Experimental results obtained for an Inconel® compressor blade rubbing a steel casing at engine speed are described. Load cell, strain gauge, and accelerometer measurements are discussed and then applied to analyze the metal-on-metal interaction resulting from sudden incursions of varying severity, defined by incursion depths ranging from 13μm to 762μm (0.0005in. to 0.030in.). The results presented describe the transient dynamics of rotor and casing vibro-impact response at engine operational speed similar to those experienced in flight. Force components at the blade tip in axial and circumferential directions for a rub of moderate incursion depth (140μm) are compared to those for a severe rub (406μm). Similar general trends of variation during the metal-to-metal contact are observed. However, in the nearly threefold higher incursion the maximum incurred circumferential load increases significantly, while the maximum incurred axial load increases much less, demonstrating the non-linear nature of the rub phenomena. Concurrently, the stress magnification on the rubbing blade at root mid-chord, at tip leading edge, and at tip trailing edge is discussed. The results point to the possibility of failure occurring first at the airfoil trailing edge. Such a failure was in fact observed in the most severe rub obtained to date in the laboratory, consistent with field observations. Computational models to analyze the non-linear dynamic response of a rotating beam with periodic pulse loading at the free-end are currently under development and are noted.

1.
Hermanek
,
F. J.
, Jr.
, 1970, “
Coatings Lengthen Jet Engine Life
,”
Metal Progress
,
97
, pp.
104
106
.
2.
Kosing
,
O. E.
,
Scharl
,
R.
, and
Schmuhl
,
H. J.
, 2001, “
Design Improvements of the EJ 200 HP Compressor. From Design Verification Engine to a Future All Blisk Version
,” ASME Paper No. 2001-GT-0283.
3.
Sinha
,
S. K.
, 2005, “
Non-linear Dynamic Response of a Rotating Radial Timoshenko Beam with Periodic Pulse Loading at the Free-end
,”
Int. J. Non-Linear Mech.
0020-7462,
40
(
1
), pp.
113
149
.
4.
Turner
,
K.
,
Adams
,
M.L.
, and
Dunn
,
M.G.
, 2005, “
Simulation of Engine Blade Tip-Rub Induced Vibration
,” ASME Paper No. GT2005-68217.
5.
Muszynska
,
A.
, 1989, “
Rotor-to-Stationary Element Rub-Related Vibration Phenomena in Rotating Machinery—Literature Survey
,”
Shock Vib. Dig.
0583-1024,
21
, pp.
3
11
.
6.
Padovan
,
J.
, and
Choy
,
F. K.
, 1987, “
Nonlinear Dynamics of Rotor/Blade/Casing Interactions
,”
ASME J. Turbomach.
0889-504X,
109
, pp.
527
534
.
7.
Adams
,
M. L.
, 2000,
Rotating Machinery Vibration. From Analysis to Troubleshooting
,
Marcel Dekker Inc.
, New York.
8.
Manwaring
,
S. R.
, and
Wisler
,
D. C.
, 1993, “
Unsteady Aerodynamics and Gust Response in Compressors and Turbines
,”
ASME J. Turbomach.
0889-504X,
115
, pp.
724
733
.
9.
Kielb
,
J. J.
,
Abhari
,
R. S.
, and
Dunn
,
M. G.
, 2001, “
Experimental and Numerical Study of Forced Response in a Full-Scale Rotating Turbine
,” ASME Paper No. 2001-GT-0263.
10.
Laverty
,
W. F.
, 1981, “
Rub Energetics of Compressor Blade Tip Seals
,”
Proceedings of the 3rd International Conference on Wear of Materials
,
pp.
714
721
.
11.
Padova
,
C.
,
Barton
,
J.
,
Dunn
,
M. G.
,
Manwaring
,
S.
,
Young
,
G.
,
Adams
,
M. L.
, and
Adams
,
M.
, 2004, “
Development of an Experimental Capability to Produce Controlled Blade Tip/Shroud Rubs at Engine Speed
,” ASME Paper No. GT2004-53322.
12.
Jiang
,
J.
,
Ahrens
,
J.
,
Ulbrich
,
H.
, and
Scheideler
,
E. M.
, 1998, “
A Contact Model of a Rotating Rubbing Blade
,”
Proceedings of the 5th International Conference on Rotor Dynamics
,
Darmstadt, pp.
478
489
.
13.
Ahrens
,
J.
,
Ulbrich
,
H.
, and
Ahaus
,
G.
, 2000, “
Measurement of Contact Forces During Blade Rubbing
,”
Vibrations in Rotating Machinery
, 7th International Conference, Nottingham, September 12-14, ImechE, London, pp.
259
263
.
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