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

The coefficients of restitution of packaging systems are evaluated to find the optimal method for decreasing the error of the equivalent free fall impact height in laboratory simulation. Single-factor tests were used to investigate the effects of the number of impacts, impact height, impact orientation, temperature, and humidity on the coefficient of restitution. Results show that the coefficient of restitution ranges from 0.25 to 0.51 and is mainly influenced by the impact orientation and number of impacts. Generally, the coefficients of restitution of the flat are larger, followed by the edge and corner, and show an asymptotic increase with the increase of number of impacts. In addition, this study reviewed the conventional coefficient of restitution calculation method and proposed a coefficient of restitution correction matrix based on the test results to predict the equivalent free fall impact height. By conducting a field road test and elastoplastic substrate drop tests, the error of the equivalent free fall impact height was decreased by 2-3 times compared to the conventional coefficient of restitution calculation method. The proposed matrix provides a novel approach to the conversion of coefficients of restitution to equivalent free fall impact heights in laboratory simulation for a wide range of applications.