Hemispherical and Conical Shaped-Charge Liner Collapse and Jet Formation

摘要

Analytical studies of the collapse of (1) hemispherical, point initiated, (2) hemispherical, surface initiated and (3) conical, point initiated warheads, using the HELP and EPIC hydrocodes predicted tubular or layered jets. Each shaped charge geometry studied revealed a different flow pattern during the jet formation and collapse process. The analysis further suggested that the liner flow process could be verified experimentally by collapsing stratified, bimetallic liners in actual warheads. Experimental verification was attempted by fabricating stratified bimetallic copper and nickel hemispherical and conical liners. Copper and nickel were chosen for the stratified liner materials due to their identical densities and similarity under shock loading conditions. The fabrication was successfully accomplished by using a diffusion bonding technique which with the appropriate temperature, time and pressure caused the alternating copper and nickel discs to adhere. The liners were then machined from this bonded stack of alternating layers of copper and nickel. Point initiated, Octol loaded, hemispherical and conical shaped charge warheads were then fired into water and typically, three to four large particles were recovered per shot. Examination of the recovered particles revealed agreement with the method of formation predicted by the two hydrocodes. Namely, the recovered particles showed the presence of two materials in alternating layers. Also, free flight flash radiographs of the jets revealed coherent, well formed jets with jet parameters closely predicted by the a priori hydrocode calculations.