Large amplitude vibrations and nonlinear dynamics characteristics of an autoparametric pendulum absorber-harvester

This study investigates the nonlinear dynamics of a pendulum absorber-harvester system under large swing angle conditions, addressing the dual objectives of vibration absorption and energy harvesting. The dynamic model of the absorber-harvester system is established and the bifurcation characteristics and chaotic motion is analyzed by a numerical method. The results indicate that the system could exhibit three distinct motion patterns within the absorption bandwidth: stable periodic motion, quasi-periodic motion, and chaotic motion. Experiment validation is conducted to verify the different motion patterns and assess the system's vibration absorption efficiency and energy harvesting performance. Furthermore, the impact of key parameters on system's dynamic response is evaluated. The findings reveal that when chaotic motion occurs within the absorption bandwidth, the left stable region can reduce the vibration amplitude of the main system, while the right stable region could increase the vibration amplitude of the main system. Also, multiple chaotic motion regions would occur under certain parameters, which could be beneficial for energy harvesting but not conducive to vibration absorption. A stable full-circle rotation motion region of the pendulum exists between two chaotic regions, and this region is beneficial for both vibration absorption and energy harvesting. The nonlinear dynamic characteristics of the absorber-harvester system exhibit significant parameter dependence, enabling practical adjustments to meet specific application requirements.