## 1 Introduction  
Complex mechanical structures usually include several subassemblies, which may have contact surfaces in common. These interfaces affect the behavior of the entire system. It can be realized grossly by introducing two contact parameters, namely contact stiffness and equivalent damping. The major sources of damping in systems, beneficial for controlling the amplitude of vibrations, are the material damping, aerodynamic damping, and friction at contact interfaces. Regarding the last type, the energy is dissipated via friction when contact surfaces undergo a relative displacement. Micro-sliding or \"microslip\", macro-sliding or \"gross-slip\", and separation or \"lift-off\" are the three common states in the surfaces contact behavior. Partial sliding of the regions at the edge of the contact generates microslip. Regarding the micro-scale measurements, sliding contacts between spherical surfaces were first analyzed by [PERSON] et al. [1], who measured the hysteresis loops for convex surfaces. [PERSON] [2] measured the static and dynamic hysteresis of steel balls pressed on flat surfaces. [PERSON] and [PERSON] [3] examined steel balls oscillating between two parallel planes in compression. [PERSON] et al. measured the friction coefficient, cycles of hysteresis and the tangential contact stiffness at room temperature [4] and at high temperature [5] for spherical surfaces in contact with flat surfaces. The sliding contacts between compliant surfaces were examined by [PERSON] et al. [6] by using a test bench, and measured the hysteresis cycles, the friction coefficient and the tangential stiffness of contact by varying normal load and excitation frequency. [PERSON] et al. [7] and [PERSON] et al. [8] obtained the coefficient of friction and tangential stiffness of a plane contact for different materials and load conditions. To compute the Jacobian matrix for 3D friction contact modeling using an alternate frequency time domain method was presented by [PERSON] et al. [9]. In a separate study [10], they showed the damping potential of multiple friction contacts in a bladed disk, and the possibility of increasing the damping effectiveness. Recently, a few studies [11; 12; 13] devoted their attention to analyze the nonlinear dynamic behavior of blade-like structures, namely disk-beam, rotating beam, and rotating disk-beam, with dry friction dampers. Regarding the macro-scale measurements, the first experimental analyses of the sliding contacts effect on global dynamic behavior of aeronautical turbine rotors were carried out by [PERSON] and [PERSON] [14], who measured the hysteresis cycles for disc-blade joints subjected to a uniform compression load. [PERSON] et al. [15] designed a test bench to study the behavior of dovetail joints between disc and blade as the centrifugal load and the vibrations amplitude vary. Firstly, the oscillations' free decay of an axially loaded beam under electromagnetic excitation was measured. Then, the obtained signals were analyzed to derive the frequency and the lost factor of the nonlinear system, as a function of the traction load and amplitude of vibration. The test bench is used in the present work for conducting experimental investigations. The same test equipment was utilized by [PERSON] and [PERSON] [16] to measure the forced response in the frequency domain to validate the numerical results based on the Harmonic Balance Method. [PERSON] et al. [17] analyzed the behavior of a cantilever beam dovetail root joints of different geometries and evaluated the corresponding friction damping in the system. [PERSON] and [PERSON] [18] employed the same method to contiguous palettes to study the tension distribution and notch effect in the blade attachments. [PERSON] and [PERSON] [19] evaluated the global dynamic behavior of a vane in contact with under platform dampers, simultaneously investigated the local contact behavior to realize the performance curves of these dampers.