ASME GT2009-59315 Luis San Andrés Mast-Childs Professor Fellow ASME Measurements of Structural Stiffness and Damping Coefficients in a Metal Mesh Foil Bearing June, 2009 ASME Turbo Expo 2009: Power for Land, Sea, and Air ASME GT2009-59315 Supported by TAMU Turbomachinery Research Consortium accepted for journal publication Thomas Abraham Chirathadam Research Assistant Tae-Ho Kim Research Associate Texas A&M University
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ASME GT2009-59315 Luis San Andrés Mast-Childs Professor Fellow ASME Measurements of Structural Stiffness and Damping Coefficients in a Metal Mesh Foil.
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ASME GT2009-59315
Luis San AndrésMast-Childs Professor
Fellow ASME
Measurements of Structural Stiffness and Damping Coefficients in a Metal
Mesh Foil Bearing
Measurements of Structural Stiffness and Damping Coefficients in a Metal
Mesh Foil Bearing
June, 2009
ASME Turbo Expo 2009: Power for Land, Sea, and Air
ASME GT2009-59315
Supported by TAMU Turbomachinery Research Consortium
accepted for journal publication
Thomas Abraham ChirathadamResearch Assistant
Tae-Ho KimResearch Associate
Texas A&M University
ASME GT2009-59315
Metal mesh foil bearings
Metal mesh ring and top foil assembled inside a bearing cartridge.
Hydrodynamic air film will develop between rotating shaft and top foil.
Metal mesh resilient to temperature variations Damping from material hysteresis Stiffness and viscous damping
coefficients controlled by metal mesh material, size (thickness, L, D), and material compactness (density) ratio.
Zarzour and Vance (2000) J. Eng. Gas Turb. & Power, Vol. 122
Advantages of Metal Mesh Dampers over SFDsCapable of operating at low and high temperaturesNo changes in performance if soaked in oil
Al-Khateeb and Vance (2001) GT-2001-0247
Test metal mesh donut and squirrel cage( in parallel)MM damping not affected by modifying squirrel cage stiffness
Choudhry and Vance (2005) Proc. GT2005
Develop design equations, empirically based, to predict structural stiffness and viscous damping coefficient
METAL MESH DAMPERS proven to provide large amounts of damping. Inexpensive. Oil-free
ASME GT2009-59315
Recent Patents: gas bearings & systems
A metal mesh ring is a cheap replacement for a “porous foil”
‘Air foil bearing having a porous foil’Ref. Patent No. WO 2006/043736 A1
Turbocharger with hydrodynamic foil bearingsRef. Patent No. US7108488 B2
Foil JournalBearings
Thrust foilBearing
ASME GT2009-59315Metal Mesh Dampers for Hybrid Bearings
Ertas &Luo (2008) ASME J. Gas Turbines Power., 130, pp. 032503-(1-8)
MM damper force coefficients not affected by shaft eccentricity ( or applied static load)
Ertas (2009) ASME J. Gas Turbines Power, 131 (2), pp. 022503-(1-11)
Two metal mesh rings installed in a multiple pad gas bearing with flexural supports to maximize load capacity and damping. Bearing stiffness decreases with frequency & w/o external pressurization; and increases gradually with supply pressure
Ertas et al. (2009) AIAA 2009-2521
Shape memory alloy (NiTi) shows increasing damping with motion amplitudes. Damping from NiTi higher than for Cu mesh (density – 30%) : large motion amplitudes (>10 um)
Recent work by OEM with MM dampers to maximize load capacity and to add damping in gas bearings
ASME GT2009-59315
Metal Mesh Foil Bearings (+/-)
No lubrication (oil-free). NO High or Low temperature limits.
Resilient structure with lots of material damping.
Simple construction ( in comparison with other foil bearings)
Cost effective
Metal mesh tends to sag or creep over time
Damping NOT viscous. Modeling difficulties
ASME GT2009-59315
MMFB dimensions and specifications
Dimensions and SpecificationsBearing Cartridge outer diameter, DBo(mm) 58.15
Bearing Cartridge inner diameter, DBi(mm)
Bearing Axial length, L (mm) 28.05
Metal mesh ring outer diameter, DMMo (mm) 42.10
Metal mesh donut inner diameter, DMMi(mm) 28.30
Metal mesh density, ρMM (%) 20
Top foil thickness, Ttf (mm) 0.076
Metal wire diameter, DW (mm) 0.30
Young’s modulus of Copper, E (GPa), at 21 ºC
110
Poisson’s ratio of Copper, υ 0.34
Bearing mass (Cartridge + Mesh + Foil), M (kg)
0.3160 ±
PICTURE
Bearing cartridge
Top foil
Donut shaped metal mesh
Rotating shaft
Gas film
Ω
ASME GT2009-59315
Static load test setup
Lathe tool holder moves forward and backward : push and pull forces on MMFB
Lathe chuck holds shaft & bearing during loading/unloading cycles.