Research on contact stiffness of tenon jointed turbine bladed disk under time-varying load

Abstract Tenon-jointed turbine blades will be impacted by airflow and centrifugal force during the high-speed rotation of the engine. The surface contact stiffness of the tenon and tenon groove will change with complex external loads. Through the analysis of the micro-morphological characteristics of the contact surface of the tenon joint bladed disk, the contact characteristics of the asperities on the rough surface are determined. At the same time, to solve the problem that the traditional microscopic contact stiffness calculation formula cannot be applied to the tangential displacement load, the periodic piecewise tangential stiffness expression is derived based on external loads of the normal force and the equivalent tangential force. Furthermore, this paper studies the properties of the tangential stiffness curves under different external load frequency ratios and phase differences. An increase in the frequency ratio will decrease the step value of the piecewise function and make it tend to a smooth transition. The change of the phase difference will directly change the monotonicity and fluctuation of the stiffness curve. The macro and micro theoretical analysis methods of contact characteristics have been established.