Nonlinear dynamic analysis of three-dimensional bladed-disks with frictional contact interfaces based on cyclic reduction strategies

In bladed disks, friction nonlinearities occurring within the contact between the blades and disk or between the blades and underplatform dampers are used to decrease the vibratory energy of the system and extend its lifespan. Modeling these nonlinearities and simulating their effects correctly are challenging: complex nonlinear phenomena such as stick, slip and separation may occur in the contact zones. Efficient numerical methods must be used to compute the dynamics of the system in a reasonable amount of time. This paper proposes a reduction strategy to tackle large cyclically symmetric finite-element models undergoing static preload from centrifugal effects and strong nonlinearities (friction and separation). It combines the nonlinear identification of the possible interacting nodal diameters with a linear component mode synthesis procedure. Its potential and performances are assessed through comparisons with some state-of-the-art methods. Complex and realistic nonlinear finite-element models of bladed disks with underplatform dampers and dovetail or fir-tree blade roots are used. The Dynamic Lagrangian Frequency Time algorithm is employed to capture the nonlinear effects. Using the proposed reduction method, the effect of underplatform dampers on bladed disk contact occurrence and damping efficiency is investigated.

Automated summary

This study investigates the use of friction nonlinearities to reduce vibratory energy and extend the lifespan of bladed disk systems, proposing a reduction strategy for handling complex nonlinear models. With the use of the Dynamic Lagrangian Frequency Time algorithm to capture nonlinear effects, the impact of underplatform dampers on bladed disk systems was explored.