Magnetostrictive-based Induced Current Inversion and Amplification: Semi-Active Vibration Suppression for Multiple-Degree-of-Freedom Flexible Structures

Vibration suppression technology is indispensable in the operation of multiple-degree-of-freedom (MDOF) structures. Properties such as a light weight and reliability are essential for an MDOF structure. However, truss structures tend to be flexible and susceptible to vibration from external influences. Hence, vibration suppression for MDOF flexible structures is necessary. This paper proposes a new semi-active vibration suppression method with a magnetostrictive transducer that can be applied to vibration suppression of an MDOF flexible structure. The proposed method is achieved through an electrical control circuit consisting a magnetostrictive transducer, an inversion capacitor, an electronic switch, and diodes. The control input of the proposed method is considered the induced current. With strategic selection of the circuit statuses, the amplitude of the induced current can be inversed and amplified. Our proposed control strategy is to control the circuit statuses so that the vibration suppression performance can be as effective as possible. The control strategy is determined based on the vibration displacement and velocity of the structure. Numerical simulations were performed to predict the vibration suppression performance. Subsequently, validation experiments were performed using a vibrating cantilevered truss structure, which was considered an MDOF structure composed of many aluminum bar members and iron joints. Under various experimental conditions, the proposed method achieved suppression rates of 12.1–26.7%. The results validated that the proposed method is more effective than a conventional passive method for the vibration suppression of an MDOF flexible structure. The proposed method may aid in ensuring the safe operation of MDOF flexible structures, such as trusses, under extreme conditions.