Fragment Velocity Formula for Reverse Detonation Driving with Opposite Initiation

Abstract

In detonation driving problems, the explosive charge is typically initiated on one side of the charge and the fragment or plate is located on the other side. Many studies have been conducted on this driving style, which has numerous practical applications. However, few studies have been conducted on reverse detonation driving, wherein the initiation point is located on the same side as that of the fragment. Reverse detonation driving can lower the shock pressure in the fragment and solve the problem of spallation. In this study, the model of opposite initiation of cylindrical charge is used to investigate the reverse detonation driving style. A long element is considered along the direction of the initiation points and the warhead center, and a fragment velocity formula is established according to the one-dimensional gas dynamics. Then, based on the influences of the assumptions, such as the rigid constraint of the element, three experimentally verified numerical models are used to validate the established formula. The ratios of the formula computations and the corresponding modeling results exhibit similar trends. Therefore, these trends are fitted together and used as a correction factor for the established formula. The corrected formula is further validated through two-dimensional modeling with a different casing material model and three-dimensional modeling of the verified experimental configuration. The established formula can be used as a reference for the problem of reverse detonation driving.