Vibration And Localization In Bladed Disk Assembles With Integral Shroud Clearances

The integral shroud with clearances has been adopted as a damper structure inturbomachinery for nearly20years. The vibration of the bladed disk assembles can bereduced by impacts between neighboring integral shrouds effectively. However, thereare two problems existing. Fist, the design criteria and rules are still not uniform.Second, there are always random deviations among the blades caused bymanufacturing tolerances, wear, and other causes. This is called mistuning which maycause vibration localization during the bladed disk’s operation. Vibration localizationcauses a great increase in vibration amplitude of some blades, compare to tunedsystem, which increases the risk of the fault of bladed disk structure. Therefore, thevibration and localization received a lot of attention.The lumped-parameter model of a bladed disk assembles is adopted. And thevibration of the system and the localization factors are numerical simulated byRunger-Kutta integration and statistic method. The major contents are follows:1. The tuning lumped-parameter model is developed. The impact condition andthe computing formula of impact force are showed. The damping mechanism andnonlinear characteristic is investigated with Runge-Kutta integration method.2. The mistuning lumped-parameter model is developed. Resonance response andimpact and friction force of the blade at different orders are computed with randommistuning from tip clearance. Localization factors for weak and strong coupledstiffness are calculated with random mistuning from stiffness and tip clearance.Illustrate the influence of impact to the localization.3. The influence of structure parameters to the frequency veering characteristichas been investigated. The localization sensitivities of the impact/non-impact systemat different locations around the frequency veering area are compared with the MonteCarlo method.