LULI2000 - Picosecond radiography to study dynamic fracture in shock-loaded materials (Th. de Rességuier)
As a major failure process in materials subjected to dynamic loading, spall fracture is one of the most widely studied issues in shock physics. For many years, laser-driven shocks have been successfully used to investigate this process over ranges of small spatial scales, pulsed loads of very short duration, and extremely high strain rates. In this proposal, we plan to characterize spall damage in four materials of engineering interest with a newly developed technique of ultra-fast, in-situ radiography, using a ps-laser-generated x-ray probe. The combination of this new diagnostic with more classical ones, including time-resolved velocity measurements, optical shadowgraphy and post-shock analyses of recovered samples, will provide new data on the successive stages of spallation, from crack nucleation to coalescence into a large, macroscopic fracture followed by fragment ejection, in both metallic and polymeric materials. It will also provide new insight into the transition from solid-state spall fracture to microspall after shock-induced melting at high loading pressures.
LULI2000 - S22-23 / 2018