The Break-Up Tendency of Long Rod Projectiles

Abstract

A model for the tendency of fragmentation of a long rod projectile subjected to flyer plates in add-on armours such as reactive armour and active protection systems is presented. The assumption behind the model is that the sliding force, with velocity νslide between the projectile and a moving plate, give rise to a transverse velocity νtrans of the projectile segment it passes, which will deflect the projectile segment. This deflection is assumed to be a major reason for the fractures that can emerge along the projectile and can be described by the dimensionless parameter δ = νtrans/νslide. The paper describes how this parameter can be expressed in terms of velocity, geometry and material of the projectile and the plate. Experiments and simulations has verified that the identified δ- parameter predicts an increased amount of fragmentation of the projectile with increasing value of this parameter.