Effect of Non-Ideal Interfaces on Detonation Propagation

Non-ideal interfaces between an energetic material (EM) and adjacent materials are often present, but their potential impact on detonation performance is typically ignored. At small scales, when the EM geometry approaches failure conditions, the impact of such interfaces can be significant. In this work, we investigate the effects of non-ideal interfaces, using vapor-deposited films of the explosives hexanitrostilbene and pentaerythritol tetranitrate on substrates with varying surface roughness. Results indicate that increasing interfacial roughness can significantly reduce detonation velocity and increase detonation failure thickness. However, as EM film thickness increases, interfacial effects on performance appear to wane, and detonation velocities trend toward values consistent with samples having more ideal interfaces. Two and three-dimensional simulations with explicit surface roughness were performed in the hydrocode CTH to provide insight into the shock interactions occurring at these interfaces. Simulated detonation velocities and shock front profiles are presented for ideal, nominal, and exaggerated roughness, and two- and three-dimensional calculations are compared.