Download or read book Blast Mitigation by Water written by Louk Absil and published by . This book was released on 2006 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Blast Mitigation Using Water Mist written by and published by . This book was released on 2006 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of experiments demonstrating the mitigation of water mist on the over-pressure effects of a TNT detonation have been conducted A series of TNT charges, 0.9 kg (2 lb), 2.2 kg (5 lb) and 3.2 kg (7 lb), were detonated both with and without employing a water mist system. The TNT detonations were characterized by five measurements: initial blast over-pressure start time, peak, and impulse, as well as quasi-static pressure and start time. The initial blast over-pressure peak and impulse, as well as quasi-static pressure were reduced by the presence of water. These experiments show that the use of water mist to mitigate the over-pressure effects of a high explosive detonation is an extremely promising concept.

Download or read book Blast Wave Mitigation by Water written by and published by . This book was released on 1998 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safety systems designed to mitigate blast wave effects are absolutely vital in the explosives industry. As a general rule, barricades made of soil, sand or concrete are used, but these systems cannot be moved once they have been constructed. Since plants or installations are frequently required to change location the concept of a mobile barricade is of considerable interest. The effect of a water wall on blast wave mitigation was studied in scale model tests. The influence of different parameters such as the thickness of the wall and the distance between the explosive charge and the water barricade was also calculated. This methodology enabled the use of nomographs giving excess pressure (overpressure) as a function of wall thickness, charge/wall distance and charge/location distance. The results showed the effectiveness of the water wall and confirmed its interest. This study was carried out by performing tests in a reduced scale model plant. The purpose of the tests was to: 1. Confirm the effect of the weight of the water wall on far-field blast mitigation. 2. Measure the effect of the water wall with regard to reflected pressures on rigid walls. In these cases water walls were created in front of the rigid walls.

Download or read book Blast Mitigation Using Water A Status Report written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to mitigate the effects of blast waves has been heightened by the recent incident with the USS Cole. In the spirit of one of the findings of the DoD USS Cole Commission, that there is a need for, 'More responsive application of currently available military equipment, commercial technologies, and aggressive research and development', this report reviews the current knowledge base on blast mitigation using water and identifies the key issues that need to be resolved in order to develop an effective waterbased blast mitigation system for shipboard use in both peacetime and wartime. There are several ways in which the use of water sprays can mitigate the effects of an explosion in a ship compartment. It may: (1) break up larger droplets into finer mist (the breakup process extracts energy from the shock and weakens it); (2) directly lead to an attenuation of the shock waves produced; (3) reduce the intensity of secondary shock and pressure wave reflections from the walls and other objects in the enclosure; (4) slow down or quench the chemical reactions taking place behind the shock waves; and (5) dilute the concentration of explosive gases in the enclosure and hence prevent a secondary gas explosion or fire. In addition, the interaction depends on whether we are dealing with a shock wave, detonation or deflagration wave and the amount of water and size of the droplets that are present. Under certain circumstances the introduction of water spray could have an adverse effect by improving fuel-air mixing and accelerating flame propagation. These conditions have been identified in this report.

Download or read book Blast Mitigation by Water Mist 1 Simulation of Confined Blast Waves written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Effectively minimizing the damage due to onboard explosions and blast waves on naval ships has always been a priority to the Navy. With recent events and the war on terrorism, this need has become important to a much broader base of people to help protect platforms and infrastructure. Water presents a flexible, cost-effective, and clean method for mitigating the effects of the blast wave and has received much attention recently from experimentalists. There is, however, only limited understanding on exactly how to use water most effectively to mitigate blasts. The purpose of this research is to clarify issues related to how water can be used to mitigate blasts within enclosures, and specifically looks at the use of water mist in mitigating blast waves. A parallel, FCT-based simulation technique was developed to examine initial blast properties and long-term pressure development in enclosures for TNT explosions. The simulation technique uses a simplified approach to modeling the area immediately surrounding the explosive (defined as the.

Download or read book Blast Mitigation written by Arun Shukla and published by Springer Science & Business Media. This book was released on 2013-07-06 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blast Mitigation: Experimental and Numerical Studies covers both experimental and numerical aspects of material and structural response to dynamic blast loads and its mitigation. The authors present the most up-to-date understanding from laboratory studies and computational analysis for researchers working in the field of blast loadings and their effect on material and structural failure, develop designs for lighter and highly efficient structural members for blast energy absorption, discuss vulnerability of underground structures, present methods for dampening blast overpressures, discuss structural post blast collapse and give attention to underwater explosion and implosion effects on submerged infrastructure and mitigation measures for this environment.

Download or read book Blast Mitigation by Water Mist 3 Mitigation of Confined and Unconfined Blasts written by and published by . This book was released on 2006 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the third in a series of reports focusing on numerical simulations of blasts and blast mitigation. This report uses the models developed in the first two to specifically examine the effect of water mists consisting of sub-50-micron droplets on blast shock-fronts and the development of quasi-static overpressure in enclosed spaces. In unconfined blasts, results showed that the water mist does not directly suppress the secondary reactions. Mitigation of the shock-front is accomplished mainly through momentum extraction and not vaporization. Quantitative results determined the exact effect of 5 to 50 micron sized droplets on the shock-front. Droplet size was found to play a secondary role compared to mass loading. Smaller droplets were less effective close to the explosive, while further downstream, the optimum droplet size depended on mass loading. The total amount of water mass between the observer and explosive was the most important factor in determining the amount of mitigation seen by the observer. Simulations were also conducted to determine the effectiveness of water mist to mitigate quasi-static pressure build-up in enclosures. Comparisons with experiments conducted at NSWC were used to validate the models and showed that the models could predict the overall mitigation efficiency to within a few percent. Absolute values of the simulation quasi-static overpressure tended to be slightly higher than experimental values, most likely because various loss mechanisms (incomplete combustion, absorption of energy by walls, and venting) were not incorporated into the model. Results also suggested that multi-dimensional simulations were required compared with simple thermodynamic and one-dimensional computations. Finally, additional needed computational work is summarized in the report. Many of these improvements are implemented and are currently being tested, and will help substantially in simulating blast mitigation scenarios of interest to the Navy and DoD.

Download or read book Blast Mitigation by Water Mist 2 Shock Wave Mitigation Using Glass Particles and Water Droplets in Shock Tubes written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is the second in a series of reports discussing mitigation of blasts using water mists. The previous report described numerical simulations of a TNT blast. The present report has combined that numerical procedure with a two-continuum model for dispersed-phase calculations. The specific approach used for the dispersed-phase calculations is the sectional approach, and is described in this report along with a series of simulations conducted for validation, and also for the purpose of better understanding interactions between shock waves and particle-seeded gases.

Download or read book Experimental Study of Blast Mitigation in a Water Mist written by and published by . This book was released on 2006 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents results of experiments on the mitigation of explosive blast using water mist. Water mists in the present study were produced by nozzles distributed around a test arena. Tests were conducted using different water mist sizes and nozzle arrangements to evaluate blast mitigation effects for in-air bare explosive charges as well as charges submerged in water and glycerine. The effects on blast wave pressure results due to the experimental blast pressure gauge mounting and set-up, as well as due to the effects of confinement in the test area, are analysed and discussed. Blast attenuation was evaluated using the CTH hydrocode and concluded that the phase transformation and mitigate liquid breakdown mechanism, under expansion by the blast products, must be considered in order to model blast mitigation adequately and to accurately evaluate mitigation effects at large stand-off distances.

Download or read book Water Mitigation of Explosion Effects Part 1 The Dynamic Pressure from Partially Confined Spaces written by and published by . This book was released on 1998 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is a contribution to an ongoing co-operative research project between FOA in Sweden and TNO-PML in the Netherlands, aimed at investigating the physics of water mitigation and to formulate instructions and standards of how to use water barriers. FOA has focused on the scalemodeling laws and to investigate if the mitigation is affected when the charges are cased. The technique of damping blast from high explosives with "water barriers" of different types has recently been studied by some research institutes and consultants. Examples on practical applications are to reduce the most severe hazard area around an ammunition storage, on equipment for manufacturing or the destruction of ammunition etc. However, the results reported in this field indicate that the mitigation effect from water is not yet fully understood. Although it has been demonstrated to work well in many tests in small scale, unexpected results have occurred when tested in full scale. This paper contains a somewhat closer look on the blast mitigation effect from water for geometries similar to a duct attached to a confined space, e.g. an access tunnel in to an ammunition storage. Of special interest is then the dynamic pressure inside the access tunnel, caused by the shock and quasi-static pressure from an explosion in the storage chamber, as well as the jet formed outside the tunnel entrance. An effort is made to explain some results from scale model experiments in terms of elementary thermodynamics and shock wave theory. This is illustrated by a set of numerical simulations with the hydrocode AUTODYN using its two phase material model for water. The calculated results are compared with the experiments, and it is concluded that the numerical model to some extent describes the phenomena involved.

Download or read book Feasibility and Design of Blast Mitigation Systems for Naval Applications Using Water Mist Fire Suppression Systems written by Julie A. Kitchenka and published by . This book was released on 2004 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Given the recent trend toward tumblehome hull forms in future Naval Combatant designs, there exists strong applicability of this system in the "dead" spaces created by the shaping of the tumblehome hull. Further work is needed in numerical modeling and laboratory testing of specific phases of the mitigation. The end goal is a feasible design of a blast mitigation system to be used in the outermost spaces of Naval Combatants to protect interior vital system spaces.

Download or read book Blast Mitigation Strategies in Marine Composite and Sandwich Structures written by Srinivasan Gopalakrishnan and published by Springer. This book was released on 2017-12-14 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book primarily focuses on methodologies to enable marine structures to resist high velocity impact loadings. It is based on invited talks presented at the recent India–USA workshop on “Recent Advances in Blast Mitigation Strategies in Civil and Marine Composite Structures” The book comprises content from top researchers from India and the USA and covers various aspects of the topic, including modeling and simulation, design aspects, experimentation and various challenges. These failure modes significantly reduce the structural integrity of the marine structures unless they are designed to resist such harsh loadings. Understanding the mechanics of these structures under harsh loadings is still an open area of research, and the behavior of these structures is not fully understood. The book highlights efforts to reduce the effects of blast loadings on marine composite structures. Intended for researchers/scientists and practicing engineers, the book focuses not only the design and analysis challenges of marine composite structures under such harsh loading conditions, but also provides new design guidelines.

Download or read book Blast Mitigation in Confined Spaces by Energy Absorbing Materials written by and published by . This book was released on 1994 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tests have been performed with different explosives (balanced as well as underbalanced with respect to Oxygen) at different loading densities (0.1 - 4 kg/m3) with different additives (e.g. water, glycol and foam) to get a basis for a better understanding of the possible mitigation effects on stored ammunition. Water has a mitigational effect on the blast wave from an explosion. This surpression of the pressure works for both balanced and underbalanced agents and seems to be independant of the loading density. The quantitative effect is depending on the way the water is distributed but the tests show that the effective charge size can be reduced with more than 50%.

Download or read book Explosion Blast Response of Composites written by Adrian P. Mouritz and published by Woodhead Publishing. This book was released on 2017-05-22 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explosion Blast Response of Composites contains key information on the effects of explosions, shock waves, and detonation products (e.g. fragments, shrapnel) on the deformation and damage to composites. The book considers the blast response of laminates and sandwich composites, along with blast mitigation of composites (including coating systems and energy absorbing materials). Broken down under the following key themes: Introduction to explosive blast response of composites, Air explosion blast response of composites, Underwater explosion blast response of composites, and High strain rate and dynamic properties of composites, the book deals with an important and contemporary topic due to the extensive use of composites in applications where explosive blasts are an ever-present threat, such as military aircraft, armoured vehicles, naval ships and submarines, body armour, and other defense applications. In addition, the growing use of IEDs and other types of bombs used by terrorists to attack civilian and military targets highlights the need for this book. Many terrorist attacks occur in subways, trains, buses, aircraft, buildings, and other civil infrastructure made of composite materials. Designers, engineers and terrorist experts need the essential information to protect civilians, military personnel, and assets from explosive blasts. Focuses on key aspects, including both modeling, analysis, and experimental work Written by leading international experts from academia, defense agencies, and other organizations Timely book due to the extensive use of composites in areas where explosive blasts are an ever-present threat in military applications

Download or read book Shock Wave Interactions written by Konstantinos Kontis and published by Springer. This book was released on 2018-03-28 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited monograph contains the proceedings of the International Shock Interaction Symposium, which emerged as an heir to both the Mach Reflection and Shock Vortex Interaction Symposia. These scientific biannual meetings provide an ideal platform to expose new developments and discuss recent challenges in the field of shock wave interaction phenomena. The goal of the symposia is to offer a forum for international interaction between young and established scientists in the field of shock and blast wave interaction phenomena. The target audience of this book comprises primarily researchers and experts in the field of shock waves, but the book may also be beneficial for young scientists and graduate students alike.

Download or read book Analytical and Test Results for Water Mitigation of Explosion Effects written by and published by . This book was released on 1998 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Small-scale tests have shown that water placed in the proximity of explosives stored in a confined space can reduce the internal gas pressure and impulse from a detonation by up to 90%. In FY 97 and 98, NFESC began development of water mitigation concepts for application in confined (e.g. Missile Test Cells, Underground Magazines) and partially confined (e.g. earth-covered magazines) facilities. Tests and analyses were conducted to establish basic parametric relationships and to identify the best numerical models for prediction of effects. Numerical model results from hydrocodes and computational fluid dynamics codes are presented and compared to test data. A limited number of tests with variable confinement (amount of venting) were also conducted. Results were very encouraging, both for adequately predicting water mitigation effects and for the effectiveness of water mitigation even when venting reduces the internal gas pressure effects.

Download or read book Protecting People and Buildings from Terrorism written by National Research Council and published by National Academies Press. This book was released on 2002-01-31 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerned with the vulnerability of U.S. civilian and military personnel to terrorist bombing attacks, the U.S. Congress directed the Department of Defense to undertake a comprehensive research and testing program aimed at protecting people in buildings from such attacks. The Blast Mitigation for Structures Program (BMSP) was initiated in 1997 and has produced a large volume of experimental and analytical data that will permit the design of new, more robust buildings as well as the development of methods to retrofit a large number of vulnerable existing structures. This report reviews the BMSP program and investigates a process that would use existing institutional infrastructures (i.e., building code and standards-writing organizations, professional and technical organizations, universities, and research centers) to disseminate knowledge.