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Abstract: Dimension
errors in root part of a turbine blade, which are formed in manufactural
process or by wearing out during service leads to contact conditions
between the blade root and disc groove changed. As a result, a shift of
fundamental frequencies of the blade and redistribution of stress in the
root will occur, which possibly causes failure of the blade. Influence
of the dimension errors on contact status between the blade root and the
disc groove and on fundamental frequencies of the blade is investigated
by three dimensional finite element analyses. A finite element model of
a blade with fir shape root and its matched disc groove is constructed
and then analyzed by taking account of large deformation of the blade
and contact nonlinear in the root. The results show that locations of
the errors have significant influence on fundamental frequencies
especially for bending modes of the blade. Magnitude of the error has
almost no influence on frequencies but affects contact status and thus
affects the stress field in the root. The results also suggest that
considering the contact between blade root and disc groove is necessary
to obtain more real fundamental frequencies of a blade-disc component.
Key words: Blade
Dimension error Fundamental frequency Contact analysis Finite
element analysis
CLC No: TK263
Received 20050618,
received in revised form 20051207
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