Improvement Effect of Discharge Circuit for the Underwater Shock Wave

2013 ◽  
Vol 767 ◽  
pp. 199-204 ◽  
Author(s):  
Osamu Higa ◽  
Takumi Matsui ◽  
Ryo Matsubara ◽  
Katsuya Higa ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
Peak Pressure ◽  
Discharge Circuit ◽  
Peak Time ◽  
Underwater Shock Wave ◽  
Improvement Effect ◽  
Underwater Shock

The purpose of this research is to examine the improvement effect of discharge circuit impedances. In this research, we decreased the inductive impedance of discharge circuit, and shorted the current peak time, and increased the current peak as well. As a result, the peak pressure increased to 135 %.

Effects of Steel Case on Underwater Shock Wave

2011 ◽  
Vol 52-54 ◽  
pp. 943-948
Author(s):  
Ji Li Rong ◽  
Da Lin Xiang ◽  
Jian Li
Keyword(s):  
Shock Wave ◽  
Peak Pressure ◽  
Underwater Explosion ◽  
Steel Shell ◽  
Cylindrical Charge ◽  
Underwater Shock Wave ◽  
Shock Wave Energy ◽  
Lag Effect ◽  
Underwater Shock ◽  
Different Thickness

The effects of steel case confinement for the aluminized explosive on underwater explosion(UNDEX) were experimentally and numerically investigated. The experimental results using 1kg cylindrical charge cased 6mm steel shell, show that steel case enhance the peak pressure, impulse, shock wave energy and decay time relative to the bare charge. The effect of different thickness of steel case was analyzed. With the increase of the case thickness, the shock wave were enhanced first and weaken later, and there is a lag-effect for the peak pressure of shock wave. There is an optimal case thickness which could maximum enhance the peak pressure. According to dimensional analysis, it's found that the ratio of case mass and charge mass( ) is a better dimensionless parameter to estimate UNDEX for a cased charge.

Study on Behavior of Underwater Shock Wave in Enclosed Vessel

2013 ◽  
Vol 767 ◽  
pp. 68-73
Author(s):  
Yusuke Seki ◽  
Hiroshi Fukuoka ◽  
Yoshitaka Miyafuji ◽  
Hirofumi Iyama ◽  
Osamu Higa ◽  
...  
Keyword(s):  
Shock Wave ◽  
Food Processing ◽  
Main Parameter ◽  
Peak Pressure ◽  
Focal Point ◽  
Processing System ◽  
Major Axis ◽  
Minor Axis ◽  
Underwater Shock Wave ◽  
Underwater Shock

We are developing the food processing system by using the underwater shock wave. The effect of the underwater shock wave on the pressure in the vessel is the important factor for food processing system in this research. The purpose of this study is to research the behavior of the underwater shock wave in the enclosed vessel to investigate the influence of the contour of the elliptical vessel on the pressure. In this research, we used the elliptical shape for the vessel and the explosive was used to generate the shock wave. Numerical calculation was carried out by using LS-DYNA. The ratio of the length of the major axis to minor axis of the elliptical were changed, as a main parameter. As a result, it was found that underwater shock wave was generated and propageated in the elliptical vessel following the explosion. The underwater shock wave was coverged at the focal point. At the same time, the pressure was increased by the coverged underwater shock wave at the focal point in the all elliptical vessels. It was also found that the peak pressure at the focal point was determined by the contour of the elliptical vessel.

scholarly journals Experimental Study on Peak Pressure of Shock Waves in Quasi-Shallow Water

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Zhenxiong Wang ◽  
Wenbin Gu ◽  
Jianqing Liu
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Peak Pressure ◽  
Small Scale ◽  
Underwater Shock Wave ◽  
Underwater Explosions ◽  
Underwater Shock ◽  
Similarity Law ◽  
Similarity Laws ◽  
Water Depths

Based on the similarity laws of the explosion, this research develops similarity requirements of the small-scale experiments of underwater explosions and establishes a regression model for peak pressure of underwater shock waves under experimental condition. Small-scale experiments are carried out with two types of media at the bottom of the water and for different water depths. The peak pressure of underwater shock waves at different measuring points is acquired. A formula consistent with the similarity law of explosions is obtained and an analysis of the regression precision of the formula confirms its accuracy. Significance experiment indicates that the influence of distance between measuring points and charge on peak pressure of underwater shock wave is the greatest and that of water depth is the least within the range of geometric parameters. An analysis of data from experiments with different media at the bottom of the water reveals an influence on the peak pressure, as the peak pressure of a shock wave in a body of water with a bottom soft mud and rocks is about 1.33 times that of the case where the bottom material is only soft mud.

A Study on Shock Energy for Concrete Destruction Using Underwater Shock Wave

2007 ◽  
Vol 566 ◽  
pp. 225-230 ◽  
Author(s):  
Masahiko Otsuka ◽  
Naoki Okamoto ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Peak Pressure ◽  
Concrete Block ◽  
Metal Vapor ◽  
Metal Wire ◽  
Underwater Shock Wave ◽  
Long Duration ◽  
Discharge Duration ◽  
Underwater Shock

In this study, the destruction of concrete block using underwater shock wave generated by high current is studied. A metal wire was connected to an electrode and a high voltage impulsive current was passed through it to generate the underwater shock wave. The underwater shock wave was investigated by optical observation using a high-speed camera and pressure measurement. A comparison was made on the shock wave generated from the electrode with and without connecting it to a metal wire. The underwater shock wave generated from electrode without metal wire showed the existence of many shock waves by continuous plasma within discharge duration, and the duration of the pressure pulse was long in this case. The peak pressure of underwater shock wave generated from metal wire explosion was higher than the previous case due to the reaction of metal vapor and water, whereas the pressure duration was less. The concrete block was efficiently destructed by the effect of underwater shock pressure of high impulse. The high peak pressure and long duration are necessary for the destruction of concrete block. It is suggested that high pressure induces crack to the structure, and the long pulse duration destructs the structure.

Explosive Welding Using Underwater Shock Wave Generated by the Detonation of the Detonating Code

2011 ◽  
Vol 673 ◽  
pp. 265-270 ◽  
Author(s):  
Akihisa Mori ◽  
Li Qun Ruan ◽  
Kazumasa Shiramoto ◽  
Masahiro Fujita
Keyword(s):  
Shock Wave ◽  
Sound Velocity ◽  
Detonation Velocity ◽  
Explosive Welding ◽  
New Method ◽  
Underwater Shock Wave ◽  
Metal Plates ◽  
Experimental Parameters ◽  
Underwater Shock ◽  
Point Velocity

Detonating code is a flexible code with an explosive core. It is used to transmit the ignition of explosives with high detonation velocity in the range of 5.5 to 7 km/s. However, it is difficult to use detonating code for the explosive welding of common metals since the horizontal point velocity usually exceeds the sound velocity. Hence, in the present work, a new method using underwater shock wave generated by the detonation of detonating code was tried. The details of the experimental parameters and the results are presented. From the results it is observed that the above technique is suitable to weld thin metal plates with relatively less explosives.

Von Neumann reflection of underwater shock wave

1999 ◽  
Vol 85 (1-3) ◽  
pp. 48-51 ◽  
Author(s):  
Y Nadamitsu ◽  
Z.Y Liu ◽  
M Fujita ◽  
S Itoh
Keyword(s):  
Shock Wave ◽  
Underwater Shock Wave ◽  
Von Neumann ◽  
Underwater Shock

Numerical Simulation on Explosive Welding Process Using Reflected Underwater Shock Wave

2007 ◽  
Vol 566 ◽  
pp. 309-314
Author(s):  
Kazumasa Shiramoto ◽  
Masahiro Fujita ◽  
Yasuhiro Ujimoto ◽  
Hirofumi Iyama ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Explosive Welding ◽  
Welding Process ◽  
Underwater Shock Wave ◽  
Underwater Shock ◽  
Effective Use

The paper describes a numerically simulated result for the explosive welding using reflected underwater shock wave. Through the numerical simulation, the effective use of reflected underwater shock wave was clearly suggested and the method to improve the assembly was demonstrated.

Sign in / Sign up

Export Citation Format

Share Document