Kruse H., Metrikine A.V. and Popp K.


Eigenfrequencies of a two-mass oscillator uniformly moving along a string on a visco-elastic foundation


Journal of Sound and Vibration 218(1), 103-116, 1998



Summary. The eigenfrequencies of a two-mass oscillator moving uniformly along a string on a visco-elastic foundation are analyzed. It is shown that in the case of purely elastic foundation the oscillator has either one or two real positive eigenfrequencies dependent on the system parameters. Taking into account the viscosity of the foundation, the complex eigenfrequencies of the oscillator are investigated. The study shows that eigenfrequencies, which are related to attenuating vibrations of the oscillator, are not uniquely determined. It is found that the existence of an eigenfrequency  with a small imaginary part  is not a sufficient condition for resonance under an external force .