Abstract:
Rotor assemblies particularly those used in flight vehicle turbines typically contain
aerodynamically shaped blades, or airfoils, which operate at high speeds and in hostile
environments. As a result, the rotor blades are subjected to steady and vibratory loads
which generate significant internal and external stresses. These vibratory stresses are the
main cause of failure in aerospace/mechanical structures and machine components.
Failure occurs due to these vibratory stresses in gas turbine engines and rotating
machinery components while operating at resonant frequency. To prevent blade failure,
the excited resonant response needs to be attenuated to an acceptable level. Several
approaches have been adopted to suppress blade vibration by providing additional
damping through blade dampers. A magnetomechanical coating is used as a very
effective method for damping of these stresses. Vibratory stress damping in components
like turbine blades through magnetomechanical coating is already established in the
literature.
The objective of this research is to explore the feasibility of using a magnetomechanical
surface coating material for increasing the high-frequency damping of turbine blades.
This research involves formulation of a parametric expression for determining the
optimum value of coating layer for a given geometry of a beams, curved plate and turbine
blade under dynamic loading conditions. Finite element method (FEM) is used for
modeling, simulation and analysis of the parametric model. Beam theory is applied as a
mathematical model for obtaining the mode shapes for the beam. A finite element
analysis procedure is performed to acquire the matrix of data and the data is correlated
with beam theory model for initial verification. The data is further evaluated to form the
required model for calculating thickness of coating for a beam, curved plate and turbine
blade. The resulting parametric expression is verified through comparison with already
published experimental data available in literature. This research has a wide ranging
application in the areas of gas turbine engines and rotating machinery components.
