Experimental Measurement of the Scaling of the Diameter- and Thickness-Effect Curves for Ideal, Insensitive, and Non-Ideal Explosives

Numerous two-dimensional high-explosive slab rate sticks were fielded for explosives that exhibit ideal (PBX 9501), slightly non-ideal (PBX 9502), and highly non-ideal (ANFO) detonation. Detonation velocity versus slab thickness $t$ (thickness-effect curves) are compared to previous diameter-effect measurements obtained by varying the diameter $d$ of cylindrical rate sticks. The scale factors $d/t$ necessary to overlay the diameter- and thickness-effect curves were computed for each explosive formulation. We observe that the scale factor varies with detonation velocity (or level of detonation ``ideality''). The measured scale factors range from 1.89--2.20, 1.41--1.87, and 1.79--1.05 for PBX 9501, PBX 9502, and ANFO formulations, respectively, as detonation velocity varies from the (near failure) critical velocity to the Chapman-Jouget velocity. These results support our previous theoretical prediction that the scale factor relating the diameter- and thickness-effect curves will increasingly deviate from two as the detonation structure becomes increasingly non-ideal.