In this paper the effect of blade crack on the mode localization of a rotat
ing blade disk is studied Pretwisted taper beams are used to simulate blade
s of a blade disk. The crack on the blade can be regarded as a local disord
er of this periodically coupled blades system. An application of Hamilton's
principle and Galerkin's method is used to formulate the equations of moti
on of the mistuned system. Effects of pretwisted angle, rotating speed, and
crack depth of the blade on the in-plane and off-plane mode localizations
of a rotating system are investigated. Numerical results indicate that the
increase of rotating speed, pretwisted angle, and crack depth could enhance
the localization phenomenon significantly.