A Theoretical Model of a Simply Supported Circular Ring Under Impulsive Loads

Metallic thin-walled circular rings are widely employed as energy-absorption components in impact protection systems. However, the dynamic deformation mechanisms under impact loads remain incompletely understood. In this study, we develop a rigid-perfectly plastic model to analyze a simply supported circular ring subjected to impulsive loads. We present a theoretical survey of the incipient deformation under step loading, establishing the relation between the applied load magnitude and the number and location of the stationary plastic hinges. Our analytical findings reveal that as load magnitude increases, the number of stationary hinges grows, with newly formed hinges progressing closer to the point of loading. We validate these theoretical predictions against finite element analyses, demonstrating the model's accuracy. Additionally, we investigate the complex deformation mechanisms involving both stationary and traveling hinges under rectangular pulse loading. This study provides fundamental insights into the dynamic plastic response of thin-walled structures, offering theoretical guidance for optimizing impact protection systems.