Scabbing of Metals under Explosive Attack: Multiple Scabbing

Further quantitative data bearing on the scabbing of metals under explosive attack are presented in this paper. In particular, the mechanics of the generation of multiple scabs is established. Experimental data have been obtained that show that multiple scabbing will occur whenever the maximum stress σ0 in the transient wave that impinges on a free surface is more than double the critical normal fracture stress σc of the material. The number of scabs that will be formed will be equal to the first whole number smaller than the quotient σ0/σc. The thickness of each scab is governed by the shape of the stress wave.