The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Tore Børvik - One of the best experts on this subject based on the ideXlab platform.
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penetration of granular materials by Small Arms bullets
International Journal of Impact Engineering, 2015Co-Authors: S Dey, Tore Børvik, L OlovssonAbstract:Abstract This paper presents an experimental and numerical study on the penetration of granular materials by Small-Arms bullets. In the experimental tests, five different types of granular material (0–2 mm wet sand, 0–2 mm dry sand, 2–8 mm gravel, 8–16 mm crushed stone and 16–22 mm crushed rock) were impacted by four different types of Small-Arms bullets (7.62 mm Ball with a soft lead core, 7.62 mm AP with a hard steel core, 12.7 mm Ball with a soft steel core and 12.7 mm AP with a tungsten carbide core). The tests were carried out using different rifles to fire the projectiles, while the granular materials were randomly packed in a 320 mm diameter specially-designed steel tube. In all tests, the initial projectile velocity and the depth of penetration in the granular material were measured for each bullet type. In the numerical simulations, a discrete particle-based approach was used to model the behaviour of sand during bullet impact. The method works with discrete particles that transfer forces between each other through contact and elastic collisions, allowing for a simple and robust treatment of the interaction between the sand particles and the bullet which is represented by finite elements. An important observation from this study is that the penetration depth is strongly influenced by deviation of the bullet from its original trajectory. Good agreement between the available experimental results and the numerical predictions is also in general obtained.
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normal and oblique impact of Small Arms bullets on aa6082 t4 aluminium protective plates
International Journal of Impact Engineering, 2011Co-Authors: L Olovsson, Tore Børvik, Magnus LangsethAbstract:Abstract Normal and oblique impact on 20 mm thick AA6082-T4 aluminium plates are studied both experimentally and numerically. Two types of Small Arms bullets were used in the ballistic tests, namely the 7.62 × 63 mm NATO Ball (with a soft lead core) and the 7.62 × 63 mm APM2 (with a hard steel core), fired from a long smooth-bore Mauser rifle. The targets were struck at 0°, 15°, 30°, 45° and 60° obliquity, and the impact velocity was about 830 m/s in all tests. During testing, the initial and residual bullet velocities were measured by various laser-based optical devices, and high-speed video cameras were used to photograph the penetration process. Of special interest is the critical oblique angle at which the penetration process changes from perforation to embedment or ricochet. The results show that the critical oblique angle was less than 60° for both bullet types. A material test programme was also conducted for the AA6082-T4 plate to calibrate a modified Johnson–Cook constitutive relation and the Cockcroft–Latham failure criterion, while material data for the bullets mainly were taken from the literature. 3D non-linear FE simulations with detailed models of the bullets were finally run. Good agreement between the FE simulations and the experimental results for the APM2 bullets was in general obtained, while it was more difficult to get reliable FE results for the soft core Ball bullets.
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perforation resistance of five different high strength steel plates subjected to Small Arms projectiles
International Journal of Impact Engineering, 2009Co-Authors: Tore Børvik, A H ClausenAbstract:Abstract Thin plates of high-strength steel are frequently being used both in civil and military ballistic protection systems. The choice of alloy is then a function of application, ballistic performance, weight and price. In this study the perforation resistance of five different high-strength steels has been determined and compared against each other. The considered alloys are Weldox 500E, Weldox 700E, Hardox 400, Domex Protect 500 and Armox 560T. The yield stress for Armox 560T is about three times the yield stress for Weldox 500E, while the opposite yields for the ductility. To certify the perforation resistance of the various targets, two different ballistic protection classes according to the European norm EN1063 have been considered. These are BR6 (7.62 mm Ball ammunition) and BR7 (7.62 mm AP ammunition), where the impact velocity of the bullet is about 830 m/s in both. Perforation tests have been carried out using adjusted ammunition to determine the ballistic limit of the various steels. In the tests, a target thickness of 6 mm and 6 + 6 = 12 mm was used for protection class BR6 and BR7, respectively. A material test programme was conducted for all steels to calibrate a modified Johnson–Cook constitutive relation and the Cockcroft–Latham fracture criterion, while material data for the bullets mainly were taken from the literature. Finally, results from 2D non-linear FE simulations with detailed models of the bullets are presented and the different findings are compared against each other. As will be shown, good agreement between the FE simulations and experimental data for the AP bullets is in general obtained, while it was difficult to get reliable FE results using the Lagrangian formulation of LS-DYNA for the soft core Ball bullet.
Latasha Solomon - One of the best experts on this subject based on the ideXlab platform.
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acoustic particle velocity sensor application to infrasonic detection
Journal of the Acoustical Society of America, 2015Co-Authors: Latasha SolomonAbstract:Infrasonics is the study of low-frequency acoustics that is below the normal limit of human hearing. Infrasound has the ability to propagate extremely long ranges and is often utilized to monitor naturally occurring phenomena and explosives. Acoustic particle velocity sensors have shown promise in detection and localization of transient signals in the audio range such as Small Arms fire, mortars, and rocket propelled grenades. Ideally, this sensor can be used to detect various targets spanning a broad range of frequencies to include that of infrasound. The primary objective of this research is to characterize the acoustic vector sensor’s localization performance for infrasonic sources given varying atmospheric conditions using algorithms developed at the Army Research Laboratory (ARL).
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transient detection via acoustic particle velocity multi mission sensor
Journal of the Acoustical Society of America, 2014Co-Authors: Latasha SolomonAbstract:In this research, we compare the direction of arrival (DOA) accuracy of a micro-electro-mechanical systems (MEMS) based acoustic particle velocity sensor developed by Microflown Technologies with that of a collocated, 1-m tetrahedral array. When deployed as an unattended sensor system, the Acoustic Multi-Mission Sensor (AMMS) greatly facilitates hardware set-up and periodic maintenance. An array of microphones is now replaced by a single sensor, saving in overall system cost, size, weight, and power usage. The single sensor has the capability to measure both the (scalar) sound pressure and the (vector) acoustic particle velocity, thus providing DOA estimates. This research will explore performance and determine limitation of the two sensors in complex environments as well as open fields for detection of both Small Arms fire (SAF) and rocket propelled grenades (RPGs).
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transient detection via micro electro mechanical systems based acoustic particle velocity sensor
166th Meeting of the Acoustical Society of America, 2014Co-Authors: Latasha SolomonAbstract:In this research, we compare the direction of arrival (DOA) accuracy of a micro-electro-mechanical systems (MEMS) based acoustic particle velocity sensor developed by Microflown Technologies with that of a collocated, 1-m tetrahedral array. When deployed as an unattended sensor system, the Acoustic Multi-Mission Sensor (AMMS) greatly facilitates hardware set-up and periodic maintenance. An array of microphones is now replaced by a single sensor, saving in overall system cost, size, weight, and power usage. The single sensor has the capability to measure both the (scalar) sound pressure and the (vector) acoustic particle velocity, thus providing DOA estimates. This research will explore performance and determine limitation of the two sensors in complex environments as well as open fields for detection of both Small Arms fire (SAF) and rocket propelled grenades (RPGs).
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transient detection via micro electro mechanical systems based acoustic particle velocity sensor
166th Meeting of the Acoustical Society of America, 2014Co-Authors: Latasha SolomonAbstract:In this research, we compare the direction of arrival (DOA) accuracy of a micro-electro-mechanical systems (MEMS) based acoustic particle velocity sensor developed by Microflown Technologies with that of a collocated, 1-m tetrahedral array. When deployed as an unattended sensor system, the Acoustic Multi-Mission Sensor (AMMS) greatly facilitates hardware set-up and periodic maintenance. An array of microphones is now replaced by a single sensor, saving in overall system cost, size, weight, and power usage. The single sensor has the capability to measure both the (scalar) sound pressure and the (vector) acoustic particle velocity, thus providing DOA estimates. This research will explore performance and determine limitation of the two sensors in complex environments as well as open fields for detection of both Small Arms fire (SAF) and rocket propelled grenades (RPGs).
L Olovsson - One of the best experts on this subject based on the ideXlab platform.
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penetration of granular materials by Small Arms bullets
International Journal of Impact Engineering, 2015Co-Authors: S Dey, Tore Børvik, L OlovssonAbstract:Abstract This paper presents an experimental and numerical study on the penetration of granular materials by Small-Arms bullets. In the experimental tests, five different types of granular material (0–2 mm wet sand, 0–2 mm dry sand, 2–8 mm gravel, 8–16 mm crushed stone and 16–22 mm crushed rock) were impacted by four different types of Small-Arms bullets (7.62 mm Ball with a soft lead core, 7.62 mm AP with a hard steel core, 12.7 mm Ball with a soft steel core and 12.7 mm AP with a tungsten carbide core). The tests were carried out using different rifles to fire the projectiles, while the granular materials were randomly packed in a 320 mm diameter specially-designed steel tube. In all tests, the initial projectile velocity and the depth of penetration in the granular material were measured for each bullet type. In the numerical simulations, a discrete particle-based approach was used to model the behaviour of sand during bullet impact. The method works with discrete particles that transfer forces between each other through contact and elastic collisions, allowing for a simple and robust treatment of the interaction between the sand particles and the bullet which is represented by finite elements. An important observation from this study is that the penetration depth is strongly influenced by deviation of the bullet from its original trajectory. Good agreement between the available experimental results and the numerical predictions is also in general obtained.
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normal and oblique impact of Small Arms bullets on aa6082 t4 aluminium protective plates
International Journal of Impact Engineering, 2011Co-Authors: L Olovsson, Tore Børvik, Magnus LangsethAbstract:Abstract Normal and oblique impact on 20 mm thick AA6082-T4 aluminium plates are studied both experimentally and numerically. Two types of Small Arms bullets were used in the ballistic tests, namely the 7.62 × 63 mm NATO Ball (with a soft lead core) and the 7.62 × 63 mm APM2 (with a hard steel core), fired from a long smooth-bore Mauser rifle. The targets were struck at 0°, 15°, 30°, 45° and 60° obliquity, and the impact velocity was about 830 m/s in all tests. During testing, the initial and residual bullet velocities were measured by various laser-based optical devices, and high-speed video cameras were used to photograph the penetration process. Of special interest is the critical oblique angle at which the penetration process changes from perforation to embedment or ricochet. The results show that the critical oblique angle was less than 60° for both bullet types. A material test programme was also conducted for the AA6082-T4 plate to calibrate a modified Johnson–Cook constitutive relation and the Cockcroft–Latham failure criterion, while material data for the bullets mainly were taken from the literature. 3D non-linear FE simulations with detailed models of the bullets were finally run. Good agreement between the FE simulations and the experimental results for the APM2 bullets was in general obtained, while it was more difficult to get reliable FE results for the soft core Ball bullets.
Lars Hagglund - One of the best experts on this subject based on the ideXlab platform.
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distribution chemical speciation and mobility of lead and antimony originating from Small Arms ammunition in a coarse grained unsaturated surface sand
Journal of Environmental Quality, 2010Co-Authors: Jeffrey Lewis, Jan Sjostrom, Ulf Skyllberg, Lars HagglundAbstract:This study quantified the heavy metal contamination caused by firing 500 high-velocity 7.62-mm jacketed Swedish military rounds. Contamination of solid and aqueous phases was studied, with Pb and Sb being the two contaminants of primary interest. The distribution of the Pb and Sb were measured in terms of depth of penetration in sand and grain size distribution of the bullet particles. The Pb- and Sb-contaminated sand was then used as a source material in two bench-scale unsaturated lysimeters to measure the transport of Pb and Sb through two coarse-grained sands, which were taken from the berms on two Swedish military Small Arms ranges. The lysimeters were subjected to an infiltration cycle that reproduced spring snowmelt, which is the most significant infiltration event of the year in northern climates. The levels of mobile Pb and Sb were monitored in the effluent from the lysimeters. Extended X-ray absorption fine-structure spectroscopy analysis was performed on the contaminated sands to determine Pb speciation before and after leaching. Ninety-three percent of the mass of bullets was found in the top 30 cm of sand. Lead oxide was the predominant species of Pb before and after leaching. Transport of Pb was Small, with aqueous concentrations remaining stable at <2 microg L(-1). Antimony was far more mobile, with solute breakthrough occurring between 5 and 14 d and concentrations rising to over 125 microg L(-1) within 1 month.
Asif Efrat - One of the best experts on this subject based on the ideXlab platform.
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toward internationally regulated goods controlling the trade in Small Arms and light weapons
International Organization, 2010Co-Authors: Asif EfratAbstract:Contrary to the general trend of trade liberalization, specific goods— such as Small Arms, drugs, and antiquities—have come under increasing international control in recent decades through a set of international regulatory agreements+ This article offers a theoretical framework of government preferences on the international regulation of these goods+ Departing from conventional models of trade policy, the theoretical framework introduces negative externalities, rather than protection, as the motivation for restricting trade; it also takes moral concerns into account+ I test this framework empirically through an original survey of government views on inter- national Small-Arms regulation+ Based on interviewing officials from 118 countries, the survey reveals a large variation in government preferences that conforms to the theoretical expectations+ I employ this variation to explain why the international reg- ulation of Small Arms is weak, despite the fact that these are the deadliest weapons of all in terms of actual death toll+
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toward internationally regulated goods controlling the trade in Small Arms and light weapons
Social Science Research Network, 2010Co-Authors: Asif EfratAbstract:Contrary to the general trend of trade liberalization, specific goods – such as Small Arms, drugs, and antiquities – have come under increasing international control in recent decades through a set of international regulatory agreements. The article offers a theoretical framework of government preferences on the international regulation of these goods. Departing from conventional models of trade policy, the theoretical framework introduces negative externalities, rather than protection, as the motivation for trade restrictions; it also takes moral concerns into account. I test this framework empirically through an original survey of government views on international Small Arms regulation. The survey – based on interviewing officials from 118 countries – reveals a large variation in government preferences that conforms to the theoretical expectations. I employ this variation to explain why the international regulation of Small Arms is weak, despite the fact that these are the deadliest weapons of all in terms of actual death toll.
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regulating rifles international control of the Small Arms trade
Social Science Research Network, 2008Co-Authors: Asif EfratAbstract:Small Arms kill many more people than any other weapon. They are the weapons of choice in the vast majority of contemporary conflicts and are often used in crime and terrorism. In stark contrast to the devastating consequences of Small Arms proliferation, the international regulatory framework for the trade in Small Arms, established in 2001, is a weak non-legally binding instrument. To explain this puzzling discrepancy, I develop a theoretical model of government preferences on international regulation. The model offers several innovations over conventional models of trade policy, including the introduction of negative externalities, rather than protection, as the motivation for trade restrictions, and the incorporation of value-based humanitarian concerns. I operationalize the model with respect to Small Arms and test it empirically through an original survey of national views on the regulation of the Small Arms trade. The survey - based on interviewing officials from 118 countries - provides strong support for my theoretical predictions. Governments backing Small Arms exporters, especially those which are state-owned, favor weak international regulation of Small Arms. Nondemocratic governments, concerned that international controls might impede their access to Arms, prefer weak international regulation as well. By contrast, governments facing high rates of gun violence and governments with humanitarian foreign policy concerns support strong regulation. The survey also reveals cross-regional variation. Africa, Latin America, and Europe support the international regulation of Small Arms; the Middle East as well as East and South Asia are less supportive of regulation. International control of Small Arms is, in fact, part of a broader phenomenon of international regulation, which the literature has overlooked. Beyond Small Arms, the theoretical framework developed in the paper can illuminate the political conflict over other internationally regulated goods, such as drugs and antiquities.
