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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.

Confined blast behavior and blast mitigation structures for the protection of occupants within a confined space subjected to high explosive blast, were examined through numerical analysis and laboratory testing. The mitigating structure's weight and geometry were of particular interest since performance was targeted for inclusion within the limited interior space of an armored vehicle. Numerical analysis using eta/VPG modeling software and LS DYNA dynamic analysis software examined the effects of blast mitigation compartments of varying geometries and dimensions for extremely close standoff distances for free field and confined blast events. Large 150 pound steel plates were used to occupy the confined space and examine occupant risk for head and chest acceleration injuries. Cylinders varied in wall thickness, diameter and shielding height. The energy absorption capability of these varying mitigation compartments produced counterintuitive results. Full scale laboratory tests of open ended cylindrical mitigation shields for free-field and confined blast correlation were conducted. Numerical blast-test dummies are introduced and found to produce analogous results to the aforementioned steel plates for chest accelerations. This dummy study shows the potential and necessity for additional research into a valuable, more advanced FEA tool to evaluate human response to direct blast.

Blast-induced traumatic brain injury is the most prevalent military injury in Iraq and Afghanistan, yet little is known about the mechanical effects of blasts on the human head, and still less is known about how personal protective equipment affects the brain's response to blasts. In this study we investigated the effect of the Advanced Combat Helmet (ACH) and a conceptual face shield on the propagation of stress waves within the brain tissue following blast events. We used a sophisticated computational framework for simulating coupled fluid-solid dynamic interactions and a three-dimensional biofidelic finite element model of the human head and intracranial contents combined with a detailed model of the ACH and a conceptual face shield. Simulations were conducted in which the unhelmeted head, head with helmet, and head with helmet and face shield were exposed to a frontal blast wave with incident overpressure of 10 atm. Direct transmission of stress waves into the intracranial cavity was observed in the unprotected head and head with helmet simulations.

In this project, a new solution for improving blast-survivability of light tactical military vehicles to detonation of a shallow-buried mine underneath them has been introduced and analyzed computationally. The solution involves the use of side-vent-channels attached to the Vshaped vehicle underbody, and tries to exploit detonation-products ultrasonic-expansion and ejected-soil venting phenomena to generate a downward thrust on the targeted vehicle. In order to accurately account for the interaction of detonation products, ejected soil and blast waves with the target structure, a novel combined Eulerian/Lagrangian finite-element/discrete-particle computational method has been developed and employed. To assess the full blast-mitigation potential of the new concept, the finite-element-based analysis has been combined with an advanced multi-objective design-optimization procedure. The results obtained show that the proposed concept has a relatively limited (but respectable) ability to reduce the detonation-induced total momentum transferred to, and the acceleration acquired by, the target vehicle.

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.

Panels comprised of honeycomb fiber reinforced polymer (FRP) laminations were evaluated to examine their utility as prefabricated fighting positions. The panels were tested for both their blast, and fragmentation mitigation ability. Static resistance functions were developed using a combination of analytical and laboratory procedures in order to obtain the panels response, the response was implemented into a single-degree of freedom (SDOF) dynamic analysis. Engineered analytical prediction models showed that the panels' response in live explosive blast testing could be predicted. Sand-filled wall panels were subjected to blast and fragmentation loadings in full-scale experiments, but experimental and analytical evaluation indicated that further refinement of the panels design would be recommended.

Panels comprised of honeycomb fiber reinforced polymer (FRP) laminations were evaluated to examine their utility as prefabricated fighting positions. The panels were tested for both their blast, and fragmentation mitigation ability. Static resistance functions were developed using a combination of analytical and laboratory procedures in order to obtain the panels response, the response was implemented into a single-degree of freedom (SDOF) dynamic analysis. Engineered analytical prediction models showed that the panels' response in live explosive blast testing could be predicted. Sand-filled wall panels were subjected to blast and fragmentation loadings in full-scale experiments, but experimental and analytical evaluation indicated that further refinement of the panels design would be recommended.

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.

A comprehensive analysis of data collected during an evaluation of blast energy-attenuation (EA) seats was conducted to review the performance of commercially available and prototype seat assets. This evaluation included twelve models of seats tested at two separate drop severities with three sizes of anthropomorphic test devices (ATDs) to develop test methodologies and assess the appropriateness of using injury assessment reference values (IARVs) for all occupant sizes.

A comprehensive analysis of data collected during an evaluation of blast energy-attenuation (EA) seats was conducted to review the performance of commercially available and prototype seat assets. This evaluation included twelve models of seats tested at two separate drop severities with three sizes of anthropomorphic test devices (ATDs) to develop test methodologies and assess the appropriateness of using injury assessment reference values (IARVs) for all occupant sizes.

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 blast volume), avoiding a costly detonation calculation for the initial explosive. Simulations show that accurate predictions of the initial gas overpressure away from the blast volume can be made with a one-dimensional spherically symmetric model. The one-dimensional solutions do not adequately capture the long-term pressure development within the enclosure. Instabilities in the contact discontinuity that require multi- dimensional simulations become important in driving the secondary Fireball reactions for TNT. Axisymmetric simulations are shown to be adequate in reproducing the long-term overpressure development in enclosures.

The Griffin 2.0 is a concept demonstrator that leveraged the structural design-for-blast methodologies, an Active Blast Mitigation System (ABMS), and a decoupled flooring system to demonstrate occupant survivability at large charge sizes. During a six month period, the team directed by TARDEC Ground Systems Survivability designed, fabricated, and evaluated three full scale demonstrators at elevated charge sizes. These tests included a baseline shot without countermeasures and two shots with counter measures, one at 150% MRAP Objective and one at 200% MRAP Objective. All tests were fully instrumented including ATDs and high speed video. The development process, test results, and recommended next steps will be presented.

The U.S. Army Corps of Engineers, Wilmington District (CESAW), has been tasked with deepening the existing shipping channel for the Port of Wilmington, NC. Because well cemented rock will be encountered, in places, in the deepening or widening of Wilmington harbor, blasting will be required to fracture rock for removal. Experience has shown that the water shock produced by underwater blasting operations can produce significant fish kills and pose a threat to other aquatic life. Several endangered species inhabit the Cape Fear River in and near the shipping channel. Because of this, minimizing the biological effects of the blasting is of great interest. Several water shock parameters have been associated, to varying degrees, with damage to aquatic life forms. Munday, et al (1986) provides an excellent overview of prior studies in this area. Peak water shock pressure is the parameter most commonly related to fish injury. However, Yelverton (1975) cites peak impulse as the most reliable parameter for predicting lethal ranges from underwater explosions. Peak energy flux density and the rate of pressure change have also been used as lethality predictors.

The recent trend of using fine water mist systems to replace the legacy HALON-1301 fire suppression systems warrants further study into other applications of the water mist systems. Preliminary research and investigation indicates that fine mists (20-25 micro droplet size) may reduce peak overpressures of a shock wave traveling through a space. Such pressure reductions could be used to mitigate the destructive effects of a shock wave (initiated by an explosive device) traveling through a structure. Currently these blast mitigation effects have only been demonstrated in small-scale shock tube tests and computer simulations. Uncertainty exists as to the scalability of such a system. The intention of this research is to investigate the applicability of such a blast mitigation system for shipboard use. Study into the degree of mitigation necessary to make a system practical for shipboard installation was conducted. In addition, a theoretical study of the mechanisms of blast mitigation using water mists was completed.

Studies have been performed aimed at an improved biomechanical understanding of blast injury with the goal of creating new technologies for the mitigation of auditory injury from blast. Fiber-optic pressure sensors were used to measure and correlate external auditory canal (EAC) and intracranial pressure profiles during blast events. A compact programmable bench top simulator system was used to recreate recorded blast pressure profiles and deliver simulated blast wave forms at high intensity to human temporal bones. Intra-cochlear pressures were measured during harmonic and impulse stimuli using off-the-shelf fiber-optic pressure probes. Intra-cochlear pressures and ossicular displacements were recorded simultaneously and compared with those predicted by an existing auditory injury model. Stapedial displacements as measured both by scanning and single axis LDV were found to exceed predicted values for extremely high pressure sand long durations characteristic of blast events. An electromechanical transducer was used to counteract ossicular movement resulting from harmonic and impulse stimuli, demonstrating feasibility of active mitigation of auditory injury from blast exposure. Future activities will be directed to improved auditory hazard models and development of active systems protective against blast injury.

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.

The blast mitigation design problem can be reduced sub problems as given. Each reduc tion in problem formulation feeds backs into the systgem above. Design objecti9ves for each sub problem are selected with the overall problem in mind.

The cooperative research and development agreement (CRADA) between the U.S. Army Tank Automotive Research Development and Engineering Center(TARDEC) Blast Mitigation Program and the Michigan Chapter of the National Defense Industrial Association (NDIA) was created based on the desire of both parties to collaborate to develop a practical and useable set of Blast Mitigation Program (BMP) design guidelines and standards. The effort focused on the following topics: occupant-centric design philosophy and terms, test procedures, Military performance specifications, and Military standard. The objective of this report is to document the BMP NDIA-MI CRADA activities and accomplishments from October 2014 through July 2017. During the three year period, the working group held 11 information exchange meetings where 20 briefs were presented and discussed. The NDIA-MI provided industry feedback on meeting topics. This work enabled the publications of 6 Military performance specification and 1 Military Standard, MIL-STD-3058, Occupant-Centric Protection for Military Ground Vehicles.

The recent trend of using fine water mist systems to replace the legacy HALON-1301 fire suppression systems warrants further study into other applications of the water mist systems. Preliminary research and investigation indicates that fine mists (20-25 micro droplet size) may reduce peak overpressures of a shock wave traveling through a space. Such pressure reductions could be used to mitigate the destructive effects of a shock wave (initiated by an explosive device) traveling through a structure. Currently these blast mitigation effects have only been demonstrated in small-scale shock tube tests and computer simulations. Uncertainty exists as to the scalability of such a system. The intention of this research is to investigate the applicability of such a blast mitigation system for shipboard use. Study into the degree of mitigation necessary to make a system practical for shipboard installation was conducted. In addition, a theoretical study of the mechanisms of blast mitigation using water mists was completed.

The recent trend of using fine water mist systems to replace the legacy HALON-1301 fire suppression systems warrants further study into other applications of the water mist systems. Preliminary research and investigation indicates that fine mists (20-25 micro droplet size) may reduce peak overpressures of a shock wave traveling through a space. Such pressure reductions could be used to mitigate the destructive effects of a shock wave (initiated by an explosive device) traveling through a structure. Currently these blast mitigation effects have only been demonstrated in small-scale shock tube tests and computer simulations. Uncertainty exists as to the scalability of such a system. The intention of this research is to investigate the applicability of such a blast mitigation system for shipboard use. Study into the degree of mitigation necessary to make a system practical for shipboard installation was conducted. In addition, a theoretical study of the mechanisms of blast mitigation using water mists was completed.

Hi, this is my first ever thing, Tarkov inspired Lantac Dragon Muzzle Break + the Blast Mitigation Device Should be fully functional, however, still untested. Threads onto standard airsoft -14mm threads.

The purpose of this MBA Project is to investigate and analyze different forms of blast mitigation technologies that provide safe temporary storage, and in the event of a detonation, provide protection measures for personnel and property. A comprehensive cost comparison of an Explosive Storage Magazine (ESM) and two alternatives: the Explosive Remnants of War Collection Point (ERW-CP) and Blastwrap are analyzed to determine future options. The goal of this project is to identify and document both cost comparisons, as well as requirement satisfaction for the safe and cost-effective temporary storage in troubled regions around the globe.

This phase of a multi-year project continues and expands studies aimed at an improved biomechanical understanding of blast injury and development of new technologies for the mitigation of auditory injury from blast. Off-the-shelf fiber optic pressure sensors were used to measure and correlate external auditory canal (EAC) and intracranial pressure profiles in a cadaver head during blast generated by a shock tube. These wave forms were recorded and reproduced through a programmable bench top blast simulator system. This system, developed in Year 1, was improved through use of a folded horn approximating an exponential reduction in cross-section. The improved system delivers simulated blast wave forms with peak pressures exceeding 180dBSPL to human temporal bone specimens. Intracochlear pressures were measured using during harmonic and impulse stimuli using off-the-shelf fiber optic pressure probes with polyimides heating to resist damage from extreme pressures. Ossicular and round window membrane displacements were recorded simultaneously using a scanning LDV. These results give system compliance and group delay for the propagating blast wave, and the rate of energy transfer to the cochlea. Those parameters will be used to improve auditory hazard models and develop active systems protective against blast injury.

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%.

The purpose of this MBA Project is to investigate and analyze different forms of blast mitigation technologies that provide safe temporary storage, and in the event of a detonation, provide protection measures for personnel and property. A comprehensive cost comparison of an Explosive Storage Magazine (ESM) and two alternatives: the Explosive Remnants of War Collection Point (ERW-CP) and Blastwrap are analyzed to determine future options. The goal of this project is to identify and document both cost comparisons, as well as requirement satisfaction for the safe and cost-effective temporary storage in troubled regions around the globe.

Polyurethane (PU) and poly(urethane urea) (PUU) based foams are currently being used as helmet pad materials. The U.S. Army still has a critical need for more efficient foam pad materials and designs that will provide warfighters with improved survivability against blast-induced traumatic brain injuries. Recent work has shown that tailoring the microphase-separated morphology is critical in controlling the high strain-rate mechanical deformation of bulk PU and PUU elastomers. In this work we focused on molecular influence and have successfully synthesized select model PU and PUU elastomers incorporating triptycene moieties. Adding triptycene-1,4 hydroquinone resulted in a 9C increase in the soft segment glass transition temperature compared to hydroquinone-containing PU. The 1,4-diaminotriptycene modified PUUs revealed improved tensile modulus and flow stress, which correlated well with the rubbery plateau modulus data determined from dynamic mechanical analysis and with the interdomain-correlation data from the small-angle X-ray scattering measurements.

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.

The purpose of this report was to assess current blast mitigation methods. Several blast mitigation walls were constructed and tested to analyze their performance against force protection criteria. The three blast mitigation walls that were tested included a Hesko-Bastion Concertainer Revetment Module, a Maccaferri FlexMac Revetment Module and a Reinforced Earth Wall using Tensar Geotextiles.

Since 1993, there have been numerous terrorist bombing attacks toward US facilities located on US or US controlled soil. This fact has motivated government organizations to take a hard look at how their facilities are constructed and what would be the consequences if a device were detonated in the vicinity to damage the facilities and injure or kill the occupants. The armed services have a large role to play in this effort, based on the number and location of installations they own or operate and the threat probability of a future attack. In response, private industry and government research facilities have developed a significant number of innovations in materials and methodologies for building construction and renovation that are now available in order to help mitigate the damage to facilities and occupants as a result of explosive blast. These innovations have been directly and indirectly prompted by the fear of other attacks on US soil, plus the recognition by private industry of the potential lucrative market. The armed services have made efforts to test and incorporate these materials and methodologies into their building codes and standards; the extent of these incorporations is the focus of this research.

Section 256 of the National Defense Authorization Act (NDAA) for Fiscal Year 2006 (FY06), Public Law 109-163, requires the Secretary of Defense to submit a report on the efforts and programs of the Department of Defense (DoD) relating to the prevention, mitigation, and treatment of blast injuries (see Appendix A, Acronyms). The report is to include the following elements of information: 1. A description of the activities undertaken under this section during the 2 years preceding the report to improve the prevention, mitigation, and treatment of blast injuries. 2. A consolidated budget presentation for DoD biomedical research efforts and studies related to blast injury for the 2 fiscal years following the year of the report. 3. A description of any gaps in the capabilities of the Department and any plans to address such gaps within biomedical research related to blast injury, blast injury diagnostic and treatment programs, and blast injury tracking and monitoring activities. 4. A description of collaboration, if any, with other departments and agencies of the federal government and with other countries during the 2 years preceding the report in efforts for the prevention, mitigation, and treatment of blast injuries. 5. A description of any efforts during the 2 years preceding the report to disseminate findings on the diagnosis and treatment of blast injuries through civilian and military research and medical communities. 6. A description of the status of efforts during the 2 years preceding the report to incorporate blast injury effects data into appropriate programs of the DoD and into the development of comprehensive force protection systems that are effective in confronting blast, ballistic, and fire threats.

Section 256 of the National Defense Authorization Act for Fiscal Year 2006, Public Law 109-163, provides that the Secretary of Defense shall submit a report on the efforts and programs of the Department of Defense (DoD) relating to the prevention, mitigation, and treatment of blast injuries. The report is to include the following elements of information: 1. A description of the activities undertaken under this section during the 2 years preceding the report to improve the prevention, mitigation, and treatment of blast injuries. 2. A consolidated budget presentation for DoD biomedical research efforts and studies related to blast injury for the 2 fiscal years following the year of the report. 3. A description of any gaps in the capabilities of the Department and any plans to address such gaps within biomedical research related to blast injury, blast injury diagnostic and treatment programs, and blast injury tracking and monitoring activities. 4. A description of collaboration, if any, with other departments and agencies of the Federal Government, and with other countries, during the 2 years preceding the report in efforts for the prevention, mitigation, and treatment of blast injuries. 5. A description of any efforts during the 2 years preceding the report to disseminate findings on the diagnosis and treatment of blast injuries through civilian and military research and medical communities. 6. A description of the status of efforts during the 2 years preceding the report to incorporate blast injury effects data into appropriate programs of the DoD and into the development of comprehensive force protection systems that are effective in confronting blast, ballistic, and fire threats.

Community reaction to noise from guns of various sizes is a continuing problem for Army training facilities. While the higher-frequency components of gun noise are substantially attenuated by the atmosphere, the low frequency components are often strong enough to cause annoyance or alarm in the surrounding community. It is desirable for training range managers to mitigate noise as much as possible at the source to avoid violating local noise regulations and risking the loss of training capacity. It has been suggested that a community in a specific direction from a firing point could be shielded significantly from gun noise by an acoustic shelter erected in the immediate vicinity of the gun. This report includes the results of mathematical analyses for two idealized shelter models-one designed to mitigate artillery and tank blast noise, the other to mitigate rifle fire noise. The results suggest that acoustic sheltering of this sort probably would not effectively shield a community from the noise of large guns but may work effectively to mitigate rifle noise.

Studies have been performed aimed at an improved biomechanical understanding of blast injury with the goal of creating new technologies for the mitigation of acoustic trauma. Fiber optic pressure sensors were used to measure pressures in cadaveric specimens during blast events. external auditory canal (EAC) pressure profiles were measured and correlated with intracranial pressure profiles. A shock tubes was used to produce blast waves and response pressures measured in acoustic manikins and cadaver heads. A portable, compact system was developed to recreate observed blast pressure profiles in human temporal bones. Ossicular displacements from simulated blast events were recorded with a scanning laser doppler vibrometer and compared with those predicted by an existing auditory injury model. Measured displacements and velocities of the ossicular chain were found to exceed predicted values for extremely high pressures and long durations characteristic of blast events. Future activities will assess the feasibility of mitigating acoustic injury in real time using an implantable system with a sensor and actuator.

Improvised Explosive Devices (IEDs) have evolved over the years to become one of the main causes of casualties and fatalities in recent conflicts. One area of research focuses on the improvement of blast attenuation using Shear Thickening Fluid (STF). The STF is a dilatant material, which displays non-Newtonian characteristics in its unique ability to transit from a low viscosity fluid to a high viscosity fluid. Although empirical research and computational models using the non-Newtonian flow characteristics of STF have been conducted to study the effects of STF on blast mitigation, to the author's best knowledge, no specific research has been performed to investigate the STF behavior by modeling and simulation of the interaction between the base flow and embedded rigid particles when subjected to shear stress. The model considered the Lagrangian description of the rigid particles and the Eulerian description of fluid flow. The numerical analysis investigated key parameters such as applied flow acceleration, particle distribution arrangement, volume concentration of particles, particle size, particle shape, and particle behavior in Newtonian and Non-Newtonian fluid base. The fluid-particle interaction model showed that the arrangement, size, shape and volume concentration of particles had a significant effect on the behavior of STF. Although non-conclusive, the addition of particles in Non-Newtonian fluids showed a promising trend of better shear thickening effect at high shear strain rates.

Occupants of buildings located in areas of high-level impulse noise usually report that the main annoyance factor is the rattle produced by house components upon vibration. This type of noise is associated with helicopter flybys and blast overpressure from artillery and other military training operations. Methods are needed for mitigating rattles both in existing structures and future construction. This report describes work on an experimental test facility being developed to study the impulse problem systematically and empirically. This facility simulates blast noise on a repeatable basis and allows alternative solutions to be evaluated. Initial data are evaluated to identify ways of improving the facility and test methods used. Keywords: Impulse noise, Buildings, Vibration, Test facilities.

Data analysis confirmed assumption that seat design plays a significant role in pelvis and lumbar outputs. Some of the current seats tested are able to adequately protect both the 50th male and 5th female. Energy attenuation performance varies as a factor of occupant size. Effectiveness of EA mechanism determined by lumbar compression. Future seat designs must account for a wide range of occupant weights. Further understanding of dynamic stroke properties of EA mechanisms and their effect on lumbar compression are key to improving seat designs. Future work: Continued interfacing with seat manufacturers to broaden occupant protection range. Record dynamic stroke on all drop tower tests to evaluate correlation between displacement rate and lumbar compression

The dynamic response of a free-standing plate subjected to a blast wave is studied numerically to investigate the effects of fluid-structure interaction (FSI) in blast wave mitigation. Previous work on the FSI between a blast wave and a free-standing plate (Kambouchev, N., et al., 2006, Nonlinear Compressibility Effects in Fluid-Structure Interaction and Their Implications on the Air-Blast Loading of Structures, J. Appl. Phys., 100(6), p. 063519) has assumed a constant atmospheric pressure at the back of the plate and neglected the resistance caused by the shock wave formation due to the receding motion of the plate. This paper develops an FSI model that includes the resistance caused by the shock wave formation at the back of the plate. The numerical results show that the resistance to the plate motion is especially pronounced for a light plate, and as a result, the previous work overpredicts the mitigation effects of FSI. Therefore, the effects of the interaction between the plate and the shock wave formation at the back of the plate should be considered in blast wave mitigation.

1. The TARDEC GSS Blast Mitigation team is responsible for System level Occupant Centric Safety system integration; 2. Designed systems are to protect the Occupant in Blast, Crash, Roll Over and other Injury Causing events; 3. Reducing occupant injury and decreasing the lethality associated with various threats; 4. Providing a system which can reliably and accurately activate systems such as Air Bags, Pyrotechnic Restraints and other potential emergency signaling systems during events; 5. Further expanding the development of System Level Occupant Protection

Improvised Explosive Devices (IEDs) have evolved over the years to become one of the main causes of casualties and fatalities in recent conflicts. One area of research focuses on the improvement of blast attenuation using Shear Thickening Fluid (STF). The STF is a dilatant material, which displays non-Newtonian characteristics in its unique ability to transit from a low viscosity fluid to a high viscosity fluid. Although empirical research and computational models using the non-Newtonian flow characteristics of STF have been conducted to study the effects of STF on blast mitigation, to the author's best knowledge, no specific research has been performed to investigate the STF behavior by modeling and simulation of the interaction between the base flow and embedded rigid particles when subjected to shear stress. The model considered the Lagrangian description of the rigid particles and the Eulerian description of fluid flow. The numerical analysis investigated key parameters such as applied flow acceleration, particle distribution arrangement, volume concentration of particles, particle size, particle shape, and particle behavior in Newtonian and Non-Newtonian fluid base. The fluid-particle interaction model showed that the arrangement, size, shape and volume concentration of particles had a significant effect on the behavior of STF. Although non-conclusive, the addition of particles in Non-Newtonian fluids showed a promising trend of better shear thickening effect at high shear strain rates.

Interest in periodic cellular metals has been driven by the structural and thermal management application potential of cellular metal sandwich structures. The research conducted in this program has led to the development of lattice structures which can be configured in the form of various core topologies of sandwich panels with high specific stiffness and strengths amenable for use in multifunctional applications (e.g. thermal dissipation, ballistic resistance). The applications of these lattice structures have been paced by two synergistic developments: the emergence of a micromechanics based approach for topology design, and scalable methods for the affordable manufacture of optimal lattices from high performance engineering materials.

This thesis investigates methods for mitigating the blast effects on the floorboard of passenger vehicles due to the detonation of explosives buried in water saturated sand underneath vehicles. The effects on floorboard acceleration of adding a vehicle hull, several types of floorboard bracing, the use of foam to fill the gap between the floorboard and hull, and the use of foam to isolate the floorboard from the hull. In addition, several tests have been conducted to examine how the distance of the floorboard from the ground affects the acceleration of the floorboard after the detonation. Testing showed that the addition of a hull to a vehicle, the hulls geometry, bracing of the floorboard, and increasing ground clearance all are able to help reduce floorboard accelerations. However, floorboard bracing had the potential to make accelerations much higher it is hit by the hull during testing. Foam filling between the hull and floorboard as well as a foam frame to isolate the floorboard from the hull did not have positive results. The primary method of investigation is differentiating a velocity profile found with the use of bar magnet velocity gages on the small scale model floorboard. Several other possible methods of investigation are discussed.

A new concept solution for improving blast survivability of the light tactical military vehicles is proposed and critically assessed using computational engineering methods and tools. The solution is inspired by the principle of operation of the rocket-engine nozzles, in general and the so called pulse-detonation rocket-engines, in particular. The proposed concept utilizes side vent channels attached to the V-shaped vehicle underbody whose geometry is optimized with respect to the attainment of the maximum downward thrust on the vehicle. In the course of the channel design optimization, analytical and computational analyses of supersonic flow (analogous to the one often used in the case of the pulse detonation engine) are employed. The preliminary results obtained reveal the beneficial effects of the side channels in reducing the blast momentum, although the extent of these effects is relatively small (2-4%).

Section 256 of the National Defense Authorization Act (NDAA) for Fiscal Year 2006, Public Law 109-163, provides that the Secretary of Defense shall submit a report on the efforts and programs of the Department of Defense (DoD) relating to the prevention, mitigation, and treatment of blast injuries. The report is to include the following elements of information: 1. A description of the activities undertaken under this section during the 2 years preceding the report to improve the prevention, mitigation, and treatment of blast injuries. 2. A consolidated budget presentation for DoD biomedical research efforts and studies related to blast injury for the 2 fiscal years (FY) following the year of the report. 3. A description of any gaps in the capabilities of the Department and any plans to address such gaps within biomedical research related to blast injury, blast injury diagnostic and treatment programs, and blast injury tracking and monitoring activities. 4. A description of collaboration, if any, with other departments and agencies of the federal government and with other countries during the 2 years preceding the report in efforts for the prevention, mitigation, and treatment of blast injuries. 5. A description of any efforts during the 2 years preceding the report to disseminate findings on the diagnosis and treatment of blast injuries through civilian and military research and medical communities. 6. A description of the status of efforts during the 2 years preceding the report to incorporate blast injury effects data into appropriate programs of the DoD and into the development of comprehensive force protection systems that are effective in confronting blast, ballistic, and fire threats.

This paper summarizes dynamic structural analysis and physical testing performed in order to develop energy absorbing connectors used for supporting pre-cast reinforced concrete panels subjected to blast waves. The work was conducted under the sponsorship of the Hoechst Celanese Chemical Group, Ltd., (Hoechst Celanese Corporation) who has authorized the release of this information. Reinforced concrete pre-cast panels can be used in new construction or as part of a building upgrade in situations where blast resistance is desired. Traditionally, these panels are mounted with fairly rigid supports and can be designed according to methods in TM 5-1300. The study described in this paper investigated the use of deformable, energy absorbing supports to achieve a reduction in panel damage and to reduce loads transferred to supporting frames. A specific energy absorbing mount was developed and tested under blast conditions. This paper includes a description of important nondimensional parameters relating blast loading to performance, application in design, and a summary of the blast testing conducted. The shock absorbing systems (panels plus mounts) were tested at quarter-scale, half-scale and full-scale for blast pressures up to 25 psi with durations out to 100 ms full-scale. There is good potential for application beyond these limits as well, in particular for higher pressures. The ability of the panels/connectors to resist load is more greatly challenged by long durations than by high pressures.

The effects water mist has on the overpressures produced by the detonation of 50 lb equivalent of high explosives (HE) TNT, Destex, and PBXN-109 in a chamber is reported. The overpressures for each charge density were measured with and without mist preemptively sprayed into the space. The impulse, initial blast wave, and quasi-static overpressure measured in the blast mitigation experiments were reduced by as much as (40%, 36%, and 35%) for 50 lbs TNT, (43%, 25%, and 33%) for 50 lbs TNT equivalent Destex, and (49%, 39%, and 41%) for 50 lbs TNT equivalent PBXN-109 when water mist was sprayed 60 seconds prior to detonation at a concentration of 70 g/m sup3 and droplet Sauter Mean Diameter (SMD) of 54 micrometer. These results suggest that current water mist technology is a potentially promising concept for the mitigation of overpressure effects produced from the detonation of high explosives.

A general process for optimization of a sandwich panel to minimize the effects of air blast loading is presented here. The panel geometry consists of two metal face plates with a crushable honeycomb or other type of core. Optimization is necessary as there is strong coupling between the several variables and the physics, which makes parametric studies relatively ineffective. Virtual testing is used to develop a homogenized model for the stress-strain curve of the honeycomb core, which can be readily applied to other types of cellular core. The homogenized model has been validated by comparison to existing results as well as to results from detailed finite element (FE) models. A design of experiments (DOE) based response surface optimization method in combination with LS-DYNA is used to minimize dynamic deflection or acceleration of the back face plate. Constraints on total mass and on plastic strain in the face plates are imposed. The mechanism of lowering the backface deflection is by increasing front face plate thickness which effectively distributes the blast load to a larger area of the core and avoids local concave deformation of the front face plate. Further, core depth is increased which increases panel stiffness. For acceleration minimization results again produce a stiffer front face plate, but accompanied by a sufficiently soft core. The mechanism of lowering the backface acceleration is by absorbing energy with low transmitted stress. A clear cut comparison between monolithic metal plates and sandwich plates, for the same loading and failure criteria, is presented here.

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.

Computational methods are currently available to perform vulnerability assessments of conventional structures and fixed facilities that are exposed to the effects of large-yield blast events. However, the same capabilities do not exist for expeditionary structures and field fortifications, which are integral parts of current US military base camps. Therefore, the United States Army Corps of Engineers (USACE), Engineer Research and Development Center (ERDC), has begun a research and development initiative directed towards developing this type of vulnerability assessment capability for field fortifications. As a part of the experimental program, attention will also be focused on identification of field expedient methods to modify these structures for the purpose of further protection from blast effects. Initial efforts, begun in FY 2004, are focused on methodology development and gathering of a representative experimental data set that would be required to support computational assessments. The experimental processes used to gather data are tri-fold, and include high-performance computing simulations, scaled modeling and full scale validations. The results of initial activities in each of these areas are presented herein.

This work is based on a current project funded by the United States Army Small Business Innovation Research (SBIR) Program and is being conducted with the Tank Automotive Research, Development and Engineering Center (TARDEC) Ground Systems Survivability (GSS) Team and Paradigm Research and Engineering. The focus of this project is to develop an advanced and novel sensing and activation strategy for Pyrotechnic Restraint Systems, Air Bags and other systems that may require activation. The overriding technical challenge is to activate these systems to effectively protect the Soldier during blast events in addition to Crash, Rollover and Other Injury Causing events. These activations of Pyrotechnic systems must occur in fractions of milliseconds as compared to typical automotive crashes. By investigating systems outside of typical accelerometer based applications and activations, the potential exists to exploit systems that require little power, are self-contained and provide the required output for the desired result. As such Constant-Flux Magnetostrictive Sensors shall be evaluated in a self-contained environment to provide the output during these events. By activating the Pyrotechnic Restraint Systems and Air Bag Systems early in Blast Events, the systems can Restrain the Occupant and provide flail protection from surfaces within the vehicle. As the system is developed various test scenarios will be introduced to activate these systems and design a robust sensing and activating strategy.

Blast energy-attenuation (EA) seats, although not new to the market, have not been fully characterized with respect to energy attenuation capability and the resulting effects on occupant protection. The U.S. Army - Tank Automotive Research, Development and Engineering Center (TARDEC) Ground Systems Survivability (GSS) Interiors Seat Team tested and evaluated EA seats over a one-year period using a drop tower test method. Data from three different anthropomorphic test devices (ATDs, or crash test dummies) was recorded on tests in twelve different seat styles that were dropped at two different heights on the drop tower. The data was checked for quality and anomalies, and a method was developed to display all of the data in an easily referenced and understood format. This data was compared to the Army Research Lab / Survivability / Lethality / Analysis Directorate (ARL/SLAD) crew injury criteria for accelerative events and the enhanced injury assessment reference values (e-IARVs) for the 5th percentile female, 50th percentile male, and 95th percentile male determined from existing biomedical literature by the Occupant Centric Platform (OCP) Technology Enabled Capability Demonstration (TECD) program's Enhanced Injury Assessment Reference Value Working Group as a pass/fail threshold. An evaluation of the data allowed the assessment of commercially available and prototype seats to understand the performance of the seats with varying occupant weights and to evaluate the test methodology and occupant injury assessment performance criteria. The results from this data review afforded a better understanding of how seat design affects performance with varying occupant size, including weight and stature. The analysis also provided the TARDEC Seat Team with an overview of general trends and lessons learned.