Instability of a conical liner during shaped-charge jet formation

Instability of a conical liner during shaped-charge jet formation has been studied. To establish the metal flow pattern during shaped-charge jet formation, we fabricated three-layer copper-copper-constantan liners consisting of a solid copper conical funnel with an cone angle of 45$^\circ$C, a wall thickness 1.5 mm, and a funnel pressed into it and rolled from a copper sheet 1.0 mm thick clad by explosion welding with constantan 0.2 mm thick. Liner implosion was carried out by an RDX charge 20 mm thick. The jet formation process was recorded by flash radiography, and the metal flow pattern was determined by micro sections of recovered slugs. Since the boundary of explosion welded metals is clearly distinguishable on the sections, the residual deformation in different sections of the slug shows the occurrence of instability of the liner during the implosion, which manifests itself in the form of folds oriented along the generatrix of the cone. However, the general flow pattern described in terms of the theory of an ideal incompressible fluid is not disturbed, which follows from radiographs of the shaped-charge jet formation process.