Transduction Efficiency of a Magnetostrictive Sensor for the Generation of Guided Waves in Pipes Using Rapidly Quenched Amorphous Ribbons

The investigation addresses the magnetostrictive sensor (MsS) signal received from pipes of different materials using an amorphous alloy as a sensor element. This sensing system also acts as a transducer to generate ultrasonic waves which appear as echoes from pipe end and defect. The static magnetic field revealed different MsS signals from magnetically different pipes, viz., aluminum (nonmagnetic), galvanized iron (nonmagnetic coating), and mild steel (magnetic) pipes. Applied static field enhanced MsS signals in all the pipes. The extent of this enhancement is influenced by transduction efficiency of the MsS transducer. This efficiency varied with the magnetic nature of the pipe. Simulation through COMSOL Multiphysics elucidated the magnetic flux intensity patterns in these pipes and the consequent behavior of MsS transducer in inspection of pipes of different materials. The study indicated the role of static magnetic field in an MsS transducer for structural health monitoring (SHM) of pipes used prevalently in domestic and industrial sites.