Detonation Driven Flyer Numerical Simulation

Explosive-loading technique is often used as a shock-loading method. Because it has the wider test specification, more layout samples and more getting information, it is extensively applied in the high-pressure physics, geophysics and space technology field, etc. But, copper flyer whose thickness ranged from 2mm to 3 mm driven by detonation wave impacts copper sample, the shock pressure generated in the sample is usually higher than 60 GPa. Thus, in order to design the series of lower pressure explosive-loading devices which can generate several GPa to 60 GPa shock pressure in copper sample, the dynamic processes of the flyer driven by detonation products through air cushion, the multi-flyer driven by detonation wave and the flyer with guard ring driven by detonation wave are calculated. Based on numerical simulation and proving experiments, some regularity conclusions got in this paper can provide instruction and reference for series of lower pressure explosive-loading devices design.The calculated results show that if the explosive-loading device has an air cushion between main charge and flyer, the flyer velocity increases gently and keeps its initial thermodynamic state and mechanical property well. The relationship between flyer velocity and air chusion thickness is agreement with gravity curve. If the device has no air cushion, the deviation of shock front is less than 100ns within 50mm diameter. But, if the air cushion thickness is up to 50mm, the range of the deviation of shock front less than 100ns will reduce to 30mm in diameter. It can not be used in high accuracy measurement test. The detonation products of 60mm thick TNT/Ba(NO3)2(21/79) or RHT-901 through 10mm thick air cushion drives 2mm or 3mm thick copper flyer individually, the shock pressure generated in copper sample is 25GPa and 61 GPa. Thus, by means of this method we can design the explosive-loading devices which can generate shock pressure in copper sample ranged form 20GPa to 60GPa. But, if we want to design the devices which generate shock pressure less than 20GPa, we must incease the air cushion thickness, simultaneous the deviation of shock front will be larger and larger.Adopting the multi-flyer (mattenuating plate/impactor) mode, the velocity of impactor can be reduced greatly. The multi-flyer will separate and then impact. Furthermore, the impaction does not occure at the whole interface. The calculated results show that the main charge, the impedance and thickness of mattenuating plate and impactor all have influence on impactor velocity, the thickness of mattenuating plate have the most influence on impactor velocity and the displacement after the impactor separates from the mattenuating plate.If the flyer is pressed into guard ring with higher impedance, the detonation wave arrives on the mental surface the pressure generated in guard ring is higher than in flyer. Thus, an additional thrust acts on the outer area of the flyer to flatten the flying flyer. The calculated results show that the thickness, inner diameter and impedance of guard ring all have influenceon the flyer shape. The smaller the guard ring's inner diameter and the larger the guard ring's thickness is, the longer time the additional thrust acts on the flyer fringe is.The material of guard ring has little influence on the additional thrust acting on the outer area of flyer. If the guard ring has cut at the joint of the guard ring and flyer, it not only extend the time of the additional thrust acting on flyer fringe, but also avoid the flyer being extruded by guard ring.Lastly, based on the simulation results we bring forward the method and procedure on the series of explosive-loading devices design. The high pressure produced by these deivces ranges from several GPa to 60GPa, and the pressure step varies from 2GPa to 5GPa.