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A common configuration for a piezoelectric vibration energy harvester is the cantilevered beam with the piezoelectric device located near the beam root to maximize energy transduction. The beam curvature in this configuration is monotonically decreasing from root to tip, so the transduction per unit length of piezoelectric material decreases with increasing patch length. As an alternative to such conventional configuration, this paper proposes a so-called inertial four-point loading for beam-like structures. The effects of support location and tip mass on the beam curvature shapes are analyzed for four-point loaded cases to demonstrate the effect of these configurations on the total strain induced on the piezoelectric patch. These configurations are tested experimentally using several different support locations and compared with results from a baseline cantilevered beam. Performance comparisons of their power ratios are made, which indicate improvement in the transduction per unit strain of the four-point loading cases over the cantilevered configuration. The paper concludes with a discussion of potential applications of the inertial four-point loaded configuration.

As the capabilities of Fiber Optic Sensing Systems continue to improve, their application to real-time distributed sensing for structural analysis and control of flexible systems is increasingly feasible. This paper will report experimental results on the use of a Fiber Optic Sensing System for static and dynamic shape estimation of a cantilever beam and plate. Demonstrating the use of this sensor technology in benchtop experiments is the first step in effectively incorporating fiber optic sensors in the Integrated Adaptive Wing Technology Maturation aeroelastic half-span wind tunnel model for real-time shape sensing and feedback for drag optimization, maneuver load alleviation, gust load alleviation, and flutter suppression control laws. The effectiveness of the sensing system will be analyzed and the application of these results to aeroelasticity experimentation will be discussed.

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.

Katherine Smith received B.S. degrees in applied mathematics and mechanical engineering from Old Dominion University and an M.S. in Applied and Computational Mathematics from Old Dominion University. Ms. Smith is currently a lecturer in the Department of Mathematics and Statistics at Old Dominion University and is pursuing a PhD in Modeling and Simulation. Her research interests include serious games for STEM education, scientific visualization, and augmented and virtual reality. Prior to teaching at ODU, she worked as an Aerospace Engineer at NASA Langley Research Center.