59528 - Numerical Analysis of the Impact of Mistuned Underplatforms Dampers on the Vibration of Bladed-Disks 

Due to the very high cost of experimental testings, the design of turboengines is mostly made through different stages of numerical simulations. Before the last experimental validation and certification of the structure, turboengineers simulate, among other things, its vibratory properties in order to estimate its lifespan and adjust the design in an optimisation process. One possible practical solution to decrease the vibratory response is to add underplatform dampers to the system. These components dissipate energy by friction and are widely employed in turbomachinery. However, a specific underplatform damper is efficient only for specific modes. Different methods exist to determine the vibrations of nonlinear cyclic symmetric systems under traveling wave excitations but creating a robust methodology to account for nonlinear mistuned systems is still a big challenge in the community. In this paper, we study the influence of the dampers material properties on the overall energy dissipation. First, assuming a cyclic symmetric structure, the performance of the dampers are assessed for specific modes. Then, employing a recent method developed by the authors, the efficiency of an intentional mistuning pattern of underplatform dampers is studied. The purpose of this work is to show that adding different kinds of underplatform dampers to the cyclic structure may decrease the vibratory energy over a larger panel of modes.