Gas turbine disks are subject to mechanical stresses due to centrifugal forces exerted by the blades, as well as thermal stresses due to high temperature gradient. High stresses in the presence of elevated temperatures cause the rotating disk material to undergo considerable creep. This phenomenon is significant particularly in cases of turbine blades for power generators, which run almost continuously. Creep strains, in time, lead to deformations resulting in increase of the disk diameter, causing the clearance between blade tips and the turbine’s outer shell to reduce in time. As the above clearance gap is usually limited, this matter is of concern in the design of such equipment for long life. In this investigation, an optimization method is formulated, which is capable of proportioning the thickness distribution of inhomogeneous rotating disks under temperature gradient, so that their long term radii increase due to creep would be minimum. An example is given, which shows the viability of the method.

1.
Millenson
M.
,
Manson
S. S.
, 1948, “
Determination of Stresses in Gas Turbine Discs Subjected to Plastic Flow and Creep
,” NACA Report No. TR-906.
2.
Mendelson
,
A.
, 1968,
Plasticity: Theory and Application
,
The Macmillan Company
,
New York
.
3.
Genta
,
G.
,
Gola
,
M.
, and
Gugliotta
,
A.
, 1982, “
Axisymmetric Computation of the Stress Distribution in Orthotropic Rotating Disks
,”
Int. J. Mech. Sci.
0020-7403,
24
, pp.
21
26
.
4.
Abdoul-Mihsein
,
M. J.
,
Bakr
,
A. A.
, and
Packer
,
A. P.
, 1985, “
Stresses in Axisymmetric Rotating Bodies Determined by the Boundary Equation Method
,”
J. Strain Anal.
0022-4758,
20
, pp.
70
86
.
5.
Yeh
,
K. -Y.
and
Han
R. P. S.
, 1994, “
Analysis of High-Speed Rotating Disks With Variable Thickness and Inhomogeneity
,”
ASME J. Appl. Mech.
0021-8936,
61
, pp.
186
191
.
6.
Jahed
,
H.
, and
Dubey
,
R. N.
, 1997, “
An Axisymmetric Method of Elastic Plastic Analysis Capable of Predicting Residual Stresses
,”
ASME J. Pressure Vessel Technol.
0094-9930,
119
, pp.
264
73
.
7.
Jahed
,
H.
, and
Sherkatti
,
S.
, 2000, “
Thermoplastic Analysis of Inhomogeneous Rotating Disk With Variable Thickness
,”
Proceedings of the EMAS Conference of Fatigue
,
Cambridge
,
Cambridge, England
, Apr.
8.
Jahed
,
H.
, and
Shirazi
,
R.
, 1997, “
Thermoplastic Analysis of Rotating at Elevated Temperatures
,”
Int. J. Pressure Vessels Piping
0308-0161,
71
(
3
), pp.
285
91
.
9.
Jahed
,
H.
, and
Bidabadi
,
J.
, 2003, “
An Axisymmetric Method of Creep Analysis for Primary and Secondary Creep
,”
Int. J. Pressure Vessels Piping
0308-0161,
80
, pp.
597
606
.
10.
Wall
,
A. M.
,
Sankey
,
G. A.
,
Manjoine
,
M. J.
, and
Shoemaker
,
E.
, 1954, “
Creep Tests of Rotating Disc at Elevated Temperature and Comparison With Theory
,”
ASME J. Appl. Mech.
0021-8936,
21
, pp.
222
235
.
11.
Penny
,
R. K.
, and
Marriott
,
D. L.
, 1995,
Design for Creep
,
2nd ed.
,
Chapman and Hall
,
London
.
12.
Malkov
,
V. P.
, and
Salgankays
,
E. A.
, 1976, “
Optimum Material Distribution in Rotating Disks for Minimum Strength
,”
Sov. Aeronaut.
,
19
, pp.
46
50
.
13.
Fox
,
R. L.
, 1970,
Optimization Methods for Engineering Design
,
Addison-Wesley
,
London
.
14.
Vanderplaats
,
G. N.
, 1990,
Numerical Optimization Techniques for Engineering Design With Applications
,
2nd ed.
,
McGraw-Hill
,
New York
.
15.
Zeinkiewics
,
O. C.
, and
Campbell
,
J. S.
, 1973,
Shape Optimization and Sequential Linear Programming in Optimum Structural Design
,
Wiley
,
New York
.
16.
Wang
,
S. -Y.
,
Son
,
Y.
, and
Gallagher
,
K. H.
, 1985, “
Sensitivity Analysis in Shape Optimization of Continuum Structures
,”
Comput. Struct.
0045-7949,
20
, pp.
855
867
.
17.
Pederson
,
P.
, 1981,
The Integrated Approach of FEM-SLP for Solving Problems of Optimal Designs in Optimization of Distributed Parameters
,
Sijthoff and Nourdhoff
,
Leydan
, pp.
757
780
.
18.
Cheu
,
T. -c.
, 1990, “
Procedures for Shape Optimization of Gas Turbine
,”
Comput. Struct.
0045-7949,
54
(
1
), pp.
1
4
.
19.
Farshi
,
B.
,
Jahed
,
H.
, and
Mehrabian
,
A.
, 2004, “
Optimum Design of Inhomogeneous Non-Uniform Rotating Discs
,”
Comput. Struct.
0045-7949,
82
(
9–10
), pp.
773
779
.
20.
Jahed
,
H.
,
Farshi
,
B.
, and
Bidabadi
,
J.
, 2005, “
Minimum Weight Design of Inhomogeneous Rotating Discs
,”
Int. J. Pressure Vessels Piping
0308-0161,
82
(
1
), pp.
35
41
.
21.
Farshi
,
B.
, and
Bidabadi
,
J.
, 2008, “
Optimum Design of Inhomogeneous Rotating Discs Under Secondary Creep
,”
Int. J. Pressure Vessels Piping
0308-0161,
85
(
7
), pp.
507
515
.
You do not currently have access to this content.