Abstract
The use of friction dampers has been proposed in a wide 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 dampers. The aim of this paper is to study three control strategies for friction dampers based on the hysteresis cycle. 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 three 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 the numerical simulations. The obtained results show the good performance for the friction damper and the selected strategy.
Highlights
The use of friction dampers has been proposed in a wide variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers
Friction dampers had been studied in a passive way, a significant improvement can be achieved by controlling the normal force in the dampers [3]
Friction dampers with variable normal force are classified as semi-active devices and their appeal is to have performance levels rivalling the active devices with low level of energy consumption [4]
Summary
The use of friction dampers has been proposed in a wide variety of mechanical systems for which it is not possible to apply viscoelastic materials, fluid based dampers or others viscous dampers. The aim of this paper is to study four cases of control strategies for friction dampers based on the hysteresis cycle. The first control strategy, named “Case A”, maximizes the energy removal in each harmonic oscillation cycle calculating the optimum normal force, i.e., uses the force that maximizes the hysteresis area reducing the vibration amplitude. Tangential stiffness for the friction damper has been settled at ்ܭൌ ͵Ǥ͵ ݇ܰȀ݉ and friction coefficient was adjusted as ߤ ൌ ͲǤ͵ʹͷ in order to calculate and simulate all studied cases These values represent the parameters identified from the test rig. 07007-p.2 frequency was chosen as close as possible to the resonant frequency These conditions guarantee the permanent slippage state to the friction damping even for small values of the normal force such as ͳͲܰ. The control law strategies was studied as proposed by Santos & Neto [13] and the equations for numerical and experimental implementation are: CASE A
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
