Meanwhile the importance of mistuning especially for blisks is well known. Most of the mistuning studies so far done are based on assumed statistical distributions of the eigenfrequencies. But it is important to know the real eigenfrequency distribution of the blades of blisks as they come out of the manufacturing process or after they are in service for some time and have experienced erosion, wear and FOD. Some of the current analytical procedures for mistuning calculations need the blade-alone frequencies, such as the reduced-order code Turbo-Reduce which is used in the subsequent analysis. One way to determine the eigenfrequency distribution is to ping-test every blade while damping all other blades. This procedure is very tedious and may take several days, depending on the number of blades. Further, it is very difficult to eliminate the influence of the disk and to obtain the pure blade-alone eigenfrequencies. In this paper a method for the analytical determination of the eigenfrequency distribution due to geometric imperfections based on optical measurements is described. Starting from the point-cloud from the optical measurements a procedure to obtain a FEM-Model of all blades of a blisk is presented. As the procedure can partly be run as a batch-job, the time to determine the eigenfrequency distribution is drastically reduced compared to the experimental way. The procedure is applied to a real blisk and the calculated eigenfrequencies are compared with the measured frequencies. Then mistuning calculations are performed based on this eigenfrequency distribution.

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