Research On The Reactive Inner Core Formulation And Structural Design As Well As Damage Mechanism Of PELE Projectile

As a new type of armor-piercing warhead,the main principle of PELE(Penetrator with Enhanced Lateral Effect)projectile is to convert part of the axial kinetic energy of projectile into the radial kinetic energy of fragments by using the difference between the outer casing and inner core,which can better solve the defect of the insufficient aftereffect of the conventional armor-piercing projectile.The metal/polymer mixture type reactive material is a new kind of energetic materials,which is very insensitive under normal conditions,but undergoes a chemical reaction under high-speed loading conditions and can release tens of times its own kinetic energy.In order to improve the comprehensive damage power of PELE projectile,this dissertation studies the feasibility of applying reactive materials to the inner core of PELE projectile by means of theoretical analysis,numerical simulation and experimental research.In addition,the structures of PELE projectile were designed,and the damage mechanism of PELE projectile with reactive inner core was studied.The main research contents and results of this dissertation are as follows:(1)The common fluorinated polymers and metal elements are comprehensively analyzed in terms of physical and chemical properties.Finally,the primary selection range of the main components of the reactive inner core materials were determined.According to the reaction characteristics among the basic components,six kinds of reactive material formulations were preliminarily designed.In addition,different sintering processes were designed according to the size requirements of different types of mechanical properties tests,and the test samples with better mechanical properties were obtained.(2)The qualitative and quantitative tests of the energy release capacity of the six pre-designed reactive material formulations were carried out,and the optimum formulation of the reactive material designed in this paper was determined to be PTFE/Al/Si.In addition,the quasi-static mechanical properties and dynamic mechanical properties of PTFE/Al/Si reactive material were tested.The basic mechanical properties of PTFE/Al/Si reactive material were obtained,and the Johnson-Cook constitutive model of sintered PTFE/Al/Si reactive material was constructed considering strain hardening effect,strain rate hardening effect and temperature softening effect.(3)In order to simulate the penetration process of PELE projectile more realistically,this dissertation improves the existing numerical simulation methods by adding the crack softening algorithm and stochastic failure algorithm in Autodyn.The results show that the simulation results after adding the two algorithms are closer to the actual penetration process of PELE projectile.In addition to improving the comprehensive damage ability of PELE projectile by changing the inner core of PELE projectile,two new types of PELE projectile(Truncated cone-shaped PELE projectile and Segmented PELE projectile)were designed from two aspects: the structural shape of projectile,the type of outer casing combination.Comparing with the damage of the conventional PELE projectiles based on the improved numerical simulation algorithm,the results show that the comprehensive damage capability(Penetration ability and Fragmentation effect)of the two new PELE projectiles are superior to the conventional PELE projectiles.Moreover,the truncated cone-shaped PELE projectile is more suitable to penetrate the single-layer thick target,while the segmented PELE projectile is more suitable to penetrate the multi-layer thin targets.(4)Based on the principle of energy conservation,a theoretical model of the radial scattering velocity of fragments was established.The analysis shows that the energy of the radial scatter kinetic energy of fragments mainly comes from three aspects: the axial kinetic energy of outer casing,the radial compression potential energy produced by the inner core material,and the chemical energy released by the reactive inner core material.Based on the numerical simulation,the pressure distribution along the axis of the PELE projectile core is approximately exponentially attenuated.Using the Powder Burn equation of state which can well describe the combustion and explosion reaction behavior of energetic materials under high-speed impact in Autodyn,the penetration ability and fragmentation effect of reactive inner core PELE projectile and conventional PELE projectile were compared comprehensively.The results show that the comprehensive damage power of the reactive core PELE projectile is superior to the conventional PELE projectile.In summary,this dissertation carried out in-depth research on reactive inner core PELE projectile from seven aspects: reactive material formulation design,preparation and sintering process,energy release capability and mechanical properties research,simulation algorithm improvement,new projectile structure design,damage mechanism analysis,and numerical simulation of reactive inner core PELE projectile.The research results have important reference value for the design of high-efficiency damage PELE projectiles.The relevant conclusions and results enrich people's understanding of energy release mechanism and engineering application of reactive materials.