In particular, vibration‐based energy harvesting has been a key focus area, due to the abundant availability of vibration‐based energy sources that can be easily harvested. Energy harvesting is a technique by which ambient energy can be converted into useful electricity, particularly for low‐power WSNs and consumer electronics. An alternative to replacing batteries of WSNs either the direct replacement or to facilitate battery regular recharging, is by looking into energy harvesting for its sustainable drive. An essential requirement for the sustainable operation of WSN is the presence of an uninterrupted power supply which is currently obtained from electrochemical batteries that suffer from limited life cycles and are associated with serious environmental hazards. Wireless sensor nodes (WSNs) and embedded microsystems have recently gained tremendous traction from researchers due to their vast sensing and monitoring applications in various fields including healthcare, academic, finance, environment, military, agriculture, retail, and consumer electronics. The model can also reasonably determine the open circuit voltage with some discrepancies at large vibration amplitudes. The comparison of measured and simulated results show that the model can accurately predict the resonant frequency with a relative error of less than 2%, validating the modeling approach. Furthermore, it is shown that the resonant frequency decreases from 201 Hz to 187 Hz at 1 g base acceleration when the magnetic bias is removed. The results show that the maximum induced voltage is obtained at the resonant frequency which decreases slightly with an increase in the vibration amplitude. Simulated and measured results are compared at base excitation amplitudes of 0.5 to 2 g under varying vibration frequencies. A unimorph cantilever beam type prototype harvester device consisting of a galfenol beam bonded to an aluminum substrate is constructed for validating the model. This allows optimizing the device design by tuning the geometric parameters and magnetic bias under available operating conditions (amplitude and frequency of vibrations) easily and efficiently.
The thermodynamic model is implemented in a 3D finite element solver using COMSOL Multiphysics software. Moreover, the paper discusses the influence of magnetostriction upon resonant frequency. As compared to some earlier modeling approaches that were tested only on specific harvester geometries, the thermodynamic model has already been validated on rod-type harvesters and is now shown to be suitable for analyzing also beam-type devices. This paper presents the validation of a thermodynamic magneto-mechanical model to analyze a galfenol based cantilever beam type energy harvesting device.
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