TRC-SFD-1-06 - Tribology Group - Texas A&M University

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Figures 26 and 27 depict the test system direct damping coefficients (C s-xx, C s-yy )identified from tests at increasing orbit amplitudes (12 μm, 25 μm, 38 μm, 50 μm) for thetwo sets of flow restrictors (2.8 mm and 1.1 mm), respectively. The system dampingcoefficients, which include the squeeze film damper and dry friction from the mechanicalseal, show a similar trend as those obtained form unidirectional load tests [2]; i.e. systemdamping decays steadily with excitation frequency. Furthermore, for the smallestamplitude (12 μm) the coefficient is significantly larger than those identified from largermotion amplitudes. This evidences the large influence of dry friction arising from themechanical seal. Importantly enough, the dependency of the damping coefficient uponthe amplitude of motion is less predominant as the excitation frequency increases. This iscommon in systems with dry friction. The size of the orifice discharge holes does notaffect the damping coefficients since the squeeze film pressure fields do not show anysigns of lubricant cavitation or air entrainment.42
3512 μmCC xxs-xxDamping coefficient [kN.s/m]282114725 μm38 μm50 μmAmplitude of motion00 10 20 30 40 50 60 70 80Frequency [Hz]35Damping coefficient [kN.s/m]302520151012 μm25 μm38 μm50 μmAmplitude of motionC s-yy C yy500 10 20 30 40 50 60 70 80Frequency [Hz]Figure 26 Identified test system direct damping coefficients (C s-xx, C s-yy ) versus excitationfrequency for increasing orbit amplitudes. (Circular Centered Orbits, lubricated <strong>SFD</strong>, 2.8mm flow restrictors)43
Page 4: List of TablesTable 1 Structural st
Page 8 and 9: Nomenclaturec Bearing radial cleara
Page 10 and 11: II Literature ReviewDella Pietra an
Page 12 and 13: III Test Rig DescriptionThe test ri
Page 14 and 15: Oil inletEddy current sensorHousing
Page 16: III.2 Lubrication systemFigure 5 de
Page 20 and 21: 0.02Work-Energy Dissipated [N.m]0.0
Page 22 and 23: V Measurements of flow rate in lubr
Page 26: 1.210.8Flow Rate0.60.40.2Flow restr
Page 29 and 30: 300150Y Load [N]-300 -150 0 150300-
Page 31 and 32: 300150Y Load [N]-300 -150 0 150300-
Page 33 and 34: 300250XY200Load [N]150Amplitude of
Page 35 and 36: 21.75Film thickness(3x)0.250[mm]Abs
Page 37 and 38: VI.2 Parameter identification metho
Page 39 and 40: where M s-xx , C s-xx , M s-yy and
Page 41: Table 3 SFD inertia coefficients id
Page 45 and 46: the dry friction interaction to the
Page 47 and 48: 353020 HzC SFDxx s-xxDamping coeffi
Page 49 and 50: opposed to the system damping coeff
Page 51 and 52: VII Conclusions and Recommendations
Page 53 and 54: VIII References[1] Zeidan, F.Y., Sa
Page 55 and 56: Appendix A Identification of Test S
Page 57 and 58: 6 . 105X/F [m/N]4 . 1052 . 105Exper
Page 59 and 60: Appendix B Uncertainty analysis of
Page 61 and 62: 2⎡⎛∂gal.⎞ ⎤Ucalib. = ⎢
Page 63 and 64: Flow (LPM)Flow (LPM)Flow (LPM)4.03.
Page 65 and 66: 30013015012 μm25 μm38 μm65Max. c
Page 67 and 68: 300130150-300 -150 0 15030012 μm25
Page 69 and 70: 300130150-300 -150 0 15030012 μm25
Page 71 and 72: Re(Hd) [MN/m]Re(Fxyx) [MN/m]202Im(H
Page 73 and 74: Re(Hd) [MN/m]Re(Fxyx) [MN/m]202Im(H

TRC-SFD-1-06 - Tribology Group - Texas A&M University

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