Effect of hydrodynamic interaction on energy harvesting in arrays of ionic polymer metal composites vibrating in a viscous fluid

Abstract

In this paper, we investigate underwater energy harvesting of a parallel array of nominally identical ionic polymer metal composites (IPMCs) subjected to low frequency base excitation in water. The IPMCs are connected in parallel and shunted with a varying resistor. We model the IPMCs as slender beams with uniform cross section undergoing small oscillations in an otherwise quiescent viscous fluid. We utilize a boundary element approach to compute the hydrodynamic loading on each structure, which is due to the oscillations of the whole array. Leveraging recent findings on sensing in ionic polymer metal composites, we propose a coupled electromechanical model for predicting energy harvesting as a function of the IPMCs' impedance and the base excitation. To validate our theoretical predictions, we perform experiments on an in-house-fabricated array of five centimeter-size composites, which we characterize on a dedicated test rig. We experimentally determine the power harvested by varying the excitation frequency in the broad range 2-35 Hz and the shunting resistance from 1 to 1000 .

Bioinspired travelling wave generation in soft-robotics using ionic polymer-metal composites

“…There are a few examples of passive IPMC array systems, primarily designed for applications of energy harvesting. Porfiri et al produced two passive IPMC array systems for energy harvesting: a turbine system with IPMCs on the airfoils that spins while in a flow channel (Cellini et al 2014a) and an IPMC array that vibrates when moved through the water (Cellini et al 2014b). Though it has been shown that passive IPMC systems are possible, an active system is best in order to recreate the flying-fish wing more accurately.…”

Ionic polymer–metal composite applications

“…[57][58][59][60] Recent applications of IPMC sensing capabilities span the measurement of force, flow, shear loading, curvature, structural health monitoring and energy harvesting. [61][62][63][64][65][66][67][68][69] IPMCs generate charges when experiencing a mechanical load or deformation. If the polymer is not deformed, the distribution of cations inside the polymer is uniform and no output voltage is detected.…”

Energy harvesting from underwater vibration of an annular ionic polymer metal composite

“…The power harvested at the radian frequency x is optimized at [8,12,61] R opt load ðxÞ ¼ jZðxÞj ð25Þ…”

“…While the very first efforts on IPMC-based energy harvesting have focused on in-air vibrations [10,61], underwater energy harvesting has been recently studied by several authors, who have contributed to an improved understanding of the process of energy transduction in these materials [4,8,12,13,18,19,29]. Underwater flexural vibrations of an IPMC undergoing base excitation have been analyzed in [8].…”

“…In [4], a similar scenario has been studied to elucidate on the role of the electrodes' properties. To understand the scalability of this design, energy harvesting from a parallel IPMC array with a common base excitation has been investigated in [12]. In [19], the possibility of harvesting energy from the undulation of a fish tail using IPMCs has been investigated.…”