THE CLAMPING STRESS IN A COLD-DRIVEN RIVET

An analysis of a model of the process of cold-driving a rivet is carri ed out with the primary aim of identifying the origin and magnitude of the resulting clamping force exerted by the rivet on the lapped sheet s. The development of high hydrostatic pressure in the rivet shank in the first stages of the driving process, and its subsequent release as the rivet head is squashed, is the key to understanding the origin of the clamping force. The average clamping stress in the rivet shank is on the order of sigma(y)/4, where sigma(y), is the yield stress of th e rivet. The model is used to explore the role of some riveting variab les, including differing yield stresses in the rivet and sheet materia ls, strain hardening, and head size. (C) 1998 Elsevier Science Ltd. Al l rights reserved.