Semi-Empirical Approaches to The Prediction of Shock Initiation from 1-D Flyer Plate and Rod Impacts

There remains considerable interest in the prediction of shock initiation thresholds for projectile impacts using simple empirical criteria. Such criteria have been, and remain, of considerable value, enabling data to be interpolated and extrapolated to predict initiation thresholds for a wide range of impact stimuli. The pioneering work of Walker and Wasley has been modified and extended by a number of workers and in this paper we compare these and discuss the basis for the different approaches. We further consider the relevance of the Pop plot relationship for sustained shock initiation and by combining this with the rarefaction-overtake criterion⁴ we develop a modified, but closely related, new criterion which we test against the impact data for several sensitive heterogeneous explosives.