Shock wave response of porous carbon fiber-epoxy composite

An experimental investigation of the shock wave structure, Hugoniot states, and spall strength of a shock-compressed porous carbon fiber-epoxy composite was conducted. To generate high dynamic pressures in the material, the impact of flat-plate aluminum projectiles accelerated by explosive planar shock wave generators to velocities ranging from 0.65 to 5.05 km/s was used. Particle velocity profiles were recorded on the composite surface-water window interface with a multichannel VISAR laser interferometer. On the velocity profiles for the composite with a transverse fiber orientation, a single shock wave was recorded, while for the parallel orientation, a two-wave structure was observed. It was found that the shock wave compressibility of the porous composite did not depend on the fiber orientation relative to the direction of shock wave propagation. A kink on the Hugoniot curve was observed at the pressure of 19 GPa. The results obtained for the porous composite were compared with data for a non-porous carbon-epoxy composite and epoxy resin used as a matrix in the composites. When analyzing dynamic fracture of the porous composite under shock compression, it was found that the spall strength of the material was significantly lower than that of epoxy resin.