A similarity method for predicting the residual velocity and deceleration of projectiles during impact with dissimilar materials

Abstract

A method for predicting the residual velocity and deceleration of a projectile during normal low-velocity impact on a 2024-O thin aluminium plate is developed based on the similarity theory. Geometric scaling, the dissimilar materials of the projectile and different target thicknesses are considered. By a similitude analysis, the simulation criteria between the modelling and prototype experiments are obtained. The dimensionless velocity and deceleration of a projectile can be predicted by the relationship equations with the dimensionless dynamic pressure, projectile density and target thickness. On the basis of experimental data, the dimensionless residual velocity relationship is obtained and verified. In the range of normalised target thicknesses of 0:5 H=D p 1 (where H is target thickness and D p is projectile diameter), the deceleration-time data during penetration is simplified as a triangular wave. Moreover, it can be characterised using the maximum deceleration, the time to the maximum deceleration and the period of the triangular wave. Through a simulation analysis, three dimensionless deceleration characteristics of the projectile are developed to replicate a prototype-like deceleration-time process in a scaled model.

A Simplified Approach for the Determination of Penetrant Residual Velocity for Penetration Processes

“…Both results recommended that increasing the content of CFRP increases the flexural properties of hybrid CFRP/AFRP laminates. The dimensional analysis methodology was also conducted by Song et al [15] to predict the residual velocity of the projectile, where dimensionless residual velocity relationship is obtained and verified, in the range of normalized target thicknesses, mainly ranging from half to full diameters of the projectile. Malik et al [16] provided a novel approach to enhance the ballistic impact resistance of Mg alloy through the "cross pre-compression" technique.…”

Study on the Equivalence of Penetration Overloading for Projectile-Borne Components in Nonproportional Penetrators

“…Up to now, there have been a few works on the similarity law of rigid-body deceleration. Most of them have concentrated on a complete-similitude scaling method according to the dimensional analysis [21]. In general, once a scale factor λ (λ > 1), the ratio of geometric dimensions, is defined, other model variables can be expressed by those of the prototype, as shown in Table 1.…”