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The magnetostrictive effect is one of the most useful properties of ferromagnetic materials. Vibrations in dynamic structures and machines represent a nontraditional alternative energy source, and ferromagnetic materials could potentially convert the kinetic energy of these vibrations into electrical energy using the inverse magnetostrictive effect. Herein, Fe–Co–Cr alloys are fabricated and these materials are applied to vibrational energy harvesting. Specifically, (Fe30Co70)100−xCrx (x = 0, 0.5, 1.0, or 3.0 at%) alloys are made by arc melting in an argon atmosphere and then heat treated at temperatures that promoted magnetostrictive characteristics. The structural properties of these materials are subsequently investigated using energy‐dispersive X‐ray spectroscopy, while their magnetic properties are assessed with a vibrating sample magnetometer (VSM) and their magnetostrictive characteristics are evaluated with a strain gauge method. Vibrational energy harvesting experiments are conducted and the relationship between the output power and the magnetic/magnetostrictive characteristics of these alloys is examined. The data shows that magnetic permeability is an important factor determining the output power of these Fe–Co alloys, in addition to their magnetostrictive properties. The results provide a basis for the systematic development of magnetostrictive material variants and for new alloys required to meet the needs of future designs. [ABSTRACT FROM AUTHOR]

The effect of magnetic fields on the stress intensity factors in a soft ferromagnetic strip under uniaxial tension is analyzed. A strain gauge method is used to determine the stress intensity factor and the stress intensity factors made between the theory and experiment are compared.

Various types of sensors such as piezoelectric ceramics and strain gauges are widely used to monitor the damage of automobile components, buildings, and so on. Among these sensors, piezoelectric sensors have a high‐energy conversion efficiency, that is a high sensitivity. Therefore, we fabricated a mullite fiber‐reinforced resin sheet with piezoelectric particles (Piezo‐MFRS) and evaluated their sensor performance. Piezo‐MFRS was fabricated by the hand layup method—the polyamide resin was mixed with piezoelectric particles and infused into the mullite fiber fabric. After that, the piezo‐MFRS was polarized by a corona discharge. We investigated the relationship between the applied impact load or vibration load to the piezo‐MFRS and the generated voltage. The piezo‐MFRS induced an output voltage of 20 mV under a compressive stress of 4 MPa, and an output voltage amplitude of 2 mV due to bending vibration of amplitude 0.5 mm. Therefore, it seems that the piezo‐MFRS is suitable for use as a load sensor. Furthermore, we confirmed that the tensile properties of piezo‐MFRS were not reduced by the addition of piezoelectric particles. Consequently, it is likely that piezo‐MFRS is a promising material for a rugged piezoelectric sensor and opens the door to monitoring large structures. [ABSTRACT FROM AUTHOR]