On the self-adaptive dynamics of a strongly nonlinear beam-slider system

About ten years ago, a group of researchers presented a fairly simple setup that exhibits highly interesting, unexpected vibration behavior. The system consists of a slender beam clamped at both ends to a stiff frame, and a slider that can move along the beam. When harmonic base excitation is applied, the slider begins to move slowly, dramatically increasing the vibration level of the beam. An important feature of this adaption process is a sudden jump in vibration amplitude that is accompanied by a change in the direction of the slider's motion. The central goal of this work is to find explanations for all phenomena observed during this adaption process. To this end, several simulation models are developed that take into account both the bending-stretching nonlinearity of the beam and the small clearance between the surfaces of the beam and the contact geometry of the slider. It is shown that the jump between coexisting vibration levels is a consequence of the nonlinearity of the beam. The slider transport can be explained by various characteristic contact patterns dominated by rolling or sliding motions. These theoretical findings are supported by a successful validation in which simulated and measured behavior is directly compared. The experimental part includes the presentation of a refined prototype of the beam-slider system and a novel method for quantifying the damping of base-excited structures.