A Self-Powered Magnetostrictive Sensor for Long-Term Earthquake Monitoring

A self-powered magnetostrictive sensor (SMS) for long-term earthquake monitoring is proposed in this article. A piece of magnetostrictive material was bonded on the upside surface of a stainless steel plate to form the proposed sensor. A force was applied on the free end of the sensor to mimic an earthquake vibration. The applied stress led to a varied permeability of the magnetostrictive material according to the Villari effect. Then, the varied permeability produced a varied magnetic field. The varied magnetic field was captured by a coil to generate electric power for an earthquake alarm. A theoretical analysis was investigated in this article. After the fabrication of a sensor prototype, the vibration characteristics and voltage output ability were measured. The maximum vibration amplitude and maximum output trust voltage were tested to be 25 mm and 0.38 V (peak to peak) under an applied force of 2 N. The proposed SMS exhibits merits of simple structure, small size, easy fabrication, and long-term working ability.