Search

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]