Publication

Abstract: In this article, we investigate the behavior of the coefficient of restitution (COR) which is an important parameter in many impact-related fields. In many cases, the COR is considered as a constant value, but it varies according to many variables. In this paper, we introduce an analytical variable COR model considering aerodynamics along with its verification through experiment. To introduce and analyze
the variable characteristic of the COR model, the collision phenomenon between a pendulum and two kinds of ball is
employed as an example and aerodynamics such as drag force is considered for analyzing the after-effect of the collision.
Collision velocity of the pendulum, dynamic parameters of colliding bodies, contact time, drag coefficient, the air density, and the cross-sectional area of the ball are found as the typical variables of analytical COR model. This observation generalizes the result in previous researches. To verify new
COR model, the travel distances for the curve-fitted constant COR model and the curve-fitted variable COR model are compared through simulation and experiment. Moreover, comparison between constant COR and variable COR is presented in several points of view. Finally, using the variable