Experimental characterisation of nonsmooth dynamics in a vibro-impact energy harvesting system

Abstract

Vibro-impact systems exhibit strongly nonlinear, non-smooth dynamics due to intermittent collisions. An accurate representation of impact-induced energy dissipation is crucial for modelling and numerical analysis. In this study, the nonsmooth dynamics of a beam with a tip mass (hitting a stopper) are understood experimentally, and the coefficient of restitution (CoR) is determined for various parameter sets. The operating deflection shape and damping are determined experimentally. High-speed video is used to track the motion of the beam tip mass before and after impact to estimate CoR. Experimental CoR shows moderate dependence on excitation parameters and stopper configuration. A constant effective CoR, defined as the mean of the measured values, is adopted to model the non-smooth system. The framework is further applied to examine vibro-impact behaviour under varying excitation amplitudes and frequencies, and across stopper configurations, with relevance to vibration-based energy harvesting. The results provide a validated experimental-numerical approach for analysing restitution-governed dissipation in non-smooth dynamical systems.