Some dynamic mechanical properties of distended carbons

Abstract

An experimental study to define the dynamic response of seven distended carbon materials to shock loading is described and the results are presented. The study included measurement of equation of state parameters to 235 kilobars, unloading behavior, and spallation strengths. In the low-stress (partially compacted) region, the response to shock loading was found to be dependent on the initial structure of the material, i.e., form of carbon and initial density, while in the high-stress region the response was primarily affected by the initial density. The results of the unloading wave experiments, attenuation data, and higher pressure free surface velocity measurements indicated that the unloading behavior of these materials was a function of the applied pressure in the partially compacted region. Accordingly, the Hugoniot data were closely represented by a previously proposed empirical model which describes the response of partially compacted porous materials. The spallation results show differences in the dynamic tensile strengths varying from 0.4-1.0 kilobar, depending on the material.