Isentropic loading experiments of a plastic bonded explosive and constituents

The plastic bonded explosive PBX 9501 and its constituents [cyclotetramethylene tetranitramine (HMX) crystals, nitroplasticized Estane ®5703 and a fine-crystallite HMX laden binder mixture] were subjected to a ramped quasi-isentropic compression load using the Z machine at Sandia National Laboratories to determine equation of state and constitutive property data. Various sample thicknesses of these materials were subjected to an identical ramp loading history up to 4.5 GPa over 350 ns and particle velocities were measured using a velocity interferometry technique to assess material response. Upon defining appropriate constitutive relationships for the individual constituents, a topologically disordered model of the composite material was numerically simulated and details of the mesoscale simulation indicate that much of the plastic deformation first occurs locally at the large HMX crystal contacts points and subsequently by the deformation of the interstitial fine-crystallite/binder material.