bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic mechanism on Thermal Degradation of a Nitrate Ester Propellant
Authors: Kimura J.
Published: May 2005

The thermal degradation of a double‐base propellant has been studied to elucidate the rate‐determining steps and the kinetic mechanism in a wide range of temperatures (60°C–200°C) by using modified Taliani test, thermogravimetry (TG), and temperature‐varied Abel (TVA) test. The results indicate that the degradation process consists of two major reactions, homolysis and autocatalysis, depending on temperature and total pressure due to evolved gases. The activation energy for the homolysis was obtained to be 35–37 kcal/mol from Taliani and TVA tests, which fall in the range of the bond dissociation energy of the weakest bonds RO–NO2. The activation energy for the autocatalysis was determined to be 46–49 kcal/mol from Taliani and TG methods. Those values observed for the two key reactions are totally opposite to reported values in the earlier literature. The temperature dependence of the reaction rates obtained in this study implies that the homolysis is the rate‐determining step in the lower temperature range, the autocatalysis in the higher temperature range.
Flyer Plate Motion by Thin Sheet of Explosive
Authors: Yadav H. S.
Published: May 2005

Acceleration of a metal plate by explosive energy at low value of charge to metal mass ratio has been studied by employing a new theoretical model based on uniform pressure and density of detonation products behind the flyer plate. Theoretical velocities of flyer plates have been compared with those measured by radiographic technique and found in good agreement. Comparing the relations for plate velocity, obtained from the present model and earlier Gurney model at low C/M values, an analytical expression for Gurney energy has been obtained in terms of detonation velocity of the explosive and adiabatic exponent of the detonation products.
Critical energy criterion for the shock initiation of explosives by projectile impact
Authors: James H. R.
Published: May 2005

The critical energy (Ec) criterion developed by Walker and Wasley for predicting the response of bare, heterogeneous explosives to flying‐plate impact, is modified for application to flat‐nosed rods and spherical projectiles. This modification redefines the shock duration term used in calculating Ec and implies that a minimum volume of explosive at a given shock energy is needed before initiation occurs. The modification also changes the L/D ratio of the projectile at which plate behaviour changes to rod behaviour from the currently accepted value of approximately 1/4 to 1/12. Comparisons between the modified criterion and published experimental data show that the same value of Ec can now be obtained from both flying‐plate and more complex projectile impacts into the same explosive.
Interaction of a Metallic Jet with a Moving Target
Authors: Yadav H. S.
Published: May 2005

Study of interaction of a high velocity jet with a moving target has been carried out on the basis of simplifying assumptions of constant velocity of the jet and the target plate. The theoretical model meets the boundary conditions of the problem and predicts satisfactorily the main features of the phenomenon and the trend in variation of parameters like depth of penetration, surface cut and total distance travelled by target during the time of interaction of complete length of the jet. Unlike jet penetration in a stationary target, the penetration in a target, accelerated by thin layer of explosive, has been found independent of density of the target. The penetration, however, has been found strongly dependent on the angle of impact and the ratio of jet and target velocities.
A new purpose‐built Continuous Processing Facility for Energetic Materials
Authors: Carter R. E.
Published: May 2005

Based on a study of the rheological properties of triple‐base gun propellants during processing, a flexible research plant has been designed and installed to define the processing parameters necessary to make gun propellants by a continuous process based upon a twin‐screw extruder.
Analysis of the shaped charge jet induced reaction of high explosives
Authors: Held M.
Published: May 2005

A new optical recording technique for analyzing the initiation of high explosives under the impact of a shaped charge jet is described. This method permits determining, in “one single” test, the type of reaction – i.c. no reaction or reaction or detonation ‐ and the parameters build‐up distance Δs run‐up time Δt, initiation time ti and initiation distance Zi in the acceptor charge by observation of the acceptor charge side‐on and, via a mirror, also end‐on with simultaneous streak and framing recording.
The effect of high spin on the performance of tracer compositions
Authors: Briére Paul
Published: May 2005

A unique tracer evaluation facility has been put into operation at the Defence Research Establishment, Valcartier (DREV), in order to characterize tracer compositions loaded in 5.56 mm envelopes. The effect of rotational speeds up to 300,000 rpm on the performances of two tracer compositions and the standard Belgian L‐110 tracer was studied in this facility. The trace duration decreased substantially with any increase in spin speed. The luminous output was observed generally to be weak at low rotational speeds and to increase with any rise in spin over 150 krpm. The formation of a convex surface of combustion in the composition under spin and the degree of obstruction of the projectile mouth by the combustion residues are postulated to explain such behaviours.
Development of a Pyrolysis‐Gas Chromatographic Method for characterization of plastic‐bonded explosives
Authors: Druet Linda M. , Degenhardt Carla A. E. M.
Published: May 2005

As part of a program to develop chemical tests which can be used to complement existing tests for mechanical properties, propellant ballistic performance, and explosive sensitivity, a detailed experimental procedure is presented for analysis of plastic‐bonded explosives (PBX's) by the coupled method of pyrolysis‐gas chromatography (PyGC). The method involves grinding the cooled PBX, pressing a controlled quantity on a pyrolysis wire, performing Curic‐Point pyrolysis, and detecting the products after separation by gas chromatography. PyGC results are presented to show the capability of the method to differentiate aged and unaged samples of PBX's and to differentiate stabilized and unstabilized PBX's based on RDX. Also included are results from several series of reproductibility studies, which suggest that the method may require only minor modifications before it can be implemented for regular screening of these complex formulations.
Initiation and detonation of RDX and HMX HTPB‐Based Plastic‐Bonded Explosives
Authors: van der Steen Albert , Verbeek Ries
Published: May 2005

Plastic‐bonded explosives (PBXes) with different cross‐link densities and based on explosives with different particle size distributions have been compared for their initiation and detonation properties. The investigations showed that HMX‐based formulations become less sensitive at lower cross‐link densities. The shock sensitivity of two RDX‐based formulations differed considerably. This could have been caused by the particle size distribution of the RDX, but it could also be due to the fact that the explosives were obtained from different sources.
Modified Cycle‐Cast of TNT Based Explosives
Authors: Lee Yng‐Long , Wu Bor‐Horng , Lin Wei‐Ming , Sung Po‐Hou , Lin Kuei
Published: May 2005

The gain sizes of TNT‐HNS cast were examined. The results show higher melt temperature of TNT‐HNS mixture produces larger crystals. Based on two assumptions, equilibrium exists among TNT, HNS and nucleant complex 2TNT:HNS, and the dissociation of the nucleant is of endorthermic nature, an one‐stage cycle‐cast process is proposed. This process also yields fine, randomly oriented grain structure as Bofors' cycle‐cast process has claimed.
Thermal Decomposition of Energetic Materials 41. Fast thermolysis of cyclic and acyclic ethanediammonium dinitrate salts and their oxonium nitrate double salts, and the crystal structure of piperazinium dinitrate
Authors: Russell T. P. , Brill T. B. , Rheingold A. L. , Haggerty B. S.
Published: May 2005

Fast thermolysis/FTIR spectroscopy of [H3NCH2CH2NH3]‐(NO3)2 (EDD), [H2N(CH2CH2)2NH2](NO3)2 (PIPDN), and [HN(CH2CH2)3NH](NO3)2(DABCOD) and new oxonium nitrate (H3O+NO−3) double salts of PIPDN and DABCOD is described. EDD initially yields HNO3 and then small molecule decomposition products from redox reactions when heated at ≥ 100°C (dcc.). PIPDN initially yields HNO3, but then generates a significant amount of N,N′‐dinitrosopiperazine along with small molecule fragments. DABCOD produces no HNO3(g), but instead gives CH2O, N,N′‐dinitrosopiperazine and small molecule products. These patterns are entirely consistent with the behavior observed for primary, secondary and teritary ammonium mononitrate salts in our previous work. The presence of nitrosamines strongly increases the health hazard of the matcrials upon heating. No nitramines were detected as thermolysis products. Thermolysis of the oxonium nitrate double salts liberates HNO3 and H2O at a relatively low temperature (≥ 60 °C). Above this temperature, the thenmolysis proceeds in the same way as that of pure PIPDN and DABCOD. The crystal structure of PIPDN is described.
Non‐Destructive Reliability Analysis of a Bridgewire Fuze Head
Authors: Leeuw Matthijs W.
Published: May 2005

In this paper a novel method to determine the reliability of a bridgewire fuze head is proposed. It is assumed that a bridgewire will respond positively to a current pulse if the bridgewire temperature exceeds a critical value as a result of the pulse. To calculate the bridgewire temperature the distributions of four thermal parameters that characterize the electrothermal response of a bridgewire fuze head are used. Preliminary results indicate that this novel approach is in agreement with classical methods. Furthermore, one needs to test a limited amount of items and only a fraction of the tested items is destroyed.
Initiation of some energetic materials by microwave heating
Authors: Hasue Kazuo , Tanabe Masami , Watanabe Nobutune , Nakahara Shoji , Okada Fumiaki , Iwama Akira
Published: May 2005

Microwave heating of ammonium nitrate (AN), tetryl, PETN, RDX, HMX, TNT, emulsion explosive, Composition C‐4, and ammonium perchlorate (AP) was carried out at the frequency of 2450 + 50 MHz. The energetic materials were confined in sodalime glass tubes with teflon and silicon rubber plugs. The order of increasing initiation delay time was AN, tetryl, PETN, RDX, HMX, and TNT. Also, the order of the initiation energy of energetic materials was the same when the anode currents of microwave power source were 1.1 A and 0.8 A. The initiation processes of energetic materials were recorded on videotapes which showed that the energetic materials gencrally melted before initiation. The temperatures of energctic matcrials were measured by K‐type (chromel‐alumel) thermocouples and an infrared thermometer. The temperature of each energetic material started to rise rapidly when the temperature neared the meiting point. Initiation occured near the ignition temperature with a delay varying from 6 to 109 seconds.
Thermal Decomposition of Energetic Materials. 36. Fast thermolysis of overoxidized nitro– and halonitro nitramines
Authors: Subramanian R. , Brill T. B.
Published: May 2005

Temperature profiling/FTIR is described for the fast thermolysis of four C‐NO2‐containing nitramines whose oxygen content exceeds the balance to CO2. The compounds are [(NO2)3CCH2N(NO2)CH2‐]2 (ONDO), [(NO2)3CCH2]2N(NO2) (BTNEN), [Cl(NO2)2CCH2]2N(NO2) (CDNEN), and [F(NO2)2CCH2]2N(NO2) (FDNEN). By themselves, these compounds are found not to be especially exothermic during the rapid decomposition off‐gasing phase probably because of their overoxidized nature. The halogen atoms appear as ClNO and FNO in the gas decomposition products.
Studies of the Sensitivity of Explosive Dusts to ignition by electric sparks
Authors: Thomas G. O. , Oakley G. L.
Published: May 2005

Results are presented of an experimental investigation of the sensitivity of clouds of high explosive dusts in air to ignition by electrostatic sparks. The sensitivities are derived from determinations of the frequency of ignition of dispersed clouds of dusts when subject to electric sparks of varying energies. In addition to dust composition the parameters considered include the density of the cloud and the particle size distribution. The influence of the discharge circuit characteristics on the ignitability of dust clouds is also investigated. The majority of the tests were conducted with quasi‐static dust clouds, but results are also presented from tests with moving dust clouds. These clearly indicate that the energy required for ignition increases with the velocity of the carrier gas.
The Dependence of Friction Sensitivity of Primary Explosives upon rubbing surface roughness
Authors: Le Roux Jurie J. J. P. A.
Published: May 2005

A large variation in surface roughness of the procclain plates, in use on the BAM friction tester (Julius Peters), was observed and confirmed by surface texture measurement. The relationship between the friction sensitivity of primary explosives and the rubbing surface roughness was investigated by using different emery‐paper grades.

The replacement of porcelain friction plates by an emery‐paper test‐piece is suggested. Apart from improved reliability of results, this modification to the existing technique greatly reduces the associated safety risk, costs and lesting time.
Fragment Mass Distribution of HE Projectiles
Authors: Held Manfred
Published: May 2005

The description of the fragmcnt mass distribution according to Held is in cxcellent agreement with the experimental data. This is true in particular when the total mass, Mo. used in describing the distribution, is slightly modified in that some of the hcavicst fragments are neglected. Because in the case of a shell they do not necessarily follow the distribution law.
The effects of thermal gradients on Performance of End‐Burning Rocket Motors
Authors: Irvine Robert D.
Published: May 2005

The effect of a non‐uniform temperature distribution on the thrust‐time performance of an end‐burning solid propellant rocket motor charge is examined. It is shown that non‐planar surfaces develop. For some classes of temperature distribution, the effect of these non‐planar surfaces os always between the limits of the thrust predicted at the maximum and minimum temperatures. The class of temperature distributions that meet this criterion is determined and a simple inequality is derived to test any actual distribution. An expression for the departure from specification is given for distributions outside this class. These results partially justify the proof of ballistic design by testing motors of uniform temperature at upper and lower limits, when service motors may be exposed to uneven heating. The validity of such testing in actual cases can be determined.
Explosion of Explosives in Subsurface Magazines and its numerical analysis
Authors: Adachi Tetsuhiko , Munemasa Kunihiko , Hasue Kazuo , Nakahara Shohji
Published: May 2005

The subsurface magazine is a new type of magazine in Japan, which is defined as a magazine constructed underground and equipped with elevators of other transportation means. and is different from the usual tunnel type underground magazine.

Explosions of explosives in model subsurface magazines were carried out. and explosion gases and shock waves blown out from their entrances were observed by schlieren photography. The blast overpressures were also measured by piezoelectric transducers. these external effects by explosion of explosives in the subsurface magazines were found to be less than those in the underground magazines.

The above phenomena were simulated by numerical analysis using PISCES 2DELK code. Caluculated maximum overpressure and velocity of gases and shock waves were in fair agreement with their experimental values.
Synthesis of 3,3′‐Bis(2,2′,4,4′,6,6′‐Hexanitortilbene)
Authors: Zeng‐Gno Feng , Boren Chen
Published: May 2005

This paper describes the synthesis of 3,3′bis(2,2′,4,4′,6,6′‐hexanitrostilbene) (5). Based on the Ullmann reaction we prepared the title compound in nitrobenzene by using 3‐chloro 2,2′,4,4′,6,6′‐hexanitroztilbene (4) as the starting material and copper powder as the catalyst. (4) was reacted with hydrazine, not to yield a desired product, azo‐3,3′bist(2,2′,4,4′,6,6′‐hexanitrostilbene.) but to form a well‐known explosive, 2,2′,4,4′,6,6′‐hexanitrostibene (6). Differential scanning calorimetrical analysis has shown that (5) begins to decompose at the temperature of 298°C.
First steps towards a scientific approach to the Processing of Filled Polymers (Propellants)
Authors: Perez Daniel L. , Ramohalli Kumar N. R. , Rao Kanury R. K. , Fulian Chen
Published: May 2005

This research is directed towards a better understanding of filled polymer processing in general, and energetic composite solid propellants, in particular. The program established is composed of four stages and isolates batch processing as the technique to be examined. The first stage in the program is a thorough compilation of literally thousands of batch data for meaningful correlation and insight as to important areas within the process. Second is developing the fundamental equations governing the material for highly filled rheological suspensions and solving them numerically (biomodal particle distributions solely are to be considered). Third is the formulation of “model” compounds for experimental verification (this includes the use of perfectly spherical solid particles). Fourth and final is the implementation of this previous work to propellant manufacture. It is desired that from this work, new more economical means of predicting and also enhancing propellant performance can be developed.

This paper presents the results of the completion of the first step within this program. A brief discussion of the latter steps is mentioned with respect to their progress. The results to be presented were funded from the College of Enginneering and Mines at the University of Arizona.
Thermal Decomposition of Energetic Materials. 43. Fast thermolysis of cubylammonium nitrate and cubane‐1,4‐diammonium dinitrate
Authors: Russell T. P. , Brill T. B.
Published: May 2005

The rapid thermal decomposition (dT/dt ≥ 70°C/s) of eubylammonium nitrate (CUBAN) and cubane‐1, 4‐diammonium dinitrate (CUBDAN) is described in terms of the temperature profile and gas products as a function of pressure (1‐200 psi Ar). In this environment the full strain energy of cubane is not released simultaneously with the redox reactions that involve the ammonium nitrate site because C2H4 and/or C2H2 are evolved. No large hydrocarbons form during rapid thermolysis, although both salts sublime to some extent below 7 psi Ar. CUBDAN is the only alkyldiammonium dinitrate salt that we have found to sublimduring fast thermolysis. An estimated gas phase basicity of about 215 kcal/mol for the cubylamines is obtained from the tendency to release HNO3(g). This value is surprising in light of the basicity values for other primary amines.
The Nitroglycerin Content Distribution in the coating of the solid propellant and the service life prediction of the charge
Authors: Heng Shu‐Yun , Pan Tong‐Xue , Kong Yang‐Hui , Liu Zi‐Ru
Published: May 2005

In this paper the distribution of the nitroglycerin (NG) content in the coating of solid double‐base propellant charge during various time at three aging temperatures were found by using thermogravimetric analysis (TG), and the separation and cracking of the coating were observed. The results showed that the differences of NG contents in the coating are significant and are a main reason giving rise to the separation and cracking of the coating. A empiric functional relation of NG content distribution in the coating to the thickness and aging time and temperature was obtained from measured data. On the basis of the NG contents in the boundary layer of the coating contracted with the propellant and times of separation or cracking of the coating. The service life of the charge was predicted.
Chromatographic determination of a polyol and/or sucrose octa‐acetate in CDB casting liquid
Authors: Keeton G. M. , Hooper A. P.
Published: May 2005

A quantitative method for the determination of a polyol and/or sucrose octa‐acetate in cast double base (CDB) casting solvent formulations is presented. The procedure utilizing liquid chromatography is based on the separation of components by differences in molecular weight during the development of the method it became apparent that this analytical approach may be of general interest where a species to be a quantified has no other conveniently exploitable property.
Flammability limits and ballistic properties of fuel‐rich propellants
Authors: Shalom Abraham , Gany Alon
Published: May 2005

The flammability limits and ballistic properties of composite fuel‐rich propellants were studied experimentally, using PBAN/AP propellant formulations. Higher pressure and AP contents as well as smaller AP particle size were found to promote sustained combustion and to increase burning rate. The addition of potassium perchlorate (KP) in place of AP increased the burning rate pressure exponent from about 0.3 to over 0.7 at optimum conditions. Ferric oxide and copper chromite catalysts caused an increase of the burning rate by a factor of 2, while the addition of aluminum powder at the expense of the fuel binder was found to have a remarkable effect on the burning rate with a maximum increase of as high as 5‐fold.
Influence of carbon on combustion characteristics of Magnesium‐Sodium Nitrate Propellant
Authors: Singh Harihar , Somayajulu M. R. , Rao R. Bhaskara , Meghasyam K. R.
Published: May 2005

Effect of addition of carbon in the form of graphite and carbolac on the combustion characteristics of Magnesium‐Sodium nitrate propellant has been studied. Results indicated that the burning rate of the propellant increased significantly by the addition of graphite upto 2%. Thermal decomposition studies revealed that the graphite particles in addition to its absorption of thermal energy being an inert material react with the decomposed products of the sodium nitrate just above the burning surface of the propellant for the exothermic heat release. This heat release which is high at low concentration of graphite is seen causing high burning rate. Any further increase in graphite concentration beyound 2% reduces the burning rate as the thermal energy absorption exceeds the heat release at the burning surface. When carbon in the form of carbolac was used in the composition reactive species diffuse out prior to the sample ignition without participating in the combustion thus reduces the burning rate. The heat of reaction data supported the suggested mechanism.
Electric‐spark sensitivity of Heat‐Resistant Polynitroaromatic Compounds
Authors: Hosoya F. , Shiino K. , Itabashi K.
Published: May 2005

Thermally statble explosives (polynitroaromatic compunds) have been studied using an electric‐spark generating device to determine their sensitivities for acrospace applications. The explosives tested were DATB, TATB, HNS and ONT. In addition, TNT was used as a reference nitro compund. The ignition energy of HNS and ONT does not depend on the initial temperature of the samples as much as does DATB, HNS and ONT are more sensitive than DATB and TATB in electric‐spark test, underwater small scale gap test and drop hammer test, and they also showed high adiabatic flame temperature.
Jet Penetration of Surrogate Steel‐Explosive Systems
Authors: Ferm Eric , Ramsay John B.
Published: May 2005

Predicting the jet initiation of an explosive that is covered and in intimate contact with an inert material, is sensitive to the history of the jet in both the cover and the explosive. If the penetration velocity in the cover is subsonic, the acceptor explosive experiences complex wave structures that are significantly different from the case where the penetration velocity is supersonic. The pressure history in the explosive may cause prompt initiation, desensitization, or delayed initiation. We have used transparent polymethylmethacrylate (PMMA) as a surrogate for the explosive, allowing us to experimentally visualize the transition between the subsonic penetration behavior in a steel cover and the quasi‐steady supersonic penetration behavior in the PMMA. The wave histories in PMMA downstream from two steel covers of different thicknesses have been measured by streak and image intensifier cameras and by flash radiography simultaneously. These were augmented with pressure gauges to measure the pressure history for one of the thicknesses. These experimental results and subsequent analysis show how initiation of an explosive acceptor can occur at various distances from the interface, depending on the thickness of the cover plate.
The Behavior of Shaped Charges with open‐poled hemispherical liners
Authors: Summers Richard L. , Walters William P. , Dick Richard D.
Published: May 2005

This paper discusses the effect of an opening at the pole of a hemispherical shaped‐charge liner. An experimental study was performed in which various diameter holes were made in otherwise similar shaped‐charge liners. Flash radiographs were taken to observe changes in the liner collapse and the jet characteristics. The collapse process and jet characteristics of a hemispherical liner are significantly altered for a hole diameter which is 10% or more of the outer liner diameter. The jet tip velocity is increased by 26% for a hole diameter‐to‐liner diameter ratio of 0.25. Explanations are presented for the behavior of the tip region of the shaped‐charge jet.
Combustion Mechanisms of High Explosives and their relation with the DDT process
Authors: Isler J.
Published: May 2005

The response fo high explosives to accidental stimuli like bullet impact or thermal aggression is largely dependent on their combustibility, then on their combustion mechanism. The need of products with limited DDT hazard has led to the works presented in this paper. The aims were:

to develop a tool allowing to detect the unusual burning process leading to the DDT

to improve the knowledge about these processes, and about the features of the high explosives which influence these processes.

These works have been performed by studying both classical melt cast high explosives and cast cured (plastic bonded) PBXs.
The effect of nitroglycerin content on the quasi‐static compaction behavior of various ball propellants
Authors: Elban W. L. , Coyne P. J. , Campbell R. L.
Published: May 2005

The quasi‐static compaction behavior of a number of single‐ and double‐base ball propellants has been investigated to determine the effect of nitroglycerin (NG) content. Simultaneous measurements were obtained of axial applied and transmitted forces, circumferential strain, and porous bed displacement, resulting in the calculation of axial average solid stress and radial stress as a function of porous bed consolidation. Five Olin ball propellants designated as WC140, TS3660, TS3659, Winchester #231, and TS3661 in order of increasing NG content, were compacted. Their NG concentrations ranged from 0 to ∼35 wt%. The most significant effects of increased NG content were to decrease the various axial and radial stress levels present at constant degree of bed consolidation and to increase the coefficient of kinetic friction at the porous bed/mold wall interface. Microscopic examination of recovered samples that had been compacted revealed that extensive plastic deformation occurred in the absence of particle fracture.
Analysis of the Accidental Explosion at PEPCON, Henderson, Nevada, on May 4, 1988
Authors: Reed Jack W.
Published: May 2005

Damages caused by a large, accidental explosion in Henderson, NV, were surveyed and interpreted for their estimated causative airblast overpressures. Results were widely scattered by uncertainty in structural (primarily window glass) response as well as weather effects, but the total pattern of estimated overpressures versus distances generally agrees with a 1‐kt NE assumption for the airburst source strength. This is duplicated by a 227‐Mg HE surface burst. Since approximately 1.36‐Gg AP were destroyed in the area of the largest single explosion, an HE explosive equivalence for ammonium per‐chlorate appears to be about 1/6. Considering the yield‐scaled response of overpressures to yield, there is no significant difference with an independent yield estimate of 454‐Mg HE, made from close‐in blast effects on relatively ideal structural elements.
Tactical Solid Rocket Motors Response to Bullet Impact
Authors: Hamaide S. , Quidot M. , Brunet J.
Published: May 2005

Vulnerability studies are very important for rocket motors development using high energy and minimum smoke solid propellant. Among the treated threats, the bullet impact is a well known test studied for many years. Nevertheless, during our experimentations against true rocket motor, the well‐known scenarios failed. A new scenario has been identified and confirmed to take into account the new phenomenon. This scenario implied the solid propellant but also the geometry of the grain. The paper presents the experimental works and describes the physics of the phenomenon supported by the associated model studies.
Gas Generator Materials Consisting of TAGN and Polymeric Binders
Authors: Eisele Siegfried , Volk Fred , Menke Klaus
Published: May 2005

This study introduces a new type of gs generator on the basis of triaminoguanidine nitrate with polymeric binders in the form of polyurethane polymers, cellulose acetate and the azidopolymer GAP with nitroplasticizer. TAGN propellants demonstrate low burning temperatures, high yields of gaseous products adn adjustable medium to high burning velocities. Together with high chemical and thermal stabilities, good mechanical properties to high and low temperatures, no exhaust of corrosive gases and very low sensitivity, the gas‐generator propellants exhibit outstanding properties.
The Effect of Radial Confinement of Explosive on the Impulse delivered to an explosively driven circular plate
Authors: Boyer Daryl L. , Bowman Barry R. , Brandt Harry , Giedt Warren H.
Published: May 2005

The effect of radial confinement of explosive on the impulse delivered to an explosively driven circular plate was investigated numerically. The results are applicable to the design of explosively formed penetrators. Aluminum radial confinement and additional radial explosive were investigated as means of increasing the impulse delivered to the plate. The radial thicknesses were varied from 0% to 10% of the explosive charge diameter with copper plates having thicknesses of 2%, 5% and 8% of the explosive charge diameter.

Results show the use of radial confinement to be more effective with thicker plates. The increase in impulse provided by aluminum confinement was as great as 18% with an 8% charge diameter thick plate, compared to 12% with a 2% charge diameter thick plate. Regardless of the plate thickness, additional radial explosive can be more effective than aluminum radial confinement in increasing the impulse. For example a 10% charge diameter thickness of explosive increases the impulse by up to 28%, compared to 18% for the same thickness of aluminum. The results do not exhibit dependence on the method of detonation, nor on the length of the explosive charge.
Prediction of Extremely Low and High Explosion Frequencies from sensitiveness tests
Authors: Strømsøe Eigil
Published: May 2005

Probit analysis is an efficient method for analyzing sensitiveness test data. If the aim is to determine themedian stimulus value, the choice of stimulus scale is of minor importance. If, on the other hand, extreme frequencies are to be predicted, great care should be taken in the selection of an appropriate stimulus scale. A scale incorporating an upper and a lower stimulus level corresponding to explosion probability 1 and 0, respectively, is suggested. In an illustrative example this scale is shown to involve considerably less bias than either a simple linear or logarithmic scale.
Low‐Sensitivity Explosive Compounds for Low Vulnerability Warheads
Authors: Becuwe Alain , Delclos A.
Published: May 2005

Looking for explosives for Low Vulnerability Ammunitions leads to an interest in explosive molecules less sensitive than the usual nitramines (RDX, HMX). If TATB is quite convenient in terms of sensitivity, its performance is too low.

The researches described here are related to synthesis and use of NTO (nitrotriazolone), another insensitive molecule. The synthesis by nitration of TO (triazolone) is easy and the two steps from available starting materials have been optimized.

A comparison of desensitivation of PBX either by TATB or by NTO have been made. The sensitivity levels were found equivalent while the detonation velocity of the NTO based PBX was slightly higher. Unfortunately in this case, the failure diameter would be larger.

The last part relates to an extensive characterization in terms of performance and vulnerability to fast cook off, slow cook off, bullet impact, shock sensitivity and sympathetic detonation of a NTO and HMX based PBX. This PBX, B 2214, was one of the first examples of explosive composition showing no sympathetic detonation, even in 248 mm large diameter.
Stabilizer Reactions in Cast Double Base Rocket Propellants. Part III: Evidence for stabilizer interaction during extraction of propellant for HPLC quantitative analysis
Authors: Bellamy A. J. , Sammour M. H.
Published: May 2005

The use of a refined HPLC technique for analysis of the stabilizers para‐nitro‐N‐n ethylaniline (pNMA) and 2‐nitrodiphenylamine (2NDPA) and their N‐nitroso derivatives, in a mixed‐stabilizer, cast, double base rocket propellant composition subjected to accelerated aging at 70°C for 18 weeks has shown that (1) the time of hot extraction of the propellant samples for HPLC analysis significantly affects the relative quantities of the stabilizers and their corresponding N‐nitroso derivatives, and (2) pNMA is completely consumed during aging. The results presented in the first two parts of this series require some qualification on the basis of these observations, but the suggestion that the N‐nitroso derivative of pNMA participates in transnitrosation with 2NDPA remains valid, and is further substantiated by its occurrence during hot extraction of the propellant.
Thermal Decomposition of BAMO/HMX Propellants
Authors: Oyumi Yoshio , Inokami Kiyotaka , Yamazaki Kazuhiro , Matsumoto Koki
Published: May 2005

Thermal decomposition of BAMO [bis(azidomethyl)oxetane/tetrahydrofuran copolymer]/HMX composite propellants was studied by isothermal TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry) in helium atmosphere, which was showing overall two steps first‐order kinetics. The effects of cross‐link ratio on the accelerated aging of the BAMO/HMX propellants were also measured with infrared spectroscopy and gas chromatography. The accelerated aging was conducted at 347 K for several weeks. BAMO/HMX propellants for a very low cross‐link ratio made the cavity between HMX and BAMO binder by N2, CO2, and H2O evolutions during accelerated aging. An exotherm, generated by the decomposition of azide binder, initiated and accelerated the thermal decomposition of HMX. The burning rate of BAMO/HMX propellant was larger than those of BAMO binder and HMX, respectively. However, the propellant could not maintain the combustion at low pressure, at which its burning rate was equal to that of BAMO binder.
The Dead‐Pressing Phenomenon in an ANFO Explosive
Authors: Nie Shulin , Deng Junhua , Persson Algot
Published: May 2005

The dead‐pressing phenomenon or pressure desensitization in ANFO as well as in other civil explosives is well‐known. However, to our knowledge, the detailed study of this phenomenon in ANFO has not been carried out or reported. Therefore, such a study was planned in a SveDeFo research program. Blasting experiments in iron pipes were performed. Mainly, the density of dead‐pressing and the transmission distance of detonation in the dead‐pressed ANFO were studied. The results show that the dead‐pressing density of the tested ANFO, Prillit A (a trademark of Nitro Nobel AB in Sweden), in diameters 45 mm, 60 mm and 75 mm of steel pipes is respectively 1.35, 1.39 and 1.43 [g/cm3]. The dependence of the detonation transmission distance on the density of the ANFO has also been outlined.
Observations on the Reactivity of Pyrotechnic Compositions containing potassium chlorate and thiourea
Authors: Wharton R. K. , Barratt A. J.
Published: May 2005

An explosion occurred recently during the operation of a grinder that had been used to process potassium chlorate and then thiourea. As part of our investigation of this accident we determined the mechanical sensitiveness of mixtures containing these components and showed that they can be very sensitive to both impact and friction stimuli. Thermo‐analytical studies indicate that the binary mixture can react at up to 200°C below the melting point of the oxidizer; the exothermic process is characterized by a high reaction energy. Temperatures of ignition of the mixtures were less than 155°C, whereas the individual components gave no ignition below 400°C.
Qualitative Assessment of Nitroglycerin Migration from double‐base and composite modified double‐base rocket propellants: Concepts and methods of prevention
Authors: Agrawal J. P. , Singh Haridwar
Published: May 2005

Several concepts explaining the phenomenon of the nitroglycerin migration from DB and CMDB propellants to the inhibitor, are presented in this review. In the light of these concepts and the data available in the literature, methods to prevent/reduce NG migration are also discussed.
Shock Compression and Initiation of LX‐10
Authors: Tarver Craig M. , Urtiew Paul A. , Chidester Steven K. , Green Leroy G.
Published: May 2005

LX‐10 is a high energy density solid explosive consisting of 94.5% octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) and 5.5% Viton A Binder pressed to 1.865 g/cm3 (98.4% of theoretical maximum density). In this paper the shock compression and initiation of chemical reaction in LX‐10 by sustained shock pressures of 0.4 to 3 GPa are studied experimentally using embedded pressure and particle velocity gauges. The resulting pressure and particle velocity histories are evaluated theoretically using the ignition and growth reactive flow computer model of shock initiation and detonation. Manganin resistance and polyvinylidene fluoride (PVF2) ferroelectric pressure gauges are both employed in the low pressure (0.4 – 0.7 GPa) shock compression experiments. Multiple manganin pressure and multiple electromagnetic foil particle velocity gauges measure the growth of reaction at various positions in LX‐10 shocked to 1 – 3 GPa. The reactive flow modeling results imply that less than one percent of the LX‐10 shocked to 0.4 – 0.7 GPa reacts in fifteen microseconds. For the higher pressure experiments, the ignition and growth model accurately calculates the pressure and/or particle velocity buildup in LX‐10 as the reaction grows toward detonation. The LX‐10 calculations are compared to those for the well‐calibrated explosive PBX‐9404, which contains 94% HMX and a reactive binder. Since it has the inert binder Viton A and better mechanical properties than PBX‐9404, LX‐10 is demonstrated to be significantly less reactive than PBX‐9404 at these shock pressures. Therefore LX‐10 is safer than PBX‐9404 in many hazard and vulnerability scenarios to which solid explosives may be subjected.
Design of an Inert Material Type Plane Wave Generator
Authors: Chen Chun‐Yu , Shiuan Jong‐Hwa , Lan I‐Feng
Published: May 2005

A simple model calculation, a hydrodynamic code simulation and experimental verifications are presented in this paper for the design of a plane wave generator (PWG), composed of plexiglass as the inert material and Composition‐B (Comp‐B) as the high explosive with a density of about 1.72 g/cm3. Along with the design concept of the PWG, a simple model, based on the steady state detonation and decaying shock wave theory is proposed to calculate the time difference. Calculation results of this model are in good agreement with those of the experiment.

The experimental verifications are done with the aid of a Hamamatsu streak camera, taking the so‐called “time difference” as a measure of the quality of a plexiglass PWG. The smaller the time difference, the better the PWG which will generate a wave approaching a plane wave.

A hydrodynamic computer code (2DL) is used to study the inert material type PWG. The results agree with experiment and with the simple model.

From our study we have the following conclusions:

The time difference is less than 0.04 microseconds;

For the generation of a plane wave, a PWG of height 30 mm requires a base angle of 25°, and a PWG of height 20 mm requires a base angle of 30°;

It is expected that the model will be applicable to other heights and base angles.
Oil‐Well Shaped Charge Penetration‐Time histories in a simulated down‐hole environment
Authors: Smith Peter D. , Keating J.
Published: May 2005

This paper describes a series of experiments to measure the penetration depth with time of shaped charge jets as used in the oil industry to perforate well‐liners. Targets comprised steel (simulating the well‐liner), cement (representing the grout surrounding the liner) and Berea sandstone (in the form of cores) as the oil‐bearing material. Results indicated cratering velocities of about 2000 m/s through the sandstone. Jet slow‐down was very gradual and performance was found to be consistent with the behaviour of shaped charges penetrating materials such as those used in military armour.
The use of analytical computer models in shaped charge design
Authors: Backofen Joseph E.
Published: May 2005

This paper briefly examines some of the more challenging aspects of shaped charge design, such as control of jet breakup and analysis of the jet's interactions with targets. Background material and experimental observations are provided for analytical models uniquely describing and providing insight into these research areas. Analytical codes incorporating these models can now predict the performance of a shaped charge against various targets. An example of a shaped charge designed using an analytical computer code in order to match its capability against a range of targets is presented and discussed.
Shaped charge jet interaction with Highly Effective Passive Sandwich Systems ‐ experiments and analysis
Authors: Thoma K. , Vinckier D. , Kiermeir J. , Deisenroth U. , Fucke W.
Published: May 2005

The development and investigation of reactive sandwich targets and their interaction with shaped charge jets is one of the many research areas, where important contributions were made by Manfred Held. Such reactive sandwiches are known to be extremely effective against jets, but have a number of disadvantages.

In this work, the interaction of the copper jet from a shaped charge calibre 136 mm with a double sandwich system, each sandwich consisting of a non‐reacting layer between outer steel plates, is investigated. In 10 experiments with identical geometrical setup, only the material of the non‐reacting layer is changed. Using flash X‐ray pictures, the interaction of the jet with the sandwich system is investigated. Evaluation of these pictures as well as the comparison of the measured residual penetrations behind the sandwich target clearly demonstrate the influence of the material of the inner sandwich layer. The deformation and movement of the steel plates, caused by the penetrating jet, can be seen in the X‐ray pictures. It is shown that it is possible to distort a shaped charge jet so that its penetration capability behind the target is reduced to a minimum.

A fully three‐dimensional hydrocode simulation of the experiments enabled the jet/sandwich interaction and steel plate deformation and rupture to be studied in detail.
Characteristics of Shaped Charges with Hemispherical Liners
Authors: Hornemann U. , Holzwarth A.
Published: May 2005

During the last 10 years shaped charges with spherical liners have arosed great interest in research and development because their application in special munition results in an increase of performance. The present report presents measured characteristics of shaped charges with hemispherical liners. A short explanation of the jet formation process and the typical jet characteristics as a function of charge geometries are given, and the effect of liner materials is described. Additionally, the influence of various explosives and wave shapers have been studied. The important feature of such shaped charges is that the projectiles are associated with a high terminal ballistic effective part of the liner mass, which is of particular interest for application.
A Model for the Collapse of Explosively Driven Liners in spinning warheads
Authors: Carleone Joseph , Stefan Ryan
Published: May 2005

An analytical model has been developed for the rapid collapse of explosively driven metal shells that includes the effects of material strength and shell spin. The model can be used to approximate the collapse process of shaped charges and EFPs. A closed form solution for shell velocity as a function of shell position is developed and compared to several two‐dimensional and three‐dimensional continuum mechanic numerical simulations. Comparisons with the simulations include a parametric evaluation of shell geometry, initial conditions, and material strengths.

The analytical model compares well with the numerical simulations for very thin shells. It shows that spin can significantly affect the final collapse velocity, and may even result in hollow penetrators. The model also shows that strength has a similar effect, and can greatly reduce the final collapse velocity.
Analytical and Numerical Study of the Shock Pressures in the Gap Test
Authors: Sanchidrián José A.
Published: May 2005

This paper analyzes the functional relationship of pressure induced in the gap versus distance travelled. P = k e−ax. An analytical shock matching calculation is described to evaluate the constant k as a function of the density and the velocity of detonation of the donor explosive. TDL code is used to check the values of the constants for several donor explosives, and to compute the decay constant a. Functions for pentolite are compared with experimental data from bibliography. The method can be used to predict equivalent gap test thicknesses for donor explosives different from the commonly used pentolite.
Combustion Behavior of Fluorocarbon/Boron/AP Propellant at high pressure
Authors: Oyumi Yoshio , Nagayama Kiyokazu
Published: May 2005

Thermal decomposition and the burning properties of fluorocarbon/boron/AP propellant granule have been investigated. The fluoro‐carbon binder (FBDR) was oxidized by the decomposition products of admixed ammonium perchlorate (AP) and its decomposition region was 150°C lowered in the slow thermolysis. The boron particles, however reacted with neither FBDR nor AP at 550°C. In the micro‐motor tests, the boron particles completely burnt at a pressure range of from 30 MPa to 80 MPa in a short period of time (one millisecond) even at a low characteristic exhaust velocity. Minimum free volume, however, was needed to complete the combustion reaction in the chamber case. The characteristic exhaust velocity significantly decreased at below the characteristic chamber length of 11 cm. The boronized propellant showed low temperature sensitivity between −30°C and 60°C.