<title>Damping designs for rotating blades</title>

Abstract

This paper presents the results of the first phase of an effort to determine the effects of centrifugal forces on viscoelastic damping concepts applicable to rotating components. The design of the experimental test specimen will be discussed along with the analytical methods used to design and evaluate damping concepts for the test specimen. A blend of classical analysis, 6th order beam theory, and finite element analysis was used. The analytical effort was divided into two tasks. The first task was to define the design of the test specimen such that: (1) a meaningful test could be conducted in the spin test facility; (2) damping concepts could be designed into the test specimen; and (3) manufacturing time and cost were reasonable. The second task of the effort was to complete a trade study evaluating various damping concepts. The trade study evaluated damping effectiveness, survivability, manufacturability, and damping material availability. The design parameters evaluated included: (1) pocket size, orientation, and number; (2) pockets with and without floating constraining layers; (3) damping concept creep potential; and (4) stresses in the test specimen due to centrifugal loading. This paper will detail the analysis techniques used, the trends found in the design parameters, and the final designs chosen for the test effort.