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Modeling and Simulating Blast Effects on Electric Substations

Description: A software simulation tool was developed at the Idaho National Laboratory to estimate the fragility of electric substation components subject to an explosive blast. Damage caused by explosively driven fragments on a generic electric substation was estimated by using a ray-tracing technique to track and tabulate fragment impacts and penetrations of substation components. This technique is based on methods used for assessing vulnerability of military aircraft and ground vehicles to explosive blasts. An open-source rendering and ray-trace engine was used for geometric modeling and interactions between fragments and substation components. Semi-empirical material interactions models were used to calculate blast parameters and simulate high-velocity material interactions between explosively driven fragments and substation components. Finally, a Monte Carlo simulation was added to model the random nature of fragment generation allowing a skilled analyst to predict failure probabilities of substation components.
Date: May 1, 2009
Creator: Roybal, Lyle G.; Jeffers, Robert F.; McGillivary, Kent E.; Paul, Tony D. & Jacobson, Ryan
Partner: UNT Libraries Government Documents Department

Test of Dribble-Type Structures

Description: From introduction: This task was conducted at Project Shoal to observe the response of simulated Dribble area building foundations to ground motions induced by a nuclear detonation.
Date: October 21, 1964
Partner: UNT Libraries Government Documents Department

Effects of Various Blowout Panel Configurations on the Structural Response of Los Alamos National Laboratory Building 16-340 to Internal Explosions

Description: Abstract: The risk of accidental detonation is present whenever any type of high explosives processing activity is performed. These activities are typically carried out indoors to protect processing equipment from the weather and to hide possibly secret processes from view. Often, highly strengthened reinforced concrete buildings are employed to house these activities. These buildings may incorporate several design features, including the use of lightweight frangible blowout panels, to help mitigate blast effects. These panels are used to construct walls that are durable enough to withstand the weather, but are of minimal weight to provide overpressure relief by quickly moving outwards and creating a vent area during an accidental explosion. In this study the behavior of blowout panels under various blast loading conditions was examined. External loadings from explosions occurring in nearby rooms were of primary interest. Several reinforcement systems were designed to help blowout panels resist failure from external blast loads while still allowing them to function as vents when subjected to internal explosions. The reinforcements were studied using two analytical techniques, yield-line analysis and modal analysis, and the hydrocode AUTODYN. A blowout panel reinforcement design was created that could prevent panels from being blown inward by external explosions. This design was found to increase the internal loading of the building by 20%, as compared with nonreinforced panels. Nonreinforced panels were found to increase the structural loads by 80% when compared to an open wall at the panel location.
Date: September 2005
Creator: Wilke, Jason P.; Pohs, Keith G. & Plumlee, Deidré A.
Partner: UNT Libraries Government Documents Department

Approximate Near-Field Blast Theory: A Generalized Approach

Description: A method for analyzing strong shock waves in arbitrary one-dimensional geometry is presented. An approximation to classical Taylor-Sedov theory is extended to the near-field case where source mass is not negligible, accounting for differences in the chemical properties of the source mass and ambient medium. Results from example calculations are compared with previously published analytical formulae.
Date: October 25, 1999
Creator: Hutchens, G.J.
Partner: UNT Libraries Government Documents Department

Modeling Coal Seam Damage in Cast Blasting

Description: A discrete element computer program named DMC_BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting (Preece & Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions. DMC_BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993). Coal seam chilling refers to the shattering of a significant portion of the coal leaving unusable fines. It is also refereed to as coal damage. Chilling is caused during a blast by a combination of explosive shock energy and movement of the adjacent rock. Chilling can be minimized by leaving a buffer zone between the bottom of the blastholes and the coal seam or by changing the blast design to decrease the powder factor or by a combination of both. Blast design in coal mine cast blasting is usually a compromise between coal damage and rock fragmentation and movement (heave). In this paper the damage to coal seams from rock movement is examined using the discrete element computer code DMC_BLAST. A rock material strength option has been incorporated into DMC_BLAST by placing bonds/links between the spherical particles used to model the rock. These bonds tie the particles together but can be broken when the tensile, compressive or shear stress in the bond exceeds the defined strength. This capability has been applied to predict coal seam damage, particularly at the toe of a cast blast where drag forces exerted by movement of the overlying rock can adversely effect the top of the coal at the bench face. A simulation of coal mine cast blasting has been performed with special attention being paid to the strength of the coal and its behavior at t he bench face during movement of the overlying material.
Date: November 23, 1998
Creator: Chung, S.H. & Preece, D.S.
Partner: UNT Libraries Government Documents Department

Blast wave diagnostic for the petawatt laser system

Description: We report on a diagnostic to measure the trajectory of a blast wave propagating through a plastic target 400 {micro}m thick. This blast wave is generated by the irradiation of the front surface of the target with {approximately} 400 J of 1 {micro}m laser radiation in a 20 ps pulse focused to a {approximately} 50 {micro}m diameter spot, which produces an intensity in excess of 1O{sup 18} W/cm{sup 2}. These conditions approximate a point explosion and a blast wave is predicted to be generated with an initial pressure nearing 1 Gbar which decays as it travels approximately radially outward from the interaction region We have utilized streaked optical pyrometry of the blast front to determine its time of arrival at the rear surface of the target Applications of a self-similar Taylor-Sedov blast wave solution allows the amount of energy deposited to be estimated The experiment, LASNEX design simulations and initial results are discussed.
Date: June 3, 1998
Creator: Budil, K. S., LLNL
Partner: UNT Libraries Government Documents Department

Behavior and evaluation of an existing underground structure subjected to impulsive loads from an internal explosion

Description: An explosion is the result of a rapid chemical reaction which generates transient air pressure waves called blast waves. There has been much research on the processes of blast wave formation, propagation of blast waves, and quantification of the incident and reflected blast overpressures. The magnitude of blast overpressure, in a partially vented environment, is mainly a function of the type and quantity of detonating material, the amount of available venting, and the orientation and configuration of the reflecting surfaces. In addition to blast overpressure, an explosion can also generate high energy missiles (such as fragments), shock loads, and rapid rise of temperature in the confined space. This study concentrates on the effects of blast overpressure on a 40 feet diameter reinforced concrete cylinder with a hemispherical dome roof, supported on a 3 feet thick reinforced concrete pad, and buried under a minimum of 15 feet of soil used for radiation shielding at the top of the dome. The scope of this study is to determine whether the structure can withstand the blast overpressure generated by the postulated explosion without exceeding allowable design criteria.
Date: December 1, 1997
Creator: Keller, M.D. & Khan, P.K.
Partner: UNT Libraries Government Documents Department

Gated IR Images of Shocked Surfaces

Description: Gated infrared (IR) images have been taken of a series of shocked surface geometries in tin. Metal coupons machined with steps and flats were mounted directly to the high explosive. The explosive was point-initiated and 500-ns to 1-microsecond-wide gated images of the target were taken immediately following shock breakout using a Santa Barbara Focalplane InSb camera (SBF-134). Spatial distributions of surface radiance were extracted from the images of the shocked samples and found to be non-single-valued. Several geometries were modeled using CTH, a two-dimensional Eulerian hydrocode.
Date: June 1, 2001
Creator: Lutz, S. S.; Turley, W. D.; Rightley, P. M. & Primas, L. E.
Partner: UNT Libraries Government Documents Department

Detonation spreading in fine TATBs

Description: A test has been devised that permits rapid evaluation of the detonation-spreading (or corner-turning) properties of detonations in insensitive high explosives. The test utilizes a copper witness plate as the medium to capture performance data. Dent depth and shape in the copper are used as quantitative measures of the detonation output and spreading behavior. The merits of the test are that it is easy to perform with no dynamic instrumentation, and the test requires only a few grams of experimental explosive materials.
Date: December 31, 1998
Creator: Kennedy, J.E.; Lee, K.Y.; Spontarelli, T. & Stine, J.R.
Partner: UNT Libraries Government Documents Department

Report on the suitability of Class 6, U.S. government security repositories for the storage of small quantities of high explosives

Description: The Explosives Review Committee initiated a study into the safety aspects of the common practice of storing small amounts (< 10 grams per drawer) of high explosives in safes. Although storage of HE in older asbestos lined safes was permitted, the newer style Class 6 Security safes are an unacceptable repository for even very small amounts of HE without the use of a blast mitigating insert. The authors have developed a drawer liner in the form of a laminated Lexan, foam, plywood box that will withstand the blast and contain the fragments from up to 10 grams of high explosives. This liner will fit into the drawer of any existing safe. The liner will provide blast and fragment protection, and the safe will provide security protection. This report describes the testing of modern safes and the performance of the liner insert.
Date: March 1, 1998
Creator: Harry, H. H. & Murk, D.
Partner: UNT Libraries Government Documents Department

Dynamics of window glass fracture in explosions

Description: An exploratory study was conducted under the Architectural Surety Program to examine the possibility of modifying fracture of glass in the shock-wave environment associated with terrorist bombings. The intent was to explore strategies to reduce the number and severity of injuries resulting from those attacks. The study consisted of a series of three experiments at the Energetic Materials Research and Testing Center (EMRTC) of the New Mexico Institute of Mining and Technology at Socorro, NM, in which annealed and tempered glass sheets were exposed to blast waves at several different levels of overpressure and specific impulse. A preliminary assessment of the response of tempered glass to the blast environment suggested that inducing early failure would result in lowering fragment velocity as well as reducing the loading from the window to the structure. To test that possibility, two different and novel procedures (indentation flaws and spot annealing) were used to reduce the failure strength of the tempered glass while maintaining its ability to fracture into small cube-shaped fragments. Each experiment involved a comparison of the performance of four sheets of glass with different treatments.
Date: May 1, 1998
Creator: Beauchamp, E.K. & Matalucci, R.V.
Partner: UNT Libraries Government Documents Department

Measuring explosive non-ideality

Description: The sonic reaction zone length may be measured by four methods: (1) size effect, (2) detonation front curvature, (3) crystal interface velocity and (4) in-situ gauges. The amount of data decreases exponentially from (1) to (4) with there being almost no gauge data for prompt detonation at steady state. The ease and clarity of obtaining the reaction zone length increases from (1) to (4). The method of getting the reaction zone length, &lt;x{sub e}&gt;, is described for the four methods. A measure of non-ideality is proposed: the reaction zone length divided by the cylinder radius. N = &lt;x{sub e}&gt;/R{sub o}. N = 0 for true ideality. It also decreases with increasing radius as it should. For N &lt; 0.10, an equilibrium EOS like the JWL may be used. For N &gt; 0.10, a time-dependent description is essential. The crystal experiment, which measures the particle velocity of an explosive-transparent material interface, is presently rising in importance. We examine the data from three experiments and apply: (1) an impedance correction that transfers the explosive C-J particle velocity to the corresponding value for the interface, and (2) multiplies the interface time by 3/4 to simulate the explosive speed of sound. The result is a reaction zone length comparable to those obtained by other means. A few explosives have reaction zones so small that the change of slope in the particle velocity is easily seen.
Date: February 17, 1999
Creator: Souers, P C
Partner: UNT Libraries Government Documents Department

Investigations on deflagration to detonation transition in porous energetic materials. Final report

Description: The research carried out by this contract was part of a larger effort funded by LANL in the areas of deflagration to detonation in porous energetic materials (DDT) and detonation shock dynamics in high explosives (DSD). In the first three years of the contract the major focus was on DDT. However, some researchers were carried out on DSD theory and numerical implementation. In the last two years the principal focus of the contract was on DSD theory and numerical implementation. However, during the second period some work was also carried out on DDT. The paper discusses DDT modeling and DSD modeling. Abstracts are included on the following topics: modeling deflagration to detonation; DSD theory; DSD wave front tracking; and DSD program burn implementation.
Date: July 1999
Creator: Stewart, D. S.
Partner: UNT Libraries Government Documents Department

Reliable estimation of shock position in shock-capturing compressible hydrodynamics codes

Description: The displacement method for estimating shock position in a shock-capturing compressible hydrodynamics code is introduced. Common estimates use simulation data within the captured shock, but the displacement method uses data behind the shock, making the estimate consistent with and as reliable as estimates of material parameters obtained from averages or fits behind the shock. The displacement method is described in the context of a steady shock in a one-dimensional lagrangian hydrodynamics code, and demonstrated on a piston problem and a spherical blast wave.The displacement method's estimates of shock position are much better than common estimates in such applications.
Date: January 1, 2008
Creator: Nelson, Eric M
Partner: UNT Libraries Government Documents Department

Controlled blasting and its implications for the NNWSI project exploratory shaft

Description: This report reviews controlled blasting techniques for shaft sinking. Presplitting and smooth blasting are the techniques of principal interest. Smooth blasting is preferred for the Nevada Nuclear Waste Storage Investigations exploratory shaft. Shaft damage can be monitored visually or by peak velocity measurements and refractive techniques. Damage into the rock should be limited to 3 ft. 40 refs., 22 figs., 7 tabs.
Date: September 1, 1987
Creator: Van Eeckhout, E.M.
Partner: UNT Libraries Government Documents Department

Lamb waves from airborne explosion sources: Viscous effects and comparisons to ducted acoustic arrivals

Description: Observations of large explosions in the atmosphere at long range are dominated by a leading pulse of large amplitude and long period that is often followed by a series of higher frequency impulses usually of smaller amplitude. This description can be interpreted using linearized acoustic-gravity wave theory in terms of a Lamb wave arrival followed by ducted acoustic and/or gravity waves. This pattern of arrivals is not the same at all ranges nor is it independent of the source energy or of the altitude of the source. Earlier, Pierce, using an isothermal, windless atmospheric model, theoretically formulated the distances beyond which the Lamb wave would just be discernible and also where it would dominate the arriving signals for a specified explosion source. In this work the authors have evaluated these distances for the cases of both an inviscid and a viscous fluid for the source energies of interest to the CTBT (Comprehensive Test Ban Treaty) R and D work at Los Alamos. Although the inviscid results are analytic, the fully viscous solutions are iterative. For the inviscid solutions, the authors find that the Lamb wave domination distance is proportional to wave frequency at frequencies large with respect to the acoustic waveguide cut-off frequency. Under similar conditions they also find that the computed distances are linearly proportional to the source height. At 1 Hz for example, the Lamb wave must propagate about 200 km before having a significant amplitude. For a viscous fluid they found slight increases in the distances compared to an inviscid fluid with the lower frequencies, near the acoustic cut-off frequency, exhibiting the greatest changes. During the period from 1981--1994 at Los Alamos, they have also observed infrasound from eight point source, near-surface ANFO explosions at White Sands Missile Range events even though the ducted acoustic waves were ...
Date: December 31, 1996
Creator: Revelle, D.O. & Whitaker, R.W.
Partner: UNT Libraries Government Documents Department

LABQUARK containment data report

Description: The LABQUARK event was detonated in hole U19an of the Nevada Test Site. Detonation time was 15:30 PDT on September 30, 1986. A surface collapse occurred at about 3 hour, 51 minutes after detonation. No measurements of the crater dimensions were made, however, visual estimates of the crater depth varied from 1 to 4 feet depending upon the observer. No radiation arrivals were detected above ground and the LABQUARK event containment was satisfactory.
Date: May 1, 1995
Creator: Hudson, B.; Stubbs, T. & Heinle, R.
Partner: UNT Libraries Government Documents Department

Palanquin post-shot exploration

Description: This report defines the plan and purpose for the Palanquin post-shot exploration program. This program is necessary to obtain data that is needed in the understanding of the Palanquin experiment, and related explosion phenomena, which can be obtained in no other way.
Date: July 28, 1965
Creator: Meyer, L.; Hansen, S. & Toman, J.
Partner: UNT Libraries Government Documents Department

Measurements of a 1/4-scale model of an explosives firing chamber

Description: In anticipation of increasingly stringent environmental regulations, Lawrence Livermore National Laboratory (LLNL) proposes to construct a 60-kg firing chamber to provide blast-effects containment for most of its open-air, high-explosive, firing operations. Even though these operations are within current environmental limits, containment of the blast effects and hazardous debris will further drastically reduce emissions to the environment and minimize the generated hazardous waste. The major design consideration of such a chamber is its overall structural dynamic response in terms of long-term containment of all blast effects from repeated internal detonations of high explosives. Another concern is how much other portions of the facility outside the firing chamber must be hardened to ensure personnel protection in the event of an accidental detonation while the chamber door is open. To assess these concerns, a 1/4-scale replica model of the planned contained firing chamber was designed, constructed, and tested with scaled explosive charges ranging from 25 to 125% of the operational explosives limit of 60 kg. From 16 detonations of high explosives, 880 resulting strains, blast pressures, and temperatures within the model were measured to provide information for the final design. Factors of safety for dynamic yield of the firing chamber structure were calculated and compared to the design criterion of totally elastic response. The rectangular, reinforced-concrete chamber model exhibited a lightly damped vibrational response that placed the structure in alternating cycles of tension and compression. During compression, both the reinforcing steel and the concrete remained elastic.
Date: January 27, 1995
Creator: Pastrnak, J. W.; Baker, C. F. & Simmons, L. F.
Partner: UNT Libraries Government Documents Department

Seismic induced architectural damage to masonry structures at Mercury, Nevada

Description: Selected masonry structures in Mercury, Nevada, were inspected for cracking before and after certain nuclear detonations and during periods of no significant nuclear activity. Detonations gave peak particle velocities whose magnitudes approached those experienced in Mississippi during the Salmon event. Findings include evidence that peak particle velocities of 0. 1 to 0. 3 cm/sec caused more cracking than normal; however, cracks at these low levels of motion are not more severe than those occurring naturally.
Date: June 1, 1966
Creator: Wall, J. F., Jr.
Partner: UNT Libraries Government Documents Department

LABAN containment data report

Description: The LABAN event was detonated in hole U2ff of the Nevada Test Site. The device had a depth-of-burial of 326 m in the alluvium of Area 4, about 240 m above the standing water level (SWL). Stemming of the 2.44 m diameter emplacement hole followed the plan. A log of the stemming operations was maintained by Holmes and Narver. Detonation time was 06:33 PDT on August 3, 1983. About 75 minutes later the chimney began collapsing to the surface. A major collapse event occurred 5 minutes later with episodes continuing for the next 20 minutes. No radiation arrivals were detected in the emplacement hole at depths less than 106 m and the LABAN containment was considered successful.
Date: May 1, 1995
Creator: Stubbs, T. & Heinle, R.
Partner: UNT Libraries Government Documents Department