A fiber optic eddy current ultrasonic composite nondestructive testing instrument and testing method

Abstract

The present invention discloses a fiber optic eddy current ultrasonic composite nondestructive testing instrument and a testing method, which relate to the field of nondestructive testing technology, including a frame, an XY two-dimensional motion module, a Z-direction linear motion module, a rotation drive module and a fiber optic eddy current and ultrasonic nondestructive testing module, wherein the fiber optic eddy current and ultrasonic nondestructive testing module is connected to the Z-direction linear motion module through the rotation drive module, and the fiber optic eddy current and ultrasonic nondestructive testing module includes a mounting substrate, an ultrasonic nondestructive testing mechanism and a fiber optic eddy current testing mechanism, and the rotation drive module is used to drive the mounting substrate to rotate so as to realize the switching of the test position of the fiber optic eddy current and ultrasonic nondestructive testing module in the XZ plane. The testing instrument and the testing method solve the problems of single output parameter, inherent lift-off effect, installation inclination angle influence, poor adaptability of complex geometric morphology, and difficulty in realizing accurate testing of machining surface and its internal damage defects and residual stress.

Description

Technical Field

[0001] The present invention relates to the technical field of nondestructive testing, and in particular to an optical fiber eddy current ultrasonic composite nondestructive testing instrument and a testing method. Background Art

[0002] The development of aerospace, national defense, and automobile manufacturing is an important guarantee for national strategy and social livelihood. Advanced composite materials are one of the bottlenecks in the development of the above fields and are also international frontier hotspots. In order to ensure the stability, durability, and reliability of materials and their products during service, the research on in-situ mechanical damage detection instruments and technologies for advanced composite material processing surfaces has extremely important scientific value and practical significance.

[0003] The development of sensor technology and the improvement of detection and control theory have enabled the rapid development of in-situ mechanical damage detection technology for machined surfaces. It has been continuously enriched in theory, method and application, and gradually formed a complete standard system. It has become the mainstream technical means for the evolution of mechanical behavior and micro-area damage and failure mechanism of cutting-edge new materials (carbon fiber reinforced polymer composites, ceramic matrix composites, additive manufacturing metal materials, etc.), advanced basic materials (such as titanium alloys, aluminum alloys, magnesium alloys, high-performance steels, etc.), and key strategic materials (such as titanium alloys, high-temperature alloys, etc.).

[0004] Compared with destructive mechanical damage detection technologies such as tension / compression, scanning probe microscopy, and X-ray diffraction, non-destructive testing technologies such as eddy current testing and ultrasonic testing have the advantages of high speed and easy online integration, which have attracted widespread attention from researchers.

[0005] However, existing research on nondestructive testing technology for machining surfaces of advanced composite materials has shown that the output parameters are single, and it is difficult to achieve simultaneous and co-located testing and characterization of multiple parameters such as machined surface and internal damage defects, residual stress, etc. At the same time, eddy current nondestructive testing technology faces the influence of inherent lift-off effect and factors such as the surface geometry of the workpiece being tested and the installation inclination angle. This not only limits the machining and manufacturing accuracy of advanced composite materials, as well as the service durability and stability under complex working conditions, but also seriously restricts the in-depth research of nondestructive testing technology in many key fields, and has become a major problem plaguing the international academic and engineering communities.

[0006] Therefore, the design and development of composite nondestructive testing instruments and methods that can achieve surface and internal damage defects and residual stress composite nondestructive testing of advanced composite materials will have great development prospects and application value in aerospace, national defense, military industry, and automobile manufacturing. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a fiber optic eddy current ultrasonic composite nondestructive testing instrument and detection method, which solves the problems of single output parameter, inherent lift-off effect, installation inclination angle influence, poor adaptability to complex geometric morphology, and difficulty in achieving accurate testing of processing surface and internal damage defects and residual stress.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] The present invention provides an optical fiber eddy current ultrasonic composite nondestructive testing instrument, comprising a frame, an XY two-dimensional motion module, a Z-direction linear motion module, a rotation drive module and an optical fiber eddy current and ultrasonic nondestructive testing module, wherein the XY two-dimensional motion module is arranged at the lower part of the frame and is used to drive a workpiece to be tested to move along an X direction and a Y direction, the Z-direction linear motion module is arranged at the upper part of the frame and is located above the XY two-dimensional motion module, the optical fiber eddy current and ultrasonic nondestructive testing module is connected to the Z-direction linear motion module through the rotation drive module, the optical fiber eddy current and ultrasonic nondestructive testing module comprises a mounting substrate, an ultrasonic nondestructive testing mechanism and an optical fiber eddy current testing mechanism, the rotation drive module is used to drive the mounting substrate to rotate so as to realize the switching of the test position of the optical fiber eddy current and ultrasonic nondestructive testing module in an XZ plane, and the ultrasonic nondestructive testing mechanism comprises an ultrasonic signal transmitting end and an ultrasonic signal receiving end symmetrically arranged on both sides of the mounting substrate, and the ultrasonic signal transmitting end and the ultrasonic signal receiving end are composed of The optical fiber eddy current detection mechanism is arranged to be inclined toward each other from top to bottom, and includes a Z-direction displacement platform, a first connecting plate, an inclination adjustment platform, a second connecting plate, a flexible hinge, a piezoelectric actuator, a pre-tightening screw, a mounting plate and an optical fiber eddy current detection unit arranged in the middle of the mounting base plate. The Z-direction displacement platform, the first connecting plate, the inclination adjustment platform, the second connecting plate and the flexible hinge are connected in sequence, the piezoelectric actuator is arranged in a groove of the flexible hinge, the pre-tightening screw is installed on the flexible hinge and is used to adjust the pre-tightening force of the piezoelectric actuator, the mounting plate is arranged at the bottom of the flexible hinge, the optical fiber eddy current detection unit includes a housing, an optical fiber displacement sensor and an array eddy current probe, the housing is arranged at the lower part of the mounting plate, the optical fiber displacement sensor and the array eddy current probe are both arranged in the housing and coaxially installed, and the central axis of the ultrasonic signal transmitting end, the ultrasonic signal receiving end and the optical fiber eddy current detection unit can intersect with the surface of the workpiece to be measured.

[0010] Preferably, the rotation drive module includes a connecting mechanism, a rotation drive component, a gear, a guiding mechanism, an arcuate guide rail and an arcuate gear ring. One end of the connecting mechanism is connected to the Z-axis linear motion module, and the other end is equipped with the rotation drive component. The rotation drive component is used to drive the gear to rotate. The guiding mechanism is arranged on the front side of the connecting mechanism. The guiding mechanism is used to guide the movement of the arcuate guide rail. The arcuate gear ring is arranged on the front side of the arcuate guide rail and meshes with the gear. The mounting base is arranged on the front side of the arcuate gear ring.

[0011] Preferably, the connecting mechanism includes an I-shaped mounting frame and a third connecting plate, the two ends of the I-shaped mounting frame are respectively connected to the Z-axis linear motion module and the third connecting plate, the rotation driving component is arranged on the rear side of the third connecting plate, and the power output end of the rotation driving component passes through the third connecting plate to the front side and is fixedly sleeved with the gear, and the guide mechanism is arranged on the front side of the third connecting plate.

[0012] Preferably, the guide mechanism includes an upper guide assembly and a lower guide assembly, the upper guide assembly includes a plurality of upper guide wheels arranged along an arc direction, the lower guide assembly includes a plurality of lower guide wheels arranged along an arc direction, the arc guide rail is located between the plurality of upper guide wheels and the plurality of lower guide wheels, an upper arc groove matching the upper guide wheel structure is provided on the upper portion of the arc guide rail, and a lower arc groove matching the lower guide wheel structure is provided on the lower portion of the arc guide rail.

[0013] Preferably, the ultrasonic nondestructive testing mechanism also includes two mounting components, which include an adjusting pad and a mounting block. The two adjusting pads are symmetrically arranged on both sides of the front of the mounting substrate, and one mounting block is arranged on the front side of each adjusting pad. The ultrasonic signal transmitting end and the ultrasonic signal receiving end are respectively installed on the two mounting blocks.

[0014] Preferably, the housing comprises a threaded connection sleeve, an insulating sleeve and a set screw, the upper portion of the threaded connection sleeve is mounted on the mounting plate, the insulating sleeve is threadedly connected to the lower portion of the threaded connection sleeve, the array-type eddy current probe is arranged in the insulating sleeve, the optical fiber displacement sensor comprises an optical fiber body, a mounting ring and an optical fiber probe, the optical fiber body is connected to the optical fiber probe, the mounting ring is fixedly sleeved at one end of the optical fiber body close to the optical fiber probe, the optical fiber probe passes through the threaded connection sleeve and extends into the insulating sleeve, the mounting ring is sleeved at the upper portion of the threaded connection sleeve, and the set screw fixes the mounting ring to the threaded connection sleeve.

[0015] Preferably, the array-type eddy current probe comprises a coil pressure plate, a preloaded compression spring, a plurality of iron cores and a plurality of hollow coils, a first center hole for the optical fiber probe to pass through is arranged in the middle of the coil pressure plate, a center tube connected to the first center hole is arranged in the lower center of the coil pressure plate, a plurality of first through holes for the iron core to pass through are arranged in the circumferential direction on the coil pressure plate, a second center hole for the center tube to extend out is arranged in the middle of the end surface of the insulating sleeve, and a plurality of through holes for the iron core to pass through are arranged in the circumferential direction on the end surface of the insulating sleeve. The second through hole for positioning, the two ends of the pre-tightening compression spring respectively abut against the lower part of the threaded connecting sleeve and the upper part of the coil pressure plate, each of the iron cores passes through one of the first through holes and extends downward, a limiting ring is fixedly sleeved on the lower end of each of the iron cores, a hollow coil is sleeved on each of the iron cores, and each of the hollow coils is located between one of the limiting rings and the coil pressure plate, and the bottom end of each of the iron cores extends into one of the second through holes and the limiting ring abuts against the upper part of the end surface of the insulating sleeve.

[0016] Preferably, the Z-axis displacement platform is a manual Z-axis displacement platform, and the inclination adjustment platform is a manual inclination adjustment platform.

[0017] Preferably, the frame comprises a base and a gantry arranged on the base, and the Z-axis linear motion module is arranged on a crossbeam of the gantry.

[0018] The present invention also provides a detection method based on the optical fiber eddy current ultrasonic composite nondestructive testing instrument, comprising the following steps:

[0019] Step 1: Clamp the workpiece to be tested on the XY two-dimensional motion module, use the industrial computer to adjust the Z-direction linear motion module so that the ultrasonic nondestructive testing mechanism and the surface of the workpiece to be tested are kept within the working distance, and at the same time adjust the Z-direction displacement platform so that the array eddy current probe is within the working range;

[0020] Step 2: Using an industrial computer to control the movement of the rotation drive module, and adjusting it in conjunction with the inclination adjustment platform, so that the displacement feedback signal detected by the optical fiber displacement sensor is acquired by the data acquisition card through the charge amplifier, so that the distance between the array eddy current probe and the surface of the workpiece to be measured in the XZ plane and the YZ plane is minimized at the same time, eliminating the tilt effect of the optical fiber eddy current detection unit caused by installation;

[0021] Step 3, for the test method of the surface damage defects of the workpiece being tested, an excitation signal is sent to the trigger coil of the array eddy current probe through a signal generator with controllable frequency and phase sequence, and then a differential amplifier is used to amplify the received signal of the pickup coil of the array eddy current probe, and the phase of the signal generator reference signal and the received signal is calculated through a phase-locked amplifier, read into a data acquisition card, and fed back to the supporting analysis and processing software of the industrial computer, and then through sample pre-scanning, the coil excitation-pickup sequence of the array eddy current probe is optimized to obtain the best detection sensitivity and resolution;

[0022] Step 4: for the test method of the internal damage defect of the workpiece under test, a pulsed laser is used to transmit an ultrasonic detection signal to the ultrasonic signal transmitting end, and the ultrasonic signal receiving end installed in a symmetrical layout receives the signal and reads it into an industrial computer for frequency domain analysis;

[0023] Step 5: In order to adapt to the complex geometric features of the workpiece being tested, the optical fiber displacement sensor coaxial with the array eddy current probe in the optical fiber eddy current detection unit is used to detect the lift-off distance in real time, and the output end position of the piezoelectric actuator is controlled by the industrial computer in a closed loop to ensure that the lift-off distance of the array eddy current probe is consistent during the eddy current detection process;

[0024] Step six: Combined with the surface geometry reconstruction model of the workpiece under test, the XY two-dimensional motion module, the Z-axis linear motion module and the rotation drive module are controlled by an industrial computer to carry out detection path planning for the workpiece under test with complex geometric features, thereby realizing the detection of surface and internal damage defects, residual stress of the workpiece under test, and fiber waviness and fiber orientation of advanced composite materials, and realizing multi-parameter synchronous in-situ test characterization.

[0025] Compared with the prior art, the present invention has achieved the following technical effects:

[0026] The fiber optic eddy current ultrasonic composite nondestructive testing instrument and testing method of the present invention, by organically integrating eddy current testing and ultrasonic testing, has a rich output parameter for advanced composite material processing surface and its internal damage defects, residual stress, etc. Compared with a single nondestructive testing technology. Based on the principle of non-contact large-stroke optical fiber displacement measurement, it solves the technical limitations of existing eddy current nondestructive testing technology, such as inherent lift-off effect, installation inclination angle influence, and poor adaptability to complex geometric morphology, and realizes the simultaneous and co-location test characterization of multiple parameters such as advanced composite material processing surface and its internal damage defects, residual stress, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A three-dimensional structural diagram of the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0029] Figure 2 A front view of the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0030] Figure 3 A side view of the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0031] Figure 4 It is a front view of the optical fiber eddy current and ultrasonic nondestructive testing modules in the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention when they are in the extreme position;

[0032] Figure 5 This is a front view of the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention after removing the optical fiber eddy current and ultrasonic nondestructive testing modules;

[0033] Figure 6 An exploded diagram of the optical fiber eddy current and ultrasonic nondestructive testing module in the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0034] Figure 7 A rear view of the optical fiber eddy current and ultrasonic nondestructive testing module in the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0035] Figure 8 A three-dimensional structural diagram of a fiber optic eddy current detection unit in the fiber optic eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0036] Fig. 9 An exploded diagram of the optical fiber eddy current detection unit in the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0037] Fig.10 A front view of a fiber optic eddy current detection unit in the fiber optic eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0038] Fig.11 for Fig.10 Sectional view along AA direction;

[0039] Fig.12A schematic diagram of the calibration correction of the installation inclination of the optical fiber eddy current detection unit in the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0040] Fig.13 A working principle diagram of the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention;

[0041] Fig.14 This is a schematic diagram of the optical fiber eddy current ultrasonic composite nondestructive testing instrument provided by the present invention for detecting surface waviness and defects of a composite material.

[0042] Explanation of reference numerals: 1. base; 2. gantry; 3. X-axis linear motion platform; 4. Y-axis linear motion platform; 5. Y-axis linear support platform; 6. Z-axis linear motion platform; 7. mounting base plate; 8. Z-axis displacement platform; 9. first connecting plate; 10. inclination adjustment platform; 11. second connecting plate; 12. flexible hinge; 13. piezoelectric actuator; 14. pre-tightening screw; 15. mounting plate; 16. optical fiber eddy current detection unit; 161. threaded connection sleeve; 162. insulating sleeve; 163. set screw; 164. optical fiber body ; 165. Mounting ring; 166. Fiber optic probe; 167. Preload compression spring; 168. Coil pressure plate; 169. Iron core; 1610. Hollow coil; 1611. Limiting ring; 1612. Center tube; 17. Ultrasonic signal transmitting end; 18. Ultrasonic signal receiving end; 19. Adjusting pad; 20. Mounting block; 21. I-shaped mounting bracket; 22. Third connecting plate; 23. Rotating drive component; 24. Gear; 25. Arc guide rail; 26. Upper guide wheel; 27. Lower guide wheel; 28. Arc gear ring; 29. ​​Workpiece to be measured. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The purpose of the present invention is to provide a fiber optic eddy current ultrasonic composite nondestructive testing instrument and detection method, which solves the problems of single output parameter, inherent lift-off effect, installation inclination angle influence, poor adaptability to complex geometric morphology, and difficulty in achieving accurate testing of processing surface and its internal damage defects and residual stress.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1-Figure 14As shown, this embodiment provides a fiber optic eddy current ultrasonic composite nondestructive testing instrument, including a frame, an XY two-dimensional motion module, a Z-direction linear motion module, a rotation drive module and a fiber optic eddy current and ultrasonic nondestructive testing module, the XY two-dimensional motion module is arranged at the lower part of the frame and is used to drive the workpiece 29 to move along the X direction and the Y direction, the Z-direction linear motion module is arranged at the upper part of the frame and is located above the XY two-dimensional motion module, and the fiber optic eddy current and ultrasonic nondestructive testing module is connected to the Z-direction linear motion module through the rotation drive module to realize the macro adjustment of the Z-direction spacing between the test probe and the surface of the workpiece 29 to be measured.

[0047] The fiber eddy current and ultrasonic nondestructive testing module includes a mounting substrate 7, an ultrasonic nondestructive testing mechanism and a fiber eddy current testing mechanism. The rotation drive module is used to drive the mounting substrate 7 to rotate to realize the switching of the test position of the fiber eddy current and ultrasonic nondestructive testing module in the XZ plane. The ultrasonic nondestructive testing mechanism includes an ultrasonic signal transmitting end 17 and an ultrasonic signal receiving end 18 symmetrically arranged on both sides of the mounting substrate 7. The ultrasonic signal transmitting end 17 and the ultrasonic signal receiving end 18 are arranged to be tilted from top to bottom. The ultrasonic nondestructive testing mechanism in this embodiment adopts non-contact air coupling, laser ultrasound and other detection modes to eliminate the influence of the coupling agent on the eddy current penetration ability.

[0048] The optical fiber eddy current detection mechanism includes a Z-direction displacement platform 8, a first connecting plate 9, an inclination adjustment platform 10, a second connecting plate 11, a flexible hinge 12, a piezoelectric actuator 13, a pre-tightening screw 14, a mounting plate 15 and an optical fiber eddy current detection unit 16 arranged in the middle of the mounting base plate 7. The Z-direction displacement platform 8, the first connecting plate 9, the inclination adjustment platform 10, the second connecting plate 11 and the flexible hinge 12 are sequentially connected from back to front. The piezoelectric actuator 13 is arranged in a groove of the flexible hinge 12. The pre-tightening screw 14 is installed on the flexible hinge 12 and is used to adjust the pre-tightening force of the piezoelectric actuator 13. The mounting plate 15 is arranged on the flexible hinge. The bottom of the chain 12, in this embodiment, the mounting plate 15 is fixed to the output end of the direct-acting flexible hinge 12, the fiber optic eddy current detection unit 16 includes a housing, a fiber optic displacement sensor and an array eddy current probe, the housing is arranged at the lower part of the mounting plate 15, the fiber optic displacement sensor and the array eddy current probe are both arranged in the housing and coaxially installed, the central axis of the ultrasonic signal transmitting end 17, the ultrasonic signal receiving end 18 and the fiber optic eddy current detection unit 16 are located in the same XZ plane, and the central axis of the ultrasonic signal transmitting end 17, the ultrasonic signal receiving end 18 and the fiber optic eddy current detection unit 16 can intersect with the surface of the workpiece 29 to be measured.

[0049] like Figure 5 and Figure 6As shown, the rotary drive module includes a connecting mechanism, a rotary drive component 23, a gear 24, a guide mechanism, an arc guide rail 25 and an arc gear ring 28. One end of the connecting mechanism is connected to the Z-axis linear motion module, and the other end is equipped with a rotary drive component 23. The rotary drive component 23 is used to drive the gear 24 to rotate. The guide mechanism is arranged at the front side of the connecting mechanism. The guide mechanism is used to guide the movement of the arc guide rail 25. The arc gear ring 28 is arranged at the front side of the arc guide rail 25 and meshes with the gear 24. The mounting substrate 7 is arranged at the front side of the arc gear ring 28. In this embodiment, the teeth of the arc gear ring 28 that match the structure of the gear 24 are arranged on its inner wall.

[0050] During operation, the rotating driving component 23 drives the gear 24 to rotate, thereby causing the arc guide rail 25, the arc gear ring 28, the mounting substrate 7, and the ultrasonic nondestructive testing mechanism and the optical fiber eddy current testing mechanism disposed on the mounting substrate 7 to rotate in the XZ plane.

[0051] The connection mechanism includes an I-shaped mounting frame 21 and a third connecting plate 22, the two ends of the I-shaped mounting frame 21 are respectively connected to the Z-axis linear motion module and the third connecting plate 22, the rotation drive component 23 is arranged at the rear side of the third connecting plate 22, and the power output end of the rotation drive component 23 passes through the third connecting plate 22 and extends to the front side and is fixedly sleeved with a gear 24, and the guide mechanism is arranged at the front side of the third connecting plate 22. The rotation drive component 23 in this embodiment is a rotation drive motor.

[0052] The guide mechanism includes an upper guide assembly and a lower guide assembly. The upper guide assembly includes a plurality of upper guide wheels 26 arranged along an arc direction. The lower guide assembly includes a plurality of lower guide wheels 27 arranged along an arc direction. The arc guide rail 25 is located between the plurality of upper guide wheels 26 and the plurality of lower guide wheels 27. An upper arc groove matching the structure of the upper guide wheel 26 is provided on the upper portion of the arc guide rail 25. A lower arc groove matching the structure of the lower guide wheel 27 is provided on the lower portion of the arc guide rail 25, thereby achieving guidance of the arc guide rail 25.

[0053] like Figure 6 As shown, the ultrasonic nondestructive testing mechanism further includes two mounting components, the mounting components include an adjusting pad 19 and a mounting block 20, the two adjusting pads 19 are symmetrically arranged on both sides of the front of the mounting substrate 7, a mounting block 20 is arranged on the front side of each adjusting pad 19, and the ultrasonic signal transmitting end 17 and the ultrasonic signal receiving end 18 are respectively mounted on the two mounting blocks 20. By using adjusting pads 19 of different thicknesses, the positions of the ultrasonic signal transmitting end 17 and the ultrasonic signal receiving end 18 in the front and rear directions can be adjusted.

[0054] like Figure 8-Figure 11As shown, the housing includes a threaded sleeve 161, an insulating sleeve 162 and a set screw 163. The upper portion of the threaded sleeve 161 is mounted on the mounting plate 15. Specifically, an offset hole for mounting the threaded sleeve 161 is disposed at the rear end of the mounting plate 15. The position of the offset hole is, on the one hand, limited by the minimum bending radius of the optical fiber body 164 at the end, and on the other hand, is to be disposed so that the central axis of the threaded sleeve 161 is coplanar with the central axis of the ultrasonic signal transmitting end 17 and the ultrasonic signal receiving end 18. The insulating sleeve 162 is threadedly connected to the lower part of the threaded connection sleeve 161, and the array eddy current probe is arranged in the insulating sleeve 162. The optical fiber displacement sensor includes an optical fiber body 164, a mounting ring 165 and an optical fiber probe 166. The optical fiber body 164 is connected to the optical fiber probe 166. The mounting ring 165 is fixedly sleeved on one end of the optical fiber body 164 close to the optical fiber probe 166. The optical fiber probe 166 passes through the threaded connection sleeve 161 and extends into the insulating sleeve 162. The mounting ring 165 is sleeved on the upper part of the threaded connection sleeve 161, and the set screw 163 fixes the mounting ring 165 to the threaded connection sleeve 161.

[0055] like Fig. 9 and Fig.11 As shown, the array eddy current probe includes a coil pressing plate 168, a preloaded compression spring 167, a plurality of iron cores 169 and a plurality of hollow coils 1610. A first center hole for the optical fiber probe 166 to pass through is provided in the middle of the coil pressing plate 168. A center tube 1612 connected to the first center hole is provided in the lower center of the coil pressing plate 168. A plurality of first through holes for the iron core 169 to pass through are provided on the coil pressing plate 168 along the circumferential direction. A second center hole for the center tube 1612 to extend out is provided in the middle of the end surface of the insulating sleeve 162. A plurality of iron cores 169 are provided on the end surface of the insulating sleeve 162 along the circumferential direction. The second through hole for positioning the core 169, the two ends of the pre-tightening compression spring 167 respectively abut against the lower part of the threaded connecting sleeve 161 and the upper part of the coil pressure plate 168, each iron core 169 extends downward through a first through hole, and a limiting ring 1611 is fixedly sleeved on the lower end of each iron core 169, and a hollow coil 1610 is sleeved on each iron core 169, and each hollow coil 1610 is located between a limiting ring 1611 and the coil pressure plate 168. The bottom end of each iron core 169 extends into a second through hole and the limiting ring 1611 abuts against the upper part of the end face of the insulating sleeve 162.

[0056] After assembly, the pre-tightened compression spring 167 applies axial force to the coil pressure plate 168, and then applies force to the limit ring 1611 on the iron core 169 through the hollow coil 1610 to make it abut against the upper end surface of the insulating sleeve 162. The bottom end of the iron core 169 extends into the second through hole, and the optical fiber probe 166 extends to the outside through the first center hole and the center tube 1612, ensuring that the coil pressure plate 168 and the optical fiber probe 166 are coaxially arranged, so that the array eddy current probe and the optical fiber displacement sensor are coaxially arranged.

[0057] The array eddy current probe in this embodiment includes eight iron cores 169 and eight hollow coils 1610 , and the coil pressing plates 168 are evenly distributed in the circumferential direction.

[0058] In this specific embodiment, the Z-axis displacement platform 8 is a manual Z-axis displacement platform, and the inclination adjustment platform 10 is a manual inclination adjustment platform.

[0059] Specifically, the frame includes a base 1 and a gantry 2 disposed on the base 1, and the Z-axis linear motion module is disposed on the crossbeam of the gantry 2. The base 1 and the gantry 2 in this embodiment are both made of marble.

[0060] In this specific embodiment, the Z-axis linear motion module is a Z-axis linear motion platform 6, and the XY two-dimensional motion module includes an X-axis linear motion platform 3, a Y-axis linear motion platform 4, and a Y-axis linear support platform 5. The Y-axis linear motion platform 4 and the Y-axis linear support platform 5 are arranged in parallel on the base 1, and the X-axis linear motion platform 3 is arranged on the Y-axis linear motion platform 4 and the Y-axis linear support platform 5. The X-axis linear motion platform 3 is used to set the workpiece 29 to be measured. Specifically, the workpiece 29 to be measured is fixed on the X-axis linear motion platform 3 using different fixtures according to its geometric characteristics.

[0061] The X-axis linear motion platform 3, the Y-axis linear motion platform 4 and the Z-axis linear motion platform 6 in this embodiment are all linear motion platforms in the prior art, and their specific structures are not described in detail.

[0062] This embodiment also provides a detection method based on the fiber optic eddy current ultrasonic composite nondestructive testing instrument, comprising the following steps:

[0063] Step 1: The workpiece 29 to be tested is accurately positioned and clamped on the XY two-dimensional motion module, and the motion instructions are sent to the motion controller of the Z-axis linear motion module through the industrial computer. The Z-axis linear motion module is then adjusted by the industrial computer so that the ultrasonic nondestructive testing mechanism and the surface of the workpiece 29 to be tested are kept within the working distance. At the same time, the Z-axis displacement platform 8 is manually adjusted so that the array eddy current probe is within the working range.

[0064] like Fig.12As shown, step 2, using the industrial computer to control the rotation drive module, the industrial computer sends a motion command to the motion controller of the rotation drive module to achieve, and cooperates with the inclination adjustment platform 10 to manually adjust, the rotation angles are θx and θy respectively, so that the displacement feedback signal detected by the optical fiber displacement sensor is acquired by the data acquisition card through the charge amplifier, and the distance between the array eddy current probe and the surface of the workpiece 29 to be measured in the XZ plane and the YZ plane is minimized at the same time, that is, d 0 <d 1 And d 0 <d 2 , eliminating the tilt effect of the optical fiber eddy current detection unit 16 caused by installation; Figure 4 As shown, in this embodiment, the fiber optic eddy current and ultrasonic nondestructive testing module realizes the extreme position detection of the maximum swing angle θ in the XZ plane through the rotation drive module, and cooperates with the inclination adjustment platform 10 to suppress the tilt effect caused by the installation of the array eddy current probe, thereby improving the nondestructive testing accuracy of advanced composite materials.

[0065] Step 3: The hollow coil 1610 for signal input in the array eddy current probe is defined as a trigger coil (T), and the hollow coil 1610 for signal output is defined as a pickup coil (P). In the test method for surface damage defects of the workpiece 29 to be tested, an excitation signal is sent to the trigger coil (T) of the array eddy current probe by a signal generator with controllable frequency and phase sequence, and then the received signal of the pickup coil (P) of the array eddy current probe is amplified by a differential amplifier, and the reference signal of the signal generator and the phase of the received signal are calculated by a phase-locked amplifier, read into a data acquisition card, and fed back to the supporting analysis and processing software of the industrial computer, and then the coil excitation-pickup sequence of the array eddy current probe is optimized by pre-scanning the sample to obtain the best detection sensitivity and resolution; the array eddy current probe in this embodiment adopts an array arrangement with an adjustable signal excitation sequence to realize multi-parameter surface damage defect detection of advanced composite materials such as carbon fiber reinforcement, such as waviness and fiber orientation.

[0066] Step 4: For the test method of internal damage defects of the workpiece 29, a pulsed laser is used to transmit an ultrasonic detection signal to the ultrasonic signal transmitting end 17, and the signal is received by the ultrasonic signal receiving end 18 installed in a symmetrical layout, and read into the industrial computer for frequency domain analysis. In this embodiment, the laser ultrasonic signal receiver receives the signal at the ultrasonic signal receiving end 18 and transmits it to the industrial computer.

[0067] Step 5. In order to adapt to the complex geometric features of the workpiece 29 to be measured, the optical fiber displacement sensor coaxial with the array eddy current probe in the optical fiber eddy current detection unit 16 is used to detect the lift-off distance in real time, and the output end position of the piezoelectric actuator 13 is closed-loop controlled by the industrial computer to ensure that the lift-off distance of the array eddy current probe is consistent during the eddy current detection process. In this embodiment, the optical fiber displacement sensor is used to measure the distance between the array eddy current probe and the surface of the workpiece 29 to be measured in real time, and the output end position of the piezoelectric actuator 13 is closed-loop controlled to adapt to the curvature change of the complex geometric feature processing surface, suppress the lift-off effect of eddy current detection, and realize the detection of damage defects on the processing surface and inside.

[0068] Step six, combined with the surface geometry reconstruction model of the workpiece 29, the XY two-dimensional motion module, the Z-axis linear motion module and the rotation drive module are controlled by the industrial computer, that is, the industrial computer is used to send motion instructions to the motion controllers of the XY two-dimensional motion module, the Z-axis linear motion module and the rotation drive module respectively, and C-scan and other detection path planning are carried out on the workpiece 29 with complex geometric features, thereby realizing the detection of surface and internal damage defects, residual stress of the workpiece 29, and fiber waviness and fiber orientation of advanced composite materials, and realizing multi-parameter synchronous co-location test characterization.

[0069] It can be seen that the fiber optic eddy current ultrasonic composite nondestructive testing instrument and testing method in this embodiment, by organically integrating eddy current testing and ultrasonic testing, has a rich output parameter for advanced composite material processing surface and its internal damage defects, residual stress, etc., compared with a single nondestructive testing technology. Based on the principle of non-contact large-stroke fiber optic displacement measurement, it solves the technical limitations of existing eddy current nondestructive testing technology, such as inherent lift-off effect, installation inclination angle influence, and poor adaptability to complex geometric morphology, and realizes the simultaneous and co-location test characterization of multiple parameters such as advanced composite material processing surface and its internal damage defects, residual stress, etc.

[0070] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A fiber optic eddy current ultrasonic composite nondestructive testing instrument, characterized in that: The invention comprises a frame, an XY two-dimensional motion module, a Z-direction linear motion module, a rotation drive module and an optical fiber eddy current and ultrasonic nondestructive testing module, wherein the XY two-dimensional motion module is arranged at the lower part of the frame and is used to drive the workpiece to be tested to move along the X direction and the Y direction, the Z-direction linear motion module is arranged at the upper part of the frame and is located above the XY two-dimensional motion module, the optical fiber eddy current and ultrasonic nondestructive testing module is connected to the Z-direction linear motion module through the rotation drive module, the optical fiber eddy current and ultrasonic nondestructive testing module comprises an installation substrate, an ultrasonic nondestructive testing mechanism and an optical fiber eddy current testing mechanism, and the rotation drive module is used to The optical fiber eddy current detection unit is used to drive the mounting substrate to rotate so as to realize the switching of the test positions of the optical fiber eddy current and ultrasonic nondestructive testing modules in the XZ plane. The ultrasonic nondestructive testing mechanism includes an ultrasonic signal transmitting end and an ultrasonic signal receiving end symmetrically arranged on both sides of the mounting substrate. The ultrasonic signal transmitting end and the ultrasonic signal receiving end are arranged to be tilted toward each other from top to bottom. The optical fiber eddy current detection mechanism includes a Z-direction displacement platform, a first connecting plate, an inclination adjustment platform, a second connecting plate, a flexible hinge, a piezoelectric actuator, a pre-tightening screw, a mounting plate and an optical fiber eddy current detection unit arranged in the middle of the mounting substrate. The Z-direction displacement platform, the first connecting plate, a tilt adjustment platform, a second connecting plate, a flexible hinge, a piezoelectric actuator, a pre-tightening screw, a mounting plate and an optical fiber eddy current detection unit. The plate, the inclination adjustment platform, the second connecting plate and the flexible hinge are connected in sequence, the piezoelectric actuator is arranged in the groove of the flexible hinge, the pre-tightening screw is installed on the flexible hinge and is used to adjust the pre-tightening force of the piezoelectric actuator, the mounting plate is arranged at the bottom of the flexible hinge, the optical fiber eddy current detection unit includes a housing, an optical fiber displacement sensor and an array eddy current probe, the housing is arranged at the lower part of the mounting plate, the optical fiber displacement sensor and the array eddy current probe are both arranged in the housing and coaxially installed, the ultrasonic signal transmitting end, the ultrasonic signal receiving end and the optical fiber eddy current The central axis of the detection unit can intersect with the surface of the workpiece to be measured; the rotation drive module includes a connecting mechanism, a rotation drive component, a gear, a guiding mechanism, an arcuate guide rail and an arcuate gear ring, one end of the connecting mechanism is connected to the Z-axis linear motion module, and the other end is equipped with the rotation drive component, the rotation drive component is used to drive the gear to rotate, the guiding mechanism is arranged on the front side of the connecting mechanism, the guiding mechanism is used to guide the movement of the arcuate guide rail, the arcuate gear ring is arranged on the front side of the arcuate guide rail and meshes with the gear, and the mounting base is arranged on the front side of the arcuate gear ring.

2. The optical fiber eddy current ultrasonic composite nondestructive testing instrument according to claim 1 is characterized in that: The connecting mechanism includes an I-shaped mounting frame and a third connecting plate, the two ends of the I-shaped mounting frame are respectively connected to the Z-axis linear motion module and the third connecting plate, the rotation driving component is arranged on the rear side of the third connecting plate, and the power output end of the rotation driving component extends to the front side through the third connecting plate and is fixedly sleeved with the gear, and the guide mechanism is arranged on the front side of the third connecting plate.

3. The optical fiber eddy current ultrasonic composite nondestructive testing instrument according to claim 2 is characterized in that: The guide mechanism includes an upper guide assembly and a lower guide assembly, the upper guide assembly includes a plurality of upper guide wheels arranged along an arc direction, the lower guide assembly includes a plurality of lower guide wheels arranged along an arc direction, the arc guide rail is located between the plurality of upper guide wheels and the plurality of lower guide wheels, an upper arc groove matching the upper guide wheel structure is provided on the upper portion of the arc guide rail, and a lower arc groove matching the lower guide wheel structure is provided on the lower portion of the arc guide rail.

4. The optical fiber eddy current ultrasonic composite nondestructive testing instrument according to claim 1 is characterized in that: The ultrasonic nondestructive testing mechanism also includes two mounting components, which include an adjusting pad and a mounting block. The two adjusting pads are symmetrically arranged on both sides of the front of the mounting substrate, and one mounting block is arranged on the front side of each adjusting pad. The ultrasonic signal transmitting end and the ultrasonic signal receiving end are respectively installed on the two mounting blocks.

5. The optical fiber eddy current ultrasonic composite nondestructive testing instrument according to claim 1 is characterized in that: The shell includes a threaded connection sleeve, an insulating sleeve and a set screw. The upper part of the threaded connection sleeve is installed on the mounting plate. The insulating sleeve is threadedly connected to the lower part of the threaded connection sleeve. The array eddy current probe is arranged in the insulating sleeve. The optical fiber displacement sensor includes an optical fiber body, a mounting ring and an optical fiber probe. The optical fiber body is connected to the optical fiber probe. The mounting ring is fixedly sleeved at one end of the optical fiber body close to the optical fiber probe. The optical fiber probe passes through the threaded connection sleeve and extends into the insulating sleeve. The mounting ring is sleeved at the upper part of the threaded connection sleeve. The set screw fixes the mounting ring to the threaded connection sleeve.

6. The optical fiber eddy current ultrasonic composite nondestructive testing instrument according to claim 5 is characterized in that: The array eddy current probe comprises a coil pressing plate, a preloaded compression spring, a plurality of iron cores and a plurality of hollow coils. A first central hole for the optical fiber probe to pass through is provided in the middle of the coil pressing plate, a central tube connected to the first central hole is provided in the lower center of the coil pressing plate, a plurality of first through holes for the iron core to pass through are provided on the coil pressing plate along the circumferential direction, a second central hole for the central tube to extend out is provided in the middle of the end surface of the insulating sleeve, a plurality of second through holes for positioning the iron core are provided on the end surface of the insulating sleeve along the circumferential direction, two ends of the preloaded compression spring are respectively abutted against the lower part of the threaded connection sleeve and the upper part of the coil pressing plate, each of the iron cores passes through one of the first through holes and extends downward, a limiting ring is fixedly sleeved on the lower end of each of the iron cores, a hollow coil is sleeved on each of the iron cores, each of the hollow coils is located between one of the limiting rings and the coil pressing plate, the bottom end of each of the iron cores extends into one of the second through holes and the limiting ring abuts against the upper part of the end surface of the insulating sleeve.

7. The optical fiber eddy current ultrasonic composite nondestructive testing instrument according to claim 1 is characterized in that: The Z-direction displacement platform is a manual Z-direction displacement platform, and the inclination angle adjustment platform is a manual inclination angle adjustment platform.

8. The optical fiber eddy current ultrasonic composite nondestructive testing instrument according to claim 1 is characterized in that: The frame comprises a base and a gantry frame arranged on the base, and the Z-direction linear motion module is arranged on a crossbeam of the gantry frame.

9. A detection method based on the optical fiber eddy current ultrasonic composite nondestructive testing instrument according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Clamp the workpiece to be tested on the XY two-dimensional motion module, use the industrial computer to adjust the Z-direction linear motion module so that the ultrasonic nondestructive testing mechanism and the surface of the workpiece to be tested are kept within the working distance, and at the same time adjust the Z-direction displacement platform so that the array eddy current probe is within the working range; Step 2: Using an industrial computer to control the movement of the rotation drive module, and adjusting it in conjunction with the inclination adjustment platform, so that the displacement feedback signal detected by the optical fiber displacement sensor is acquired by the data acquisition card through the charge amplifier, so that the distance between the array eddy current probe and the surface of the workpiece to be measured in the XZ plane and the YZ plane is minimized at the same time, eliminating the tilt effect of the optical fiber eddy current detection unit caused by installation; Step 3, for the test method of the surface damage defects of the workpiece being tested, an excitation signal is sent to the trigger coil of the array eddy current probe through a signal generator with controllable frequency and phase sequence, and then a differential amplifier is used to amplify the received signal of the pickup coil of the array eddy current probe, and the phase of the signal generator reference signal and the received signal is calculated through a phase-locked amplifier, read into a data acquisition card, and fed back to the supporting analysis and processing software of the industrial computer, and then through sample pre-scanning, the coil excitation-pickup sequence of the array eddy current probe is optimized to obtain the best detection sensitivity and resolution; Step 4: for the test method of the internal damage defect of the workpiece under test, a pulsed laser is used to transmit an ultrasonic detection signal to the ultrasonic signal transmitting end, and the ultrasonic signal receiving end installed in a symmetrical layout receives the signal and reads it into an industrial computer for frequency domain analysis; Step 5: In order to adapt to the complex geometric features of the workpiece being tested, the optical fiber displacement sensor coaxial with the array eddy current probe in the optical fiber eddy current detection unit is used to detect the lift-off distance in real time, and the output end position of the piezoelectric actuator is controlled by the industrial computer in a closed loop to ensure that the lift-off distance of the array eddy current probe is consistent during the eddy current detection process; Step six: Combined with the surface geometry reconstruction model of the workpiece under test, the XY two-dimensional motion module, the Z-axis linear motion module and the rotation drive module are controlled by an industrial computer to carry out detection path planning for the workpiece under test with complex geometric features, thereby realizing the detection of surface and internal damage defects, residual stress of the workpiece under test, and fiber waviness and fiber orientation of advanced composite materials, and realizing multi-parameter synchronous in-situ test characterization.

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