Determination of the Grueneisen gamma for Beryllium at 1.2 to 1.9 Times Standard Density

摘要

In shock-wave work, a simple approximation that works well for metals assumes that the ratio of the Grueneisen parameter to the specific volume remains constant during compression. The results of the various experiments on beryllium are displayed in terms of that ratio. The experiments that involved a high-impedance reflector were not as precise as the others. The weighted average value of gamma /V is indicated as a dashed line. For all of the higher compression experiments, the determination of gamma involved a comparison of an experimentally achieved state with one of the same compression on the principal Hugoniot. Experimental data for the principal Hugoniot, however, are not available for volumes less than 0.35 m exp 3 /Mg. Thus, the four highest compression results are really determined from a comparison with the extrapolation of the experimental principal Hugoniot. (ERA citation 02:057113)