Trajectory Deflection Rigid Projectile Penetrating Into Concrete Laws

Oblique penetration and penetration with attack angle are common situations when the projectiles penetrate the targets. At home and abroad, the number of researches on the laws of ballistic deflection of oblique penetration and penetration with attack angle into concrete medium was smaller than normal penetration into concrete. Based on experimental research, theoretical analysis and numerical simulation method, the influence of different factors on the laws of ballistic deflection when rigid projectiles penetrating concrete targets was studied in this dissertation. The aim of the research is to provide certain reference for kinetic energy warhead design. The primal contents and conclusions in this dissertation are as follows:1. A calculation model of rigid projectile penetrating semi-infinite thick concrete targets was developed. The relation between the projectile surface normal stress and surface normal velocity was determined by using empirical formula method, theoretical analysis method and numerical simulation method. On this basis, the surface normal stress was loaded onto the surfaces of projectiles by ABAQUS/EXPLICIT software as the resistance during the process of penetrating into the targets.The influence of the free surface effect when the projectiles oblique penetrating into the targets was also considered. By using Fortran language, we wrote the VDLOAD subroutine programs. Eventually, the calculation model of the projectiles oblique penetration into the semi-infinite concrete was developped. The trajectories of the mass center of the projectiles were calculated by this model. The calculation results of the model and the previous experimental results are in good agreements.2. The numerical simulation of rigid projectile penetrating into concrete targets was carried out. In order to reconstruct the process of projectiles penetrating into concrete targets, the LS-DYNA software was used to simulate the process of the projectiles penetration into concrete targets. The HJC concrete constitutive model and the rigid model of projectile were used to simulate the process of normal penetration, oblique penetration and oblique penetration with attack angle. The impact velocity and acceleration change during the penetration process were analyzed. The numerical simulation results and experimental results are in good agreements.3. The trajectory deflection influence factors and deflection laws of rigid projectiles penetration into concrete targets were studied. On the basis of numerical simulation, the laws of trajectory deflection by the influence of different factors (oblique angle, attack angle, speed, projectile centroid position) were studied. Eventually, we got the conclusions of deflection laws of rigid projectiles penetration into concrete targets.These conclusions can be used to guide the kinetic energy warhead design.