AN EXPERIMENTAL INVESTIGATION ON THE STATIC AND DYNAMIC CHARACTERISTICS OF JOURNAL BEARINGS UNDER THE INFLUENCE OF TWISTING MISALIGNMENT

The misalignment between the journal and the bearing in a rotor-bearin g system may be due to manufacturing error, elastic deflection, therma l expansion etc. In the present work, the eight linearized stiffness a nd damping coefficient of the cylindrical and three lobe bearings are identified at different levels of bearing misalignment (twisting misal ignment) and at different speeds of the rotor. The identification meth od used here needs FRFs (Frequency Response Functions) obtained by the measurements and the finite element method. The twisting misalignment changes the stiffness and damping coefficients in the vertical and ho rizontal directions. In the case of three lobe bearings, for 0.7 degre e of misalignment, the stiffness in the vertical direction is increase d by about 12 percent.