SBIR-STTR Award

To prevent blade failure, the excited resonant response needs to be attenuated to an acceptable level. Several investigators have presented approaches to suppress blade vibration by providing additional damping through blade dampers. Among them, a surface high-damping magneto-mechanical coating layer, so-called free layer damper developed by the PI, is likely to be more practical. The proposed Phase I efforts include: (1) characterization and identification of magneto-mechanical coating stress/strain dependent nature associated with the damping mechanism at various temperature levels (room-1500 F), (2) development of a vibration testing procedure to characterize the dynamic properties of uncoated and coated beams at various temperature levels (room-1500F), (3) a framework will be developed for the estimation of the effect of static mean stress on damping properties of the coating, and (4) developing an analytical approach for predicting the dynamic performance and the nonlinear behavior of the beams and blades coated with a thin layer coating with thickness < 0.005 inch. In Phase I option, assessment of total fatigue life of the coating materials under bending condition will be conducted. In addition, the corrosion of the coating material will be examined thoroughly. Finally, a new nanotechnology will be developed to systematically organize and manipulate stress-induced irreversible movement of the coating magnetic atom domain walls to achieve high damping and damage resistance. Benefit The work is expected to enhance the readiness of Navy and other Armed Forces air fleets as well as significantly reduce of multi-million dollar annual costs of HCF preventative maintenance. The research will have less direct, yet significant, implications to other industries which design products subject to vibration induced high frequency fatigue. This includes, but is not limited to, Power Generation, Automotive, and Offshore/Pipeline industries. Keywords Fatigue, Vibration, coating, damping, Gas Turbine Blades

In this SBIR effort, a novel free layer blade damper using a thin layer of Magneto-mechanical coating has been developed for enhancing vibration damping and resistance to erosion, corrosion, and oxidation. The objective in Phase II is to develop a framework for the estimation of the damping mechanism assessment with the consideration of the effects of the real-world pertinent characteristics to real engine blades and IBR/blisks response. The successful completion of Phase II will prove that the novel coating system is an effective solution providing significant damping to blades/blisk. At the completion of Phase II, we will have accomplished the following: (1) Extensive analytical-experimental evaluations and assessments on fatigue life, effects of centrifugal and thermal forces, high cycle survivability, long-term durability, microstructure, bonding strength, and resistance to erosion, corrosion, & oxidation. These evaluations will demonstrate the effectiveness of the coating system; (2) A fully functioning prototype, demonstrating the full implementation of the coating system; (3) A finite element based analysis and design tool, the finite element procedure developed in Phase I will be extended to real blades and blisks which accounts for the effects of centrifugal and thermal loading; (4) Complete planning on real-world implementation and production for Phase III.

Keywords:
Damping, Coating, Turbine Blade, High Cycle Fatigue