Nowadays, heavy and bulky rotors are replaced by the light yet strong rotor, where the composite material is only supplementary. The composite may be constructed either by reinforcing long unidirectional fiber into matrix material or stacking of lamina, where each lamina has different orientation of fiber. But mathematical modelling of such type of rotor is little difficult when considering different orientation of fiber. This invokes us to construct multilayer rotors of different isotropic material and associated formulation to show its better dynamic performance.
Generally internal damping has an enormous effect on the dynamics of rotor shaft system. For the sake of modelling, all layers are assumed to made of viscoelastic material and perfectly bonded. The constitutive relationship of each layer is represented by two element voigt model and equation of motion is obtained in time domain.
This paper involves the development of both classical and finite element mathematical model of multilayer viscoelastic rotors, which contents system characteristics. Under these conditions, the complex modal behaviour of the rotor-shaft is studied to get an insight of the dynamic characteristics of the system, in terms of Decay rate, Stability Limit of Spin-speed, First Natural Frequency and also Unbalance frequency response.