Study On The Formation Mechanism Of Kill Element From Shaped Charge With Double Layer Liners

Double Layer Liners Shaped Charge(DLSC),which produces jets with different materials or tandem EFP(Explosively Formed Projectile),can significantly increase the penetration capacity of shaped charge warhead。DLSC is composed of one charge and two liners.The liners can either be set close or be set with gap between them.The liners'materials can be the same or be different.But there must be free surface between the liners which allow them to slide or impact against each other.If more than two liners are compact in one charge, it is called Multi-Liners Shaped Charge(MLSC).DLSC with little cone angle can produce non-slug jet with high tip velocity or jet which has a following burning effect.DLSC with large cone angle can produce EFP with large length diameter ratio or two EFPs,which can be widely applied in anti-tank,anti-warship,anti-submarine and anti-helicopter fields.The study on DLSC can improve the penetration capacity of shaped charge significantly and gives a theoretic foundation and technical support for high efficiency damage.By using theoretical analysis,numerical simulations and experimental methods,the formation mechanisms of DLSC,especially the key factors that influence the penetrator performance,are studied systemically,which would give a theoretic foundation and technical support for the design and improvement of DLSC.The followings are the main contents of this dissertation:(1)The formation mechanism of jet DLSC is studied.By theoretical analysis,the interaction between DLSC and detonation products,the collapse of DLSC and the jet formation of DLSC are described.The PER theory was used to build an analytical model to study the collapse of DLSC.Using Bernoulli equation,mass and momentum conversation,the theoretic models which describe the TLSL jet formation at the collapse point are established and then the mass and configuration of jet and slug coming from TLCL are determined.(2)The formation mechanism of tandem EFP DLSC is investigated.The formation of DLSC into tandem EFP is described,and the factors that influence the formation of tandem EFP are investigated.It is concluded that the velocity gradient is the key factor which produce tandem EFP,based on which the velocity equations of tandem EFP is deduced further.(3) Utilizing two-dimensional finite element dynamic code AUTODYN,the numerical simulations about the influences of DLSC configurations,detonation method and liner materials on the formation of tandem EFP is carried out.The simulation results are summarized and compared with test results.The laws that govern the DLSC parameters and the formation of tandem EFP are gained.(4)On the base of theory analysis and numerical simulation,DLSC with cone-arc liner is designed and the tests of DLSC forming into tandem EFP are carried out.The tests and numerical results agree well and the results show that the DLSC can form tandem EFP and the penetration capacity of DLSC is better than Single Liner Shaped Charge.