ABSTRACT
Shock sensitivity of explosives, as far as blast engineering is concerned, has been linked to impact energy through the energy fluence criterion (Walker and Wasley, 1969). The criterion utilizes the shock amplitude and its duration to claim that the energy per unit area, the energy fluence, is proportional to the square of the pressure amplitude and the duration of the pulse. This is valid for a square pulse; for an arbitrary pulse the energy fluence can be described by:
E PU dtp∫ (1) where E is the energy fluence, P is pressure, Up is the particle velocity and t is time. The above integral can be easily calculated using numerical modelling codes, since all parameters are known at each time step. In the case of a square pulse, the above equation becomes:
E P tU= 2
0ρ (2)
where ρ0 is the initial density and U is the shock wave velocity. Experimentally the energy fluence is often calculated using flyer plate impact experiments.
