Dry friction damping blade structural vibration analysis of ocean nuclear power platform steam turbine

The ocean nuclear platform turbine blade is studied. Based on the nonlinear finite element method, the contact pressure load on the friction contact surface is analyzed. The three-dimensional finite element vibration characteristic numerical model is established. The spring damping element is applied to describe the friction damping characteristics between the shroud and snubber contact surfaces of adjacent blades. The equivalent stiffness and damping coefficients of the shroud and snubber contact surfaces are calculated based on the experiment results of dry friction dynamic characteristics with blade material. The structural vibration response under different contact pressure load is analyzed by harmonic balance method. Furthermore, the simulation results are compared with the experiment results. The results show that the blade structural vibration response decreases significantly as a result of the damping between friction contact surfaces. The relative error of the resonance frequency for free blade is only 0.53%. The relative errors of modal damping ratio for the free blade and constrained blade are less than 2.65% and 20% respectively. The relative error of the constrained blade resonance amplitude is less than 15%. The reliability of the numerical analysis method is verified by comparison with experimental data. (paper)