NEW SCALING LAWS ON IMPACT FRAGMENTATION

A theoretical model of impact fragmentation is presented on the basis of many numerical, experimental, and theoretical results. The model indicates a new nondimensional parameter, PI, called nondimensional impact stress (NDIS), to be a key parameter controlling the impact fragmentation. NDIS takes the form PI= 1 2ΞρO1(Ct+Ξ v 2)v( Lp Lt)3 Yt3 where ρ{variant} = density, C = bulk sound velocity, s = (∂Ks/∂P + 1)/4, v impact velocity, L = representative size Y = fracture strength, the suffixies t and p indicate target and projectile, and ξ is a nondimensional constant related to the acoustic impedance ratios of projectile and target. The maximum mass of fragments normalized by the original mass of target and the size distribution of fragments are well scaled by NDIS. We also propose a scaling law for the velocity, νa, of a fragment ejected from the antipodal point to the impact point: νa/(Yt/ρ{variant}0tCt) ∞ PI. The theoretical is in good agreement with the experimental data. © 1990.