Design and Stress Analysis of Extraterrestrial ... - The Black Vault

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Stress analysis of turbine disks
Turbine disks are the main• load-bearing components of the ro~tor
and enable the development of high circular velo~cties' (up to 300-
350 m/s). Turbine disks, just As rotor :blades, 'work under very
severe conditions. The following stresses appear in them:
- stress from the centrifugal forces of the disk itself as well
as from the centrifugal forces of the bladesfixed to the disk;
- assembly stresses (when a disk is fit tightly'to a shaft;;
- bending stress (from the axial forces df tht gas acting~on the
blades and from the centrifugAl fobrces otf the blades with the
unsymmetric location of their centers of gravity relative to the
middle plane of the disk);
- temperature stresses (duibing the uneven heating of the disk
along the radius and thickness);
- torsional stresses (from the torque on the, blaoes being
transferred by the disk to the shdft)'. , *
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Furthermore, it'is necessary to cdnsider that the physical
properties of the disk. material deteriorate with a temperature
increase - E, a.' -aT decrease and the tendency toward plastic
flows increases. Thus, the materialiof theiturbine disk must
resist creep and fatigue well at elevated temperacures.
Bending stresses and torsion, as airule, are'considerably le•i
than the others and are z.ot usually consid.ered ih
of disks.
stress analysis
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Disk analysis is
a domplicated, statically undefinable problemn
There are three forinslof stress analysis for disIs.
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1. Determining stresses in a disk of known shapes (check
calculations).
2. Plotting the disk shapeý acbording to a given law of stress
distribution ("disks of cohstant strength").
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