J. Phys. IV France
Volume 134, August 2006
EURODYMAT 2006 - 8th International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading
Page(s) 745 - 750
Published online 26 July 2006
EURODYMAT 2006 - 8th International Conference on Mehanical and Physical Behaviour of Materials under Dynamic Loading
J. Cirne, R. Dormeval, et al.
J. Phys. IV France 134 (2006) 745-750

DOI: 10.1051/jp4:2006134115

Characteristics analysis of Isentropic Compression Experiments (ICE)

S.D. Rothman and J. Maw

AWE Aldermaston, Reading RG7 4PR, UK

Published online: 26 July 2006

Several new techniques for high-pressure (quasi-) isentropic compression of materials are becoming available: pulsed-power-driven magnetic pressure, graded-density impactors on gas-guns, and laser drive. These experiments are analysed to give sound speed as a function of particle velocity, which may then be integrated to pressure and volume, giving data for a complete isentrope with one shot. However, to do this the experimentally-measured free-surface - or window-interface - velocities must be corrected to give the in-situ material velocities in the absence of the surface or interface. This may be done by either “backward integration” (integrate the equations of motion in space rather than time using surface velocity vs time as the boundary conditions) or by a characteristics method. This presentation describes the characteristics method and its application to AWE experiments on the isentropic compression of lead. The experiment has produced results consistent with pre-existing experimental data within errors in sound speed and pressure of $\sim $4%. Iterative corrections to in-situ velocity, using the EOS calculated during the previous step, reduce - or do away with - any dependence of the results on an assumed EOS. Simultaneous characteristics calculations of the “input” pressure-time are used to estimate the errors.

© EDP Sciences 2006