A new motion model of rifle bullet penetration into ballistic gelatin

•New frameworks for drag and lift coefficients are proposed.•A penetration model for rifle bullets penetrating ballistic gelatin is established.•The motion model is well consistent with the penetration tests and simulated results.

An accurate description of the motion of bullets in ballistic gelatin penetration can only be given if a corresponding mathematical model is derived. In this paper, change of the effective wetted area of the bullet is studied well with the increase of angle of yaw in the penetration process. By introducing an area detached ratio and the influence of slenderness, a novel framework is proposed for drag and lift coefficients. Further, a new motion model of rifle bullet is established based on the new frameworks and validated by comparison with the results from experiment data and FEA. The comparative analysis shows that results of the new motion model have a better fit with experiment data than that of the traditional models in previous literatures and the proposed framework for drag and lift coefficients is better than the traditional ones in literatures by comparison with the numerical results. In addition, the calculation of the new motion model is in great accordance with FEA in terms of penetration depth, deflection path, yaw angle, velocity, lift force and drag force at different initial conditions. Benefitting from the motion model based on the new frameworks for drag and lift coefficients, the behavior of rifle bullet in gelatin penetration can be characterized accurately, the prediction of the distribution of energy deposited along the penetration trajectory and the potential for incapacitation of rifle bullets may become possible.