Dynamic study of composite material shaft in high-speed rotor-bearing systems

In this work the composite material shaft in high-speed rotor-bearing systems is analysed to achieve better rotor dynamics along with the effect of internal damping of the composite shaft. The pioneering studies on rotating composite shaft and internal damping are revisited to evaluate its effects on rotor dynamics of high-speed rotor-bearing systems. Two practical rotor-bearing systems are selected to study their suitability for composite shaft application where the composite material is used in the cold section while the existing steel alloy is retained in the hot section as well as at the ends. The rotor dynamic analysis shows significant improvements in rotor dynamics of one of the rotor-bearing systems where the first lateral mode changes to desirable rigid mode from flexure mode shape of existing metallic shaft rotor-bearing system. The frequency values of second and third modes also increase above the operating speed indicating a clear advantage in rotor dynamics.