Research On The Ballistic Characteristics Of Asymmetrical Grooved Projectile Head Penetrating A Typical Target Obliquely

In order to study the trajectory characteristics of oblique penetration of asymmetrical grooved-nose projectile into typical target,an experimental study of asymmetrical groovednose projectile obliquely penetrating into double-layer spaced and multi-layer spaced concrete targets was performed in this paper firstly.Based on the analysis and discussion of the test results,simulations corresponding to the experiments were carried out.The influence of projectile incidence angle,projectile velocity,target thickness and projectile deformation on the trajectory characteristics of multi-layer spaced steel target subjected to the asymmetrical grooved-nose projectile were analyzed.Finally,simulation of asymmetrical grooved-nose projectile obliquely penetrating concrete targets of finite thickness and semiinfinite thickness was developed in combining the method of projectile-target separation with the free surface effect.The main contents are as follows:（1）Experimental study on oblique penetration of asymmetrical grooved-nose projectile into double-layer spaced concrete targetsExperiments on the penetration of a double-layer spaced concrete target subjected to the asymmetrical grooved-nose projectile and ogive-nose projectile of the same structural parameters at the same speed and at the same angle of incidence of 30° and 45° were carried out respectively.The remaining velocity,projectile posture and trajectory deflection of projectile were recorded by the high-speed camera.The law of trajectory deflection and the mechanism of the spin effect of the grooved projectile are analyzed.The results show that asymmetrical grooved-nose projectile spins obviously during the penetration process and the asymmetric grooved-nose can effectively improve the trajectory stability.（2）Experimental study on the oblique penetration of asymmetrical grooved-nose projectile into multi-layer spaced steel targetsExperiments of two types of asymmetrical grooved-nose projectiles（5-grooved projectiles and six-grooved projectiles）with the same mass and length and ogive-nose projectiles penetrating into the four-layer spaced steel at incident angle of 10° and 20° were performed.The change of penetration trajectory and the characteristics of target failure were obtained.By using the high-speed camera,the remaining velocity and trajectory deflection after obliquely penetrating each space of steel target were recorded and the interaction law of the projectile and target was analyzed.The results show that the projectile deformed severely when penetrating the multi-spaced steel targets,which leads to a negligible spin effect of the projectile with the asymmetrical grooved projectile.（3）Numerical simulation on the oblique penetration of a multi-layer spaced targetSimulation of asymmetrical grooved-nose projectile obliquely penetrating the doublelayer spaced concrete target and the multi-layer spaced steel target were carried out in LSDYNA.After verifying the reliability of the simulation method according to the experimental data,the influence of projectile incidence angle,projectile velocity,target thickness and projectile deformation on the trajectory characteristics of oblique penetration of multi-layer spaced steel target were analyzed.（4）Numerical study on the asymmetrical grooved-nose projectile penetrating into concrete target by using projectile-target separation method and considering free surface effectBased on the projectile-target separation method,the numerical model of the projectile was established and the target response force subroutine was compiled in finte element modeling software.The reliability of the simulation model was agree with the experimental data.The relation of trajectory and velocity with time were discussed,as well as the passive rotation angle-time curves and passive rotation angular velocity-time curves of asymmetrical grooved-nose projectile.Simulation of asymmetrical grooved-nose projectile obliquely penetrating the semi-infinite concrete target was carried out.The numerical results show that asymmetric grooved-nose has better trajectory stability than ogive-nose projectile.