The effect of frequency detuning and seismic energy scavenging on the host structure and harvesting performance under broadband excitation

Abstract

In this work, the effect of seismic energy harvesting on the host structure and the harvesting performance will be discussed under broadband excitation with a view to exploring a more practical case. This work focuses on the harvester design for a fixed host structure under broadband force excitation. The modeling of the whole system is based on stochastic theory and the system performance is discussed with numerical calculations using this stochastic modeling. In addition to analysis on the coupling between the host structure and the harvester, the effect of frequency detuning between the harvester and host structure resonant frequencies is also presented. Two design criteria (constant force factor and constant electromechanical coupling factor) are proposed to show different energy conversion processes. In both cases, the optimal harvested powers are found when the resonant frequency of the harvester is perfectly matched with the resonant frequency of the host structure. With a constant force factor, the harvester performance is very sensitive to the frequency detuning effect. With a constant electromechanical coupling factor, however, there is very little variation in the harvested power when the two resonant frequencies are detuned.