Damping prediction technique of the bolted joint structure considering pretension force

At the initial phase of the mechanical product development, it is very important to effectively obtain the modal damping ratio of the bolted joint structure for accurately predicting dynamic response. The energy dissipation has been estimated using a finite element model incorporating the effect of pretension force of the bolted joint. First, the modal damping ratios of the first four modes are extracted by experimental method. Secondly, the lap joint finite element model with pretension force parameter is constructed and based on which, modal analysis of the structure is conducted. The modal shape scaling results are used as the boundary conditions of the finite element model and the energy dissipations and modal damping ratios of the lap joint under different pretension forces are calculated out. By comparing the numerical calculation result and the experimental result, the validation of the damping prediction approach proposed in this paper is proved.