A Fractal Contact Friction Model and Nonlinear Vibration Response Studies of Loosely Assembled Blade With Dovetail Root

To investigate the friction damping effect of a loosely assembled blade with dovetail root, a fractal contact friction model is proposed to describe the friction force. In the proposed model, the friction contact interface is discretized to a series of friction contact pairs and each of them can experience stick, slip, or separate. Fractal geometry is used to simulate the topography of contact surfaces. The contact stiffness, which is related to the parameters of contact interfaces including normal load, roughness, Young’s modulus, and Poisson’s ratio, is calculated using Hertz contact theory and fractal geometry. The nonlinear vibration response of loosely assembled blade with dovetail root is predicted using the proposed model, the multiharmonic balance method and Newton iterative algorithm. The effect of centrifugal force, friction coefficient and exciting force on the forced response of a loosely assembled blade with dovetail root is studied. The numerical vibration responses are compared to the experimental results. It will verify the reliability of the numerical method and provide theoretical basis for structure design of the loosely assembled blade with dovetail root.