Time-Variable Normal Contact Force Influence on Dry-Friction Damping of Self-excited Vibration of Bladed Turbine Wheel

This conference paper deals with dry friction contacts in tie-boss couplings on reduced modal synthesis model of turbine bladed wheel with 66 blades. Due to deformation of the cascade caused by forced excitation from the stator flow and self-excitation instability modelled by Van der Pol model, the motion in friction contacts causes slipping of the surfaces and also changes in normal contact forces. Both friction and variable normal forces are considered in this contribution and effect of contact parameters, such as normal force and angle of contact surfaces, are studied.