Expanding cylinder experiments in Cu-2wt{\%}Be

Expanding cylinder techniques are useful methods of investigating dynamic fracture properties since uniform radial strains are achieved at high strain-rates. A gas-gun technique to achieve uniform radial expansion of a cylinder is explored in which the motion of the cylinder is driven by impact of a plastic projectile upon silastomer rubber that partially fills the specimen cylinder. Cylinders of age-hardened copper-beryllium alloy Cu-2wt{\%}Be (TF00 treatment) have been expanded to failure at radial strain-rates in the range 1.2 - 5.7 $\times $10$^{3}$ s$^{-1}$. The temporal history of fracture activation is captured using high speed photography and modelled using a combined statistics and energy based fragmentation theory [1]. The model is shown to reproduce the crack dynamics and strain-rate dependence reasonably well.\\[4pt] [1] D. E. Grady, and M. L. Olsen, Int. J. Impact Engng. \textbf{29}, 293 (2003).