Numerical and Experimental Investigation of Friction Damping in Shrouded Blades

Abstract The blade is a critical turbine engine component that faces a high risk of high-cycle fatigue (HCF). To reduce its vibration, shrouded blades are often employed. However, the dynamic behavior of the shrouded blade is complex, making it challenging to accurately predict its damping ratio and resonance frequency. In this study, an economical experimental setup was designed, which requires only two blades to investigate the dynamic characteristics of shrouded blades. A novel method was adapted to measure the contact force and friction coefficient of the shrouds. Sinusoidal excitations were executed, and frequency response functions (FRFs) were recorded. Subsequently, study established a relationship between resonance frequency to vibrational stress using these FRFs. Additionally, the experiment was simulated by the harmonic balance method (HBM). A hysteresis spring contact model was adapted to simulate the contact of the shrouds. Vibrational stress, resonance frequency and damping ratio were computed base on the displacement outcomes from the HBM simulation. The consistency between the obtained simulation outcomes and experimental results was found to be satisfactory, indicating that the proposed approach effectively captured the complex behavior of the shrouded blades.