Vibration Reduction of an Assembly by Control of the Tightening Load

Due to their lightness, the aerospace structures are vulnerable to vibrations. Their amplitudes need to be mitigated through damping devices. The aim of this paper is to control the tightening force of a bolted joint in order to improve the vibration reduction. The work focuses on a single vibration mode modeled by two degrees of freedom coupled with a Jenkins' cell. Then two control strategies are proposed in order to reduce the harmonically forced vibrations and transient vibrations. The first control law uses a constant optimum clamping for each excitation level. The second law consists in a sinusoidal variation of the clamping force adapted to each level and frequency of excitation. Finally, in the third section, the control law is modified in order to reduce transient vibrations. For each control law, the performances of the model are discussed according to the aimed application.