Numerical study of the effect of the yield drop phenomenon on the deformation behaviour of a Taylor projectile

Abstract

This article deals with the effects of parameters relating to the yield drop phenomenon on the deformation of Taylor projectiles. The numerical modelling approach performed using LS-DYNA was validated by considering a solid cylindrical projectile made of AA7010 aluminium alloy impacted against a massive, rigid target as described in the literature. Both the projectile and target were modelled using three-dimensional brick elements. A popular strain rate and temperature-dependent constitutive relation known as the Johnson–Cook model was used to represent the alloy projectile material behaviour, whilst the target plate was assumed to be rigid. A generally good agreement between test and numerical results was found. A steel projectile was then considered using a simple piecewise linear plasticity model which has provision for introducing the yield drop effect and in which temperature effects were ignored. The impact velocities varied from 200 to 1000 m/s. Significant influence of the yield drop on the deformation behaviour of the projectile at low impact velocities was found. However, the effect was far less significant at higher impact velocities (>400 m/s).

Investigations on deformation and fracture behavior of workpiece material during high speed machining of 7050-T7451 aluminum alloy

“…The research techniques mainly include material testing machine [6], hammer dropping experiment [7], Charpy impact test [8,9], split Hopkinson pressure bar [10] and Taylor bar [11], etc. The strain rate of deformed material during these testing methods covers the range from quasi-static to 10 3 s À1 .…”