DEVICE AND METHOD FOR ULTRASONIC DETECTING OF MECHANICAL MEMBER BASED ON MAGNETIC FLUID COUPLING

Abstract

A device and a method for ultrasonic detecting a mechanical member based on magnetic fluid coupling. The device comprises a magnetic field generating apparatus, magnetic fluid and an ultrasonic probe. The magnetic field generating apparatus has a cylindrical structure, into which the magnetic fluid is injected, where an upper portion of the apparatus is provided with the ultrasonic probe a front end that vertically extends into a liquid level of the magnetic fluid, and a bottom portion of the apparatus covers a detected position of a member under detection. The magnetic fluid at least contains magnetic suspension particles and oil-based or water-based liquid. With the device and the method, the ultrasonic probe is coupled with the member under detection to realize ultrasonic detecting of the service stress of the member under detection.

Claims

1. A device for ultrasonic detecting a mechanical member based on magnetic fluid coupling, comprising a magnetic field generating apparatus, magnetic fluid and an ultrasonic probe; the magnetic field generating apparatus has a cylindrical structure, into which the magnetic fluid is injected, wherein an upper portion of the apparatus is provided with the ultrasonic probe a front end of which vertically extends into a liquid level of the magnetic fluid, and a bottom portion of the apparatus covers a detected position of the member under detection; and the magnetic fluid at least contains magnetic suspension particles and an oil-based or water-based liquid.

2. The device of claim 1, further comprising a flexible fence for sealing the bottom portion of the magnetic field generating apparatus, by which the detected position of the member under detection is covered, wherein the flexible fence is made of soft sound-transmitting materials.

3. The device of claim 1, wherein the magnetic field generating apparatus comprises a cylindrical permanent magnet frame.

4. The device of claim 3, wherein an inner wall of the magnetic field generating apparatus is matched in shape with the front end of the ultrasound probe.

5. The device of claim 3, wherein the magnetic field generating apparatus has a depth of 1-5 mm.

6. The device of claim 3, wherein a curvature of the bottom portion of the magnetic field generating apparatus is matched with a corresponding position of the member under detection.

7. The device of claim 1, wherein the front end of the ultrasonic probe has an acoustic impedance matching layer that matches acoustic impedance of the magnetic fluid.

8. The device of claim 1, wherein the magnetic fluid further contains thickeners.

9. The device of claim 2, wherein a periphery of the flexible fence extends upwards along an outer wall of the magnetic field generating apparatus and tightly surrounds a lower half part of the outer wall of the magnetic field generating apparatus.

10. A method for ultrasonic detecting a mechanical member based on magnetic fluid coupling using a device including a magnetic field generating apparatus, magnetic fluid and an ultrasonic probe, comprising: placing the member vertically below a bottom portion of a flexible fence of the device for ultrasonic detecting the mechanical member based on magnetic fluid coupling; causing the member to move or stand still according to detection requirements; and transmitting ultrasonic waves by the ultrasonic probe, and detecting, by the ultrasonic probe, ultrasonic echoes refracted critically by an inside of the member to calculate service stress of the member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a block diagram of a device for ultrasonic detecting according to an embodiment of the present disclosure.

[0034] FIG. 2 is a flow chart of a method for ultrasonic detecting according to an embodiment of the present disclosure.

DESCRIPTION OF REFERENCE SIGNS

[0035] 10—Ultrasonic probe, 11—Acoustic impedance matching layer, 20—Magnetic field generating apparatus, 30—Flexible fence, 40—Magnetic fluid, and 50—Member under detection.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present disclosure provides a device and a method for ultrasonic detecting of mechanical member based on magnetic fluid coupling.

[0037] The device and the method of the present disclosure will now be described in detail with reference to the embodiments shown in the accompanying drawings.

[0038] As shown in FIG. 1, the present disclosure provides a device for ultrasonic detecting of mechanical member based on magnetic fluid coupling, which includes a magnetic field ultrasonic probe 10, a magnetic field generating apparatus 20, magnetic fluid 40, and a flexible fence 30.

[0039] The magnetic field generating apparatus 20 has a cylindrical structure, such as a vertically hollow circular ring or rectangular structure, and the magnetic fluid 40 is injected into a hollow portion of the apparatus. An upper portion of the apparatus is provided with the ultrasonic probe 10 that vertically extends into a liquid level of the magnetic fluid 40, a bottom portion of the apparatus is sealed by the flexible fence 30, and the flexible fence 30 vertically covers a detected position of the member 50 under detection.

[0040] Wherein, the magnetic field generating apparatus 20 may be made of a permanent magnet, which has an inner wall completely matched with a shape of a front end of the ultrasonic probe 10, a depth of 1-5 mm, and a bottom portion whose curvature is matched with that of the member 50 under detection.

[0041] Wherein, the magnetic fluid 40 may at least include magnetic suspension particles and oil-based or water-based liquid, and contain thickeners, antioxidants or antiseptics.

[0042] Wherein, a front end of the ultrasonic probe 10 is provided with an acoustic impedance matching layer 11 matched with an acoustic impedance of the magnetic fluid 40, a thickness of the acoustic impedance matching layer 11 is smaller than or equal to ¼ ultrasonic wave length, and a surface of a piezoelectric ceramic of a ultrasonic transducer of the ultrasonic probe 10 is provided with a chamfer.

[0043] Wherein, a periphery of the flexible fence 30 extends upward along an outer wall of the magnetic field generating apparatus 20, and tightly encloses a lower half part of the outer wall of the magnetic field generating apparatus 20.

[0044] The working principle of the device for ultrasonic detecting of mechanical member based on magnetic fluid coupling is described below.

[0045] The magnetic fluid 40 couples the ultrasonic probe 10 and the detected position of the member 50 under detection.

[0046] The magnetic field generating apparatus 20 provides a semi-closed magnetic field, by which the suspended particles protruding from the surface of the magnetic fluid 40 are attracted and attached to the acoustic impedance matching layer 11 of the ultrasonic probe 10 and do not fall off therefrom. The flexibility of the flexible fence 30 realizes close contact with the magnetic fluid 40 and the surface of the member 50 under detection, thus further enhancing the coupling between the ultrasonic probe 10 and the member 50 under detection.

[0047] The ultrasonic probe 10 transmits ultrasonic waves that are transmitted to the detected position of the member 50 under detection and enter the interior of the member 50 under detection by utilizing the acoustic permeability of the magnetic fluid 40, ultrasonic echoes are refracted critically through the inside of the member 50 under detection to calculate the service stress of the member under detection, and the ultrasonic echoes are detected by the ultrasonic probe 10, which realizes the ultrasonic detection of the internal service stress of the member 50 under detection.

[0048] The advantages of the device for ultrasonic detecting of mechanical member based on magnetic fluid coupling are described below.

[0049] Wherein, the acoustic impedance matching layer 11 is matched with the acoustic impedance of the magnetic fluid 40, which reduces the propagation loss between the ultrasonic probe 10 and the magnetic fluid 40, improve the signal-to-noise ratio of ultrasonic propagation, and improve the accuracy of the detection. Particularly, when the thickness of the acoustic impedance matching layer 11 is ¼ wavelength of the ultrasonic waves used for detection or thinner, the propagation loss between the ultrasonic probe 10 and the magnetic fluid 40 is reduced, and the accuracy of the detection is further improved.

[0050] Wherein, the chamfer angle on the surface edge of the piezoelectric ceramic piece of the ultrasonic transducer of the ultrasonic probe 10 reduces the noise of the ultrasonic transducer of the ultrasonic probe 10, improves the sensitivity of the detection and improves the accuracy of the detection.

[0051] Wherein, the magnetic suspension particles of the magnetic fluid 40 are in micro-nano scale, which improves the sound permeability of the magnetic fluid 40.

[0052] Wherein, the magnetic fluid 40 contains thickeners, which can increase the density of the magnetic fluid 40 and reduce the transmission loss of the ultrasonic waves in the magnetic fluid 40.

[0053] Wherein, the magnetic fluid 40 contains antioxidants or antiseptics, which can extend the life of the magnetic fluid 40.

[0054] Wherein, the inner wall of the magnetic field generating apparatus 20 is completely matched with the front end of the ultrasonic probe 10 in shape, which keeps the magnetic fluid 40 from leaking upwards, and improves the stability of the detection.

[0055] Wherein, the depth of the magnetic field generating apparatus is 1-5 mm, and the depth can be adjusted according to the intensity of the magnetic field generated by the magnetic field generating apparatus 20.

[0056] Wherein, the curvature of the bottom portion of the magnetic field generating apparatus 20 matches the curvature of the surface of the member 50 under detection, which keeps the magnetic fluid 40 from leaking, and improves the stability of the detection.

[0057] Wherein, the periphery of the flexible fence 30 extends upward along the outer wall of the magnetic field generating apparatus 20, and tightly surrounds the lower half part of the outer wall of the magnetic field generating apparatus 20, thus fixing the whole device.

[0058] In the present disclosure, the magnetic fluid 40 is attracted and attached to the acoustic impedance matching layer 11 of the ultrasonic probe 10 by utilizing the magnetic field generated by the annular magnetic field generating apparatus 20, and meanwhile, the magnetic fluid 40 is kept to be closely attached to the flexible fence 30 which closely covers the member 50 under detection, thus coupling the ultrasonic probe 10 and the member 50 under detection. The ultrasonic probe 10 transmits and receives the ultrasonic signals by utilizing the sound permeability of the magnetic fluid 40, which realizes ultrasonic nondestructive detecting of the mechanical member. Finally, combination of the flexibility of the flexible fence 30 and the impermeability to the magnetic fluid 40 maintains the thickness and concentration of the magnetic fluid 40, and realizes the ultrasonic detecting of the moving member.

[0059] An embodiment of the present disclosure also provides a method for ultrasonic detecting of mechanical member based on magnetic fluid coupling, which may include steps S110 to S130.

[0060] At the step S110, the member 50 under detection is vertically placed below a bottom portion of the flexible fence 30 of the device for ultrasonic detecting of mechanical member based on magnetic fluid coupling, wherein the detected position is closely aligned with the bottom portion of the flexible fence 30.

[0061] At the step S120, the member 50 under detection is made to move or stand still according to detection requirements.

[0062] At the step S130, the ultrasonic probe 10 transmits ultrasonic waves, and detects ultrasonic echoes critically refracted by the member 50 under detection to calculate the service stress of the member under detection.

[0063] Calculating of the service stress of the member under detection based on the ultrasonic echoes is carried out by a peripheral device, which does not belong to the content of the present disclosure and is not described herein.

[0064] The above description is only for the purpose of illustrating the preferred embodiments of the present disclosure and is not intended to limit the scope of the present disclosure. Any modifications, equivalents and improvements, which are made within the spirit and principle of the present disclosure, should be included in the scope of protection of the present disclosure.