Nature of the Buildup to Detonation in Solid High Explosives During Plane Shock Initiation. [PBX-9404 and PBX-9502].

Nature of the Buildup to Detonation in Solid High Explosives During Plane Shock Initiation. [PBX-9404 and PBX-9502]. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
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.

Nature of the Buildup to Detonation in Solid High Explosives During Plane Shock Initiation. [PBX-9404 and PBX-9502].

Nature of the Buildup to Detonation in Solid High Explosives During Plane Shock Initiation. [PBX-9404 and PBX-9502]. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
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.

Initiation of Preshocked High Explosives PBX-9404, PBX-9502, PBX-9501, Monitored with In-material Magnetic Gauging

Initiation of Preshocked High Explosives PBX-9404, PBX-9502, PBX-9501, Monitored with In-material Magnetic Gauging PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 9

Get Book Here

Book Description
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.

Publications of Los Alamos Research

Publications of Los Alamos Research PDF Author: Los Alamos National Laboratory
Publisher:
ISBN:
Category : Research
Languages : en
Pages : 348

Get Book Here

Book Description


Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 372

Get Book Here

Book Description


Initiation of Propagating Detonations

Initiation of Propagating Detonations PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
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.

Toward Detonation Theory

Toward Detonation Theory PDF Author: Anatoly N. Dremin
Publisher: Springer Science & Business Media
ISBN: 1461205638
Category : Technology & Engineering
Languages : en
Pages : 163

Get Book Here

Book Description
It is known that the Chapman-Jouguet theory of detonation is based on the assumption of an instantaneous and complete transformation of explosives into detonation products in the wave front. Therefore, one should not expect from the theory any interpretations of the detonation limits, such as shock initiation of det onation and kinetic instability and propagation (failure diameter). The Zeldovich-Von Neuman-Doring (ZND) theory of detonation appeared, in fact, as a response to the need for a theory capable of interpreting such limits, and the ZND detonation theory gave qualitative interpretations to the detonation limits. These interpretations were based essentially on the theoretical notion that the mechanism of explosives transformation at detonation is a combustion of a layer of finite thickness of shock-compressed explosive behind the wave shock front with the velocity of the front. However, some experimental findings turned out to be inconsistent with the the ory. A very small change of homogeneous (liquid) explosives detonation velocity with explosive charge diameter near the rather sizable failure diameter is one of the findings. The elucidation of the nature of this finding has led to the discovery of a new phenomenon. This phenomenon has come to be known as the breakdown (BD) of the explosive self-ignition behind the front of shock waves under the effect of rarefaction waves.

Detonation of Condensed Explosives

Detonation of Condensed Explosives PDF Author: Roger Cheret
Publisher: Springer Science & Business Media
ISBN: 1461392845
Category : Science
Languages : en
Pages : 442

Get Book Here

Book Description
This work marks a stage in the evolution of a scientific and technical field which has been developed by the Commissariat a l'Energie Atomique (CEA) over several decades. Many members of the staff of the CEA have won re nown in this field, and their work has brought it to the high degree of excel lence for which it is internationally recognized today. These scientists had to consider every aspect of the field, as it concerned: modeling, which has recourse to fluid thermodynamics, molecular phys ics, and chemistry; numerical evaluation, which relies on mathematical analysis and data processing; and experiments in the firing area, which require specific stress generators and instrumentation. Whilst this book is a testament to the activity and success of staff of the CEA, it also reviews a number ofthe advances made in the discipline. How ever, it is not intended to be an exhaustive account of those advances; it is assumed that the reader can, if desired, consult the standard monographs, and more recent, more specialized works (notably W.C. Davis and W. Fickett, and C.L. Mader). The history of the discipline is interesting in itself, and also as an illustra tion of the causes which lead to progress in a coherent body of scientific work. I should like to make some comments on this progress, of which there is a fascinating summary in the introduction, and which will figure largely throughout the work.

Preshock Desensitization of PBX Explosives

Preshock Desensitization of PBX Explosives PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5

Get Book Here

Book Description
Preshocking delays initiation of PBX-9404 and PBX-9501, relative to unshocked material. In PBX-9404 preshock experiments, a first shock of 2.3 GPa was followed 0.65 [mu]s later by a second shock of 5.6 GPa. In PBX-9501, a preshock of 2.8 GPa and 0.32 us duration was followed by an initiating shock of 6.0 GPA. Both PBX explosives show clear desensitization while the preshock persists. In PBX-9404, initiation of detonation occurs nearly as anticipated for the material, after coalescence of the preshock and main shock into a single wave. Multiple embedded magnetic gauges were used to measure the shock histories. Our data indicates a slightly longer run to detonation than expected, even though a single wave is initiating the material. A slight stress reduction at coalescence, as required by the shock dynamics, may be responsible for the overrun. A reactive waste is clearly evident while the preshock persists. The long run to detonation indicates that this reactive wave is not driving the initiation. A set of four preshock experiments were preformed on PBX-9502, which is unreactive at these pressures, to investigate the shock dynamics of the two waves in the HE.

Shock Wave Science and Technology Reference Library, Vol. 5

Shock Wave Science and Technology Reference Library, Vol. 5 PDF Author: Blaine Asay
Publisher: Springer
ISBN: 9783642262401
Category : Technology & Engineering
Languages : en
Pages : 618

Get Book Here

Book Description
Los Alamos National Laboratory is an incredible place. It was conceived and born amidst the most desperate of circumstances. It attracted some of the most brilliant minds, the most innovative entrepreneurs, and the most c- ative tinkerers of that generation. Out of that milieu emerged physics and engineering that beforehand was either unimagined, or thought to be f- tasy. One of the ?elds essentially invented during those years was the science of precision high explosives. Before 1942, explosives were used in munitions and commercial pursuits that demanded proper chemistry and con?nement for the necessary e?ect, but little else. The needs and requirements of the Manhattan project were of a much more precise and speci?c nature. Spatial and temporal speci?cations were reduced from centimeters and milliseconds to micrometers and nanoseconds. New theory and computational tools were required along with a raft of new experimental techniques and novel ways of interpreting the results. Over the next 40 years, the emphasis was on higher energy in smaller packages, more precise initiation schemes, better and safer formulations, and greater accuracy in forecasting performance. Researchers from many institutions began working in the emerging and expanding ?eld. In the midst of all of the work and progress in precision initiation and scienti?c study, in the early 1960s, papers began to appear detailing the ?rst quantitative studies of the transition from de?agration to detonation (DDT), ?rst in cast, then in pressed explosives, and ?nally in propellants.

The Hydrodynamic Hot Spot and Shock Initiation of Homogeneous Explosives

The Hydrodynamic Hot Spot and Shock Initiation of Homogeneous Explosives PDF Author: Charles L. Mader
Publisher:
ISBN:
Category : Detonation waves
Languages : en
Pages : 48

Get Book Here

Book Description