| In this paper, the theory and experiment techniques of accelerating metallic flyers to ultra high speed by strong detonation or multi-stage system are studied, where the next stage slab is impacted by the flyer of previous stage and is accelerated to a higher speed. This work is of important value for further understanding properties of detonation products and developing detonation driven theories. It is also one of the main research area of the application of detonation physics.This paper contains seven chapters. Chapter one has systematically overviewed the general research situation on dynamic loading technique of multi-stage detonation system including plane and converging detonation system for high-pressure studies.Chapter two studies the theoretical propagating and accelerating t models of strong detonation, produced by the impact of stiff flyer. The wedge test method is employed to record the over-driver detonation front' s track for both TNT/RDX(40/60) and J0-9195 explosives. And results are compared with our model.Chapter three describes theoretical design for multi-stage detonation system. Based on the momentum and energy conservation law, for multi-stage explosive/flyer system, the Gurney model for explosive acceleration has been improved, and employed to analyze the typical two stage device. After compared with numerical simulation of DYNAIID, the system is optimized by the Gurney formula combined with the analytic equation from Stanyukovich under fixed initial Condition.Chapter four gives our main experimental works, including test set-up, diagnostic techniques and results. Firstly, we design the experimental set-up, and three-stage flyers' velocities are measured in one shot using electrical-pin techniques. Experimental results indicate that for the first flyer of 4. 87km/s, the second steel flyer with 1mm thickness can be feasibly speed up to approximately 6.5~7km/s. And the third flyer of 0. 2mm molybdnum can approximately be accelerated up to over 9km/s.Secondly, the velocity profiles of the second flyer driven by strong detonation are measured by VISAR interferometer. Results show that high pressure plateau keeps on accelerating the flyer for quite a few microseconds.Then we conduct the high speed impacting test, the pictures of impact process between the second flyer with speed about 6. 4km/s and static metal target at two or three moment are photographed by means of flash X-rays and electrical pins techniques. Results show the flyer keep integrity and with good planarity, and the broke cloud formed from the flyer clearly.In chapter five, we have compared the differences of two-stage system among plane, cylinder and sphere geometry which was first proposed by Russian Schoolar Zababakhin. For our model, flyer velocities accelerated by slab, cylinder and sphere system reach 6. 7km/s, 8. 8km/s and 12km/s respectively.In chapter six, based on the feed through perturbation growth equations in incompressible slab, cylinder shell and spherical shell geometry, the Rayleigh-Taylor instabilities of the second steel flyer with initial perturbation on the outer surface are numerically calculated. For cylinder shell and spherical shell geometry, the acceleration reaches 10'km/s2. At 3 s after starting, flyer' s perturbation amplitude of inner and outer surface reaches 2CT25 times than the initial amplitude, far more than in slab geometry situation.Chapter seven describes the research works on the equation of state (EOS). Universal EOS, recent developed by Pascal Vinet et al, and another by Parsafar and Mason, which have been widely used for a series of elements, metals, alloys and plastics, were fitted with those obtained shock wave data by linear fitting method.
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