Parametric Self-Excitation of a Belt Into Transverse Vibration

As a belt is taken up on a pulley, a varying tension will be laid down, or “recorded,” as a strain pattern. As the belt pays off, the pattern “plays back” creating a corresponding varying tension on the next span. If the delay is proper, the oscillating tension associated with transverse vibration of a belt span can feed around the belt circuit and parametrically drive the vibration. A belt span may be self-excited into vibration by this mechanism without imperfections in either the belt or pulleys.