Vibration mitigation of a flexible bladed rotor dynamic system with passive dynamic absorbers

The main objective of this paper is to study the application of tuned mass damper (TMD) and nonlinear energy sink (NES) on vibration mitigation of a flexible bladed rotor system. TMD tunes to a specific frequency of the main system and reduces its amplitude only in a vicinity of that frequency. NES is another well-known passive dynamic absorber comprises a mass, nonlinear spring, and linear or nonlinear damper. The nonlinearity of this absorber allows it to reduce the vibrations of the main system in a wider frequency range. In this study to reduce the contact of flexible bladed rotor system, the mentioned passive absorbers are attached both to the disk and to the tips of the blades, such that to deactivate the effect of disk's eccentricity force and stabilizing the behavior of the system. The optimum parameters of the absorbers are obtained through optimization. The bifurcation diagrams, and Lyapunov exponent of the system are obtained with respect to different parameter and rotational speed are obtained and consequently, the efficiency of the absorbers are investigated. The obtained results show how these passive absorbers can decrease the vibration of the rotor system and remove the contact at higher clearance values between the blades and the stator; although, there are limitations in their performances at lower values of clearance.