Shear Lag Based Iwan Model for Interface Friction Contacts

Reduced order models for characterizing friction interfaces have been investigated for the last 75 years. Recent work has been focused on microslip formulation of the interface behavior, where continuous contact is approximated with a multi-point contact model. A novel multi-point contact model is presented in this work, which is entirely derived from a shear lag approach to resolve the kinematic state of the friction interface under the presence of tangential loading. Both static and dynamic loading conditions are analyzed and comparisons are drawn between the continuous and discrete models. The series Iwan model presented in this work differentiates between the elastic and friction components of the interface displacement, both parameters being calibrated using material properties and model geometry. Convergence behavior of such models with increasing model order is demonstrated. The response characteristics of the series Iwan model under dynamic loading conditions is also investigated. The series Iwan model is in good agreement with the shear lag approach for results such as propagation of the slip zone with increasing pullout force. The transient response of the the structural mass and the kinematic states of the damping elements are convergent with increasing model order.