Download or read book Increased Shock Sensitivity of the Insensitive Explosive LX 17 at High Temperatures written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shock Sensitivity of IHE at Elevated Temperatures written by and published by . This book was released on 1993 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Insensitive high explosives (IHE's) based on triamino-trinitrobenzene (TATB) have been demonstrated to be very insensitive to shock, thermal, friction and other stimuli. Hazard scenarios can involve more than one stimulus, such as heating followed by fragment impact (shock). The shock sensitivity of the IHE's LX-17 and PBX-9502 preheated to a temperature (250°C) just below thermal runaway is quantitatively studied using embedded manganin pressure gauges. The thermal expansion of TATB to 250°C is measured to determine the state of the explosive prior to shock initiation. LX-17 and PBX-9502 are found to be significantly more sensitive at 250°C than at lower temperatures, but still less sensitive than ambient temperature HMX-based explosives. An ignition and growth reactive flow computer model of the shock initiation of hot IHE is developed to allow predictions of the response of hot IHE to impact scenarios which can not be tested directly.
Download or read book Shock Sensitivity of LX 04 Containing Delta Phase HMX at Elevated Temperatures written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: LX-04 is a widely used HMX-based plastic bonded explosive, which contains 85 weight% HMX and 15 weight% Viton binder. The sensitivity of LX-04 to a single stimulus such as heat, impact, and shock has been previously studied. However, hazard scenarios can involve multiple stimuli, such as heating to temperatures close to thermal explosion conditions followed by fragment impact, producing a shock in the hot explosive. The sensitivity of HMX at elevated temperatures is further complicated by the beta to delta solid-state phase transition, which occurs at approximately 165 C. This paper presents the results of shock initiation experiments conducted with LX-04 preheated to 190 C, as well as density measurements and small scale safety test results of the[delta] phase HMX at room temperature. This work shows that LX-04 at 190 C is more shock sensitive than LX-04 at 150 C or 170 C due to the volume increase during the[beta] to[delta] solid phase transition, which creates more hot spots, and the faster growth of reaction during shock compression.
Download or read book Cat chisme de la gr ce written by and published by . This book was released on with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shock Sensitivity of LX 04 at Elevated Temperatures written by and published by . This book was released on 1997 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hazard scenarios can involve multiple stimuli, such as heating followed by fragment impact (shock). The shock response of LX-04 (85 weight % HMX and 15 weight % Viton binder) preheated to temperatures hear 170C is studied in a 10.2 cm bore diameter gas gun using embedded manganin pressure gauges. The pressure histories at various depths in the LX-04 targets and the run distances to detonation at several input shock pressures are measured and compared to those obtained in ambient temperature LX-04. The hot LX-04 is significantly more shock sensitive than ambient LX-04. Ignition and Growth reactive flow models are developed for ambient and hot LX-04 to allow predictions of impact scenarios that a can not be tested directly.
Download or read book The Effects of Confinement and Temperature on the Shock Sensitivity of Solid Explosives written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of heavy steel confinement on the shock sensitivity of pressed solid high explosives heated to temperatures close to thermal explosion conditions were quantitatively measured. Cylindrical flyer plates accelerated by a 101 mm diameter gas gun impacted preheated explosive charges containing multiple embedded manganin pressure gauges. The high explosive compositions tested were LX-04-01 (85 wt.% HMX and 15 wt.% Viton A) heated to 170 ° C and LX-17 (92.5 wt.% TATB and 7.5 wt.% Kel-F) heated to 250 ° C. Ignition and Growth reactive flow models for heated, heavily confined LX-04-01 and LX-17 were formulated based on the measured pressure histories. LX-17 at 250 ° C is considerably less shock sensitive when confined by steel than when confined by aluminum or unconfined. LX-04-01 at 170 ° C is only slightly less shock sensitive when confined by steel than when it is unconfined. The confinement effect is smaller in LX-04-01, because HMX particle growth i s much less than that of TATB.
Download or read book A Literature Review of Shock Sensitivity Changes of TATB Due to Thermal Cycling written by and published by . This book was released on 2016 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Insensitive high explosives (IHEs) based on 1,3,5-triamino 2,4,6-trinitro-benzene (TATB) are the IHEs of choice for use in nuclear warheads over conventional high explosives when safety is the only consideration, because they are very insensitive to thermal or mechanical initiation stimuli. It is this inherent insensitivity to high temperatures, shock, and impact, which provides detonation design challenges when designing TATB explosive systems while at the same time providing a significant level of protection against accidental initiation. Although classified as IHE, over the past few years the focus on explosive safety has demonstrated that the shock sensitivity of TATB is influenced with respect to temperature. A number of studies have been performed on TATB and TATB formulations, plastic bonded explosives (PBX) 9502, and LX-17-01 (LX-17), which demonstrates the increase in shock sensitivity of the explosive after it has been preheated or thermally cycled over various temperature ranges. Many studies suggest the change in sensitivity is partly due to the decomposition rates of the temperature elevated TATB. Others point to the coefficient of thermal expansion, the crystalline structures of TATB and/or the combination of all factors, which create voids which can become active hot spots. During thermal cycling, TATB is known to undergo an irreversible increase in specific volume called ratchet growth. This increase in specific volume correlates to a decrease in density. This decrease in density and increase in volume, demonstrate the creations of additional void spaces which could serve as potential new initiation hot spots thus, increasing the overall sensitivity of the HE. This literature review evaluates the published works to understand why the shock sensitivity of TATB-based plastic bonded explosives (PBXs) changes with temperature.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-12 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Temperature dependent Shock Initiation of LX 17 Explosive written by and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: LX-17 samples, heated to temperatures up to 250 C, were impacted by 3 to 10-mm-wide, 50.8-mm-long strips of 0.13-mm-thick Kapton polyimide film at velocities up to 7.7 km/s. The Kapton strips were laminated onto a thin aluminum bridge foil and were launched to the desired velocity by discharging a capacitor bank through the foil, causing the foil to explode. The LX-17 samples were confined in a steel holder and heated in an oven to the desired temperature. After the capacitor bank was charged, the LX-17 sample in its steel holder was remotely drawn out of the oven on rails and positioned over the bridge-foil/Kapton-strip laminate. When the sample was in position, the bank was discharged, launching the Kapton strip against the LX-17 surface. The shock initiation threshold was measured for 3, 7, and 10-mm-wide strips at room temperature, 200 C and 250 C. The authors found a significant reduction in the velocity threshold and in the critical area for initiation when the samples were heated. The authors compare the results with the earlier data of Bloom, who measured the initiation threshold of LX-17 over the density range 1.8--1.91 g/cm3 at room temperature and -54 C. LX-17 has a large coefficient of thermal expansion, as reported by Urtiew, et al., which reduces its density significantly t elevated temperatures. They find that the change of shock initiation threshold with temperature is consistent with the change in sample density, using the relation between threshold and density reported by Bloom.
Download or read book Numerical Modeling of Explosives and Propellants written by Charles L. Mader and published by CRC Press. This book was released on 2007-10-18 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: Major advances, both in modeling methods and in the computing power required to make those methods viable, have led to major breakthroughs in our ability to model the performance and vulnerability of explosives and propellants. In addition, the development of proton radiography during the last decade has provided researchers with a major new experimental tool for studying explosive and shock wave physics. Problems that were once considered intractable – such as the generation of water cavities, jets, and stems by explosives and projectiles – have now been solved. Numerical Modeling of Explosives and Propellants, Third Edition provides a complete overview of this rapidly emerging field, covering basic reactive fluid dynamics as well as the latest and most complex methods and findings. It also describes and evaluates Russian contributions to the experimental explosive physics database, which only recently have become available. This book comes with downloadable resources that contain— · FORTRAN and executable computer codes that operate under Microsoft® Windows Vista operating system and the OS X operating system for Apple computers · Windows Vista and MAC compatible movies and PowerPoint presentations for each chapter · Explosive and shock wave databases generated at the Los Alamos National Laboratory and the Russian Federal Nuclear Centers Charles Mader’s three-pronged approach – through text, computer programs, and animations – imparts a thorough understanding of new computational methods and experimental measuring techniques, while also providing the tools to put these methods to effective use.
Download or read book Shock Initiation of Damaged Explosives written by and published by . This book was released on 2009 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.
Download or read book Multiple Shock Initiation of LX 17 written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The response of the insensitive TATB-based high explosive LX-17 to multiple shock impacts is studied experimentally in a four inch gas gun using embedded manganin gauges and numerically using the ignition and growth reactive flow model of shock initiation and detonation. Pressure histories are reported for LX-17 cylinders which are subjected to sustained shock pulses followed by secondary compressions from shocks reflected from metal discs attached to the backs of the explosive targets. These measured and calculated pressure histories show that the threshold for hot spot growth in LX-17 is 7 GPa, that LX-17 can be dead pressed at slightly lower pressures, and that the reaction rates behind reflected shocks increase greatly as the impedance of the metal increases. A study of the response of LX-17 to the collision of two reacting, diverging shocks forming a Mach stem wave inside the LX-17 charge demonstrated that this interaction can result in a high pressure region of sufficient size and strength to cause detonation under certain conditions.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1996 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 1038 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Behavior of Explosives at Very High Temperatures written by JOSEPH. WENOGRAD and published by . This book was released on 1960 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent work at the Naval Ordnance Laboratory has indicated that the impact sensitivities of organic high explosives are related in a simple manner to the velocities of their thermal decomposition reactions at very high temperatures, 300 -1000 C. It has been possible, by means of a new experimental technique, to measure the time delay to explosion for a series of explosives in this hitherto unexplored range of temperature and reaction rate. This has been accomplished by loading the explosive into fine hypodermic needle tubing which can then be heated, essentially instantaneously, by a capacitor discharge. The temperature and explosive event are recorded by monitoring the resistance of the tube. The measured delay times are related to the impact sensitivities of high explosives as sensitive materials are found to explode more rapidly at a given high temperature than less sensitive ones. (Author).
Download or read book Numerical Modeling of Explosives and Propellants Second Edition written by Charles L. Mader and published by CRC Press. This book was released on 1997-08-29 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Charles Mader, a leading scientist who conducted theoretical research at Los Alamos National Laboratory for more than 30 years, sets a new standard with this reference on numerical modeling of explosives and propellants. This book updates and expands the information presented in the author's landmark work, Numerical Modeling of Detonations, published in 1979 and still in use today. Numerical Modeling of Explosives and Propellants incorporates the considerable changes the personal computer has brought to numerical modeling since the first book was published, and includes new three-dimensional modeling techniques and new information on propellant performance and vulnerability. Both an introduction to the physics and chemistry of explosives and propellants and a guide to numerical modeling of detonation and reactive fluid dynamics, Numerical Modeling of Explosives and Propellants offers scientists and engineers a complete picture of the current state of explosive and propellant technology and numerical modeling. The book is richly illustrated with figures that support the concepts, and filled with tables for quick access to precise data. The accompanying CD-ROM contains computer codes that are the national standard by which modeling is evaluated. Dynamic material properties data files and animation files are also included. There is no other book available today that offers this vital information.
Download or read book The Increased Shock Sensitivity of PBX 9502 at High Temperature written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
