Optimization of cascade blade mistuning. II — Global optimum and numerical optimization

E. Nissim, R. T. Haftka

Research output: Contribution to journalArticlepeer-review


The values of the mistiming which yield the most stable eigenvectors are analytically determined, using the simplified equations of motion which were developed in Part I of this work. It is also shown that random mistunings, if large enough, may lead to the maximal stability, whereas the alternate mistunings cannot. The problem of obtaining maximum stability for minimal mistuning is formulated, based on numerical optimization techniques. Several local minima are obtained using different starting mistuning vectors. The starting vectors which lead to the global minimum are identified. It is analytically shown that all minima appear in multiplicities which are equal to the number of compressor blades. The effect of mistuning on the flutter speed is studied using both an optimum mistuning vector and an alternate mistuning vector. Effects of mistunings in elastic axis locations are shown to have a negligible effect on the eigenvalues. Finally, it is shown that any general twodimensional bending-torsion system can be reduced to an equivalent uncoupled torsional system.

Original languageEnglish
Pages (from-to)1402
Number of pages1
JournalAIAA Journal
Issue number9
StatePublished - Sep 1985
Externally publishedYes

Bibliographical note

Funding Information:
The work presented herein was supported by NASA Lewis Research Center, under NASA Grant NAG-3-347.


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