Exploring factors affecting the conversion of the coefficient of restitution to equivalent free fall drop height

Abstract

The coefficient of restitution (COR) is used to estimate the equivalent free fall drop height of packaging during handling and transportation. Various experimental studies were designed to explore factors affecting the conversion of the COR to equivalent free fall drop height. These factors include the number of drops, drop height, drop orientation, drop base, temperature and humidity on the COR. The results indicate that the number of drops and drop orientation are the two most influential factors affecting COR values. As the package undergoes more drops, the COR increases. Among the various orientations, the COR is largest for flat drops, followed by edge and corner orientations. Within flat drops, a smaller impact area results in a smaller COR. Manufacturing joints and the flats, edges and corners adjacent to manufacturing joints tend to yield smaller COR values. A COR correction matrix was developed to correct the conventional COR calculation. This matrix allows engineers to refine COR values based on the number of drops and drop orientations in the field. The matrix‐corrected equivalent free fall drop heights demonstrated an average accuracy of 96%. Compared to the conventional COR calculation method, it effectively reduces errors by a factor of 2–3.