Overdriven detonation phenomenon in high explosive

Author(s):  
Z. Liu
2004 ◽  
Vol 126 (4) ◽  
pp. 409-413 ◽  
Author(s):  
Toru Hamada ◽  
Yuichi Nakamura ◽  
Shigeru Itoh

The detonation pressure from the steady detonation of high explosives is a characteristic. Nevertheless, in materials processing using high explosives, there are cases when the detonation pressure does not match the intended pressure. In this investigation, as a new method of generating the overdriven detonation effectively, a double cylindrical high explosive set up using two kinds of explosives was developed, and its basic performance is analyzed. The concentric double cylindrical high explosive set up was composed of a high velocity explosive and a low velocity explosive, and the overdriven detonation was performed in the low velocity explosive. In this experiment, the ion gap was set up in the high velocity explosive and low velocity explosive respectively, and the detonation velocity was measured. The detonation pressure was also measured by setting up a manganin gauge (Kyowa Electric Instrument Co., Ltd.,) at the position where the generation of the overdriven detonation phenomenon was expected. Furthermore, the overdriven detonation process of the concentric double cylindrical high explosive was continually observed by numerical analysis and the framing photography. From the experimental results, the very high pressure region including the mach stem was observed in the low velocity explosive, and the overdriven detonation phenomenon was confirmed. The maximum pressure value of the concentric double cylindrical high explosive set up was 2.3 times higher than the Chapman-Jouguet pressure of the single explosive.


1999 ◽  
Vol 6 (4) ◽  
pp. 295-302 ◽  
Author(s):  
Shigeru Itoh ◽  
Zhi-yue Liu ◽  
Shiro Nagano ◽  
Hiroshi Kitaki

Author(s):  
Shigeru Itoh ◽  
Hirofumi Iyama ◽  
K. Raghukandan ◽  
Shiro Nagano ◽  
Ryo Matsumura ◽  
...  

In the material processing such as shock synthesis and powder consolidation by shock waves the method for generating dynamic pressure is of very importance for the final recovered materials. A general and convenient way for producing shock wave needed in such field is to take advantage of the explosion effect from high explosive. Therefore, it becomes an interest subject how to produce dynamic pressure as high as possible under the given high explosive. Starting from this motivation, we put forward a method of high-pressure generation by using the overdriven detonation of high explosive. The basic configuration for this device is summarized in the following. A metal flyer accelerated by the high explosive is used to impact another layer of high explosive to incur an overdriven detonation in this layer of explosive. The overdriven detonation of high explosive acts on the powder materials, providing the high dynamic pressure for it. To examine the efficiency of this combination, a numerical computation is performed to this system. The details on the illustration of this system and numerical treatment will be given.


Author(s):  
K. Mahmadi ◽  
M. Souli ◽  
N. Aquelet

The overdriven detonation refers to detonation process in which the main detonation parameters, such as detonation pressure and propagating velocity, exceed the corresponding Chapman-Jouguet (C-J) values. This kind of detonation can be occurred when the flyer plate of high velocity impacts the explosive. So, in this work numerical simulation of overdriven detonation (following O.D.D.) phenomenon, which brings out higher detonation pressures than C-J pressure of an explosive is considered. The shock-structure interaction in this fast event is modeled by a penalty coupling, which permits to couple a Lagrangian mesh of the plate to material points of a multi-material Eulerian flow. This technique has been used successfully in many areas of applications, including automotive and industrial fields. By using an explicit finite element method, a good agreement between numerical and experimental results will valid penalty coupling capabilities to solve accurately O.D.D. phenomenon.


2004 ◽  
Vol 126 (2) ◽  
pp. 264-268 ◽  
Author(s):  
Zhi-Yue Liu ◽  
Katsumi Tanaka ◽  
Shigeru Itoh

In the material processing such as shock synthesis and powder consolidation by shock waves the method for generating dynamic pressure is a vital factor for the quality of the final recovered materials. A general and convenient way for producing shock wave demanded in such applications is to take advantage of the explosion effect from high explosive. Under normal conditions, a given high explosive can only provide some kind of magnitude of dynamic pressure after its explosion. Therefore, it is whether possible to obtain the higher dynamic pressure by adequately changing the form of the explosion of high explosive. Starting from this motivation, we put forward a new method for producing high dynamic pressure from the use of the overdriven detonation of high explosive. The proposed device consists of the following configurations. A metal flyer accelerated by the high explosive is used to impact another layer of high explosive to incur an overdriven detonation in this layer of explosive. The overdriven detonation of high explosive acts on the powder materials, bringing out high dynamic pressures to the materials studied. To examine the efficiency of this combination on the improvement of dynamic pressure, a numerical computation is performed on this system. The details on the illustration of this method as well as the results of numerical investigation will be given.


Author(s):  
Zhi-Yue Liu ◽  
Katsumi Tanaka ◽  
Shigeru Itoh

In the material processing such as shock synthesis and powder consolidation by shock waves the method for generating dynamic pressure is of very importance for the final recovered materials. A general and convenient way for producing shock wave needed in such field is to take advantage of the explosion effect from high explosive. Therefore, it becomes an interest subject how to produce dynamic pressure as high as possible under the given high explosive. Starting from this motivation, we put forward a method of high-pressure generation by using the overdriven detonation of high explosive. The basic configuration for this device is summarized in the following. A metal flyer accelerated by the high explosive is used to impact another layer of high explosive to incur an overdriven detonation in this layer of explosive. The overdriven detonation of high explosive acts on the powder materials, providing the high dynamic pressure for it. To examine the efficiency of this combination, a numerical computation is performed to this system. The details on the illustration of this system and numerical treatment will be given.


Author(s):  
Shigeru Itoh ◽  
Hideyuki Morimoto ◽  
Shiro Nagano ◽  
Masahiko Otsuka ◽  
Eiji Hida ◽  
...  

The pressure occured by an explosive is limited by its own property and its own performance. This pressure is called “C-J pressure”. If the pressure that is higher than C-J pressure can occur, it is very effective for a development field of new materials. So, Overdriven Detonation phenomenon in explosive is considered, that brings out higher detonation pressures than C-J pressure of an explosive. In this study, the flying metal plate accelerated by driver explosive impact against driven explosive, and Overdriven Detonation phenomenon occurs, the relation between driver explosive and driven explosive and the work on the front of the explosive is reported.


2001 ◽  
Author(s):  
Zhi-Yue Liu ◽  
Shiro Kubota ◽  
Shirou Nagano ◽  
Shigeru Itoh

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