Structure-integrated electromagnetic ultrasonic transverse and longitudinal wave stress measurement method

Abstract

The invention belongs to the technical field of ultrasonic measurement, and discloses a structure-integrated electromagnetic ultrasonic transverse and longitudinal wave stress measurement method. According to the method, a vertically-arranged electromagnetic ultrasonic coil is designed, and high-frequency pulse voltage excited by an ultrasonic excitation system is combined, so that induced eddy current in the orthogonal direction is generated on the surface of a material; the arrangement mode of magnets is optimized based on the coil configuration, and a horizontal magnetic field and a vertical magnetic field are generated in the effective area of the coil; based on the acoustic elastic birefringence principle and the acoustic velocity ratio characteristic, the relationship between the plane stress and the unidirectional stress and the ultrasonic propagation time is determined. An electromagnetic ultrasonic probe is compact in structure and high in spatial measurement resolution, longitudinal waves propagating in the thickness direction of a material and two beams of orthogonally polarized transverse waves can be excited at the same time, and the problems of low precision, low efficiency and the like caused by probe rotation in the traditional stress measurement process are solved; the influence of the material thickness on the ultrasonic propagation sound time is eliminated, and the rapid and accurate in-situ measurement requirements of plane stress and unidirectional stress can be met at the same time.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic measurement, in particular to a structurally integrated electromagnetic ultrasonic transverse and longitudinal wave stress measurement method. Background technique [0002] During the manufacturing process of parts, due to the influence of mechanical processing and external loads, residual stress is easily generated inside the material, including plane stress state and unidirectional stress state, which seriously affects the mechanical properties and safe life of parts. It is extremely important to carry out regular non-destructive measurements of residual stresses. Compared with other non-destructive testing methods, the ultrasonic method has the advantages of strong penetrating ability, wide application range and high measurement efficiency. However, the commonly used piezoelectric ultrasonic excitation method is susceptible to coupling state interference, and the measurement repeatability i...

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Problems solved by technology

[0004] In 2013, Ji Cheng disclosed the "Electromagnetic Ultrasonic Detection Probe" in the invention patent CN201110324997.2. This method uses three racetrack-shaped coils of the same size to be overlapped and switched by switches. The coils are connected in parallel to increase the excitation energy when transmitting. When receiving Coils are connected in series to improve receiving sensitivity; however, this method can only generate transverse waves in one polarization direction and cannot generate longitudinal waves

In 2015, Wu Dehui and others disclosed "an electromagnetic ultrasonic probe with a variable structure" in the invention patent CN201410024733.9. In this method, multiple magnets are alternately arranged above the zigzag coil and connected to the lever, and the deflection is changed by moving the lever. Set the relative position of the magnetic field and the coil, and switch to generate body waves and surface waves; however, this method changes the measurement position to generate different waveforms, which cannot meet the requirements of stress measurement

[0005] However, none of the above mentions a structurally integrated electromagnetic ultrasonic transverse and longitudinal wave stress measurement method

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