Research On The Process Of Projectile Penetration Into Typical Rock Targets At High Speed

With increasing use of rock-like material and fortification laid deeper,the anti-penetration performance of defense works is becoming more and more stronger which requires better penetration performance of penetrating warhead.Analysis of the process of projectile penetration into rock-like material has a significant effect on the design of penetrating warhead.This paper focuses on the penetration process at certain velocity which varies within the range between 1000 and 3000m/s.Target resistance,penetration dynamic and influences of translation velocity were studied by experimental,theoretical and numerical method.Main contents of this paper are as follows:(1)Experiment study on penetration into rock material at elevated impact velocityThe study on rock-like target subjected to projectiles at high velocity was carried out by using ? 30mm ballistic gun.According to the experimental results,the relationship of impact velocity and depth of penetration was studied And he splash model and cater figure of different kinds of rock were compared.This part of research provides experimental study and numerical simulations with guidance.(2)Study on resistance model of rock-like materialThe difference between dynamic cavity expansion in metal material and rock-like material was analyzed.It was considered that the strength criterion used in rock material was more complex than that in metal material so that it was difficult to obtain analytical solutions.By combining classical geometric model of cavity expansion with numerical simulation,the problem of dynamic cavity expansion in rock material,especially the target resistance can be solved.The determined target resistance can be the basis of study on penetration dynamics.(3)Analytical model of penetration dynamics in rock target at elevated impact velocityBased on dynamic cavity expansion model,a rigid penetration model in rock was established.This model can predict the target resistance and determine the relation between the range of expansion and penetration velocity.Therefore,the relation between target resistance and penetration velocity can be obtained at elevated impact velocity.The transition velocity model of rock-like target was established according to the model of metal material.A theoretical model of rock-liked target behavior under elevated impact velocity was depicted by combining rigid penetration model and hypervelocity penetration model.(4)Numerical study on factors effecting transition velocity at elevated velocityNumerical simulations of rock material subjected to long-rod projectile were carried out in AUTODYN-2D in order to analysis the function of several factors,such as the hardness of projectile,nose shape of projectile and materials of projectile and target,which have an influence on the transition point.