Single mass dual frequency fixed delayed resonator (DFFDR)

A novel concept, the delayed resonator (DR), as a tunable active vibration absorber has been introduced by the authors´ group at the University of Connecticut. This unique technique uses a very simple control which has only a time delayed feedback of the absorber mass displacement. The absorber can completely remove oscillations from the primary structure when the primary is excited by a simple harmonic force. The work presented here treats a considerably more complex proposition dual frequency fixed delayed resonator (DFFDR). The device, DFFDR, is obtained by a similar delayed position feedback mechanism as in the case of DR, but this feedback imparts two (instead of one) distinct and fixed resonance frequencies. The interesting feature is in the simplicity of the control which can enforce two natural frequencies (and two corresponding natural modes), to a single mass, or single degree of freedom (SDOF) system