Planar impacts in hybrid chains of cylinders and balls

Abstract

In this paper, we study low-velocity multiple impacts of chains of balls and cylinders. We use three types of materials including steel, wood, and rubber. We perform collision experiments of balls and cylinders of three-, four-, and five-body chains and obtain their corresponding pre- and post-impact velocities. Although the common solution methods such as rigid body and bimodal models can not deal with this type of problems, we use a discretization method presented in Alluhydan et al. (2019, "On Planar Impacts of Cylinders and Balls," ASME J. Appl. Mech., 86(7), p. 0710091) to accurately calculate the post-impact velocities of the colliding bodies in the chain. We use the bimodal Hertz-Crook contact force model and employ the ball-ball coefficient of restitution at the contacting segments to analyze the impact dynamics of the colliding objects. A segmentation method is used for ball-cylinder and cylinder-cylinder Collisions. The number of segments for each collision is determined by using a relationship that relates the stiffness ratio of two objects to the number of the segments. In ball-ball collisions, however, we do not use the segmentation method. The outcomes demonstrate that the overall average percentage error of post-impact velocities among experimental results and numerical predictions was less than 6.2% for all results.