SPALLATION DAMAGE IN COPPER WITH COLUMNAR GRAINS.

The TRIDENT laser at Los Alamos has been used to drive small plate impact experiments. Flyers are typically 8 mm in diameter and 0.1 to 1.0 mm thick, while the targets are 10 mm in diameters and 0.2 to 2.0 mm thick. One of the sample materials is copper composed of large columnar grains. These samples can reveal information about damage in single crystals and bi-crystals. This work will focus on simulating these experiments to reveal the stress loading histories. A phenomenological single crystal plasticity model in the FLAG hyrdocode will be used. At the time of first negative pressure, calculated stress and strain concentrations occur at regions of high damage seen by metallurgical examination of a recovered sample. These calculated concentrations help to reveal the driving conditions that cause damage formation. [ABSTRACT FROM AUTHOR]