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In this paper the finite element model updating technique is evaluated for the estimation and modeling of material damping of composite material intended to be used in a high-speed rotor-bearing support system. An accurate estimation and modeling of material damping is required for the proper understanding of the dynamic behavior of composite material used in the high-speed rotor-bearing system. Due to the contrasting relevance of material damping as rotating internal damping and stationary external support damping in a high-speed rotor-bearing system, updating methodology is required to be varied. Hence to start with, the finite element numerical model updating of stationary damping of composite material is presented here using the test data extracted from the experimental free vibration and dynamic mechanical analysis (DMA) tests. [ABSTRACT FROM AUTHOR]

Fiber metal composites made up of alternative layers of metallic and composite are now widely used in Aircraft structures are result of one such effort which bring in the combined strengths of composites and metals. In a similar way, the use of metal fiber composites made up of composite material laminates sandwiched between metallic sheets firmly bonded with high quality adhesives can become an effective replacement of conventional metallic components in high speed machinery such as gas turbines. The benefits of this hybrid form of composite material has the potential of use in areas where fiber reinforced composite material cannot be directly exposed due to the harsh environment of gas turbines. In addition, the metallic surfaces can easily interface into their respective metallic assemblies. Such hybrid composite materials used in static structures can push some of the structural natural frequencies beyond the operating speeds. Composite material used in supporting structures can effectively dampen the excessive vibrations and to further improve the damping capacity the viscoelastic material can also be strategically inserted between the layers. In rotating systems hybrid composite material can be used for some of the long slender shafts to push the critical speeds away from the operating speeds. But unlike supporting structures the damping present in the composite material can induce rotor dynamic instability of rotor-bearing systems. Hence the right combination of metal and fiber reinforced composites can effectively avoid or place the resonances and drastically reduce the vibrating stresses to improve the overall fatigue life of rotating machinery. [ABSTRACT FROM AUTHOR]

In this paper some of the important parameters that influence the effectiveness of composite material shaft of high speed rotor-bearing system on rotor dynamics are analyzed. The type of composite material composition, the number of layers along with their stacking sequences are evaluated as they play an important role in deciding the best configuration suitable for the high-speed application. In this work the lateral modal frequencies for five types of composite materials shaft of a high-speed power turbine rotor-bearing system and stresses due to operating torque are evaluated. The results are useful for the selection of right combination of material, number of layers and their stacking sequences. The numerical analysis is carried out using the ANSYS Rotor dynamic analysis features. [ABSTRACT FROM AUTHOR]