Additive Manufacturing of Resonant Vibration Absorbers for Turbomachinery Blisks

Turbomachinery blisks are essential components in gas turbine compressors. Blisks are structures manufactured as one single piece, exhibit low damping, and operate under high forcing magnitudes, which makes them subject to high-cycle fatigue. Therefore, it is important to identify and implement methods that reduce blisk vibrations. The state-of-the-art blisk dampers include techniques that use energy transfer from the host structure (i.e., blisk) to an attached resonant vibration absorber (RVA) to reduce the vibration of the host. In addition, RVAs can benefit from energy dissipation via nonlinear contacts (e.g., friction and/or impacts). Previous literature includes the authors’ investigation of RVAs applied to a cantilever beam. This paper analyzes the effects of an RVA attached to a blisk sector. The RVA is placed under the blade, in the disk, and is designed as a small cantilever beam with a hemispherical end to allow for both friction and impact contacts. The energy dissipated depends on the excitation forcing magnitude, material properties, contact surface, and normal force at contact surfaces. The blisk sector and the RVA are additively manufactured from titanium to allow for future exploration of tuning options through microscopic material changes rather than structural geometric modifications. Results reveal that for fixed excitation amplitude and material selection, there is a range of normal forces at the friction contact interface where there is a significant blade tip response reduction. Furthermore, blade tip responses shift to higher frequencies when impacts are introduced due to the stiffening effect present at contacts. Additionally, the gap (at equilibrium) between the RVA and the impact interface significantly affects the energy dissipation. It was further observed that RVAs with both friction and impact contacts can significantly reduce blade tip vibration in blisks for optimal impact gap sizes and friction contact normal loads.