Numerical Study of the Trajectory Stability of Lateral-Abnormal Projectiles Penetrating Soil at Small Angles of Attack

Abstract

Lateral-abnormal projectiles with different geometrical nose pin on the front of the penetrator are designed as soil penetrator. A comparative analysis of the twodimensional motion of the non-normal penetration of different lateral-abnormal projectiles into soil at small angles of attack (AOA) is carried out with Modified Integrated Force Law (MIFL) methods in which the stress algorithms are numerically integrated over the top and bottom surfaces of the projectile to determine the force and moment acting on the projectile based on the spherical cavity expansion theory. Critical conditions for the occurrences of the instability and the reverse of the lateralabnormal projectile trajectory are discussed. The proposed model in which the wake separation and reattachment between projectile body and target are taken into account is capable of predicting J-hook trajectory of the lateral-abnormal projectiles into soil at various small AOA and shows good agreement with the field test data.