Modeling and experimental characterization of a multi-point loaded piezocomposite beam for actuation and energy harvesting

This article proposes a multi-point support and inertial loading for beam-like piezocomposite vibration energy harvesters as an alternative to the common cantilevered beam configuration. In the proposed configuration, symmetrical overhanging free segments extend beyond two interior pinned supports, and tip masses are attached to the free ends for inertial tip-loading. The dynamic response of this multi-point loaded beam can be significantly altered by varying two configuration parameters: the support location and tip-loading. In this article, the transverse vibration due to harmonic excitation of a piezocomposite beam in this multi-point configuration is analyzed. The effects of configuration parameters on the natural frequency and curvature shapes of the beam are shown. Results from experimental testing of several support locations and tip masses are compared with analytical predictions, and it is demonstrated that the fundamental frequency of this system can be tuned by adjusting the support location and tip-loading. Comparisons of the output-to-input power ratios for the different configurations during vibration energy harvesting are also made, which demonstrate increased strain-normalized transduction for the multi-point configurations over a reference cantilevered beam. This article concludes with a discussion of the potential application of this configuration as a vibration energy harvester.