| Polymer Bonded Explosive(PBX)is widely used in weapon warhead,missile charge and solid propellant.PBX explosives will be subjected to impact load during processing,transportation or accidental collision.If it is used as an internal charge such as ground penetrating projectile or penetrating projectile,it is bound to be subjected to strong impact load when working.In conventional weapons,users want the PBX to be as "sensitive" as possible,while in non-combat accidental collision,users also want the PBX to be as "insensitive" as possible,so it is of great significance to study the initiation characteristics of PBX explosives under impact load.The reaction dynamic model of PBX can well reflect the state characteristics of PBX in the three stages of nonexplosion,explosion and explosion.It is also a necessary material model to study the detonation of PBX under the impact load by using numerical simulation and other technologies.Therefore,this paper studies the reaction kinetics model of PBX-1 and its initiation characteristics under impact load,mainly including the following aspects:(1)Cylinder detonation experiment was carried out to record the time history information of the detonation product of PBX-1 explosive driving the radial expansion of the cylinder wall,and the isentropic expansion characteristics of the detonation product gas of PBX-1 material were studied.The equation of state of the detonation product of PBX-1 explosive was established and the parameters of the equation of state in the form of JWL were calibrated.The stable propagation of detonation wave and cylinder expansion process in PBX-1 explosive in cylinder detonation experiment were calculated by numerical simulation method,and the correctness of the equation of state and parameters of detonation product were verified.(2)Based on the first-stage light gas gun device,the dynamic mechanical response of PBX-1 explosive under the plane impact loading condition was studied.The "symmetrical impact" method was adopted,and the equation of state of the unreactants of PBX-1 explosive was obtained by fitting the theories of flight-plate velocity measured in the experiment,the time difference monitored by the pressure sensor and the plane positive shock wave.(3)Lagrange experiment was used to measure the historical information of pressure at multiple positions in the path of detonation wave transformation in PBX-1explosive.Other physical quantities in the flow field were obtained through pull analysis,and the trinomial ignition growth reaction rate equation was calibrated.The equation of state of unreactants,the equation of state of detonation products and the mixing rule were combined.The reaction kinetics model of PBX-1 explosive was established.The correctness of the kinetic model was verified by numerical simulation.(4)Based on the self-designed charging projectile body and the initial closed test chamber,the PBX-1 initiation characteristic experiment was carried out.The velocity of the projectile body,the maximum pressure of the plate after the impact of the projectile body on the test chamber,and the overpressure in the test chamber after the explosion of the PBX-1 explosive were collected.The critical condition of PBX-1explosive initiation is obtained by combining with the photos of PBX-1 explosive initiation taken by high-speed camera.Based on the theory of energy flux in closed container,the energy released by PBX-1 during detonation is calculated.Finally,the numerical simulation of the experiment was carried out with the established reaction dynamics model,and the details of the pressure and reactivity of each part in the detonation process of PBX-1 explosive were obtained.The research results obtained in this paper can provide the basis and guidance for the detonation characteristics of PBX explosive,and also provide the basis for the charge design of national defense weapon warhead,which has a certain reference value. |
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