Preethi K.H.
Name
: Preethi. K. H.
Designation : Senior Lecturer
Qualification: Master of Technology (Machine Design)
ME
Dissertation Project (2005):
“Contact stress analysis of compressor blade/disc assembly”
Synopsis:
The stress analysis of single tooth attachments or ‘dovetails’
used to secure fan and compressor blades to disks in gas turbines has received
the attention of several experimental and numerical investigations. A
consideration of typical geometry and loading conditions for such joint
indicates that a maximum principal tensile stress occurs on the free surface of
the fillet radius at the root of the projection in both blade and disc. Not all
failures of such components originate from cracks in this region, however, it
is necessary to consider the stress distributions internal to the contact areas
of the blade root and disc.
The aerodynamic loads on compressor blades are small in
comparison to the radial loads due to rotation and many compressors have
blades, which are located in axial dovetail slots in the periphery of the
discs. It was therefore considered that a two-dimensional model of blade-disc
joint would be more appropriate for carrying out the internal stress analysis.
The photo elastic experimental techniques were extensively used to investigate
the stress distributions in these joints using both live load analysis method
and stress freezing techniques.
This report presents the details of parametric studies carried
out to analyze the contact stress distributions around the dovetail type
blade/disc interface of a fan of an aero engine. The effect of flank angle
variation on the contact stress distribution was studied.
The investigations were carried out using the
front-end commercial software ANSYS 5.4 with its contact stress analysis
capabilities. Plane stress elements (PLANE42) were used in the FEM formulation
of the problem. The interface between blade and disc was modeled using contact
elements(CONTACT12).
Some typical results of the project work
Address:
Faculty
of Mechanical Engineering Department
The
Bommanahalli,
Karnataka
Phone : 080-26692271
Mobile : 9448688971
E-mail : preethihgowda@yahoo.com
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