Research On Damage Effects Of Multi-layered Concrete Targets Impacted By Explosively Formed Penetrator

The concept and its development of reactive materials have provided a novel tool for commanders to destroy airfield runway.Reactive jet that formed by reactive material liner not only has a satisfactory penetration,but also,what is more important,releases appreciable chemical energy by detonation/deflagration inside the target.Thus,much catastrophic damage could be achieved by the combination of penetration and deflagration,improving the lethality of conventional warhead greatly.The enhanced lethality and its mechanism of explosively formed penetrator are mainly investigated by the methods of theoretical analysis,numerical simulation and physical experiments.The results would provide important guidance and reference to enhance the lethality of shaped charge warhead,and accelerate the application of reactive materials on anti-airfield warhead.The main work and innovation are as follows:1.The test system for energy release of reactive jet is established,the influence factors of behind-armor overpressure of reactive jet are analyzed;the theretical model for energy release of reactive jet is provided,and the relationship between behind-armor overpressure and energy release is obtained.2.The formation behavior of explosively formed reactive penetrator is investigated on the platform of AUTODYN-2D code,and the influences of liner and reactive material parameters are obtained;X-ray experiments are carried out to verify the formation of explosively formed reactive penetrator.3.In the aspect of penetration behavior of explosively formed reactive penetrator,based on the analysis of geometry and structure characteristics,the equivalent model of airport runway is established;the influence of liner structure and projectile-target condition on the penetration behavior is studied,and the relationship between liner cone angle,liner thickness,stand-off and penetration depth,penetration time is obtained.4.The physical experiments of concrete multi-layered target impacted by reactive jet are carried out;based on the rock demolition model,the theoretical model of deflection and crack growth effects is developed by introducing the crack growth theory,and the relationship between crack length,deflection and liner mass,initiation depth is obtained;thus,the damage mechanism of concrete multi-layered target is uncovered,providing important guidance and reference to the designe of reactive material liner.5.Based on the platform of AUTODYN-2D code,the failure mechanisms of concrete under internal blast are uncovered by employing RHT concrete model;the results show different failure mechanisms for these damage zones;crushed zone is caused by shear failure while fractured zone is induced by tensile failure,and spalled zone is formed by a combination of shear and tensile failure.6.Based on the results of physical experiments and numerical simulation,the lethality performance of reactive jet is analyzed theoretically;based on the analysis of operational requirement of explosively formed reactive penetrator,the theoretical model of optimal initiation depth for explosively formed reactive penetrator is developed,providing an important method to enchance the damage effects of reactive material liner shaped charge.