Vibration of Cantilever Beams to which Dynamic Absorbers are Attached

The simultaneous application of two dynamic absorbers to an undamped cantilever beam is discussed theoretically. The dynamic absorbers possess viscous damping. They are tuned and damped in the so‐called optimum manner for which it is possible to suppress the resonances of the beam in a uniform and symmetrical fashion. The beam is exalted by a sinusoidally varying force situated either at its free end or at its midpoint. It is to these locations that the dynamic absorbers are attached. The absorbers are tuned to suppress the first and second beam resonances, the optimum values of absorber tuning and damping depending upon the location of the absorbers and upon the beam resonance that is of concern. In addition to the role of the absorbers in suppressing the first and second beam resonances, excitation of the third resonance is essentially avoided when the driving force is situated at the midpoint of the beam because a nodal point of the third mode occurs very near to the beam center.