Download or read book Shock Initiation of the TATB based Explosive PBX 9502 Heated to 76C written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Temperature dependent Shock Initiation of TATB based High Explosives written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of temperature on the shock sensitivity of two TATB formulations PBX 9502 and LX-17 are studied over the temperature range -54°C to 252°C. The shock Hugoniot curves over this same temperature range are developed. Thermal expansion properties and porosities are used to help determine the mechanisms of thermal sensitization. Impact sensitivities over the range from ambient to 300°C are reported. Analyses of these results imply that thermal sensitization is the result of purely chemical kinetics enhancement and intracrystalline hot-spot growth. Additional results on the ambient shock sensitivity of PBX 9502 and LX-17 following thermal cycling to 252°C and back to ambient is presented.

Download or read book Embedded Electromagnetic Gauge Measurements and Modeling of Shock Initiation in the TATB Based Explosives PBX 9502 and LX 17 written by and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have completed a series of shock initiation experiments on PBX 9502 (95 weight % dry aminated TATB explosive, 5 weight % Kel-F 800 binder) and LX-17 (92.% wet aminated TATB, 7.5 % Kel-F 800). These experiments were performed on the gas/gas two stage gun at Los Alamos. Samples were prepared with ten or eleven embedded electromagnetic particle velocity gauges to measure the evolution of the wave leading up to a detonation. Additionally, one to three shock tracker gauges were used to track the position of the shock front with time and determine the point where detonation was achieved. Wave profiles indicate little delay between formation of hot-spots in the shock front and release of hotspot energy. In other words, a great deal of the buildup occurs in the shock front, rather than behind it. Run distances and times to detonation as a function of initial pressure are consistent with published data. The Ignition and Growth model with published parameters for LX-17 replicate the data very well.

Download or read book The Thermal Response of TATB Based PBXs written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the design mode of operation, TATB-based PBXs, such as PBX 9502 or LX-17, are promptly initiated by a detonator and booster system. In abnormal situations, such as accidents, a wide variety of non-design-mode insults can arise and it is desirable that these do not produce detonation but rather that, at most, they lead to a low chemical energy release. The most significant abnormal hazard is the direct shock initiation threat arising from high-velocity fragment impact. This is quite well defined and may result in a detonative response if the fragment is large enough and fast enough. However, it is of considerably greater significance to the safety envelope of these explosives whether they are at all capable of DDT (deflagration-to-detonation transition), either at ambient or elevated temperatures since accidental insults to the explosive, either mechanical or thermal, that may produce local burning are both more numerous and more likely than shock loading. The purpose of this document is to demonstrate, based on the accumulated body of conservative experimental testing, that in explosive geometries and masses relevant to the Weapons Program, TATB-based PBXs do not present a deflagration-to-detonation transition (DDT) hazard at any temperature. This is a significant statement since it removes detonative outcome concerns from the majority of insult scenarios on TATB-based charges. It does not address the response of included detonator and booster assemblies, the response of which must be considered separately.

Download or read book Shock Initiation of PBX 9502 at Elevated Temperatures written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nature of the Buildup to Detonation in Solid High Explosives During Plane Shock Initiation PBX 9404 and PBX 9502 written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two models for the initiation process are compared to results of experimental studies of initiation of detonation in two high explosives, PBX-9404 (HMX-based) and PBX-9502 (TATB-based), by sustained shock waves. A critical examination of the model known as single-curve buildup is made. Several comparisons are made with experimental results for the two explosives. The model describes the observed shock trajectories moderately well although it has some limitations. These are manifested by an examination of the relation between input pressure and distance of run to detonation. The data are also compared with model solutions for the initiation process which assume self-similar flow. The model can fit the experimental shock trajectory reasonably well but difficulties are encountered in attempting to complete the solution for the entire flow field. For PBX-9404, published pressure-time profiles are examined for self-similar character. The measured profiles show substantial disagreement with the similarity model.

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 Detonation Reaction Zone Studies on TATB Explosives PBX 9502 95 written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interface velocity histories between heterogeneous detonating explosives and transparent windows, separated by a thin (13 .mu.m) aluminum shim, have been obtained with an image-intensified rotating-mirror streak camera and a Fabry-Perot velocity interferometer system. Seven TATB-based explosives were studied with PMMA windows for typically three charge lengths. Two of the explosives were also studied with LiF windows. In each case a non-steady detonation was observed, with each increasing charge length showing a corresponding increase in the interface velocity histories. Time resolution and velocity error are estimated to be about 6 ns and 2%, respectively. Numerical simulations for one of the explosives, for which a shock-strength modified Arrhenius rate law (DAGMAR) and an assumed equation of state (HOM) had been previously calibrated wth shock initiation gauge data, gave good agreement with the experimental velocity histories. 19 refs., 8 figs., 2 tabs.

Download or read book Detonation Shock Dynamics Calibration for PBX 9502 with Temperature Density and Material Lot Variations written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a methodology for scaling the detonation shock dynamics D{sub n}[[kappa]] calibration function to accommodate variations in the HE starting material. We apply our model to the insensitive TATB-based explosive PBX 9502, for which we have enough front curvature rate stick data to characterize three material attributes: initial temperature T0, nominal density [rho]0, and manufacturing lot (representing different microstructures). A useful feature of the model is that it returns an absolute estimate for the reaction zone thickness, [delta]. Lacking demonstrated material metrics(s), we express microstructural variation indirectly, in terms of its effect on [delta]. This results in a D{sub n}[[kappa]] function that depends on T0, [rho]0, and [delta]. After examining the separate effects of each parameter on D{sub n}[[kappa]], we compute an arc geometry as a validation problem. We compare the calculation to a PBX 9502 arc experiment that was pressed from one of the calibrated HE lots. The agreement between the model and experiment is excellent. We compute worst, nominal, and best-performing material parameter combinations to show how much difference accrues throughout the arc.

Download or read book Impact Shock Sensitivity of a TATB Based Explosive Relevant to Specific Heat Properties written by and published by . This book was released on 2006 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is a supplementary follow-on to U.S. Army Missile Command (MICOM) TR-RD-SS-95-2, and Aviation and Missile Command (AMCOM) TR-RD-SS-99-8 that related plane impact shock sensitivity of CHNO energetic material to specific heat (Cp) per average atom magnitude and reactive temperature (TR) conditions. Specifically, plane shock energy input equal to the thermal vibratory energy increment (this is the area under the Cp versus T data curve between experimental temperature, (T sub EXP), conditions and reactive temperature conditions) is sufficient to cause shock induced reactions, up to and including detonation in energetic materials. This is demonstrated at four different test temperatures ((T SUB EXP)) for PBX-9502.

Download or read book The Hydrodynamic Hot Spot and Shock Initiation of Homogeneous Explosives written by Charles L. Mader and published by . This book was released on 1962 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ignition and Growth Modeling of the Shock Initiation of PBX 9502 at 55C and 196C written by and published by . This book was released on 2015 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Initiation of Propagating Detonations written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The initiation of propagating detonation in PBS 9404, PBX 9502, and X0219 by hemispheric intiators of PBX 9404, 1.8 g/cm3-TATB, and X0351 is described numerically, using the two-dimensional Lagrangian code, 2DL, and the Forest Fire rate to describe the heterogeneous explosive shock initiation process. The initiation of propagating detonation in the insensitive explosive PBX 9502 by triple-shock-wave interaction from three initiators has been modeled using the three-dimensional, reactive, Eulerian hydrodynamicd code, 3DE.

Download or read book Initiation of Preshocked High Explosives PBX 9404 PBX 9502 PBX 9501 Monitored with In material Magnetic Gauging written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Desensitization of explosives by preshocking is being studied using the well-supported plane shock waves generated by a gas gun. Evolution of the waves in the explosive is monitored using in-material multiple magnetic gauges to measure particle velocity in the lagrangian frame, over ≈ 3[mu]s of run. PBX-9404, PBX-9502 have been studied, at pressures up to 10.5 GPa. A substantial extension of the run to detonation is observed in PBX-9404, with the run beginning approximately at the end of the preshocked region. A reactive wave is observed while the preshock persists in both PBX-9404 and PBX-9501, but evidently does not contribute to the detonation wave or shorten the run to detonation. PBX-9502 is inert at pressures accessible with the gas gun, but serves to clarify the progress of multiple shocks over the off-Hugoniot EOS surface and the shock dynamics of wave coalescence.

Download or read book Summary of Shock Initiation Data for TATB based Explosives written by and published by . This book was released on 2010 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This short summary of previously published data was compiled to provide the actual in-situ gauge data to allow modeling of these experiments. Although the purpose here is to fulfill a deliverable for a JOWOG 9 Focused Exchange (09-006), it is just as applicable to other exchanges as well. The TATB materials described here are Ultra Fine (UF) TATB and LX-17 (92.5% TATB and 7.5% Kel-F by weight), with the details of the experiments provided in the prior publications. The data is provided in the appendices of the document, but will be provided electronically as text files due to being amenable to importing into the code in that manner for comparison.

Download or read book SHOCK INITIATION EXPERIMENTS ON THE TATB BASED EXPLOSIVE RX 03 GO WITH IGNITION AND GROWTH MODELING written by and published by . This book was released on 2009 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shock initiation experiments on the TATB based explosive RX-03-GO (92.5% TATB, 7.5% Cytop A by weight) were performed to obtain in-situ pressure gauge data, characterize the run-distance-to-detonation behavior, and calculate Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the explosive sample with manganin piezoresistive pressure gauge packages placed between sample slices. The RX-03-GO formulation utilized is similar to that of LX-17 (92.5% TATB, 7.5% Kel-f by weight) with the notable differences of a new binder material and TATB that has been dissolved and recrystallized in order to improve the purity and morphology. The shock sensitivity will be compared with that of prior data on LX-17 and other TATB formulations. Ignition and Growth modeling parameters were obtained with a reasonable fit to the experimental data.

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.