Seminarium Zakładu Mechaniki i Fizyki Płynów Proton Radiography of the Process of Shock Melting Metals dr Hanna Makaruk, Los Alamos, USA środa, 3 stycznia 2007

This paper discusses the analysis of proton radiography (pRad) images of shockwave metal melting. The experiments investigated the physical properties of metals under extreme pressure and temperature conditions. Aluminum, copper, and steel coupons were melted and/or damaged by the shockwave of a diverging high explosive. Multiple experiments were performed in identical conditions, with various coupon thicknesses and metal types. pRad was used to record each explosion and the resulting images were then analyzed by software written in Mathematica. The program used a level set type method to extract numerical data. Data obtained from a series of images captured during an individual experiment was used to calculate the velocities of metal fragments. The measured velocities of the top surfaces of the explosions agreed very well with the data collected by the Velocity Interferometer System for Any Reflector (VISAR). This technique additionally allowed the velocities of occluded surfaces to be measured even though they could not be seen by VISAR. Also, velocities calculated for identical experiments almost perfectly agreed with one another. This result showed that in these experiments both the velocities and shapes of the major fragments of the metal coupons are highly deterministic functions of coupon thickness and metal type. These findings are being used to verify the predictions of hydrocode modeling that is currently being developed.