Enhancement of Inverse Magnetostrictive Effect through Stress Concentration for a Notch-Introduced FeCo Alloy

The authors investigate the magnetic flux leakage for a class of magnetostrictive FeCo alloys with a notch undergoing compression and impact with respect to energy harvesting. The magnetic flux leakage plays a crucial role in the practical energy transition in terms of the features for energy harvesting. Therefore, the corresponding situations are systematically studied by combining finite element analysis (FEA) with practical experiments. The FeCo alloys are categorized into three groups with different three-dimensional notch shapes, and the depths of the notches are 0, 0.5, and 1 mm, respectively. The parameters in both the simulations and practical tests are completely consistent. The results of compression test carried out with a stepwise-increasing stress from 0 to 100 MPa reveal that the variations of magnetic induced flux increase with the increasing depth of the notches. The following FEA herein provides a feasible interpretation that the stress concentration around the notch is largely responsible for the notch-induced enhancement. The findings of the impacting experiments simultaneously exhibit an analogous tendency that the output power is proportional to the depth of notch. Furthermore, the stress rate has no obvious effect on the output electricity. The maximum magnitude of the improvement for the output power increases by almost 400% comparing the specimens with notches of 0 and 1 mm. This study indicates a promising feasibility to achieve vibration-energy harvesting from various irregular components.