Vibration Prediction of Bladed Disks Coupled by Friction Joints

Abstract

The present review article addresses the vibration behavior of bladed disks encountered e. g. in aircraft engines as well as industrial gas and steam turbines. The utilization of the dissipative effects of dry friction in mechanical joints is a common means of the passive mitigation of structural vibrations caused by aeroelastic excitation mechanisms. The prediction of the vibration behavior is a scientific challenge due to (a) the strongly nonlinear and non-uniform contact interactions involving local sticking, sliding and liftoff, (b) topological complexity of the coupled structure, and (c) the multidisciplinary character of the problem associated with the need to account for structural mechanical as well as fluid dynamical effects. The purpose of this article is the overview and discussion the current state of the art of vibration prediction approaches. The modeling approaches in this work embrace the description of the rotating bladed disk, the contact modeling, the consideration of aeroelastic effects, appropriate model reduction techniques and the exploitation of the rotationally periodic nature of the problem. The simulation approaches cover the direct computation of periodic, steady-state externally forced and self-excited vibra

Reduced-order modelling using nonlinear modes and triple nonlinear modal synthesis

“…However, taking into account nonlinearities in the simulations can be of primary importance in the design process since they are known to have a strong impact on the vibration level, as pointed out in several numerical and experimental investigations [41][42][43]. A detailed review on vibration prediction of bladed disks in the presence of friction phenomena can be found in [44].…”

Modeling Friction for Turbomachinery Applications: Tuning Techniques and Adequacy Assessment of Heuristic Contact Models

“…Some authors adopt a Dynamic Lagrangian method to solve on the contact patch [6,7], that is, the contact constraints are taken into account in their non-regularized form without additional compliance. Other authors, for example, [4,8] apply a contact element to each meshed node belonging to the contact area, introducing normal and tangential stiffnesses and a Coulomb friction law. This last method is preferred here, as its calibration parameters (k n , k t and μ), however difficult to determine, represent a physical measurable property.…”

“…The answer to point 3 is investigated using three pre-optimized damper configurations [40], that is, curved-flat dampers not affected by lift-off/rolling, jamming or partial detachment. 4 The user-controlled working conditions investigated during this chapter are limited to a variation of centrifugal load on the damper (i.e. normal load at the contact).…”

“…The presence of friction-induced nonlinearities makes solving the equilibrium equations a challenging task, therefore standard FE codes are not suited to the purpose: a complex hierarchy of techniques has been developed, a thorough review can be found in [4]. Furthermore, modeling friction entails:…”

“…It is based on the observation that typical reduction techniques (e.g. CB-CMS [4]), used to reduce the size of FE models, may neglect the small local deformations. A "correction factor" is introduced to take into account this effect.…”