Nonlinear analysis method and experiment on rotationally cyclic structure with a ring damper suppressing vibration under traveling wave excitation

During the design of gas turbine aircraft engines, it is essential to analyze the vibration and damping characteristics of the rotationally cyclic structure experiencing traveling wave vibration. A finite element model of a single sector is established. The cyclic symmetry boundary conditions and Craig-Bampton reduction method are combined to construct a reduced order model. Based on the harmonic balance method, the structural forced responses under traveling wave excitation are calculated. By integrating the nonlinear complex vibrational pattern method, the proposed approach enables the calculation of the nonlinear vibrational pattern. A method based on the nonlinear vibrational pattern is proposed to calculate the resonant response of the blisk. A sensitivity analysis is conducted on the blisk with a ring damper, and a response surface model of the key design parameters is constructed. The results reveal two key findings: damping characteristics exhibit negligible sensitivity to traveling wave direction and increasing the ring damper cross-sectional dimension enhances peak damping ratios but may increase critical amplitudes. The actual blisk is modified to add a ring damper. A rotational excitation test is performed. The results show that the ring damper reduces the amplitude by approximately 80%. This method provides an effective tool for damping analysis and structural optimization of cyclic structures under traveling wave vibration.