The Performance of Pressure Vessel Using Concentric Double Cylindrical High Explosive

2003 ◽  
Author(s):  
Toru Hamada ◽  
Yuichi Nakamura ◽  
Kenji Murata ◽  
Yukio Kato ◽  
Shigeru Itoh
Keyword(s):  
High Pressure ◽  
Detonation Velocity ◽  
Pressure Vessel ◽  
High Explosive ◽  
Detonation Pressure ◽  
Flyer Plate ◽  
Low Velocity ◽  
High Explosives ◽  
Detonation Velocity And Pressure ◽  
Manganin Gauge

In recent year, it has been hoped to develop a device that generate high pressure in the field of the material consolidation. Therefore a phenomenon of over driven detonation (O.D.D.) [1] that was one of the detonation phenomenons has been researched. The detonation velocity and pressure that is higher than Chapman-Jouguet state generate in the state of O.D.D.. But, in the method of using the flyer plate that has been investigated, it is difficult to apply to the material consolidation since the region where O.D.D. phenomenon generates is very small. Therefore, as a new method of effectively generating O.D.D., the method of combining two kinds of the high explosives was developed. This method is a technique that is generated O.D.D. in the low velocity explosive by making a double cylindrical explosive of the high velocity explosive and low velocity explosive. The detonation pressure of low velocity explosive in a double cylinder was measured by Manganin gauge. The detonation pressure was 2.0 times over higher than the Chapman-Jouguet pressure.

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.

Pressure Measurement of Non-Ideal Detonation in Ammonium Nitrate Based High Energetic Material

2014 ◽  
Vol 566 ◽  
pp. 385-390 ◽  
Author(s):  
Yuuki Yamamoto ◽  
Shiro Kubota ◽  
Tei Saburi ◽  
Yuji Wada ◽  
Atsumi Miyake
Keyword(s):  
Ammonium Nitrate ◽  
Detonation Velocity ◽  
Peak Pressure ◽  
Energetic Material ◽  
Pressure Gauge ◽  
Steel Tube ◽  
Accurate Information ◽  
Detonation Pressure ◽  
Tube Test ◽  
Detonation Velocity And Pressure

In order to know accurate information on the non-ideal detonation pressure, steel tube test was carried out on ammonium nitrate (AN) and activated carbon (AC) mixtures. In this test, detonation velocity and pressure were measured simultaneously by varying thickness of PMMA placed between AN/AC and pressure gauge. The length and the diameter of the steel tube were 350 mm and 35.5 mm. The results showed that shock pressure attenuation in PMMA was not observed for this experimental condition (PMMA gap; 3-5 mm). The averaged measured peak pressure and detonation velocity were 3.4 GPa and 3.2 km/s.

Investigation of Jet Formation with Overdriven Detonation in High Density Explosive

2007 ◽  
Vol 566 ◽  
pp. 327-332 ◽  
Author(s):  
Hisaatsu Kato ◽  
Kenji Murata ◽  
Shigeru Itoh ◽  
Yukio Kato
Keyword(s):  
Numerical Simulation ◽  
Detonation Velocity ◽  
Tungsten Powder ◽  
High Density ◽  
Shaped Charge ◽  
Detonation Pressure ◽  
Jet Formation ◽  
High Explosives ◽  
Overdriven Detonation ◽  
Penetration Velocity

To increase largely the performance of shaped charge, it is required to generate detonation velocity much higher than CJ velocity or detonation pressure much higher than CJ pressure of existing high explosives. One solution is the application of overdriven detonation phenomena. In this study, the effects of overdriven detonation in tungsten loaded high density explosive on the performance of shaped charge were demonstrated by experiments and numerical simulation. Sample shaped charge was composed of the inner layer tungsten loaded high density PBX and outer layer high velocity PBX. Concentration of tungsten powder in high density PBX was varied from 20 to 60% in mass. The pressure of overdriven detonation in inner layer PBX was measured by PMMA gauge, and was shown to be higher than 50GPa. The experimental results showed that the initial jet velocity and jet penetration velocity in target plates were largely increased by the effects of the overdriven detonation in tungsten loaded high density PBX.

Measured temperature and pressure dependence of Vp and Vs in compacted, polycrystalline sI methane and sII methane–ethane hydrate

2003 ◽  
Vol 81 (1-2) ◽  
pp. 47-53 ◽  
Author(s):  
M B Helgerud ◽  
W F Waite ◽  
S H Kirby ◽  
A Nur
Keyword(s):  
High Pressure ◽  
Shear Wave ◽  
Pressure Dependence ◽  
Gas Hydrate ◽  
Pressure Vessel ◽  
Wave Speed ◽  
Measured Temperature ◽  
Shear Wave Speed ◽  
Temperature And Pressure ◽  
Fixed End

We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane–ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17°C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between –20 and 15°C and 0 to 105 MPa applied piston pressure. PACS No.: 61.60Lj

Compressibility of water in magma and the prediction of density crossovers in mantle differentiation

2008 ◽  
Vol 366 (1883) ◽  
pp. 4239-4252 ◽  
Author(s):  
Carl B Agee
Keyword(s):  
High Pressure ◽  
Compressible Liquid ◽  
Silicate Melt ◽  
Liquid Density ◽  
Low Velocity ◽  
Oxide Component ◽  
The Earth ◽  
Liquid Oxide ◽  
Planetary Differentiation ◽  
Pressure Regime

Hydrous silicate melts appear to have greater compressibility relative to anhydrous melts of the same composition at low pressures (<2 GPa); however, at higher pressures, this difference is greatly reduced and becomes very small at pressures above 5 GPa. This implies that the pressure effect on the partial molar volume of water in silicate melt is highly dependent on pressure regime. Thus, H 2 O can be thought of as the most compressible ‘liquid oxide’ component in silicate melt at low pressure, but at high pressure its compressibility resembles that of other liquid oxide components. A best-fit curve to the data on from various studies allows calculation of hydrous melt compression curves relevant to high-pressure planetary differentiation. From these compression curves, crystal–liquid density crossovers are predicted for the mantles of the Earth and Mars. For the Earth, trapped dense hydrous melts may reside atop the 410 km discontinuity, and, although not required to be hydrous, atop the core–mantle boundary (CMB), in accord with seismic observations of low-velocity zones in these regions. For Mars, a density crossover at the base of the upper mantle is predicted, which would produce a low-velocity zone at a depth of approximately 1200 km. If perovskite is stable at the base of the Martian mantle, then density crossovers or trapped dense hydrous melts are unlikely to reside there, and long-lived, melt-induced, low-velocity regions atop the CMB are not predicted.

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