The Analysis of Transient Stress Conditions Developed in a Target Confining Structure of a Projectile Launching System

Abstract In the technical arena of experimental shock physics the desire is to utilize the largest experiment loading capability on a given target assembly while also preserving the structural integrity of the confining structures. The confining structures protect the sensitive and expensive diagnostic equipment that is deployed to interrogate and gather data from the impact event, as well as the overall facility that houses the experiment apparatus. Washington State University (WSU) desires to modify a projectile launching system that is operated in the Dynamic Compression Sector (DCS) of the Advanced Photon Source (APS) located at Argonne National Laboratory (ANL), USA. The launcher system enables shock physics experiments to be conducted while using the APS x-rays to probe the sample in real time during the dynamic event. A 0.5 inch (1.27 cm) diameter bore single-stage powder gun launch tube will be increased to a 1.0 inch (2.54 cm) diameter bore, and will thus accommodate a larger projectile and also a higher propellant load in the breech of the launcher system. The same confining structures, a target chamber and a catch tank, from the 0.5 inch (1.27 cm) diameter bore launcher system are intended to be used with the larger bore launcher, and thus a higher powder gun load will be induced into the confining structures. A structural analysis of the confining structures is needed to predict their structural dynamic response in the higher loading scenario. In addition, users of the DCS desire to perform certain impact experiments that include a high-explosive material in the impact target. The possibility of causing full detonation of the high-explosive material in the impact experiment needs to be considered in the structural loading. The combined loading in the confining structures of both the propellant gas flow pressures and the explosively generated impulsive pressures is addressed in the structural dynamic simulations. The structural acceptance criterion for this effort is to apply a reasonable engineering margin against material failure, i.e. rupture, for the various loading scenarios. In order to capture a reasonable engineering margin against material failure the pressure vessel dynamic loading response acceptance criteria of the ASME B&PV Code, Section VIII, Division 3, in particular Part KD-240 are used as guidance to establish a reasonable margin where material plasticity is predicted.