Shock Propagation in Nonreactive Porous Solids

Shock propagation and attenuation have been studied in porous graphite and aluminum foams (40% to 80% of crystal density). The effects of such material parameters as particle (or pore) shape, size, and size distribution on response of the materials to shock loading were investigated, and Hugoniot measurements below 25 kbar were made. It was found that in the pressure and porosity range studied, the ``compacted'' volumes for pressures above a few kilobars are essentially those of the solid materials at the same pressure. The densities of specimens of aluminum foam recovered after shocking to about 10 kbar correspond approximately to that of solid aluminum, while the densities of recovered specimens of ATJ graphite are very close to their initial densities, even after shocking to 50 kbar. An artificial viscosity computer code has been successfully adapted to calculation of shock attenuation in porous solids. Within the idealizations of the models employed, calculated transit times and shock profiles are in ...