Electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor and detection method

Abstract

The invention discloses an electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor and a detection method, and the sensor comprises an electromagnetic ultrasonic surface wave excitation unit which is composed of a magnet group and a fold-back line type excitation ring. The two-dimensional component electromagnetic ultrasonic surface wave receiving unit consists of a magnet group, a vertical rectangular receiving coil and a horizontal runway type coil; the detection method comprises the following steps: the electromagnetic ultrasonic surface wave excitation unit excites an ultrasonic surface wave on the near surface of a detected object, and the ultrasonic surface wave generates an elliptically polarized wave with two-dimensional components of out-of-plane displacement and in-plane displacement and transmits the elliptically polarized wave forwards; a horizontal magnetic field and a vertical magnetic field are respectively cut below the two-dimensional component electromagnetic ultrasonic surface wave receiving unit and are respectively received by two coils of the receiving unit to form receiving signals of an out-of-plane component and an in-plane component; and the polarization coefficient, the wave velocity and the surface wave coefficient of the surface wave can be respectively obtained according to the two component signals and the distance between the excitation unit and the receiving unit, so that multi-parameter synchronous detection is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to electromagnetic ultrasonic testing technology, in particular to a kind of electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor and detection method, which can be used for material aging damage and material quality degradation detection. BACKGROUND

[0002] Electromagnetic ultrasonic is a kind of linear diameter nondestructive testing technology, based on electromagnetic induction and ultrasonic vibration coupling, can carry out efficient detection in the absence of coupling agent, it is widely used in aerospace, automobile manufacturing, energy equipment and other fields of material detection and performance evaluation. It has important significance to guarantee equipment safe operation, improve product quality and improve production process.

[0003] Electromagnetic ultrasonic surface wave has high sensitivity to near-surface defects and material performance changes, fast detection speed and low requirements for the surface quality of the detected workpiece. At present, there are few studies on multi-parameter synchronous detection at home and abroad. In order to better characterize the material performance change, a new type of electromagnetic ultrasonic surface wave sensor is designed and developed. SUMMARY

[0004] In order to solve the problems existing in the prior art, the present application aims to provide a kind of electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor and detection method, the sensor is simple structure, simple operation of non-magnetic material electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor. It can realize multi-parameter synchronous rapid nondestructive testing on the measured workpiece.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: A kind of electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor, the sensor includes side-by-side magnetic pole reverse arrangement of excitation end magnet group 2, side-by-side magnetic pole reverse arrangement of receiving end magnet group 3, backfolded excitation coil 4, vertical rectangular receiving coil 5, horizontal runway type coil 6; The two magnets of the side-by-side magnetic pole reverse arrangement of excitation end magnet group 2 are close together, the backfolded excitation coil 4 is arranged directly below the side-by-side magnetic pole reverse arrangement of excitation end magnet group 2, and the two constitute an electromagnetic ultrasonic surface wave excitation unit;There is a gap between the two magnets of the side-by-side magnetic pole reverse arrangement of receiving end magnet group 3, the vertical rectangular receiving coil 5 is placed in the gap between the two magnets, and the horizontal runway type coil 6 is placed directly below the side-by-side magnetic pole reverse arrangement of receiving end magnet group 3, which constitutes a two-dimensional component electromagnetic ultrasonic surface wave receiving unit.

[0006] The axial center distance of the two wire bundles of the backfolded excitation coil 4 and the horizontal runway type coil 6 is the wavelength of the excited surface wave. Since the magnetic field directions below the two wire bundles are opposite, the phases of the ultrasonic surface waves excited and received by the two wire bundles are consistent, so that the surface wave excitation strength and the received signal amplitude can be improved.

[0007] The sensor housing 1 is also used for fixing the excitation end magnet group 2 of the side-by-side magnetic pole reverse arrangement and the receiving end magnet group 3 of the side-by-side magnetic pole reverse arrangement.

[0008] The sensor has an overall cuboid structure.

[0009] The detection method of the electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor, the electromagnetic ultrasonic surface wave excitation unit excites ultrasonic surface waves near the surface of the measured object, the ultrasonic surface waves generate elliptical polarization waves with two-dimensional components of off-surface displacement and in-surface displacement, the horizontal magnetic field and the vertical magnetic field are cut below the two-dimensional component electromagnetic ultrasonic surface wave receiving unit, and the two-dimensional component electromagnetic ultrasonic surface wave receiving unit receives the two components to form the receiving signals of the two components, and the polarization coefficient, the wave speed and the surface wave coefficient of the surface wave are obtained from the receiving signals of the two components and the distance between the electromagnetic ultrasonic surface wave excitation unit and the two-dimensional component electromagnetic ultrasonic surface wave receiving unit, so that the multi-parameter synchronous detection is realized.

[0010] The detection method, the surface wave multi-parameter synchronous detection sensor is placed on the surface of the non-ferromagnetic metal block, the eddy current field is induced in the skin depth range of the non-ferromagnetic metal block when the radio frequency current is input into the excitation coil 4, the Lorentz force is generated as the ultrasonic wave source under the action of the horizontal magnetic field parallel to the non-ferromagnetic metal block below the center of the excitation end magnet group 2 of the side-by-side magnetic pole reverse arrangement; when the ultrasonic surface wave 7 propagates along the surface of the non-ferromagnetic metal block, the material particles move in an elliptical trajectory in the plane perpendicular to the surface and parallel to the propagation direction; the magnet in the receiving end magnet group 3 of the side-by-side magnetic pole reverse arrangement generates the vertical magnetic field perpendicular to the non-ferromagnetic metal block below the horizontal runway type coil 6 and generates the horizontal magnetic field parallel to the non-ferromagnetic metal block below the center of the receiving end magnet group; when the ultrasonic surface wave propagates to the two-dimensional component electromagnetic ultrasonic surface wave receiving unit, based on the inverse effect of the Lorentz force, the in-surface displacement component 8 and the off-surface displacement component 10 of the ultrasonic surface wave elliptical polarization cut the vertical magnetic field to generate the eddy current field, which are inducted by the horizontal runway type coil 6 and the vertical rectangular receiving coil 5 respectively; the surface wave polarization value is calculated by the ratio of the amplitudes of the off-surface displacement component 10 and the in-surface displacement component 8, the off-surface displacement component 10 signal arrival time is used to calculate the surface wave speed, and the frequency domain signal obtained by the Fourier transform of the off-surface displacement component 10 signal is used to calculate the nonlinear coefficient.

[0011] Compared with the prior art, the present application has the following advantages: This invention is a sensor for the synchronous measurement of multiple parameters (polarization, wave velocity, and nonlinearity) of electromagnetic ultrasonic surface waves. An electromagnetic ultrasonic surface wave excitation unit, consisting of a pair of rectangular magnets with opposite polarities and a folded excitation coil, simultaneously receives the out-of-plane displacement and in-plane displacement components (8) of the surface wave using a vertical rectangular receiving coil positioned between another pair of rectangular magnets and a horizontal racetrack-shaped coil positioned below, thus achieving polarization measurement. The out-of-plane displacement component (10) signal is selected as the signal for calculating the wave velocity and nonlinear coefficient. Cross-correlation analysis is performed on the signal to analyze the wave velocity; Fourier transform analysis is performed to analyze the nonlinear coefficient. This invention achieves synchronous detection of multiple parameters (polarization, wave velocity, and nonlinearity) of surface waves. Compared with traditional methods, this invention, through multi-parameter analysis, can assess the degree of material aging damage and material degradation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the sensor of the present invention.

[0013] Figure 2 This is a schematic diagram of the folded-back coil in this invention.

[0014] Figure 3 This is a schematic diagram of the vertical rectangular receiving coil in this invention.

[0015] Figure 4 This is a schematic diagram of the horizontal runway-shaped coil in this invention.

[0016] Figure 5 This is a polarization trajectory diagram in this invention. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, this invention proposes an electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor, comprising an excitation magnet group 2 with side-by-side magnetic poles arranged in opposite directions, a receiving magnet group 3 with side-by-side magnetic poles arranged in opposite directions, a folded-back excitation coil 4, a vertical rectangular receiving coil 5, a horizontal racetrack-shaped coil 6, and a sensor housing 1 that fixes the side-by-side excitation magnet group 2 and the side-by-side receiving magnet group 3 with side-by-side magnetic poles arranged in opposite directions. The sensor as a whole has a cuboid structure. The folded-back excitation coil 4 and the horizontal racetrack-shaped coil 6 are respectively fixed below the two pairs of magnet groups, and the vertical rectangular receiving coil 5 is sandwiched between the two magnets of the receiving magnet group 3. Each magnet group consists of a pair of magnets with opposite polarities.

[0019] The detection principle of the sensor of this invention is as follows: The surface wave multi-parameter synchronous detection sensor of this invention is placed on the surface of a non-ferromagnetic metal block. When a radio frequency current is passed through the folded excitation coil 4, an eddy current field is induced within the skin depth range of the metal block. Under the action of the horizontal magnetic field parallel to the metal block and directly below the center of the excitation end magnet group 2 with parallel magnetic poles arranged in opposite directions, a Lorentz force is generated as the ultrasonic wave source. When the ultrasonic surface wave 7 propagates along the surface of the metal block, the material particles move in an elliptical trajectory in a plane perpendicular to the surface and parallel to the propagation direction. The magnets in the receiving end magnet group 3 with parallel magnetic poles arranged in opposite directions can generate a vertical magnetic field perpendicular to the metal block directly below the horizontal racetrack-shaped coil 6, and a horizontal magnetic field parallel to the metal block directly below the center of the receiving end magnet group with parallel magnetic poles arranged in opposite directions. When the ultrasonic surface wave 7 propagates to the two-dimensional component electromagnetic ultrasonic surface wave receiving unit, based on the inverse effect of the Lorentz force, the displacement component 8 in the elliptical polarization plane and the displacement component 10 out of the plane of the ultrasonic surface wave cut the vertical magnetic field to generate an eddy current field, which is induced by the horizontal racetrack-shaped coil 6 and the vertical rectangular receiving coil 5, respectively. The surface wave polarization value is 10 times the amplitude of the out-of-surface displacement component of the received signal. With the 8 amplitudes of the in-plane displacement components The ratio: Amplitude and Figure 5 The polarization trajectory diagram shown has the same major and minor axes. The surface wave velocity travels through the excitation-detection distance d and the arrival time of the out-of-surface displacement component 10. calculate: The fundamental amplitude was extracted from the frequency domain signal obtained by performing a Fourier transform on the out-of-plane displacement component 10 signal. With second harmonic amplitude Calculate the nonlinear coefficients: .

Claims

1. An electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor, the sensor comprising an excitation end magnet group (2) with side-by-side magnetic poles arranged in opposite directions, a receiving end magnet group (3) with side-by-side magnetic poles arranged in opposite directions, a folded excitation coil (4), a vertical rectangular receiving coil (5), and a horizontal racetrack-shaped coil (6). The two magnets of the excitation end magnet group (2) with parallel magnetic poles arranged in opposite directions are close together, and the folded excitation coil (4) is arranged directly below the excitation end magnet group (2) with parallel magnetic poles arranged in opposite directions. The two together constitute an electromagnetic ultrasonic surface wave excitation unit. There is a gap between the two magnets of the receiving end magnet group (3) with parallel magnetic poles arranged in opposite directions. The vertical rectangular receiving coil (5) is placed in the gap between the two magnets, and the horizontal racetrack-shaped coil (6) is placed directly below the receiving end magnet group (3) with parallel magnetic poles arranged in opposite directions. The three together constitute a two-dimensional component electromagnetic ultrasonic surface wave receiving unit.

2. The electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor according to claim 1, characterized in that: The axial center distance between the two wire bundles of the folded-type excitation coil (4) and the horizontal runway-type coil (6) is the wavelength of the surface wave being excited. Since the magnetic field directions below the two wire bundles are opposite, the ultrasonic surface waves excited and received by the two wire bundles are in phase, thereby improving the surface wave excitation intensity and the received signal amplitude.

3. The electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor according to claim 1, characterized in that: It also includes a sensor housing (1) for fixing the excitation end magnet group (2) with side-by-side magnetic poles arranged in opposite directions and the receiving end magnet group (3) with side-by-side magnetic poles arranged in opposite directions.

4. The electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor according to claim 1, characterized in that: The sensor has an overall rectangular parallelepiped structure.

5. A detection method using an electromagnetic ultrasonic surface wave multi-parameter synchronous detection sensor as described in any one of claims 1 to 4, characterized in that: An electromagnetic ultrasonic surface wave excitation unit generates ultrasonic surface waves near the surface of the object under test. The ultrasonic surface waves generate elliptically polarized waves with two-dimensional components of out-of-plane displacement and in-plane displacement, which propagate forward and cut into the horizontal and vertical magnetic fields below the two-dimensional component electromagnetic ultrasonic surface wave receiving unit. These magnetic fields are received by the two coils of the two-dimensional component electromagnetic ultrasonic surface wave receiving unit, forming two received signals with out-of-plane and in-plane components. The polarization coefficient, wave velocity, and surface wave coefficient of the surface wave are obtained from these two received signals and the distance between the electromagnetic ultrasonic surface wave excitation unit and the two-dimensional component electromagnetic ultrasonic surface wave receiving unit, respectively, thereby realizing multi-parameter synchronous detection.

6. The detection method according to claim 5, characterized in that: When a surface wave multi-parameter synchronous detection sensor is placed on the surface of a non-ferromagnetic metal block, and radio frequency current is applied to the folded-back excitation coil (4), an eddy current field is induced within the skin depth range of the non-ferromagnetic metal block. Under the action of the horizontal magnetic field parallel to the non-ferromagnetic metal block and directly below the center of the excitation end magnet group (2) with parallel magnetic poles arranged in opposite directions, a Lorentz force is generated as the ultrasonic wave source. When the ultrasonic surface wave (7) propagates along the surface of the non-ferromagnetic metal block, the material particles move in an elliptical trajectory in a plane perpendicular to the surface and parallel to the propagation direction. In the receiving end magnet group (3) with parallel magnetic poles arranged in opposite directions, the magnets generate a vertical magnetic field perpendicular to the non-ferromagnetic metal block directly below the horizontal racetrack-shaped coil (6). A horizontal magnetic field parallel to the nonferromagnetic metal block is generated directly below the center of the receiving end magnet group. When the ultrasonic surface wave propagates to the two-dimensional component electromagnetic ultrasonic surface wave receiving unit, based on the inverse effect of the Lorentz force, the displacement component (8) in the elliptic polarization plane and the displacement component (10) of the ultrasonic surface wave cut the vertical magnetic field to generate eddy current fields, which are respectively induced by the horizontal runway-shaped coil (6) and the vertical rectangular receiving coil (5). The polarization value of the surface wave is calculated by the ratio of the amplitude of the displacement component (10) of the received signal to the amplitude of the in-plane displacement component (8). The arrival time of the displacement component (10) signal is used to calculate the surface wave velocity. The frequency domain signal obtained by performing a Fourier transform on the displacement component (10) signal is used to calculate the nonlinear coefficient.

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