Multiphysics modeling of an MSMA-based clamped–clamped inertial energy harvester

Abstract

In this paper, an alternative way of harvesting energy from ambient vibration is investigated through proposing a novel inertial energy harvester using magnetic shape memory alloys (MSMAs). To this end, a clamped–clamped beam is coupled with MSMA units which are attached to its roots. A shock load is applied to a proof mass in the middle of the beam. The beam vibration causes longitudinal strain in the MSMAs and as a result the magnetic flux alters in the coils wounding around the MSMA units and produce an AC voltage. To have a reversible strain in MSMAs, a bias magnetic field is applied in transverse direction of the MSMA units. The large scale vibration of Euler–Bernoulli beam is modeled with the help of von Kármán theory and a thermodynamics-based constitutive model is used to predict the nonlinear strain and magnetization response of the MSMAs. In order to predict the output voltage during martensite variant reorientation in MSMAs is studied with the help of Faraday’s law of induction. After showing the results for a clamped–clamped energy harvester, its performance is compared with cantilever one. The results show that this novel energy harvester has the capability of using as an alternative to the current piezoelectric and magnetostrictive ones for harvesting energy from ambient vibrations. Comparing the performance of clamped–clamped MSMA based energy harvester with cantilever one state that it can have some advantages over the cantilever energy harvester.