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Blade Vibrations (blade + vibration)
Selected AbstractsHollow Cathode Gas Flow Sputtering of NixAly Coatings on Ti-6Al-2Sn-4Zr-6Mo: Mechanical Properties and Microstructures,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2009Andreas Kohns A W-TiB2 -multilayer erosion resistant coating with a NixAly bond coat deposited by hollow cathode gas flow sputtering is under development for Ti6246 aero engine compressor blades. Blade vibrations in service can produce cracks in the coating propagating into the substrate and reducing the high-cycle fatigue strength of the component. It is assumed, that this effect can be diminished by adapting the mechanical and morphological properties of the NixAly bond coat. In this context, process parameter variations are performed and discussed. [source] The harmonic adjoint approach to unsteady turbomachinery designINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3-4 2002M. C. Duta Abstract In recent years, there has been rapid progress in aerodynamic optimization methods which use adjoint flow analysis to efficiently calculate the sensitivity of steady-state objective functions to changes in the underlying design variables. This paper shows that the same adjoint approach can be used in turbomachinery applications in which the primary concern is blade vibration due to harmonic flow unsteadiness. The paper introduces the key engineering concepts and discusses the derivation of the adjoint analysis at the algebraic level. The emphasis is on the algorithmic aspects of the analysis, on the iterative solution method and on the role played by the strong solid wall boundary condition, in particular. The novel ideas are exploited to reveal the potential of the approach in the minimization of the unsteady vibration of turbomachinery blades due to incident wakes. Copyright © 2002 John Wiley & Sons, Ltd. [source] The Vibrational Behavior of Bladed Disks in Consideration of Friction Damping and Contact ElasticityPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2005Christian Siewert Rotating turbine blading is subjected to fluctuating gas forces during operation that cause blade vibrations. One of the main tasks in the design of turbomachinery blading is the reduction of the vibration amplitudes of the blades to avoid high resonance stresses that could damage the blading. The vibration amplitudes of the blades can be reduced significantly to a reasonable amount by means of friction damping devices such as underplatform dampers. In the case of blade vibrations, relative displacements between the friction damping devices and the neighboring blades occur and friction forces are generated that provide additional damping to the structure due to the dry friction energy dissipation. In real turbomachinery applications, spatial blade vibrations caused by a complex blade geometry and distributed excitation forces acting on the airfoil accur. Therefore, a three dimensional model including an appropriate spatial contact model to predict the generalized contact forces is necessary to describe the vibrational behavior of the blading with sufficient accuracy, see [1] and [2]. In this paper the contact model presented in [2] is extended to include also local deformations in the contacts between underplatform dampers and the contact surfaces of the adjacent blades. The additional elasticity in the contact influences the resonance frequency of the coupled bladed disk assembly. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||