Axial stress measuring device with novel electromagnetic ultrasonic longitudinal wave transducer

Abstract

The invention discloses an axial stress measuring device with a novel electromagnetic ultrasonic longitudinal wave transducer, which comprises a permanent magnet assembly, a spiral coil and an aluminum alloy rod. The lower end surface of the spiral coil is fixedly arranged in the middle of the upper end of the aluminum alloy rod, and the lower end of the permanent magnet assembly is fixedly arranged on the upper end surface of the spiral coil. The electromagnetic ultrasonic longitudinal wave transducer in the axial stress measuring device is provided with a novel annular permanent magnet, so that very high horizontal magnetic field intensity can be provided, and the longitudinal wave transduction efficiency is greatly improved. The spiral coil is adopted to excite longitudinal ultrasonic waves, and the propagation effect is good; and the spiral coil is simple in structure, high in transduction efficiency, simple in use process and suitable for axial stress measurement.

Description

technical field [0001] The invention relates to an aluminum rod axial stress measuring device, in particular to an axial stress measuring device with a novel electromagnetic ultrasonic longitudinal wave transducer. Background technique [0002] Rod-shaped fasteners, such as bolt connections, are often used for connection, fixing, positioning, etc. between engineering structures, and their working status affects the reliability of the main engineering structures. Therefore, in order to prevent fracture failure of fasteners and improve the overall reliability of the mechanical system, we need to accurately measure and control its preload. [0003] The principle of ultrasonic measurement of stress is the acoustoelastic effect, that is, the propagation speed of elastic waves in statically deformed structures will change with the different stress states. Under the action of different stresses, the propagation speed of the ultrasonic wave in the rod-shaped sample is different. By...

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Problems solved by technology

[0006] (1) When measuring stress with a traditional contact ultrasonic probe, the coupling conditions between the probe and the test piece are not repeatable, so a small disturbance will cause the result great changes have taken place

[0007](2) Usually the detection frequency is limited to a very low range. Although it can travel a long distance, the measurement measurement is not high

[0008](3) The modal aliasing phenomenon of the actual detection signal is relatively serious, and the resolution is not high

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