This paper focuses on the modelling of harmonic vibration of two rotating blades affected by friction in contact of a rigid body placed in between the blade shroud. Harmonic blade excitation uniformly distributed in blade nodes in circumferential and axial direction is supposed. Flexible blades are discretized by FEM using 1D Rayleigh beam elements. The nonlinear friction forces in contact surfaces between the blade shroud and the friction element are taken into account using the harmonic balance method. Orbits of central contact points and dissipation energy are investigated in dependence on the excitation frequency. Dissipation energy amount in contact surfaces is confronted with blade tips vibration. and Obsahuje seznam literatury