Bill Beckman December 9 th, 2013 Wear of a Gas Turbine Friction Damper MANE-6960 Friction, Wear, and...
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Transcript of Bill Beckman December 9 th, 2013 Wear of a Gas Turbine Friction Damper MANE-6960 Friction, Wear, and...
Bill BeckmanDecember 9th, 2013
Wear of a Gas Turbine Friction Damper
MANE-6960Friction, Wear, and Lubrication of Materials
Overview Wear of a dry friction damper in turbine section of
engine investigated Blade excitation is one of many failure concerns due to
risk of cyclic crack propagation from dynamic loading coupled with high thermal and static loading
Turbine blade vibration amplitude mitigated by use of under platform “cottage-roof” damper to dissipate kinetic energy by means of frictional contact and heat generation
Theory and Methodology Archard’s law for adhesive wear: Relative tangential slip movement between damper
wearing surface and blade counter surface on the order of 25 micrometers
Damper wear due to adhesion and fretting cannot be avoided, but mitigated with appropriate materials
Low change in damper volume is essential in retaining vibrational damping capability over the lifetime of the component
Results Various hardness values of high temperature alloys
have an effect on damper wear rates Nickel and Cobalt-Chromium alloy hardness can range
from 165 BHN to 515 BHN in a high temperature environment
Surface modification by means of carburization can be an effective low cost solution over high bulk material hardness alloys
Conclusion Adhesive wear due to plastic deformation of asperity
and bulk material cannot be avoided over high cyclic loading
Increasing material hardness retains damping capability of the part over lifetime of engine operation
Gas carburizing further improves part capability Softer and lighter Ni alloy can behaves as high hardness Co-Cr
alloy for most of part lifetimeDamper volume
lost over lifetime
165 BHN
235 BHN
305 BHN
375 BHN
445 BHN
515 BHN
Carburized
19.8% 14.5% 11.5% 9.6% 8.2% 7.2% 9.8%