An analysis is presented for the Frahm-type blade-vibration-absorber (BVA) when the second flapwise bending natural circular frequency (ω
2) coincides with the three per revolution (3Ω). The rate of change in ω
2 with increasing the mass of BVA is drastic for the smaller mass ratio, but becomes mild for the larger one. For the purpose of comparison, the effect of a simply fixed weight is also investigated. The effect of BVA is much larger than that of the fixed weight for a same mass ratio in the both devices, if the mass ratio is reasonably small and if the station does not coincides with modal shape nodes.
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