Mechanics in frictional penetration with a blind rivet

The mechanics of frictional penetration driven by a blind rivet to sheet metals is analyzed for a friction stir blind riveting process. Analytic models are deduced to calculate the material removal rate, penetration force and torque during the frictional penetration process. Frictional penetration tests with modified rivets and an Al alloy sheet were carried out at various rotation speed-feed rate combinations, where the penetration force and torque were recorded with a data acquisition system. An analysis of the contact condition between the rivet tip and the work material based upon the assumption of pure sliding contact in the initial penetration to partial sticking contact beyond a critical penetration depth of the rivet is completed, and the results are discussed based on the comparison of the analytically calculated and experimentally measured torque-force ratios.