangian marker method to ballistic impact problems relevant to defense applications., The original document contains color images.

An efficient method was needed to perform ballistic testing using 0.30-cal. Fragment Simulating Projectiles at or near subsonic velocity in order to screen new resin systems for advanced composite/ceramic armor scaled-down test coupons. This technical note outlines the custom gun system and testing methods developed to enable this ballistic testing., The original document contains color images.

The impact response of an ultrahigh molecular weight polyethylene (UHMWPE) fiber reinforced polymer matrix composite laminate has been investigated. The laminate encapsulated an aluminum alloy sandwich panel whose corrugated core was filled with prismatic alumina inserts. The laminate encased hybrid core target could sustain ceramic prism base impacts by a spherical, 12.7 mm diameter steel projectile with velocities in excess of 2.7 km s-1. This was 150% higher than the ballistic limit of an equal areal density, similarly encapsulated aluminum plate target. By contrast, when the projectile impacted a hybrid core target at the apex of a ceramic prism insert, failure of the UHMWPE laminate on the rear face occurred at a lower impact velocity. High-speed imaging, three-dimensional digital image correlation and x-ray tomography measurements are used to show that upon impact the projectile and the ceramic insert fragment. These fragments then load the UHMWPE laminate on the rear face with a significantly reduced pressure compared to the impact pressure of the projectile on the front surface of the target. The loading area on the inner surface of the rear laminate was highest for a prism base impact and lowest for a prism apex impact. The inability to penetrate the rear laminate of the base impacted samples is consistent with the recent identification of an impact pressure controlled mechanism of progressive penetration in this class of laminate.

The purpose of this paper is to implement a random death process into a persistent random walk model which produces sub-ballistic superdiffusion (Lévy walk). We develop a stochastic two-velocity jump model of cell motility for which the switching rate depends upon the time which the cell has spent moving in one direction. It is assumed that the switching rate is a decreasing function of residence (running) time. This assumption leads to the power law for the velocity switching time distribution. This describes the anomalous persistence of cell motility: the longer the cell moves in one direction, the smaller the switching probability to another direction becomes. We derive master equations for the cell densities with the generalized switching terms involving the tempered fractional material derivatives. We show that the random death of cells has an important implication for the transport process through tempering of the superdiffusive process. In the long-time limit we write stationary master equations in terms of exponentially truncated fractional derivatives in which the rate of death plays the role of tempering of a Lévy jump distribution. We find the upper and lower bounds for the stationary profiles corresponding to the ballistic transport and diffusion with the death-rate-dependent diffusion coefficient. Monte Carlo simulations confirm these bounds. © 2015 American Physical Society.

At TNO mind sized engineering models are created for specific penetration conditions. The models are energy based and calculate the energy absorbed by target deformation (strain energy) and displacement (kinetic energy). The input parameters are restricted to basic target material properties (density, Young’s modulus), impact velocity, mass and the dimensions of projectile and target. In this paper an engineering model for impact of blunt projectiles on metallic sheets is presented. During blunt projectile impact a shock phase precedes the global deformation of the target. It results in increasing membrane and shear deformation of the target, while the projectile deforms and is retarded. These effects are included in the model. When the conditions for shear- and/or tensile failure of the target material are met, the target fails and is penetrated. Calculation results on projectile deformation and penetration behavior are compared with experimental results.

This thesis discusses how bending of Armox 500T and Armox 440T affects the ballistic properties; it also discusses the bending performance of Armox 500T and Armox 440T. The purpose is to develop new bending recommendations, and to investigate the correlation between bending radius and maintaining ballistic performance and offer more reliable bending recommendations to the Armox customers. The new bending recommendations will satisfy both mechanical and ballistic performance. To achieve the purpose, bending tests was made, and then the bended specimens were used to investigate the deformation from the bending. The method hardness mapping was used to describe the deformation in the specimen, because of the lack of information of deformation mechanism in martensitic steels. To test the ballistic properties, V50-tests were made on bended specimens at Åkers Krutbruk Protection AB. The V50-value is the calculated average value from six rounds, with three stops and three penetrations in a span of 40 m/s. The result from the testing shows that the bending does not have any significantly effect on the ballistic properties on the tested combinations of materials and ammunitions. The conclusions from the testing results are that the bending does not significantly influence the ballistic properties for the tested materials and ammunitions and the bending recommendations were greatly improved.

This thesis discusses how bending of Armox 500T and Armox 440T affects the ballistic properties; it also discusses the bending performance of Armox 500T and Armox 440T. The purpose is to develop new bending recommendations, and to investigate the correlation between bending radius and maintaining ballistic performance and offer more reliable bending recommendations to the Armox customers. The new bending recommendations will satisfy both mechanical and ballistic performance. To achieve the purpose, bending tests was made, and then the bended specimens were used to investigate the deformation from the bending. The method hardness mapping was used to describe the deformation in the specimen, because of the lack of information of deformation mechanism in martensitic steels. To test the ballistic properties, V50-tests were made on bended specimens at Åkers Krutbruk Protection AB. The V50-value is the calculated average value from six rounds, with three stops and three penetrations in a span of 40 m/s. The result from the testing shows that the bending does not have any significantly effect on the ballistic properties on the tested combinations of materials and ammunitions. The conclusions from the testing results are that the bending does not significantly influence the ballistic properties for the tested materials and ammunitions and the bending recommendations were greatly improved.

Despite excellent ballistic protection properties, Ultra High Molecular Weight Polyethylene (UHMWPE) material has generally not been considered for certain applications in protective apparel due to its low melting point. This report describes a research effort to test UHMWPE fabric and composite material in a flash flame environment when protected by a flame-resistant (FR) fabric outer layer. This research was funded and managed through a US Army science and technology program Technology Enabled Capability Demonstration (TeCD): Force Protection Soldier and Small Unit. Testing was conducted at the Natick Soldier Research, Development and Engineering Center (NSRDEC) Ouellette Thermal Test Facility in accordance with the ASTM F1930 Standard Test Method for Evaluation of Flame Resistant Clothing for Protection Against Fire Simulations Using an Instrumented Manikin. Several UHMWPE fabrics were tested underneath an FR fabric outer layer of Tencate Defender M. Prior to fabricating test garments, preliminary flash flame testing was conducted with a midscale test setup, which guided the full-scale thermal manikin test plan. Test garments were fabricated for evaluation on the instrumented thermal test manikin, which included the UHMWPE undergarments (shorts and vest) and an FR fabric coverall as well as the FR Army Combat Uniform (FRACU). All tests were conducted according to ASTM F1930 with a 4-s flame duration calibrated to 84 kW/m2. The UHMWPE undergarments remained intact after all of the flash flame tests. Some distortion of the UHMWPE fabric was observed in localized areas. No melt/drip response was observed in the FR fabric shielded UHMWPE undergarments, and they provided a similar reduction in transmitted heat flux as was measured in tests with cotton undergarments., The original document contains color images.