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This TOP provides tests for evaluating damage to combat vehicles (self-propelled artillery and assault vehicles) and their components by muzzle blast. Muzzle blast overpressure can affect the structural integrity of weight-restric...
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This TOP provides tests for evaluating damage to combat vehicles (self-propelled artillery and assault vehicles) and their components by muzzle blast. Muzzle blast overpressure can affect the structural integrity of weight-restricted vehicles. Measuring blast pressure loading and resultant stress can provide a basis for predicting damage that will occur when the weapon is fired. Two methodologies are presented in this TOP to determine the effects of blast overpressure on a test vehicle. The first methodology assesses combined forces of recoil energy and blast overpressure. This is accomplished by firing an instrumented test vehicle and measuring the resultant strain, acceleration, and blast overpressure effects imparted to the vehicle. The second methodology separates the effects of blast overpressure from recoil forces. This is accomplished by firing an instrumented test vehicle and measuring the resultant strain, acceleration, and blast overpressure. Then, fire a second vehicle, identical to the first, from a position to impart a worst case blast overpressure wave onto the test vehicle; measure the blast overpressure. These tests will yield data describing the pure blast effects and blast/recoil effects upon the test vehicle. (fr)
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It is likely that the mild TBI and cognitive impairments observed among many of the troops returning from OIF and OEF result from repeated exposures to blast overpressure. Although the clinical symptoms of concussion are typically...
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It is likely that the mild TBI and cognitive impairments observed among many of the troops returning from OIF and OEF result from repeated exposures to blast overpressure. Although the clinical symptoms of concussion are typically transient, there is both a cumulative risk for persistent damage due to repeated concussions, and a post-concussion period of greatest vulnerability to a second impact. Specific risk assessments and guidelines should be established for exposure to blast overpressure. We are using a preclinical model of blast overpressure in rats to investigate the cumulative effects of multiple blast exposures on neurologic status, neurobehavioral function, and brain histopathological endpoints. Repeated exposures to blast overpressure with varied inter-blast intervals are used to characterize and define the temporal window of brain vulnerability to repeated blast overpressure. We anticipate that these data will provide a critical first step in establishing rational risk guidelines and developing mitigation strategies.
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DALOC SHELTEC AB M1000 blast valve has been tested for blast load by FOA in211 Maersta. The test shows that the blast valve resist the decided blast wave of 211 1.86 MPa maximum reflected pressure and 5.38 ms duration.
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Blast-induced ground vibrations from surface coal mine, quarry, and construction blasting were measured and analyzed for frequency content and duration characteristics. Eighteen commercially available ground vibration measurement ...
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Blast-induced ground vibrations from surface coal mine, quarry, and construction blasting were measured and analyzed for frequency content and duration characteristics. Eighteen commercially available ground vibration measurement systems were evaluated in the field and laboratory for linearity, accuracy, and crosstalk. Buried, surface, and sandbagged transducer placement methods were compared, along with peak and vector-sum measurements. The recommended minimum frequency ranges for ground vibration instrumentation are 2 to 150 Hz for coal mine and quarry blasting, and 5 to 200 Hz for construction and excavation blasting. When higher or lower frequency vibrations are possible, as in construction blasting or for a quarry shot close to a residence, care should be taken to insure proper choices of instrumentation and vibration criteria. Several instruments operating in these ranges are available, and all but one of the seismographs tested fell within plus or minus-dB accuracy limits (+ 41 pct, - 29 pct). Waveform recordings of all three ground vibration components are recommended as the peak amplitude and frequency may vary among the three. Peak or vector-sum readings are adequate if only amplitude levels are desired. The soil density matched box should be anchored or buried, particularly for high-frequency, high-amplitude construction blasting.
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Objectives: Increased use of explosive devices in recent military conflicts have resulted in, blast overpressure is the primary cause of traumatic brain injury among combat veterans (Owens, 2008). Primary blast injury has been stu...
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Objectives: Increased use of explosive devices in recent military conflicts have resulted in, blast overpressure is the primary cause of traumatic brain injury among combat veterans (Owens, 2008). Primary blast injury has been studied extensively in air-c
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The Bureau of Mines has investigated techniques and instrumentation that measure accurately the airblast overpressures from surface mine blasting. The results include equivalencies between broadband research instrumentation and co...
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The Bureau of Mines has investigated techniques and instrumentation that measure accurately the airblast overpressures from surface mine blasting. The results include equivalencies between broadband research instrumentation and commercially available impulse precision sound level meters measuring: root-means-square, peak, fast, slow, impulse, A and C weighting, C-weighted sound exposure level (CSEL), and 'linear' (flat) response. These values were obtained from field measurements and broadband FM tape recordings of production blast at area and contour coal mines, limestone quarries, and iron mines. Frequency response was determined for 14 commercial systems.
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Program material consists of 11 training booklets (modules): Introductory module; Preparing/using a blast design; Handling/transportation/storing explosives/blasting agents/other blasting supplies/materials; Using electric firing ...
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Program material consists of 11 training booklets (modules): Introductory module; Preparing/using a blast design; Handling/transportation/storing explosives/blasting agents/other blasting supplies/materials; Using electric firing system test equipment/blasting machines; Loading boreholes; Using a detonating cord firing system; Using an electric firing system; Using a nonel firing system; Using the Hercudet non-electric delay blasting cap system; Detecting and handling misfires; Secondary blasting. Also, a module pretest is available and if successful, the module can be omitted. The report covers Module II.
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Numerical simulations are used to investigate the transient shock physics and loads that arise when a non-lethal blast wave impinges upon an unprotected human head located atop a complete, anatomically correct body. Two non-leth...
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Numerical simulations are used to investigate the transient shock physics and loads that arise when a non-lethal blast wave impinges upon an unprotected human head located atop a complete, anatomically correct body. Two non-lethal, hemispherical blast waves, each of which corresponds to the detonation of a high explosive charge, are considered for configurations in which the body is facing either towards or away from the explosive charge. The shock wave interactions that arise when the blast wave impinges upon the head are characterized and correlated with the resulting transient surface pressures, forces, and moments on the head. The transient forces and moments are compared to those of an analytical model based upon the work of Zaslavskii, et al. [J. App. Mech. Tech. Phys., 42(3):533-537, 2001], who derived expressions for the drag force on an arbitrary-shaped body due to the interaction with a weak to moderate strength shock wave. The results of this study indicate that Zaslavskii, et al.’s model provides a straightforward means of estimating the transient loads on the head during a non-lethal blast wave interaction
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DALOC SHELTEC AB M1000 blast valve has been tested for blast load by FOA in211 Marsta. The test shows that the blast valve resists the, by the client, decided 211 blast load of 1.86 Maa maximum reflected pressure and an impulse de...
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DALOC SHELTEC AB M1000 blast valve has been tested for blast load by FOA in211 Marsta. The test shows that the blast valve resists the, by the client, decided 211 blast load of 1.86 Maa maximum reflected pressure and an impulse density of 5.0 211 kPas within 9.0 ms duration, and with a maximum let through impulse behind the 211 blast valve of 48.3 kPa-ms measured side-on.
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The blast mitigation potential of architecturally appealing alternatives to blastwalls is investigated numerically. Seven different designs are compared. It is found that for some of these, the maximum pressure is comparable to us...
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The blast mitigation potential of architecturally appealing alternatives to blastwalls is investigated numerically. Seven different designs are compared. It is found that for some of these, the maximum pressure is comparable to usual, closed wallwalls, and the maximum impulse approximately 50% higher. This would indicate that such designs could offer an alternative blast mitigation device that city planners may find acceptable.
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