An eddy current non-destructive testing device and method

Abstract

The application discloses a kind of eddy current nondestructive testing device and method, including sensor clamping mechanism, blade clamping mechanism and vector control mechanism, the middle part of the vector control mechanism is equipped with blade clamping mechanism, the upper of the vector control mechanism is equipped with sensor clamping mechanism, the vector control mechanism of the vector control mechanism is used to adjust sensor clamping mechanism;When the adjusting sensor clamping mechanism accepts the adjustment of vector control mechanism, sensor measuring head can be made perpendicular to blade surface to be detected.The application fixes blade by blade clamping mechanism, then adjusts the angle between sensor clamping mechanism and blade by vector control mechanism, realizes that the axis of measuring head is always perpendicular to the profile of blade when detecting blade, so as to accurately and quickly reflect the crack position of blade, greatly improves the nondestructive testing precision and efficiency of blade crack, avoids the problem that handheld detection cannot be accurately positioned and handheld swing causes unstable data, leading to misjudgment and low efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of non-destructive testing of aero-engines, and particularly relates to an eddy current non-destructive testing device and method. BACKGROUND

[0002] Turbine blades are important components of turbine parts in aero-engines, and provide aircraft with flight power by doing work on gas. Turbine blades generally bear large working stress and high working temperature, and the stress and temperature change frequently and sharply. The harsh working environment makes the blades prone to crack defects, and under the combined action of vibration and stress, the blades are prone to fatigue fracture, which is the main cause of engine failure. At present, the detection method for surface crack defects of the blades is usually non-destructive testing. Since the blade cracks are surface micro-cracks, the magnetic field change caused by the eddy current is very small, so the non-destructive testing requires high sensitivity of the sensor probe. However, high sensitivity means that the anti-interference ability of the measurement system is reduced.

[0003] At present, since the turbine blade is a variable cross-section curved surface with a complex shape, there is no device on site to control the vector of the probe axis to be perpendicular to the surface of the blade, and the operator can only hold the sensor to measure, resulting in poor detection accuracy and low efficiency, and the method cannot meet the large number of blade final inspection requirements. In order to reduce the interference factors affecting the measurement results, the probe must be perpendicular to the surface to be detected to realize the detection of the surface and near-surface defects of the blade. SUMMARY

[0004] The purpose of the present application is to provide an eddy current non-destructive testing device and method to solve the technical problem that the probe is difficult to be perpendicular to the surface to be detected in the existing non-destructive testing process.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, an eddy current non-destructive testing device includes a sensor clamping mechanism, a blade clamping mechanism, and a vector control mechanism. The vector control mechanism has the blade clamping mechanism in the middle, and the sensor clamping mechanism is arranged above the vector control mechanism.

[0007] Further improvements of the present application are that the sensor clamping mechanism includes a bracket, a connecting rod, a mounting block, a fixed block, a guide pin, and a spring. The bracket is uniformly provided with a plurality of connecting rods below, and is provided with a mounting block above. A plurality of guide pins are arranged between the mounting block and the bracket. Each guide pin is provided with a spring outside. A fixed block is arranged between the mounting block and the bracket. The fixed block, the mounting block, and the bracket are provided with a through hole in the center, and the through hole is used to clamp the sensor probe.

[0008] Further improvements of the present application are that the fixed block and the sensor probe are connected by a screw.

[0009] Further improvement of the present application is that the support is of an I-shaped structure, and the connecting rod is perpendicular to the support.

[0010] Further improvement of the present application is that the end of the connecting rod away from the support is a ball, which is used for sliding fit with the vector control mechanism.

[0011] Further improvement of the present application is that the vector control mechanism comprises a bottom plate, four guide blocks are arranged above the bottom plate, and a guide rail is arranged above each guide block.

[0012] Further improvement of the present application is that the blade clamping mechanism comprises a pressing screw, a blade positioning block and a positioning plate, the positioning plate is U-shaped, one end of the positioning plate is provided with the positioning block, and the other end is provided with the pressing screw, and the positioning block and the pressing screw are used for fixing the blade.

[0013] Further improvement of the present application is that the pressing screw is threadedly connected with the positioning plate, a top block is further arranged between the pressing screw and the blade, and the top block is nested outside the pressing screw.

[0014] Further improvement of the present application is that the top block is provided with a supporting block below.

[0015] In the second aspect, an eddy current nondestructive testing method comprises the following steps:

[0016] The blade is fixed by the blade clamping mechanism;

[0017] The sensor probe is fixed by the sensor clamping mechanism;

[0018] The sensor clamping mechanism is adjusted by the vector control mechanism, so that the sensor probe is perpendicular to the surface to be detected of the blade for detection.

[0019] Compared with the prior art, the present application has at least the following beneficial effects:

[0020] 1、The blade is fixed by the blade clamping mechanism, and then the angle between the sensor clamping mechanism and the blade is adjusted by the vector control mechanism, so that the axis of the probe is always perpendicular to the profile of the blade during detection, so as to accurately and quickly reflect the crack position of the blade, greatly improve the nondestructive testing precision and efficiency of the blade crack, avoid the problems of inaccurate positioning and unstable data caused by hand-held detection, and reduce the detection period from 40 minutes per piece to 10 minutes per piece, improve the detection efficiency by 75%, and greatly shorten the working period.

[0021] 2、The application can be used for detecting different planes of the blade by replacing the guide block on the bottom plate, compared with the traditional detection mode, the manufacturing of the excess tool is saved, and the integrated design reduces 5 sets of tool for each blade compared with the conventional design structure, the tool manufacturing cost of 25-30 thousand yuan for each blade is saved, and the effect is more prominent under the conditions of batch production type and large task quantity;

[0022] 3、The application realizes the function of auxiliary support by arranging the supporting block below the top block, solves the problem that the blade moves in the use process due to the short positioning of the blade and the stress on the blade tip, and stabilizes the positioning of the blade. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings constituting a part of the specification of the application are used to provide further understanding of the application, the illustrative embodiments of the application and the description thereof are used to explain the application, and do not constitute improper limitation on the application.

[0024] In the drawings:

[0025] Figure 1 It is a schematic view of the measured section of the blade to be measured in the eddy current nondestructive testing device of the application;

[0026] Figure 2 It is a structural schematic view of the eddy current nondestructive testing device of the application;

[0027] Figure 3 It is a structural view of the blade clamping mechanism of the eddy current nondestructive testing device of the application;

[0028] Figure 4 It is a structural view of the sensor clamping mechanism of the eddy current nondestructive testing device of the application;

[0029] Figure 5 It is a vector control mechanism view of the eddy current nondestructive testing device of the application;

[0030] Figure 6 It is a stylus guide track calculation schematic view of the eddy current nondestructive testing device of the application;

[0031] In the drawing: 1, support; 2, connecting rod; 3, mounting block; 4, fixed block; 5, sensor stylus; 6, screw; 7, guide pin; 8, spring; 9, blade; 91, inner edge plate of the blade; 92, edge plate of the blade; 10, compression screw; 11, blade positioning block; 12, top block; 13, supporting block; 14, positioning plate; 15, bottom plate; 16, guide block. DETAILED DESCRIPTION

[0032] The application will be described in detail below with reference to the drawings and in combination with the embodiments. It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0033] The following detailed description is merely exemplary in nature and is intended to provide further detail on the application. All the technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this application belongs. The terminology used herein is for describing particular embodiments only and is not intended to be limiting according to the example embodiments of the present application.

[0034] Embodiment 1

[0035] An eddy current non-destructive testing device, as shown in Figure 2 , comprises a sensor clamping mechanism, a blade clamping mechanism and a vector control mechanism, the blade clamping mechanism is arranged in the middle of the vector control mechanism, the sensor clamping mechanism is arranged above the vector control mechanism, the sensor probe 5 clamped in the sensor clamping mechanism is perpendicular to the axis of the blade 9 clamped in the blade clamping mechanism.

[0036] As shown in Figure 4 and Figure 6 , the sensor clamping mechanism comprises a bracket 1, a connecting rod 2, a mounting block 3, a fixed block 4, a sensor probe 5, a screw 6, a guide pin 7 and a spring 8. The bracket 1 is an I-shaped structure comprising two side beams and a cross beam. The two side beams are parallel to each other, and the cross beam is perpendicular to the side beams. One connecting rod 2 is arranged at each of the four corners of the bracket 1, i.e. one connecting rod 2 is arranged below each end of the two side beams. The connecting rod 2 is fixedly connected with the bracket 1 and perpendicular to the bracket 1. The end of the connecting rod 2 away from the bracket 1 is a ball. The mounting block 3 is arranged on the cross beam and has a U-shaped structure. The mounting block 3 is fixedly connected with the cross beam at both ends of the opening. A through hole is formed in the center of the top of the mounting block 3 and the center of the bracket 1 for arranging the sensor probe 5. The fixed block 4 is arranged between the cross beam of the mounting block 3 and the bracket 1 and surrounds the outside of the sensor probe 5. A plurality of guide pins 7 are arranged above the fixed block 4, and a spring 8 is arranged outside each guide pin 7. The sensor 5 is fixed in the fixed block 4 by the screw 6, so that the fixed block 4 can move up and down along the two guide pins 7. When the sensor probe 5 contacts the blade to be detected, the screw 6 is adjusted to adjust the up and down position of the sensor probe 5, so that the sensor probe 5 and the fixed block 4 are lifted by the blade, the spring 8 is compressed under stress, and the probe 5 can always contact the blade profile, and the contact force can be adjusted by the fixed position of the sensor probe 5.

[0037] The sensor probe 5 is an eddy current detection coil, also known as a probe. When an alternating current is applied, it can generate a sudden magnetic field and excite eddy current in the conductive body close to it. The induced magnetic field generated by the eddy current is converted into an alternating electric signal by the electromagnetic coil, and the detection signal is transmitted to the detection instrument.

[0038] As shown in Figure 5As shown, the vector control mechanism includes a base plate 15 and four guide blocks 16. The base plate 15 is a horizontal plate, and four guide blocks 16 are evenly arranged above the base plate 15. Each guide block 16 has a guide groove on its top, which is used to cooperate with the ball at the bottom of the connecting rod 2 to adjust the positional relationship between the sensor probe 5 and the blade 9.

[0039] like Figure 3 As shown, the blade clamping mechanism includes a clamping screw 10, a blade positioning block 11, a top block 12, a support block 13, a positioning plate 14, and a blade 9 to be clamped. The blade positioning block 11 is U-shaped and is located above the base plate 15. Two guide blocks 16 with the same inclination angle are provided on both sides of the blade positioning block 11. The opening of the blade positioning block 11 faces upward. A first threaded hole is provided on one side arm of the blade positioning block 11. The clamping screw 10 passes through the first threaded hole and is threadedly connected to the blade positioning block 11. One end of the clamping screw 10 inside the blade positioning block 11 is connected to the top block 12. The top block 12 is nested outside the clamping screw 10. The top block 12 is in contact with the blade edge plate 92 of the blade 9. A support block 13 is provided below the top block 12 adjacent to the blade edge plate 92. The bottom of the support block 13 is located on the blade positioning block 11. The blade 9 has an inner edge plate 91 and a blade edge plate 92 at its two ends. The blade 9 is positioned between the two side arms of the blade positioning block 11. The blade edge plate 92 contacts the top block 12. The inner edge plate 91 is fixedly connected to the positioning plate 14, which is located on the side wall of the blade positioning block 11 away from the clamping screw 10. The positioning plate 14 restricts the blade's degrees of freedom by fitting against the positioning surface of the inner edge plate 91, thus achieving positioning. The side wall of the positioning plate 14 has several second threaded holes. When the positioning plate 14 is fitted against the inner edge plate 91, screws are screwed into all the second threaded holes to laterally fix the blade 9. The positioning plate 14 restricts the blade 9's back-and-forth movement by fitting against the side of the inner edge plate, thus achieving positioning by restricting all degrees of freedom. The support block 13 provides auxiliary support. Because the blade 9 is positioned too short, it may move during use due to force on the blade tip. The support block 13 solves the problem of movement caused by the cantilever structure at one end under stress, stabilizing the positioning of the blade 9. The clamping screw 10 applies a preload to the blade 9 to ensure sufficient contact in positioning the blade 9, achieving pre-positioning and deformation during installation. After all positioning and auxiliary support are completed, the blade 9 is clamped in place by the clamping screw 10.

[0040] Vector control mechanism such as Figure 4As shown: by four guide block 16 a bottom plate 15. According to the vector and position of the blade measurement section, the spherical center coordinates of the four connecting rod spherical ball are calculated, the motion trajectory of each spherical center is fitted, the motion envelope graph of the spherical ball is generated, and the motion profile of the semicircular guide groove on the guide block 16 is calculated. Each different blade section can use different vector control mechanisms, while the blade clamping mechanism and sensor clamping mechanism can be shared, through the unified size interface, the blade clamping mechanism is quickly replaced when detecting different sections of the blade, the blade clamping mechanism and sensor clamping mechanism are saved, and the tooling cost is saved.

[0041] Guide block 16 motion trajectory calculation method: as Figure 5 shown, the coordinate system {O}-(X0, Y0, Z0) is established with the spherical center position of the bottom ball of the connecting rod 2, and the measurement point on the blade 9 is P. The geometric elements in the coordinate system {O} are (X P , Y P , Z P , i p , j p , k p ). Where (X P , Y P , Z P ,) is the coordinate value, (i p , j p , k p ) is the projection value of the unit vector on the x, y, z coordinate axis. The position of the spherical center S1 fixed on the connecting rod 2 relative to the P point is (60, 40, 11), and the coordinate value of the spherical center S1 in the process ball coordinate system {O} is the motion trajectory point. Convert it into a mathematical model, that is, to find the point in the coordinate system {P}. The new coordinates o of S1 in the process ball coordinate system {O} are as follows: Where the rotation matrix represents the position of the coordinate system {P} relative to {O}. As shown in Figure 6 , the P coordinate system rotates around the Z P axis by α, α = tan -1 (k p / i p ), and then rotates around the Y P axis by β on the new rotation result, β = sin -1 (j p ). Substitute the rotation matrix where cα = cosα, sα = sinα. Substitute the unit vector (0.083944, -0.732645, -0.675414) into the matrix calculation formula to get The movement track of S1 is obtained when the sensor probe 5 moves in the detection section, the envelope of the sphere is obtained, and the semicircular groove guide of the guide block 16 is obtained by difference calculation. The positions of S2, S3 and S4 in the coordinate system {O} are calculated in the same way. The sensor clamping mechanism is placed on the semicircular groove guide to move, so that the sensor probe 5 is always in contact with the measurement section when nondestructive testing is performed, and the vector of the probe axis is perpendicular to the blade surface, thereby realizing the function of the device.

[0042] Embodiment 2

[0043] An eddy current nondestructive testing method based on the eddy current nondestructive testing device in Embodiment 1, comprising the following steps:

[0044] The blade inner edge plate 91 of the blade 9 is attached to the positioning plate 14, the blade edge plate 92 is placed above the support block 13, and the blade is fixed by tightening the compression screw 10. The sensor probe 5 detects the blade 9 by adjusting the position of the ball under the connecting rod 2 in the guide block 16.

[0045] It is known from common technical knowledge that the present application can be realized by other embodiments without departing from the spirit or essential characteristics thereof. Therefore, the above disclosed embodiments are merely illustrative in all aspects and are not the only ones. All changes within the scope of the present application or within the scope equivalent to the present application are included in the present application.

[0046] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or replaced equivalently without departing from the spirit and scope of the present application, any modification or equivalent replacement which does not depart from the spirit and scope of the present application should be included in the protection scope of the claims of the present application.

Claims

1. An eddy current nondestructive testing device, characterized in that, It includes a sensor clamping mechanism, a blade clamping mechanism, and a vector control mechanism. The vector control mechanism has a blade clamping mechanism in the middle and a sensor clamping mechanism above it. The vector control mechanism is used to adjust the vector control mechanism of the sensor clamping mechanism. When the adjustment sensor clamping mechanism is adjusted by the vector control mechanism, it can make the sensor probe perpendicular to the surface of the blade to be detected. The sensor clamping mechanism includes a bracket (1), connecting rods (2), mounting block (3), fixing block (4), guide pins (7), and springs (8). Several connecting rods (2) are evenly arranged below the bracket (1). The end of the connecting rod (2) away from the bracket (1) is a ball. The ball is used to slide with the vector control mechanism. The mounting block (3) is arranged above the bracket (1). Several guide pins (7) are arranged between the mounting block (3) and the bracket (1). A spring (8) is arranged on the outside of each guide pin (7). A fixing block (4) is arranged between the mounting block (3) and the bracket (1). A through hole is opened in the center of the fixing block (4), the mounting block (3), and the bracket (1). The through hole is used to clamp the sensor probe (5). The vector control mechanism includes a base plate (15), and four guide blocks (16) are provided above the base plate (15). Each guide block (16) has a guide groove on its top. The guide groove is used to cooperate with the bottom ball of the connecting rod (2) to adjust the positional relationship between the sensor probe (5) and the blade (9). The method for calculating the trajectory of the guide groove on the top of each guide block (16) is as follows: establish a coordinate system {O}-(X0, Y0, Z0) with the center position of the bottom ball of the connecting rod (2), the measurement point on the blade (9) is P, and the geometric elements under the coordinate system {O} are (X0, Y0, Z0). P Y P Z P i p j p k p ), where (X) P Y P Z P ) represents the coordinate value, (i p j p k p The projection of the unit vector onto the x, y, z coordinate axes is given by point S1, which is fixed to the connecting rod (2) and its position relative to point P is given by point S1. The coordinates of the sphere center S1 in the process spherical coordinate system {O} are the points on the motion trajectory. Converting this to a mathematical model means finding the point in the coordinate system {P}. New coordinates in the process spherical coordinate system {O} The mathematical expression is: , where the rotation matrix This indicates the position of coordinate system {P} relative to {O}, with coordinate system P revolving around Z. P Axis rotation , Then, on the new rotation result, around Y... P Axis rotation β, Substitute into the rotation matrix ,in , , , will the unit vector (i p j p k p Substituting into the matrix calculation formula, we get The motion trajectory of the center S1 of the ball is obtained when the sensor probe (5) moves across the detection section. The envelope of the ball is obtained. The semi-circular guide groove of the guide block (16) is obtained by subtraction calculation. The positions of S2, S3, and S4 in the coordinate system {O} are calculated in the same way. The blade clamping mechanism includes a clamping screw (10), a blade positioning block (11), and a positioning plate (14). The positioning plate (14) is U-shaped. One end of the positioning plate (14) is provided with a blade positioning block (11), and the other end is provided with a clamping screw (10). The blade positioning block (11) and the clamping screw (10) are used to fix the blade (9).

2. The eddy current nondestructive testing device according to claim 1, characterized in that, The fixing block (4) and the sensor probe (5) are connected by screws (6).

3. The eddy current nondestructive testing device according to claim 1, characterized in that, The bracket (1) has an I-shaped structure, and the connecting rod (2) is perpendicular to the bracket (1).

4. The eddy current nondestructive testing device according to claim 1, characterized in that, The clamping screw (10) is threadedly connected to the positioning plate (14), and a top block (12) is provided between the clamping screw (10) and the blade (9), the top block (12) being nested outside the clamping screw (10).

5. The eddy current nondestructive testing device according to claim 4, characterized in that, A support block (13) is provided below the top block (12).

6. An eddy current nondestructive testing method, characterized in that, An eddy current nondestructive testing device according to any one of claims 1 to 5 includes the following steps: The blade is fixed by a blade clamping mechanism (9); The sensor probe is fixed by the sensor clamping mechanism (5); The sensor clamping mechanism is adjusted by the vector control mechanism to make the sensor probe (5) perpendicular to the surface to be detected on the blade (9) for detection.

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