Dynamic plastic deformation of rings under impulsive load

Abstract

A study of the plastic response of rings of different materials to different types of dynamic load is presented.Inertial loading of rings was obtained by allowing heavy lead rings to fall freely on to flat and pointed rigid anvils and impulsive loading was obtained by subjecting stationary lead, copper and aluminium rings to a high-speed bullet or to contact explosives. Heavy mass, low velocity impact loading was obtained by allowing a large tup to freely fall on to the ring. Collision loading was obtained by allowing one ring to fall on to one or two stationary rings.Two types of approach are employed to analytically investigate the loading of rings. The first is a numerical one which assumes a simple approximate model for the structure of the ring; it reduces the ring to small masses concentrated around the circumference, connected to each other by weightless links possessing the strength properties of the material of the ring. The problem is then reduced to solving the dynamical equations of each mass around the ring with the help of a digital computer. The second is an energy method which utilizes Lagrange's equations for the motion of approximated links within the ring.Results of each of these approaches are compared with experiments presented in terms of instantaneous deformation obtained from high-speed photographs.