The Empirical Survey on the Effect of Using Media in Explosive Forming of Tubular Shells

The special and unique advantages of explosive forming, has developed its use in different industries. Considering the important influence of improving the current explosive forming techniques on increasing the efficiency and control over the explosive forming procedure, the effects of air and water as the energy-conveying medium, and also their differences will be illustrated in this paper. Hence, a large number of explosive forming tests have been conducted on two sizes of thin walled cylindrical shells by using air and water as the working medium. Comparative diagrams of the maximum radial deflection of work-pieces of the same size, as a function of the scaled distance, show that for the points with the same values of scaled distance, the maximum radial deformation caused by the under water explosive loading is 4 to 5 times more than the deflection of the shells under explosive forming, while using air. Results of this experimental research have also been compared with other studies which show that using water as the energy conveying media increases the efficiency up to 4.8 times. The effect of the media on failure modes of the shells, and the necking mechanism of the walls of the specimens, while being explosively loaded, are also discussed in this issue. Measuring the tested specimens shows that, the increase in the internal volume has been accompanied by necking of the walls, which finally results in the radial rupture of the structure.




References:
[1] Murr, E.M., "Shock Waves for Industrial Applications", Noyes
Publications, USA; 1988
[2] Kinney, G.F., Graham, K.J., "Explosive Shocks in Air", Second Edition,
Springer-Verlage, ISBN: 3-540-15147-8;1985.
[3] Perrone N., Bhadra P., Simplified Method to Account for Plastic Rate
Sensitivity with Large Deformation, Journal of Applied Mechanics, 46,
811-16 (1979).
[4] Cole R., Underwater Explosions, NJ, Princeton University Press; 1948.
[5] 5.Goodman H.J,"Compiled free-air blast data on bare spherical
pettolite",Ballistic Research Laboratories, Aberdeen proving ground,
Maryland, BRL-1092;1960
[6] Keil AH. Introduction to underwater explosion research. UERD, Norfolk
Naval Ship Yard, Portsmouth, Virginia; 1956.
[7] R. Rajendran, K. Narasimhan, Deformation & Rupture Behavior of Plate
Specimens Subjected to Underwater Explosion- a Review, Int. J. of
Impact Eng. 31 May 2005.
[8] Pishevar E. A., Simulation of under Water Explosion., Esteghlal Journal,
Iran, April 2004
[9] Benham, R.A., Duffey, T.A., "Experimental-Theorical Correlation on
the Contaminent of Explosions in Closed Cylindrical Vessels", Int. J.
Mech. Sci. Vol.16, pp. 549-558; 1974