Study On The Equation Of States Of Overdriven Detonation And Related Phenomena

It's academically and practical valuable to study the detonation properties and equation of states of products of high explosives, because this study results can make the energy of the explosives effectively used and enhance the safety during the machining,carrying, storing and applying. Through theoretical analysis combined with experimental investigation and numerical simulation, this dissertation presented the reaction rate equation of the explosives and equations of state of the overdriven detonation products systemically, and these results can be used in such fields as overdriven detonation, equations of state and warhead design, and so on.Firstly, this dissertation discussed the classical model of the CJ theory and ZND model. And established the shock initiation reaction rate CZT model with relation to initial porosity and pore size was established based on review the reaction rate equation of high explosives. Using CZT model, numerical analysis was carried out about one dimension shock initiation problems of the PBX-9404 explosive, and the influence of hot spot, initial porosity and particle size of this explosive on the reaction rate equation. In addition, numerical analysis was also studied on two-dimension tests of the clapboard for different initial porosities rate and particle sizes of the PBX-9404 explosive, and the critical thickness of the clapboard was gained.This dissertation gained the coefficients of the reaction rate equation by using the genetic method with good global optimized ability. The speed of convergence was improved by revising the genetic method. The coefficients of the CZT model for the PBX-9404 explosive were determined by using revised genetic method and combined with the DNYNA2D program effectively.The equation of states of the overdriven detonation products of the high explosive was studied by experiment in this dissertation. This dissertation presented the method for measuring the Hugoniot of the overdriven detonation products, and the relations of the overdriven Hugoniot of the JB-9014 explosive by using the classical comparing method were also abtained. Then, the method for measuring the sound velocity under the overdriven detonation conditions was built; and the sound velocity of the overdriven detonation products of JB-9014 explosive was measured by the optical analysis, and the state point on the curve of the Hugoniot sound velocity of overdriven detonation products changed with the pressure for this explosive; and the corresponding method for determining the CJ state was also built and the CJ state of the JB-9014 explosive was gained. Secondly, the basic method was built to fit the overdriven equation of state based on the Hugoniot curve and the data of sound velocity tests, and three sets of JB-9014 explosive overdriven equations of state were built based on P.K. Tang's ideas about the equation of state of detonation products of PBX-9501 and PBX-9502 explosives. These three sets of equations were embedded in DNYNA2D program to analyse the unloading tests numerically, and the shortest pursuant time of refraction wave was consistent with experimental results for this explosive.Finally, three typical types of applications of overdriven detonation were investigated in this work.. The theoretical model of overdriven detonation was built, and the Gurney model was extended; multiple-stage overdriven detonation was studied experimentally, the theory model was verified, and several key problems were discussed. The shaping and motion process of the jet and the projectile were analyzed numerically, and three set-ups of shaping and motion process of the jet and the projectile were designed respectively. The relations between detonation pressure and the velocity of the jet or projectile were gained, the method is that the pressure can be adjusted by the velocity of the flyer when the flyer impact the main explosive. Compared different high-pressure loading methods, this thesis also discussed the feasibility if sphere loading technique can be applied to the study on overdriven equation of states.