Metrology and detonics: Analysis of necking

摘要

The purpose of the experiment discussed in the present paper is to study the deformation of a structure (here a coppercylinder) induced by explosives. During its expansion, the (initially 3-mm thick) cylinder keeps on thinning until fractureappears. Some tens of microseconds before failure, strain localization occurs, which induces mechanical necking. Inorder to characterize the time for the onset of localization and the necking development, two diagnostic techniques aredesigned to provide images: one based on X ray observations (for total thickness variations) and a second consisting in25 stereoscopic acquisitions at about 400,000 frames per second. The latter enables us to estimate the three dimensionalshape changes of the cylinder with time.