Recent Results in Nondestructive Testing with Electromagnetic Ultrasonic Transducers

摘要

Electromagnetic ultrasonic transducers (EMUS) are a broad class of ultrasonic transducers that open new possibilities in the field of nondestructive testing. The reasons are: they don!t need liquid couplants; they can be designed to operate at elevated temperatures and to scan at high speed. They can provide a large variety of bulk and guided wave modes including shear waves with horizontal polarization, and their operating characteristics are easily reproducible. All these and other advantages are faced with a general disadvantage of a larger insertion loss than conventional transducers. However proper sensor and electronic design permits sufficient signal-to-noise levels to be achieved. When properly designed and instrumented an EMUS-based ultrasonic system can be used for many practical applications.