The Jet Mechanisms Of Shaped Charge With High Polymer Liner And Its Applications

The progress of human society is closely related to the development of material technology.Polymer material is a new material developed in the twentieth Century,polymer materials are generally divided into three categories of plastic,rubber and fiber,and the composite material compared to traditional material polymers have unique properties,have been widely used in military and civilian fields.This paper mainly researches the application of polymer materials in plastic cavity effect in the mechanical properties and mechanical model of polymer based research methods,through theoretical analysis,experimental research and numerical simulation,theoretical analysis and macro meso mechanism combining the jet performance and penetration mechanism of polymer liner is analyzed and study on system.First,the tensile stress-strain curves and stress-strain curves of PTFE,nylon and polycarbonate at different strain rates were obtained through the universal material testing machine(WDW-20)and the split Hopkinson pressure bar(SHPB)experiment.Through experimental data and fitting curves,PTFE is a soft and tough material,while nylon and polycarbonate are hard and tough materials,and their mechanical properties are closely related to strain rate.The results showed that:(1)The elongation at break of nylon is the smallest and the tensile strength is the largest,while the elongation at break of PTFE is the largest and the tensile strength is the smallest.The mechanical properties of polycarbonate are between two.(2)The impact resistance of polycarbonate in the three polymer materials is the best,the next of nylon and the worst of polytetrafluoroethylene.(3)when the strain rate is high,the strain softening phenomenon of polycarbonate is similar to that of nylon.There is no obvious curve of quasi-static compression test.This indicates that the strain and strain hardening of polymer materials will have a competitive trend at high strain rate.(4)using static and dynamic compression experimental data,the Johnson-Cook constitutive equation of different polymer materials at normal temperature is fitted.By studying the theory of metal and powder combined jet formation and considering the characteristics of polymer materials,the formation rule of polymer expansion jet is put forward,which provides a theoretical basis for calculating the initial radius of expansion jet.The polymer liner formed jet is simulated using the finite element software AUTODYN,first the Shock equation of state parameters of three kinds of polymer liner,and then make a comparative study of different calculation methods,selecting suitable to describe the calculation method of the jet expansion polymer,finally the polymer drug effects of parameters on the performance of jet expansion cover the.The numerical simulation results show that the polymer jet of different materials has expanded to a certain extent,but because of the difference of material properties,leading to the expansion of the head of the jet diameter and solid condensate in different degrees,of which the minimum diameter of nylon jet expansion,PTFE jet of polycarbonate and jet expansion diameter the largest and highest density.The penetration models of cohesive energy jet and powder polymer composite particle flow are introduced and analyzed.Considering the compressibility and viscosity of materials,combined with the characteristics of polymer cover materials,a computational model of expansion jet penetration is proposed.The damage characteristics of polymer expansion jets on different target plates were studied respectively,and compared with the copper jet penetration test,revealing the damage mechanism of high polymer liner with low explosion and high reaming.Numerical simulation was carried out for polymer impinging and explosive reactive armor,and the effect of explosion height on polymer penetration and non explosion was analyzed.Finally,Teflon and nylon impact impact armor were tested.The results showed that:(1)with the increase of explosion height,the velocity and density of polymer jet decreased,and the diameter and length increased.The jet performance of different materials varied with different degrees.(2)PTFE jet explosive reactive armor reaction with fried high increase gradually,explosive reactive armor in only 1 times the charge caliber high detonation completely fried,fried in other high in the combustion reaction in the following;polycarbonate is 2 times larger than the jet charge diameter height fried are realized the wear of explosive reactive armor without explosion;and the jet at different height are nylon fried detonated an explosive reactive armor.(3)the numerical simulation of polymer impact impact armor shows that the reaction state of explosive reactive armor is mainly affected by the decrease of polymer jet head density and the initial contact area.(4)verification test results show that Teflon jet can reliably achieve the role of explosive reactive armor without wearing out,and reducing the cone angle of liner can reduce the reaction degree of sandwich charge.The research work in this paper provides a new guiding idea for the design and application of polymer charge type charge.