Chapter 20: Models for the Pinching of a Confined Hollow Explosive Cylinder Containing Air

The pinching of a solid cylinder of explosive on an anvil by a hammer has been investigated experimentally in drop tests and with both hydrocode and analytical modelling by many researchers. This paper studies the pinch of a confined hollow explosive cylinder containing air. The explosive is modelled as deforming in two ways: in potential flow and in plastic flow. The trapped gas is modelled as an ideal gas. The equations of continuum mechanics and boundary conditions have been solved analytically to find closed form solutions for the inner radius and the temperature of the gas as functions of time. Gas temperatures well above the critical temperature for ignition are achieved and the ensuing reactions are modelled. The work shows how confinement plays an important part in affecting explosive response.