Study On Ignition Response And Numerical Simulation Of Penetration Process Of Cast PBX Charge Warhead

Cast PBX explosive is widely used in the warhead of high-speed penetration weapons.Whether the charge warhead can be detonated at the predetermined target position in the process of penetration will directly affect the reliability and damage energy of weapons.In the process of penetration,The cast PBX explosive will be subjected to the impact load of low amplitude long pulse（10～10³MPa,>0.1ms）,which is prone to accidental non-shock ignition,and will seriously affect the reliability and safety of the weapon.Therefore,it is of great significance to study on the ignition response of cast PBX charge warhead during penetration.In this paper,drop hammer impact ignition and friction ignition experiments were carried out on cast PBX tablets,and then macro and meso impact ignition experiment simulation and macro and meso friction ignition experiment simulation were carried out on the samples.The accuracy of the numerical model was analyzed according to the ignition experiment results of the measured samples.Finally,the method was used to analyze the ignition response and safety penetration threshold of the penetrator warhead charge.The main research contents and results are as follows:HTPB based cast PBX samples were prepared and made into tablets of certain specifications,and drop hammer impact ignition and friction ignition experiments were carried out.By the Bruceton method,the critical drop height H₅₀of the tablets for ignition was 46.5cm and the critical hydraulic pressureσ₅₀was 3.7MPa.Through the design of impact drop hammer impact test device and friction pendulum impact test device,the drop hammer impact force of the tablet under different drop height and the impact force of the pendulum under different hydraulic pressure are tested,and the load conditions of the tablet under impact and friction are analyzed,so as to provide boundary load for macro numerical simulation.The drop weight impact ignition experiment and friction ignition experiment of PXB were simulated at macro and micro level respectively,and the ignition interval was judged based on the temperature rise of explosive.The results of numerical simulation are basically consistent with the experimental results.The critical height range of ignition under the action of drop weight is 46～48cm,and the critical hydraulic pressure of ignition under the action of friction is between 3.5～4MPa.Under the action of impact and friction,the internal temperature rise of explosive mainly comes from the friction of micro cracks generated after the adhesive and explosive particles are damaged.For the friction ignition experiment,the internal temperature rise of explosive is mainly caused by the friction with the external friction.The heat generated by friction has little effect on the ignition of explosive particles,but the external friction can affect the damage of the internal interface of cast PBX and the friction of micro-cracks,which can affect the ignition results;the random distribution of explosive particles and particle size gradation in the meso-model can affect the ignition results,but it has little effect.The mechanical response and deformation of charge during penetration process of projectile are analyzed by macro simulation.The mechanical response process of charge is similar to mechanical impact and friction.Then,through the micro model of impact and friction ignition response,the ignition situation of charge under different initial velocity of target is analyzed.The maximum safe initial velocity of the projectile is 1200m/s based on the micro model of random circle.To study the influence of particle shape on ignition,the meso-model of explosive crystal particles with different shapes is constructed based on voronoi diagram,the maximum initial velocity of target is 200～400m/s when the crystal is polygon,the maximum safe initial velocity of target is increased to 400～600m/s when the crystal is spheroidized simply.