β Scribed by Hoon-Voon Liew; Teik C. Lim
No coin nor oath required. For personal study only.
This paper extends the rolling element bearing stiffness matrix formulation developed by to include the time-variation effect of raceway rotation. In that earlier work, the rolling element bearing stiffness matrix was formulated in time-invariant form assuming fixed element position. However, due to the orbital motion of the elements under most rotating conditions, the true nature of the bearing stiffness is periodic in time. Characterizing the timevarying form of the stiffness function, and computing its impact on the vibration response of geared rotor system is the focus of this communication.
The first few major works on rolling element bearing were performed by Jones [6], Harris [7], and Palmgren [8]. They described the radial and axial load-deflection behavior using a nonlinear stiffness coefficient, which were subsequently adopted in numerous bearing analyses [9][10][11]. However, these early bearing stiffness models were inadequate and incapable of predicting the vibration transmission across bearings. To address the problem, a more generalized formulation based on the Hertzian theory, which relates the raceway displacement vector to the bearing load vector, was formulated by . The new theory led to the derivation of a timeinvariant bearing stiffness matrix Β½K bm of dimension 5 corresponding to 2 radial, 1 axial, and 2 angular coordinates; the rotation about the shaft axis by design is free. This new bearing stiffness
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Vibration signals resulting from rolling-element bearings present a mixture of physical information, the proper analysis of which can lead to the identi"cation of possible faults. Traditionally, this analysis is performed by the use of signal processing methods, which assume statistically stationary
The most fundamental cause of noise and unsteady running of rolling bearings is the so-called varying compliance vibrations. These are parametrically excited vibrations that occur irrespective of the quality and accuracy of the bearing. Varying compliance of the bearing assembly can give rise to bot