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Experimental Investigations Concerning the Limits of Detonation in Gaseous Mixtures: Part 2

Description: Memorandum presenting an investigation concerning the limits of detonation in gaseous mixtures. In regards to the results, by progressive dilution of the explosive, the course of the chemical reaction becomes slower and slower until finally the transformation within the reaction zone becomes so slow that it is not there completed.
Date: February 1930
Creator: Wendlandt, Rudolf
Partner: UNT Libraries Government Documents Department

High explosive violent reaction (HEVR) from slow heating conditions

Description: The high explosives (HEs) developed and used at the Los Alamos National Laboratory are designed to be insensitive to impact and thermal insults under all but the most extreme conditions. Nevertheless, violent reactions do occasionally occur when HE is involved in an accident. The HE response is closely dependent on the type of external stimulus that initiates the reaction. For example, fast heating of conventional HE will probably result in fairly benign burning, while long-term, slow heating of conventional HE is more likely to produce an HEVR that will do much more damage to the immediate surroundings. An HEVR (High Explosive Violent Reaction) can be defined as the rapid release of energy from an explosive that ranges from slightly faster than a deflagration (very rapid burning) to a reaction that approaches a detonation. A number of thermal analyses have been done to determine slow heat/cook-off conditions that produce HE self-heating that can build up to a catastrophic runaway reaction. The author specifies the conditions that control reaction violence, describes experiments that produced an HEVR, describes analyses done to determine a heating rate threshold for HEVR, and lists possible HEVR situations.
Date: March 1, 1999
Creator: Vigil, A.S.
Partner: UNT Libraries Government Documents Department

Numerical modeling of shear band formation in PBX-9501

Description: Adiabatic shear bands in explosives may be a source of ignition and lead to detonation. Three possible mechanisms leading to shear banding are (1) thermal softening, (2) mechanical softening due to microcracking, and (3) quasi-granular constitutive response. The latter two mechanisms can lead to shear band formation in PBXs at nominal strains much smaller than those required for the thermal softening mechanism. The authors study formation of shear bands with models including the latter two mechanisms under unconfined compression. Statistical variation of numerical results is similar to that observed in some experiments. However, the commonly used methods of calibrating constitutive models can be misleading because of effects due to shear band formation. One model currently being used for studies of shear band formation and ignition in PBX 9501 was calibrated in this way and may need re-examination.
Date: December 31, 1998
Creator: Dey, T.N. & Kamm, J.R.
Partner: UNT Libraries Government Documents Department

Statistical analysis of high explosive detonation data

Description: This study investigates the detonation behavior of two different high explosive compounds, PBX 9404 and PBX 9502. One reason these two high explosives were selected is because data is abundant relative to other types of high explosives. Statistical analysis of data for two different high explosives was performed. The goal of the analysis was to determine how the probability of detonation varies for different run lengths and pressures.
Date: May 10, 1998
Partner: UNT Libraries Government Documents Department


Description: The Brookhaven National Laboratory (BNL) High-Temperature Combustion Facility (HTCF) was used to perform hydrogen deflagration and detonation experiments at temperatures to 650 K. Safety features that were designed to ensure safe and reliable operation of the experimental program are described. Deflagration and detonation experiments have been conducted using mixtures of hydrogen, air, and steam. Detonation cell size measurements were made as a function of mixture composition and thermodynamic gas conditions. Deflagration-to-detonation transition experiments were also conducted. Results of the experimental program are presented, and implications with respect to hydrogen safety are discussed.
Date: June 11, 2000
Partner: UNT Libraries Government Documents Department

Explosive morphology from fractal analysis of micrographs

Description: The effect of particle size on the details of the initiation and detonation of condensed explosives has long been known. The effect of the three-dimensional nature of explosive particles as a neat pressings (with voids), or as dispersed in a second (or third) phase (with or without voids), has been the subject of many investigations of detonation phenomena. However, succinct and accurate descriptions of the compacts and pressings are difficult to achieve because the morphology and size distributions are generally altered by processing into useful configurations and densities. Three-dimensional measurements of near-full-density pressings are not easy and have not been done with great accuracy. The authors explore the analysis of various particle-size and morphological measurements using the formalisms of fractal geometry. They intend to show, by a combination of modeling and data analysis, that a three-dimensional description of the explosive, the binder, and the voids can be constructed from one- and two-dimensional measurements of surface. In the long term, they hope to correlate these descriptions with the measurements of explosive behavior.
Date: December 31, 1998
Creator: McAfee, J.M. & Nelson, R.A.
Partner: UNT Libraries Government Documents Department

Metastable nanosized aluminum powder as a reactant in energetic formulations

Description: Aluminum powder is an important ingredient in many propellant, explosives and pyrotechnic applications. The production of nanosized aluminum powder by the electroexplosion of metal wire has been practices in the former USSR since the mid 1970`s. Differential scanning calorimetry, differential thermal analysis and x-ray phase analysis was performed on aluminum powder both before and after air passivation, as well as aluminum that was protected under kerosene, pentane, toluene and hexane. Earlier Soviet reports of unexplained thermal releases and metastable behavior have been investigated. Anomalous behavior previously reported included phase transformations at temperatures far below melting with the release of heat and chemoluminescence and self sintering of particles with a heat release large enough to melt the powders.
Date: December 1, 1998
Creator: Katz, J.; Tepper, F.; Ivanov, G.V.; Lerner, M.I. & Davidovich, V.
Partner: UNT Libraries Government Documents Department

XTX8003 Aging Study Status Report

Description: XTX8003 is an extrudable explosive composed of 80% PETN and 20% Sylgard 182 (polydimethylsiloxane). Knowledge of the aging characteristics of XTX8003 is desired to understand the relationship between chemical and physical changes and performance. This understanding will allow improved assessment of the current state and also projected lifetime of components that contain this material. A literature search revealed few published studies of the aging behavior of XTX8003 or a chemically similar material, LX-13. Two studies showed that detonation velocity had decreased after storage at 70 C for two years. Another study showed a 30% decrease in target penetration by conical shaped charge after 12 weeks of storage at 82 C. Only one study was found which evaluated chemical and physical changes, but no information was available to correlate performance degradation to chemical and physical changes in the material. In summary, the major changes seen in aged XTX8003 are in detonation velocity and particle morphology, but particle morphology does not appear to be the determining factor in the loss of detonation velocity. The study will continue at least 24 months, at which time the data will be evaluated to determine how best to continue with the remaining test samples.
Date: March 8, 1999
Creator: Cates, M.; Coleman, K.; Foster, P.; Klassen, S. & Loyola, V.
Partner: UNT Libraries Government Documents Department

Slow PBX development. Quarterly report, October--December, 1971

Description: A total of nine batches of pressable baratol and pressable Composition B-3 were made and analyzed. One pressing was made for P/040 fabrication and test fire. The first P/040 plane wave lenses designed were fabricated and fired, yielding a center-leading average of 0.17 {micro}sec asimultaneity. The interface contour was redesigned and two lenses were fabricated and fired, resulting in center-lagging asimultaneity of 0.098 {micro}sec and 0.074 {micro}sec.
Date: December 31, 1972
Creator: Slape, R.J. & Crutchmer, J.A.
Partner: UNT Libraries Government Documents Department

Porous HMX initiation studies -- Sugar as an inert simulant

Description: For several years the authors have been using magnetic particle velocity gauges to study the shock loading of porous HMX (65 and 73% TMD) of different particle sizes to determine their compaction and initiation characteristics. Because it has been difficult to separate the effects of compaction and reaction, an inert simulant was needed with properties similar to HMX. Sugar was selected as the simulant for several reasons: (1) the particle size distribution of C and H granulated sugar is similar to the coarse HMX the authors have been using (120 {micro}m average size), (2) the particle size of C and H confectioners (powdered) sugar is similar to the fine HMX in the studies (10 {micro}m average size), (3) it is an organic material, and (4) sugar was readily available. Because the densities of HMX and sugar are somewhat different, the authors chose to do the experiments on sugar compacts at 65 and 73% TMD. As expected, no reaction was observed in the sugar experiments. Compaction wave profiles were similar to those measured earlier for the HMX, i.e., the compaction waves in the coarse sugar were quite disperse while those in the fine sugar were much sharper. This indicates that the compaction wave profiles are controlled by particle size and not reaction. Also, the coarse sugar gauge signals exhibited a great deal of noise, thought to the be result of fracto-emission.
Date: November 1, 1997
Creator: Sheffield, S.A.; Gustavsen, R.L. & Alcon, R.R.
Partner: UNT Libraries Government Documents Department

HE friction sensitivity. Oblique impact sensitivity of explosives (the skid test). Quarterly report, April--June, 1971

Description: Oblique impact tests were performed on both artificially aged and unaged LX-09-0. Oblique impact, instrumented vertical drops, and friction tests were performed on RX-25-AA. An extensive oblique impact and instrumented vertical drop test series was performed using three compositional variations of LX-10-0.
Date: December 31, 1971
Creator: Velkinburgh, J.H. van
Partner: UNT Libraries Government Documents Department

Explosive performance. Quarterly report, July--September, 1970

Description: The objectives of this study are the determination of detonation velocity, shock sensitivity, impact sensitivity, etc.; and the acquisition of high-precision one-dimensional hydrodynamic data for use in establishing detonation product equations-of-state, performance of explosives, etc. A wedge test series was begun on RX-25-AA. This is the first attempt in this work to study a composite explosive with the wedge test. Behavior appears to be quite different from the standard explosives.
Date: December 31, 1970
Creator: Kramer, P.E.
Partner: UNT Libraries Government Documents Department

H.E. formulation. Quarterly report, July--September, 1964

Description: Emphasis was placed this quarter on the manufacture of extrudable explosives. This included the recrystallization of PETN which was used to manufacture two batches of LX-02-1 and one batch of RX-02-AK. The materials were examined for composition, extrudability and burning via detonation velocity. Also, a Sunburst and Sunray were performed on the first batch of LX-02 made. Results were all satisfactory except for detonation velocity; some of the channels were yielding somewhat erratic results which could be due either to the test or incomplete mixing. The recrystallization of PETN progressed satisfactorily and the final crystals as viewed under the microscope had the expected appearance.
Date: December 31, 1964
Creator: Osborn, A.G.
Partner: UNT Libraries Government Documents Department

Oblique impact sensitivity of explosives: The skid test. Quarterly report, April--June, 1968

Description: RX-04-CW, LX-07-1, and RX-09-CD were tested. The RX-04-CW and LX-07-1 are not complete; however, results so far show the TX-04-CW comparable in sensitivity to PBX 9404 while the LX-07-1 is less sensitive at 14{degree}. The RX-09-CD was slightly more sensitive than the RX-09-CB previously tested.
Date: December 1968
Creator: Washburn, B. M.
Partner: UNT Libraries Government Documents Department

Thermal properties and chemical reactivity. January--March, 1971

Description: Two coupon test samples containing LX-09/Sylgard/Mulberry and LX-10/Sylgard/Mulberry were disassembled for evaluation. Thermal analysis data for the explosives and the analysis of the atmosphere are reported. Identification of several components in the atmosphere was made. The problems associated with the analysis of LX-09 for FEFO by gas chromatography are discussed and the data from the analysis of two specially prepared samples of LX-09 are reported. The data for a series of standard and modified Henkin time-to-explosion for PETN are reported. The modified time-to-explosion runs are first cooled for a fixed time, preheated for 40 to 80 seconds, recooled for a fixed time and then reheated until the sample explodes. A 0.42 cc liquid sample was trapped during the pump out of the W-68 AAU and a preliminary analysis of the sample is reported. The analysis of the atmosphere in the first samples from the PASS A LX-09 evaluation program is reported.
Date: December 31, 1971
Creator: Myers, L.C.
Partner: UNT Libraries Government Documents Department

Formulation facility. Quarterly report, April--June, 1969

Description: Two 250-pound batches of LX-09 were made for BAECP for special studies. Twenty Micronizer runs were made to ascertain the effects of various fluids and wetting gents upon the stability of high surface area PETN and to establish the limits within which repeatability can be expected. One sample, after being treated with the wetting agent dodecyl sodium sulfate, stabilized at 7,400 cm{sup 2}/gm after the 300-hour bake at 100 C. A study was begun to determine the effects of deaeration upon the rheological and firing properties of Extex. Rheological data indicate that deaeration has little effect on extrudability. Firing data are currently being obtained.
Date: December 31, 1969
Creator: Osborn, A.G.
Partner: UNT Libraries Government Documents Department

Modeling energy dissipation induced by quasi-static compaction of granular HMX

Description: A simple extension of a conventional two-phase (inert gas and reactive solid) continuum model of Deflagration-to-Detonation Transition (DDT) in energetic granular material is given to account for energy dissipation induced by quasi-static compaction. To this end, the conventional model equations,, valid in the limit of negligible gas phase effects, are supplemented by a relaxation equation governing irreversible changes in solid volume fraction due to intergranular friction, plastic deformation of granules, and granule fracture. The proposed model constitutes a non-strictly hyperbolic system of equations, and is consistent with the Second Law of Thermodynamics for a two-phase mixture. The model predicts stress relaxation and substantial dissipation induced by quasi-static compaction; such phenomena are commonly observed in quasi-static compaction experiments for granular HMX. Predicted intergranular stress histories compare well with experimental data.
Date: November 1, 1997
Creator: Gonthier, K.A.; Menikoff, R.; Son, S.F. & Asay, B.W.
Partner: UNT Libraries Government Documents Department

Explosive performance. Quarterly report, July--September, 1969

Description: This project is for experimentally determining the detonation pressure, etc., of explosives. The detonation pressure of several sizes of PBX 9404 charges was determined using the aquarium technique. Pressure data (from the larger shots) were generally in good agreement with the quoted values for PBX 9404 in these geometries. The small unconfined charge pressure values were consistently about 6% below the accepted 375 kbar value. Experimental shock velocity and computed pressure data are reported.
Date: December 31, 1969
Creator: Rigdon, J.K.
Partner: UNT Libraries Government Documents Department

Measurement of explosion time as a function of impact pressure for PBX 9501 subject to weak planar shocks

Description: At low pressures, the mechanical heating of the material is insufficient to generate ignition. At high pressures, prompt ignition is observed. At intermediate pressures, between {approximately} 0.75 to 2.0 GPa, mechanical heating is calculated to achieve sufficient heating to generate ignition after a variable induction time, equivalent to the induction time observed in purely thermal ignition experiments. These calculations depend on the calculation of at least two complex physical mechanisms in the material, mechanical heating and thermal decomposition. The authors present measurements of the surface temperature of confined PBX 9501 subject to weak planar shock with pressures spanning the range from moderate heating to prompt ignition.
Date: October 1, 1997
Creator: Henson, B.; Asay, B.W.; Dickson, P.M.; Fugard, C. & Funk, D.J.
Partner: UNT Libraries Government Documents Department

Characterization of TNAZ

Description: The explosive TNAZ has recently become available in pilot-plant quantities. We have found its small-scale safety properties similar to those of other nitramines. Detonation calorimetry showed TNAZ to have 96% the energy of HMX and 150% of TNT. The shock sensitivity of neat TNAZ is greater than LX-14. A retonation wave was observed when the material was shocked at 2.0 GPa. The initiation behavior of neat TNAZ cannot be classified as either homogeneous or heterogeneous. Six plastic bonded TNAZ-based explosives have been developed for the Army.
Date: December 14, 1994
Creator: Simpson, R. L.; Garza, R. G.; Foltz, M. F.; Ornellas, D. L. & Utriew, P. A.
Partner: UNT Libraries Government Documents Department