Control strategies for friction dampers: numerical assessment and experiemtal investigations

The use of friction dampers are wide proposed for a variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers.An important example is the application of friction dampers in aircraft engines to reduce the blades vibration amplitudes.In most cases, friction dampers have been studied in a passive way, however, a significant improvement can be achieved by controlling the normal force in the contact region.The aim of this paper is to study four control strategies for friction dampers based on three different hysteresis cycles.The first control strategy maximizes the energy removal in each harmonic oscillation cycle, by calculating the optimum normal force based on the last displacement peak.The second control strategy combines the first one with the maximum energy removal strategy used in the smart spring devices.Finally, is presented the strategy which homogenously modulates the friction force.Numerical studies were performed with these four strategies defining the performance metrics.The best control strategy was applied experimentally.The experimental test rig was fully identified and its parameters were used for numerical simulations.The obtained results have shown the good performance for the friction damper and selected strategy, also, the agreement between numerical and experimental results.