Finite element analysis of sprayed magnetostrictive powder-based transducers for ultrasonic guided waves monitoring

This paper explores a sprayed magnetostrictive powder-based transducer designed for the generation and reception of ultrasonic guided waves UGW. This transducer is composed of two distinct components: a passive element and an active element. The passive component consists of a ferromagnetic coating, produced using the Cold Spray process, which is integrated into the monitored structure. The active component is a coil responsible for generating the necessary magnetic field, which induces magnetostrictive strain in the ferromagnetic coating. This strain subsequently produces UGW that propagate through the monitored structure. To comprehensively investigate the impact of the ferromagnetic coating’s characteristics on the transducer efficiency, a numerical model based on the finite element method was developed. The study revealed that transducer efficiency exhibits a nonlinear relationship with the coating thickness. Specific resonance thicknesses were identified, leading to a significant enhancement in UGW amplitude. Additionally, the microstructure of the coating was found to play a critical role in transducer performance. Experimental tests were conducted to validate the performance of the fabricated magnetostrictive transducer in generating and receiving UGW. The obtained results confirmed that the coating thickness and microstructure have a substantial effect on the transducer efficiency.