Investigation of a converging underwater shock wave using high-speed photography

1995 ◽  
Author(s):  
Shigeru Itoh ◽  
S. Kubota ◽  
Shirou Nagano ◽  
I. Morita ◽  
A. Chiba ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
High Speed Photography ◽  
Underwater Shock Wave ◽  
Underwater Shock

A Study of Developing Composite Material of Penetrated Diamond Particles Into Metal Plate

2009 ◽  
Author(s):  
Keijiro Nishi ◽  
Shigeru Tanaka ◽  
Shigeru Itoh
Keyword(s):  
Thermal Conductivity ◽  
Shock Wave ◽  
Composite Material ◽  
High Speed ◽  
High Hardness ◽  
Optical Microscope ◽  
Metal Plate ◽  
Underwater Shock Wave ◽  
Diamond Particles ◽  
Underwater Shock

An explosive welding technique which uses underwater shock wave to weld thin aluminum plate has been studied and the technical advantages were reported. In this research, we propose a method to produce a composite material using an underwater shock wave generated by detonation of explosive. In the production process, a metal plate (flyer plate) accelerates to a high speed by the underwater shock wave, and collided with diamond particles and penetrated the metal plate. Diamonds were used as the particles and aluminum plates (A1050) as the flyer plates. Diamond has high hardness and excellent thermal conductivity, therefore diamond should provide improvement in the thermal conductivity of the composite material. From recovered sample, the multilayer joined surface including diamond particles was observed using an optical microscope. The production of the pipe of composite materials was attempted using this technique as the application. Details of the experimental methods and results are reported in this paper.

New Technique for “Cullet” Generation of Glass Bottles by Using Underwater Shockwave

2006 ◽  
Vol 326-328 ◽  
pp. 1551-1554
Author(s):  
Hidetoshi Sakamoto ◽  
Shinjiro Kawabe ◽  
Kazuo Satoh ◽  
Masahiro Himeno ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Fracture Process ◽  
Image Converter ◽  
Glass Bottle ◽  
Underwater Shock Wave ◽  
Application Technique ◽  
System A ◽  
Underwater Shock ◽  
Glass Bottles

As the application technique for glass bottle’s recycling system, a new “Cullet” generation method by using underwater shock wave was proposed. This small fragmentation technique of glass bottles has a lot of excellent advantages such as the simplification of process by simultaneous cleaning and crushing operation, the high collect rate of “Cullet” and so on. In this study, the relation between of the explosive conditions and “Cullet” sizes were clarified and the high speed fracture process of glass bottle was observed by framing photograph of high speed image converter.

Exfoliation of Marine Organisms Technology by Using Underwater Shock Wave

2005 ◽  
Author(s):  
Toshiaki Watanabe ◽  
Hirofumi Iyama ◽  
Ayumi Takemoto ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Marine Organisms ◽  
High Speed Camera ◽  
Sluice Gate ◽  
Underwater Shock Wave ◽  
Manual Operation ◽  
Fluid Resistance ◽  
Personnel Expenses ◽  
Underwater Shock

Adhesion problem of marine organisms often becomes a problem, in the case of ship, marine floating construction and sluice gate of power plant. These make fluid resistance of a hull increase, cause a buoyancy fall, or cause reducing coolant etc. Although these are chiefly removed by manual operation now, immense expense and immense labors, such as personnel expenses and time and effort, are needed. We tried application of an underwater shock wave, in order to solve these problems. Interference of a shock wave and the mechanism of marine organisms exfoliation were explored using the explosive and PMMA plate, which imitated a marine organisms adhesion. The process of exfoliation of organisms from PMMA plate was observed by using of the high-speed camera.

Basic Study on the Crushing of Frozen Soil by Shock Loading

2007 ◽  
Author(s):  
Toshiaki Watanabe ◽  
Hironori Maehara ◽  
Masahiko Otsuka ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Shock Loading ◽  
Underwater Explosion ◽  
Frozen Soil ◽  
High Speed Camera ◽  
Underwater Shock Wave ◽  
Basic Study ◽  
Underwater Shock ◽  
A New Technique

The aim of study is to confirm a new technique that can crush the frozen soil and/or ice block using underwater shock wave generated by the underwater explosion of explosive. This technique can lead to the earlier sowing, which can have the larger harvest because the duration of sunshine increases. Especially, in Hokkaido prefecture, Japan, if the sowing is carried out in April, we can expect to have 150% of harvest in the ordinary season. This technique is effective against the cold regions. For example, Korea, China, Mongolia, Russia, Norway, and Sweden, etc. At first, we carried out experiments usung a detonating fuse and ice block. The process of ice breaking was observed by means of a high-speed camera. In order to check about that influence we tried to give an actual frozen soil a shock wave.

A Deburring Process Performed by Underwater Shock Wave

2011 ◽  
Vol 673 ◽  
pp. 271-274 ◽  
Author(s):  
Kazumasa Shiramoto ◽  
Junki Shimizu ◽  
Akiyoshi Kobayashi ◽  
Masahiro Fujita
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Present Report ◽  
Shock Pressure ◽  
Normal Operation ◽  
Underwater Shock Wave ◽  
Water Flows ◽  
Underwater Shock ◽  
Machining Operations ◽  
Equipment Performance

A burr is most commonly created after machining operations, such as drilling. Drilling burrs, for example, are common when drilling almost any material. When burrs are broken during the operation of a machine including the parts with the created burrs, the broken piece is in fear of disturbing normal operation or damaging the parts of the machine, so that the sufficient deburring is requested because it can affect equipment performance, reliability, and durability. Several deburring method have been developed up to date. In the present report, we proposed a deburring method by means of applying underwater shock wave. The method is as follows: after all entrance of holes is closed with seal tape, the equipment is submerged, so that all passages for running fluid are filled with air. The explosive is set under water near the entrance of the main hole. As soon as the explosive is detonated, the underwater shock wave generated at the detonation point arrives at the entrance of the hole and breaks through the tape. The water flows into the hole with a high speed. The burr is broken by water hummer action of high speed. In the present investigation, the experiments of deburring are performed under some setting conditions of explosive. It is found by experimental results, that the burr is sufficiently removed with the newly proposed method. When the shock pressure is sufficiently high at the entrance of hole, the burr is broken surface is smooth as polished one. When the shock pressure is not sufficiently high, the broken surface of the burr is notched.

Propagation of Underwater Shock Wave and Gas Bubble Behavior Induced by Electrical Discharge in Water

2014 ◽  
Vol 566 ◽  
pp. 403-408
Author(s):  
Hideki Hamashima ◽  
Seisaku Iwasa ◽  
Hironori Maehara ◽  
Shigeru Itoh ◽  
Kazuyuki Hokamoto
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Electrical Discharge ◽  
High Speed ◽  
Optical Observation ◽  
Gas Bubble ◽  
Bubble Behavior ◽  
Underwater Shock Wave ◽  
Whole Process ◽  
Underwater Shock

The basic behavior during underwater electrical discharge up to 10 kJ stored energy is investigated through both numerical analysis and optical-observation experiments. Since the authors have been investigating the use of underwater exploding phenomena for food processing and other applications, it is necessary to know the whole process which may affect the quality of the samples recovered. In the present investigation, the propagation of underwater shock wave was measured using a high-speed camera and compared with the numerically simulated results using LS-DYNA. Also, the motion of gas bubble, which is induced quite after the propagation of the shock wave, was measured and compared with the numerical simulation using the same code. The pressure of the bubble is not such high as the shock wave, but it is known that the impulse is not possible to be ignored due to its relatively long duration of the pressurization. Through a series of optical-observation experiments, it is confirmed that the numerical simulation is potentially possible to predict the whole phenomena for processing foods and other materials.

An Investigation on Underwater Explosive Bonding Process

2001 ◽  
Vol 123 (4) ◽  
pp. 486-492 ◽  
Author(s):  
Hirofumi Iyama ◽  
Akio Kira ◽  
Masahiro Fujita ◽  
Shiro Kubota ◽  
Kazuyuki Hokamoto ◽  
...  
Keyword(s):  
Shock Wave ◽  
Numerical Analysis ◽  
High Speed ◽  
Base Plate ◽  
Amorphous Film ◽  
Experimental Result ◽  
Flyer Plate ◽  
Underwater Shock Wave ◽  
Good Reliability ◽  
Underwater Shock

In this paper, we propose a new explosive bonding method for bonding materials by using the underwater shock wave from the explosion of explosives in water. This method is especially suitable to bond the materials with thin thickness and largely dissimilar property. In bonding those materials, the shock pressure and the moving velocity of shock wave on the flyer plate should be precisely managed to achieve an optimum bonding conditions. In this method, the bonding conditions can be controlled by varying of the space distance between the explosive and the flyer plate or by inclining the explosive charge with the flyer plate. We made the experiment of this technique bond the amorphous film with the steel plate. A satisfactory result was gained. At the same time, numerical analysis was performed to investigate the bonding conditions. The calculated deformation of the flyer plate by the action of underwater shock wave was compared with the experimental recordings by high-speed camera under the same conditions. The comparison shows that the numerical analysis is of good reliability on the prediction of the experimental result. Furthermore, the numerical simulation also gives the deformations of the flyer and the base plate, and the pressure and its variation during the collision process.

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