Quasistatic strain fields in normally- and tangentially-loaded elastomeric rollers under impending slip

Elastomeric rollers are important components in applications such as printing and roll-to-roll manufacturing. To gain insight into roller mechanics and provide a basis for further investigations into dynamic rolling problems where rolling instabilities may arise, we employ a specially-designed apparatus to obtain displacement and strain fields via digital image correlation (DIC) under applied loads. We test loading scenarios leading to impending slip of an elastomeric roller, mounted on a steel hub, and in contact with a glass (rigid) substrate. We first examine strain fields under normal loading and compare them with the closest analytical predictions. We then progress to analyzing the strain fields under combined normal and tangential loading. For each loading scenario, we discuss the displacement and strain fields of the roller sidewall and contact interface. We use a conceptual string model to explore how stick and slip zones develop within the contact area as well as how memory effects arise during cyclic loading. This memory effect is then verified experimentally using the DIC strain fields. Additionally, we demonstrate a means for identifying the stick zone area between the roller and substrate using the experimentally-obtained displacement fields. We believe the apparatus, and the ability to obtain experimental displacement and strain fields, will prove valuable in understanding roller mechanics and associated instabilities.