On analysing vibration energy harvester with auxetic core and magneto-electro-elastic facings

Powering systems without heavy maintenance-intensive batteries is a challenge for various engineering applications. Often, energy in the form of heat, vibration, sound etc., is squandered while operating many machines/structures. A judicious utilisation of these potent energies using energy harvesters (EH) will reduce the degree of dependency on depletable energy sources. Sometimes, EH acts as a parasitic mass and consumes additional space. To address this issue, the current work proposes a lightweight vibration-based bimorph beam (VBBB) EH constituted of multifunctional magneto-electro-elastic (MEE) facesheets and auxetic metamaterial core (AMC). The frequency response functions, which consider series and parallel configurations of the active ME layers, are derived using distributed parameter single-mode formulation to quantify the system's output response. The overall effect of the negative Poison's Ratio of the auxetic materials, combined with the material, geometric and parameters such as the number of turns and resistances, is investigated. The advantage of using an auxetic core to enhance the energy harvester's performance is realised through an improved power output as the thickness of the auxetic core layer rises. The maximum values of the output parameters are witnessed for larger auxetic angles and lower rib-length ratios. Meanwhile, greater values of the geometrical parameters like length-to-thickness ratio and length-to-width ratio result in enhanced power harvested. A comparative study justifies that under similar working conditions, the power output of the auxetic-based energy harvester is almost 1.5 times more than the conventional metal-based energy harvesters. Further, auxetic-based EH reported a 22% weight reduction for the same power output obtained from the conventional metal-based EH. This enables the lightweight construction of low-powered smart systems with enhanced efficiency. It is believed that the results of this article will lead to further studies on utilising multifunctional composites and metamaterials for complex engineering applications.