Abstract:Attaching dry friction dampers to turbine blades can effectively reduce vibration and suppress high-cycle fatigue failure. As the design speed of engines continues to increase, dry friction damping blades may excite torsional vibration modes during service. Considering the micro-slip characteristics of interface and bending-torsional coupling vibration, in this paper, a bending-torsional coupling dry friction oscillator with a mass of finite dimensions is introduced. By modeling distributed friction force through multiple contact points and discretizing the two-dimensional dry friction interface, the dry friction contact element for analyzing the bending-torsion coupling vibration and the discrete numerical calculation method are established. Three typical normal load distributions (uniform, convex, and concave) are designed, and the steady-state vibration energy reduction rate and displacement amplitude reduction rates are introduced as evaluation criteria for overall and all directions vibration reduction effects, respectively. Combined with micro-slip contact analysis of interface, the fourth-order Runge-Kutta method is applied to solve the dynamic response of the bending-torsion coupling dry friction oscillator. The influence of key parameters on the vibration reduction characteristics of bending-torsion coupling vibration under different normal load distributions is deeply researched. Simulation results demonstrate that the proposed numerical method for the bending-torsion coupling dry friction oscillator has high computational efficiency. Among the different normal load distributions, the concave and uniform distributions have better vibration reduction effects than convex distribution. Furthermore, the vibration reduction effect of the system is significantly improved through the design of normal load distributions. The conclusions provide valuable insights for the engineering design of bending-torsion coupling dry friction damping systems.
