Influence of friction bearings on the frequency response of a variable stiffness mechanism

Journal
Mechanism and machine theory  
Volume
168
Article Number
104588
Citation
Mechanism and Machine Theory 168: 104588 (2022-02)
Publisher DOI
10.1016/j.mechmachtheory.2021.104588
Scopus ID
2-s2.0-85118182797
This contribution examines a variable stiffness mechanism that is intended for the use as a boundary element in vibration tests. The mechanism consists of two antagonistic nonlinear springs guided along the central axis. The axis is axially guided via two bearings. This paper concerns itself with comparing the effects of friction and roller bearings on the frequency response. Further, a comparison of different measurement techniques for the dynamic characterization of the aforementioned mechanism is in focus. An experimental study utilizing a multisine, sine-sweep, and impulse excitation signal is conducted. A nonlinear numerical model as well as a linear approximation are presented and compared with the measurement results. The results indicate that friction bearings have a strong influence on the frequency response of the system, especially at low displacement amplitudes. The influence of the friction contact on the results of different measurement methods is shown. The presented variable stiffness mechanism with the roller bearing configuration yielded in a predictable vibration behavior even for high mechanism pretensions.
Subjects
Adjustable impedance elements
Friction bearing
Mechanical impedance
Variable stiffness mechanism