A Novel Test Rig for the Basic Nonlinear Characterization of Bolted Joints

The paper aims at performing a comprehensive experimental study on the peculiar properties of a bolted joint, and investigates the damping induced at different interfaces (between flanges, bolt head/nut and flange, threads) during vibrations. A novel, simplified, single-bolt system joining a two-beam structure is designed and tested. Experimental results under different boundary conditions are presented, and the influence of the harmonic excitation force, as well as the bolt tension, is investigated. The test results show how the contact interface between the clamped flanges plays an important role in terms of frictional damping provided to the system during vibration, while the contact interfaces between the head/nut and flange, and secondarily between the threads, affect the system response at a less, but not negligible, extent. The test setup and test procedure can provide a database to validate single bolt contact models to be included in a more complex structure.