Progress in the Development of a Shock Initiation Model

Abstract

We used an Eulerian hydrocode to guide the development of an engineering model of shock initiation. The model in its current form has two types of hotspots‐ one from void collapse, and one from interactions at grain boundaries. The dependence of hotspot and bulk temperatures upon shock strength is estimated using a Gruneisen equation of state for the bulk solid, calibrated against measurements of reaction times for steady state detonation. Arrhenius kinetics are used to predict ignition times associated with hotspot temperatures. The hotspots contribute a small amount of energy to the shock front, thereby causing some shock front acceleration, and also serve to initiate erosive burning. The two erosive burn reactions that result from the two different types of hotspots compete to consume the material. The energy release rate resulting from the competition of these reactions was used as input to a method of characteristics code. This in turn was used to calculate particle velocity — time profiles at various simulated gauge locations. These calculated profiles were compared with experiment.