Influence of Pressure Vessel Shape on Explosive Forming

2018 ◽  
Author(s):  
Hirofumi Iyama ◽  
Masatoshi Nishi ◽  
Yoshikazu Higa
Keyword(s):  
Shock Wave ◽  
Pressure Vessel ◽  
Underwater Explosion ◽  
Metal Plate ◽  
Reflected Shock Wave ◽  
Underwater Shock Wave ◽  
Reflected Shock ◽  
Final Deformation ◽  
Underwater Shock ◽  
Explosive Forming

The explosive forming is a characteristic forming method. This technique is a metal forming using an underwater shock wave. The underwater shock wave is generated by underwater explosion of the explosive. The metal plate is formed with involving the high strain rate on this technique. In generally, the pressure vessel is used in this method due to the effective utilization of the explosion energy. The underwater shock wave is propagated in water and reflected on inside wall of the pressure vessel. This reflected shock wave is affected on the deformation shape of a metal plate. Therefore, the inside shape of pressure vessel is often changed. In other words, the shape of pressure vessel is changed, the shock pressure distribution on the metal plate and it is possible that final deformation shape of the metal plate is changed. Some numerical simulations and experiments have been carried out to clear the influence of the inside shape of pressure vessel in the explosive forming. This paper is included the results and discussions on the numerical simulation and experiment used those conditions.

Study on the Effects of Shock Wave Propagation on Explosive Forming

2013 ◽  
Vol 767 ◽  
pp. 132-137
Author(s):  
Hirofumi Iyama ◽  
Yoshikazu Higa ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
Pressure Vessel ◽  
Pressure Pulse ◽  
Metal Plate ◽  
Water Medium ◽  
Underwater Shock Wave ◽  
Pressure Transmission ◽  
Underwater Shock ◽  
Explosive Forming ◽  
Primary Shock

Explosive forming is one of the unconventional techniques, in which, most commonly, the water is used as the pressure transmission medium. The explosive is set at the top of the pressure vessel filled with water, and is detonated by an electric detonator. The underwater shock wave propagates through the water medium and impinges on the metal plate, which in turn, deforms. There is another pressure pulse acting on the metal plate as the secondary by product of the expansion of the gas generated by detonation of explosive. The secondary pressure pulse duration is longer and the peak pressure is lower than the primary shock pressure. However, the intensity of these pressure pulse is based also on the conditions of a pressure vessel. In order to understand the effects of the configuration of the pressure vessel on the deformation of a metal plate, numerical simulation was performed. This paper reports those results.

Numerical Simulation on Manufacturing of Pressure Vessel for Shock Food Processing Using Explosive Forming

2016 ◽  
Author(s):  
Hirofumi Iyama ◽  
Masatoshi Nishi ◽  
Yoshikazu Higa ◽  
Ken Shimojima ◽  
Osamu Higa ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Pressure Distribution ◽  
Pressure Vessel ◽  
Food Processing ◽  
Metal Plate ◽  
Underwater Shock Wave ◽  
Deformation Velocity ◽  
Underwater Shock ◽  
Explosive Forming

The explosive forming is a characteristic forming method. An underwater shock wave is generated by underwater explosion of the explosive. A metal plate is affected high strain rate by the shock loading and is formed along a metal die. Although this method has the advantage of mirroring the shape of the die, a free forming was used in this paper. An expensive metal die is not necessary for this free forming. It is possible that a metal plate is formed with simple supporting parts. However, the forming shape is depend on the shock pressure distribution act on the metal plate. This pressure distribution is able to change by the shape of explosive, a mass of explosive and a shape of pressure vessel. On the other hand, we need the pressure vessel for food processing by the underwater shock wave. Therefore, we propose making the pressure vessel by the explosive forming. One design suggestion of pressure vessel made of stainless steel was considered. However, we cannot decide suitable conditions, the mass of the explosive and the distance between the explosive and the metal plate to make the pressure vessel. In order to decide these conditions, we have tried the numerical simulation of this explosive forming. The basic simulation method was ALE (Arbitrary Laglangian Eulerian) method. Mie-Grümeisen EOS (equation of state), JWL EOS, Johnson-Cook constitutive equation for a material model were applied in the numerical simulation. In this paper, the underwater pressure contours to clear the propagations of the underwater shock wave, forming processes and deformation velocity of the metal plate is shown and it will be discussed about those results.

Deformation Mechanism of Metal Plate on Explosive Forming

2005 ◽  
Author(s):  
Hirofumi Iyama ◽  
Takeshi Hinata ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
High Speed ◽  
Underwater Explosion ◽  
Metal Plate ◽  
Sufficient Accuracy ◽  
Underwater Shock Wave ◽  
Underwater Shock ◽  
Explosive Forming ◽  
Forming Methods

The explosive forming is one of the forming methods of a metal plate performed since the 1950s. This method is different from usual static press forming. The metal plate is accelerated by underwater shock wave, which is generated by underwater explosion of an explosive. In order to deform a metal plate in predetermined form with sufficient accuracy using this forming method, it is important to grasp the mechanism. At first, it is necessary to grasp that an underwater shock wave spreads and it collides with the metal plate. And it is also necessary to show clearly what deformation of the metal plate with high-speed. Then, we investigated about the mechanism in the numerical simulation. In this research, LS-DYNA, which is the software for shock analysis was used. Moreover, the experiment was also conducted in order to confirm whether this numerical simulation is exact.

High Pressure Vessel Made by Explosive Forming

2010 ◽  
Author(s):  
Hirofumi Iyama ◽  
Hideki Hamashima ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Numerical Simulations ◽  
Pressure Vessel ◽  
Metal Plate ◽  
The Other ◽  
Underwater Shock Wave ◽  
Pressure Transmission ◽  
Underwater Shock ◽  
Explosive Forming

Explosive forming is one particular forming technique, in which, most commonly, water is used as the pressure transmission medium. In recent years, we have done the development of the method which obtains a necessary form of the metal by the control of underwater shock wave acts on the metal plate, without a metal die. On the other hand, the pressure vessel is required in various fields, but we think that the free forming using the underwater shock wave is advantageous in the production of pressure vessel of a simple spherical, ellipse, parabola shape. In this paper, we will introduce an experiment and several numerical simulations that we carried out for this technical development.

Numerical Simulation of Eccentric Explosive Forming Using Cylindrical Pressure Vessel

2012 ◽  
Author(s):  
Hirofumi Iyama ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Metal Forming ◽  
Metal Plate ◽  
Forming Process ◽  
Underwater Shock Wave ◽  
Metal Forming Process ◽  
Underwater Shock ◽  
Explosive Forming ◽  
Free Metal

Explosive forming is one of the effective metal forming methods using underwater shock wave generated by the detonation of an explosive. The experiment of eccentric spherical free metal forming by this method was carried out. This free metal forming process does not use require expensive metal die. We used simple metal die with only circular edges and considered the metal plate formed to required shape using this method. It was possible to change the pressure distribution applied on the metal plate by changing the set-up position of the explosive and the shape of the device. We have considered this method to cause lessen cost in the small production by various types of metal forming process. In this paper, we introduce the method of eccentric spherical free metal forming using underwater shock wave and present the experimental results. The numerical simulation on this method by FDM (Finite Difference Method) was carried out. In this paper, those results are discussed.

The Effect of Pressure Vessel in Explosive Forming

2003 ◽  
Author(s):  
Hirofumi Iyama ◽  
K. Raghukandan ◽  
Shiro Nagano ◽  
Shigeru Itoh
Keyword(s):  
Pressure Vessel ◽  
Pressure Pulse ◽  
Peak Pressure ◽  
Metal Plate ◽  
Water Medium ◽  
Underwater Shock Wave ◽  
Pressure Transmission ◽  
Underwater Shock ◽  
Explosive Forming ◽  
Primary Shock

Explosive forming is one of the unconventional techniques, in which, most commonly, the water is used as the pressure transmission medium. The explosive is set at the top of the pressure vessel filled with water, and is detonated by an electric detonator. The underwater shock wave propagates through the water medium and impinges on the metal plate, which in turn, deforms. There is another pressure pulse acting on the metal plate as the secondary by product of the expansion of the gas generated by detonation of explosive. The secondary pressure pulse duration is longer and the peak pressure is lower than the primary shock pressure. However, the intensity of these pressure pulse is based also on the conditions of a pressure vessel. In order to understand the influence of the configuration of the pressure vessel on the deformation of a metal plate, numerical analysis was performed. This paper reports those results.

Study on Explosive Forming Using Pressure Vessel and Metal Die

2007 ◽  
Author(s):  
Hirofumi Iyama ◽  
Shigeru Itoh
Keyword(s):  
Pressure Vessel ◽  
Shock Loading ◽  
Pressure Pulse ◽  
Metal Plate ◽  
Water Medium ◽  
Underwater Shock Wave ◽  
Distribution Shape ◽  
Underwater Shock ◽  
Explosive Forming ◽  
Primary Shock

Explosive forming is one particular forming technique, in which, most commonly, water is used as the pressure transmission medium. An explosive is set at the top of the pressure vessel filled with water and is exploded by an electric detonator. An underwater shock wave propagates through the water medium and impinges on the metal plate causing it deformation. If a metal die is used, the metal plate deforms to a specified form. Generally, explosive forming has little spring back of the metal plate, because sufficient plastic deformation is obtained. There are two pressure actions to the metal plate on explosive forming. The first pressure pulse is from the shock loading and the second pressure pulse is caused by the expansion gas generated by the detonation of the explosive. The secondary pressure pulse duration is longer, but the peak pressure is lower than the primary shock pressure. The intensity of the pressure pulse is based on the conditions of the pressure vessel. We have also been using the metal die for explosive forming. The deformation shape of the metal plate is effected by a distribution shape of shock loading. In this technique, the pressure vessel has a desired internal shape. The pressure vessel has an internal shape of a parabola. In order to understand the deformation mechanism of the metal plate, some experiments and numerical analysis were carried out.

Numerical Simulation for Development of Pressure Vessel for Food Processing by Shock Loading

2006 ◽  
Author(s):  
Masahiko Otsuka ◽  
Toshiaki Watanabe ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Numerical Analysis ◽  
Pressure Vessel ◽  
Food Processing ◽  
Shock Loading ◽  
Underwater Explosion ◽  
Underwater Shock Wave ◽  
Reflected Wave ◽  
Underwater Shock

In this study, it has aimed at the design of the pressure vessel where an underwater shock wave is applied to food efficiently. This study aims at the desigh of a pressure vessel in which the underwater shock wave generated by the underwater explosion of detonating fuse was experimentally investigated by the optical observation and the pressure measurement. Therefore the pressure vessel is designed so that suitable pressure may apply on food. This designed vessel is evaluated by the numerical analysis that used LS-DYNA3D. The interaction of the underwater shock wave, the incident wave and the reflected wave are investigated by the numerical analysis. The agreement between the experimental results and the numerical analysis was found to be good.

Shock Wave Propagation Inside of Pressure Vessel Used for Food Processing

2012 ◽  
Author(s):  
Hirofumi Iyama ◽  
Yoshikazu Higa ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Wave Propagation ◽  
Pressure Vessel ◽  
Food Processing ◽  
High Explosive ◽  
Underwater Explosion ◽  
Underwater Shock Wave ◽  
Reflected Wave ◽  
Underwater Shock

In this study, it has aimed at the design of the pressure vessel for food processing using an underwater shock wave. This study aims at the design of a pressure vessel in which the underwater shock wave generated by the underwater explosion of high explosive was experimentally investigated by the optical observation and the pressure measurement. Therefore the pressure vessel is designed so that suitable pressure may apply on food. This designed vessel is evaluated by the numerical simulation. The interaction of the underwater shock wave, the incident wave and the reflected wave are investigated by the numerical simulation.

Eccentric Spherical Forming of Metal Plate by Underwater Shock Loading

2011 ◽  
Vol 673 ◽  
pp. 291-296 ◽  
Author(s):  
Hirofumi Iyama ◽  
Shigeru Itoh
Keyword(s):  
Shock Wave ◽  
Metal Forming ◽  
Metal Plate ◽  
Forming Process ◽  
Underwater Shock Wave ◽  
Metal Forming Process ◽  
Underwater Shock ◽  
Set Up ◽  
Explosive Forming ◽  
Free Metal

Explosive forming is one of the effective metal forming methods using underwater shock wave generated by the detonation of an explosive. We have done the experiment of eccentric spherical free metal forming by this method. This free metal forming process does not use require expensive metal die. We used simple metal die with only circular edges and considered the metal plate formed to required shape using this method. It was possible to change the pressure distribution applied on the metal plate by changing the set-up position of explosive and the shape of the device. We have considered this method to cause lessen cost in the small production by various types of metal forming process. In this paper, we introduce the method of eccentric spherical free metal forming using underwater shock wave and present the experimental results.

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