Abstract: An apparatus and method for quantitative nondestructive testing (NDT) of a wire wherein noncontacting ultrasonics is used. A transmitter-transducer coil is held in close proximity of a test wire or tube and high amplitude electrical current pulses are passed in the coil. A magnetic field perpendicular to the longitudinal axis of the wire is applied in the region. As a result of the electrical current pulses in the transducer coil, eddy currents are produced on the surface of the test wire. As a result of the magnetic field applied in the region, these eddy currents lead to Lorentz forces in the wire, which in turn generate corresponding torsional waves in the test wire. These waves speed down the wire and are received by a reciprocal transduction process, by means of a receiver-transducer. The velocity and attenuation measurements of the torsional waves along the axis of the test wire are made precisely and accurately via multiple-transducer setups.

Abstract: Extremely sensitive velocity and position measurements are achieved with a surface acoustic wave (SAW) resonator device. A surface acoustic standing wave field is established on a movable SAW propagation surface by means of induced SAW pulses traveling on the propagation surface and their reflection from a SAW reflecting mechanism. Movement of the propagation surface causes periodic variations in the standing wave field amplitude. The frequency of the standing wave field amplitude variation is directly related to the SAW propagation surface velocity and its phase (i.e., total number of standing wave field amplitude variations from a reference point) indicates the SAW propagation surface position or how far it has moved from the reference point.One implementation comprises a rotatable aluminum cylinder on the surface of which SAWs are launched and detected by proximate but non-contacting transmitting and receiving electromagnetic transducers (EMTs).

Abstract: A handheld, compact, self-contained transducer unit for electromagnetic generation and detection of ultrasound on or in metals and other media is realized by mounting short, flat cable sections directly on a small, powerful permanent magnet. The cable sections are interconnected in an electromagnetic transducer circuit configuration and the plane of the flat cable transducer circuit structure is perpendicular to the magnet magnetization axis. Fabrication of the device can be accomplished by selectively connecting the conductor ends of a flat strip electrical conductor segment and affixing the conductor segment to an appropriate surface of a samarium-cobalt permanent magnet.