Investigation of system parameters towards safer impact based shock-to-detonation transition in a novel laser driven flyer plate prototype

Abstract

Laser driven flyer plate technology offers improved safety and reliability for detonation of explosives in industrial applications ranging from mining and stone quarrying to the aerospace and defense industries. This study is based on developing a safer laser driven flyer plate prototype comprised of a laser initiator and a flyer plate subsystem that can be used with secondary explosives. System parameters were optimized to initiate the shock-to-detonation transition (SDT) of a secondary explosive based on the impact created by the flyer plate on the explosive surface. Rupture of the flyer was investigated at the mechanically weakened region located on the interface of these subsystems, where the product gases from the deflagration of the explosive provide the required energy. A bilayer energetic material was used, where the first layer consisted of a pyrotechnic component, zirconium potassium perchlorate (ZPP), for sustaining the ignition by the laser beam and the second layer consisted of an insensitive explosive, cyclotetramethylene-tetranitramine (HMX), for deflagration. A plexiglass interface was used to enfold the energetic material. The focal length of the laser beam from the diode was optimized to provide a homogeneous beam profile with maximum power at the surface of the ZPP. Closed bomb experiments were conducted in an internal volume of 10 cm³ for evaluation of performance. Dependency of the laser driven flyer plate system output on confinement, explosive density, and laser beam power were analyzed. Measurements using a high-speed camera resulted in a flyer velocity of 670 ± 20 m/s that renders the prototype suitable as a laser detonator in applications, where controlled employment of explosives is critical.