Influence of trajectory and pitch angle on the deflection characteristics of projectiles penetrating into thin concrete targets

To investigate the influence of trajectory angle and pitch angle on the deflection characteristics of a projectile penetrating into concrete thin targets, numerical simulation methods were validated by comparing parameters such as projectile velocity, attitude, and trajectory deflection with experimental data from multi-layered concrete thin-target penetration tests. This verification methodology ensured the accuracy and reliability of the numerical model for subsequent parametric studies.Based on this validation, the projectile was divided into six axial segments (the nose section comprising two segments and the body section divided into four segments) to systematically analyze the force distribution characteristics and overall motion behavior under both individual and combined effects of different trajectory angles (ranging from 5° to 30°) and pitch angles (ranging from −6° to 6°). The results show that the direction of the resultant force acting on the projectile body maintains stability across all tested impact conditions, demonstrating consistent patterns regardless of angle variations.While the reversal of the force direction on the projectile nose and the change in the deflection moment caused by the forward motion of the projectile body jointly contribute to the projectile's deflection. Under a positive trajectory angle, the trajectory exhibits an upward deflection. When a pitch angle is introduced, the deflection direction is dominated by the trajectory angle if the negative pitch angle is less than 2° and the trajectory angle exceeds 20°; otherwise, the pitch angle determines the deflection direction. When the trajectory angle and pitch angle are in the same direction, the projectile's attitude angle first decreases after exiting the target and then reverses to increase. When they are in opposite directions, a small pitch angle causes the attitude angle to continuously increase after exiting the target, while a larger trajectory angle induces three deflection reversals during penetration. If the pitch angle exceeds 2°, the attitude angle initially decreases after exiting the target before reversing to increase.