Characteristics of the Flying Metal Plate System Using Overdriven Detonation

2002 ◽  
Author(s):  
Shigeru Itoh ◽  
Hideyuki Morimoto ◽  
Shiro Nagano ◽  
Masahiko Otsuka ◽  
Eiji Hida ◽  
...  
Keyword(s):  
Metal Plate ◽  
New Materials ◽  
Overdriven Detonation ◽  
Detonation Phenomenon ◽  
Plate System

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.

The Performance of Pressure Vessel Using Concentric Double Cylindrical High Explosive

2004 ◽  
Vol 126 (4) ◽  
pp. 409-413 ◽  
Author(s):  
Toru Hamada ◽  
Yuichi Nakamura ◽  
Shigeru Itoh
Keyword(s):  
High Velocity ◽  
High Explosive ◽  
Maximum Pressure ◽  
Detonation Pressure ◽  
Low Velocity ◽  
High Explosives ◽  
Detonation Process ◽  
Set Up ◽  
Overdriven Detonation ◽  
Detonation Phenomenon

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.

Numerical Study of Overdriven Detonation Phenomenon

2005 ◽  
Author(s):  
K. Mahmadi ◽  
M. Souli ◽  
N. Aquelet
Keyword(s):  
Numerical Study ◽  
Detonation Pressure ◽  
Explicit Finite Element ◽  
Structure Interaction ◽  
High Velocity Impacts ◽  
Detonation Process ◽  
Material Points ◽  
Overdriven Detonation ◽  
Detonation Phenomenon ◽  
Good Agreement

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.

VISUALIZATION OF AN OVERDRIVEN DETONATION PHENOMENON IN A HIGH EXPLOSIVE

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

A new type of defect structure in 124-superconducting oxide revealed by HREM

1991 ◽  
Vol 49 ◽  
pp. 1092-1093
Author(s):  
R. Sharma ◽  
B.L. Ramakrishna ◽  
N.N. Thadhani ◽  
D. Hianes ◽  
Z. Iqbal
Keyword(s):  
Shock Wave ◽  
Defect Structure ◽  
Neutron Radiation ◽  
Weak Links ◽  
Defect Structures ◽  
New Materials ◽  
New Type ◽  
Current Densities ◽  
Processing Techniques ◽  
Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

Discussion on “New materials and processes in the field of engineering” at the Preston Section of the Institution

1936 ◽  
Vol 15 (12) ◽  
pp. 686
Author(s):  
Hodgson ◽  
Johnson ◽  
Skipper ◽  
Wilcock ◽  
Bailey ◽  
...  
Keyword(s):  
New Materials
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