Influence of particle rotation on the oblique penetration in granular media

Abstract

The rotation of a particle has significant influence on the dynamic response of a granular bed subjected to the oblique impact of a spherical projectile. Based on the discrete element method, the dynamical behavior of two-dimensional granular media impacted obliquely by rotating particles has been examined in this work, especially for the influence of rotational angular velocity on its penetration depth. The simulations show that the incident rotational velocity will not only act on the characteristics of velocity distribution of the bed after impacting, but also influence the trajectory of the projectile qualitatively. For low angular velocities, particle rotations will significantly increase the vertical penetration depths, while the different directions of rotation will exert opposite effects on the horizontal penetration depths. In addition, the influence of particle rotation on its penetration depth will be enhanced with increasing angular velocity, but such effect will reach an asymptotic plateau for sufficiently large angular velocities. This indicates that the angular velocity has an obvious criticality. Furthermore, the variation of critical angular velocity may be linear with the impact velocity and square with the impacting angle, approximately. Finally, the influence of the initial particle rotation on the scaling law of penetration depth is also considered, and we find that the linear scaling with impact velocity is still applicable for most impact conditions.

On the Horizontal Deviation of a Spinning Projectile Penetrating into Granular Systems

“…On the other hand, the bigger the size of the bed's particles, the higher the horizontal deviation values of the projectile's ultimate penetration stopping point from that of its original impact point as shown in Figures 2(a) and 2(b). These results are in good agreement with previous experimental and computational results [31,32]. Now, based on the above analysis of the proposed normal penetration processes, a function that describes the trajectory profile of the spinning projectile beneath the granular bed can be introduced as follows:…”

Effects of density ratio and diameter ratio on penetration of rotation projectile obliquely impacting a granular medium

“…Meanwhile, the influence of angular velocity on its penetration depth has an obvious criticality, that is, the effect would tend to an asymptotic plateau when this rotational angular velocity is large enough. Such variation laws have been demonstrated in the study of the rotation influence on oblique penetration (Ye et al, 2012).…”

“…It indicates the influence of angular velocity on its penetration depth has an obvious criticality under different density ratios. Here we have defined the critical angular velocity using the method proposed in our previous paper (Ye et al, 2012). In following analysis, all critical angular velocities are obtained using such pre-defined uniform manner.…”

“…Therefore, the discrete dynamical method can be adopted as a powerful way to achieve this purpose. Our previous simulations (Ye et al, 2012) find that physical properties of projectile and bed particles play important roles during overall impact dynamics process.…”

“…Although almost real impacts in granular material belong to a 3-D problem in a strict sense, many existing experiments and simulations (Ciamarra et al, 2004;Seguin et al, 2009;Wang et al, 2012;Ye et al, 2012) based on a 2-D impact exhibit some meaningful phenomena that are very similar to those observed in 3-D situations. Therefore, using easy-controlling 2-D experiments or simulations is a very important quantitative approach to explore these complex dynamical processes in real situations of granular impact.…”