부산대학교 도서관

The interaction of a shock wave with the free surface of a material can lead to the ejection of material, ejecta, from the surface. The mass of ejecta produced is heavily dependent on whether the material melts after the shock wave releases from the free surface. Current research is concerned with multiple shock wave loading of materials and the ejecta produced from subsequent shocks. The ability to impart multiple strong shocks with plate impact is limited by the flyer velocity achievable. Two new techniques have been investigated for reducing the flyer velocity required to achieve melt-on-release and therefore make multiple shock wave experiments possible on the single-stage, large bore, gas guns available in the UK. Single shock wave plate impact experiments were conducted to investigate the mass of ejecta, and the melt-on-release pressure, from heated tin and from the eutectic alloy lead–bismuth. It was discovered that the melt-on-release pressure for lead–bismuth was between 11.6 and 13.0 GPa. It was further discovered that heating tin to 180 °C reduced the flyer velocity required to achieve melt-on-release by 270 m/s. As part of the experimental series the Hugoniot of lead–bismuth was approximated. It was determined that, using either heated tin or lead–bismuth that at a minimum a two shock wave experiment could be conducted using a UK single-stage gas gun facility.