Experiments on routes to chaos in ball bearings

The theoretical motion of a ball bearing has been studied in a previous paper. Using a control parameter, different routes to chaos were described. The aim of this paper is to study the experimental routes to chaos in a ball bearing and to confirm whether theoretical predictions of the phenomena are realistic.An experimental test bench has been used and a numerical procedure has been proposed for observing Poincaré maps. As the control parameter varies the bearing clearly shows the appearance of instability in its motion. Two different routes to chaos are described as expected from the theory.The first route is related to the first resonant frequency of the bearing. It is a sub-harmonic route. The second route, associated with the second resonant frequency, is a quasi-periodic route.