Blade couple with dry friction connection

Abstract

Vibration of blade couple damped by a dry friction contact in shroud is investigated by means of hysterezis loops and response curves analysis of blades couple. The studied system is excited by one harmonic external force in frequency range near to the lowest eigenfrequency of real blades. Models of blades are connected by means of damping element consisting of dry friction part linked in series with linear spring. This “stick-slip” damping element is supposed either weightless or with a very small mass modeling elastically deformed parts of contacting bodies near the friction surface. Two approximate mathematical models of “stick-slip” dry friction elements are suggested and analysed. Response curves of blades couple model connected by stick-slip damping element are presented for different values of slip friction forces and two values of mass of elastically deformed parts.