This study evaluates the performance of a compressive-mode vibration energy harvester with two flextensional actuators from the viewpoint of global dynamics. The distance between two external magnets is considered as a key structural parameter. Based upon the dynamic system of this energy harvester, unperturbed dynamics is studied for configuring bistable potential wells. It is found that the decrease in the distance between two external magnets helps to configure and deepen double potential wells of the energy harvesting system. Then, the extended averaging method is applied to the analysis of the intra-well and inter-well periodic responses. The numerical simulations are in good agreement with the analytical results, validating the analysis method. It follows that the maximum value of the key parameter for configuring bistable wells is most practical and advantageous for efficient energy harvesting. Sequences of the coexisting attractors and Basins of Attraction (BAs) with the rise in the frequency and amplitude of the excitation are presented. Initial-sensitive phenomena such as fractal BAs, chaos and hidden attractors can be successively observed with the growth of the excitation strength. It is evident that the increase in the frequency and level of the excitation is beneficial for the performance improvement of the bistable compressive-mode vibration energy harvester.
Li et al. (Tue,) studied this question.