Coefficients of Restitution

Abstract

Simplified procedures for predicting post-collision motion in a mechanical system usually incorporate a “coefficient of restitution,” a ratio that must be estimated before the prediction can be completed. Two such ratios have been widely used for some time and a third has been introduced recently by W. J. Stronge. The dependence of these ratios on parameters that characterize various collisions is examined here, using simplifying assumptions about the contact mechanism and with a finite element code. For some collisions all three coefficients of restitution are identical, while significant distinctions can result from other combinations of system configuration, direction of approach velocity, and coefficient of friction.