Multi-direction residual stress testing method suitable for complex curved surface and normal adjusting device

Abstract

The invention belongs to the technical field of complex curved surface detection, and particularly relates to a multi-direction residual stress testing method suitable for a complex curved surface and a normal adjusting device.The multi-direction residual stress testing method suitable for the complex curved surface comprises the following steps that firstly, a three-dimensional model and an absolute coordinate system of a test piece are established, and absolute coordinates of a tested point are determined; step 2, determining the normal of the detected point, and enabling the direction of the normal of the detected point to be collinear with the direction of a probe of the X-ray stress detector; and 3, detecting the residual stress of the detected point, wherein the device also comprises a curved surface test point normal deflection angle adjusting device. According to the invention, the normal direction of the detected point is collinear with the probe direction of the X-ray stress detector, so that the accuracy of residual stress detection data is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of complex curved surface detection, and in particular relates to a multi-directional residual stress testing method and a normal adjustment device suitable for complex curved surfaces. Background Art

[0002] In the vast field of mechanical engineering, there are a large number of complex curved surface structural parts such as compressor blades. The working environment they are in is often extremely harsh, facing extreme conditions such as high speed, high load, and high stress. The structure of these structural parts is extremely complex, and the load-bearing conditions are extremely difficult. In addition to bearing huge pressures such as centrifugal loads and bending and torsion loads, they may also be subjected to many severe challenges such as violent impacts from external objects, continuous vibrations, erosion by various corrosive substances, strong impacts of strong airflows, and long-term fatigue at any time. From a wide range of actual situations and detailed data statistics, the failure of such complex curved surface structural parts accounts for a considerable proportion of the entire huge mechanical system failure. Among them, common problems are varied, covering a series of defects such as cracks in the root, cracks in the tenon teeth, fractures in the blade body, and wear on the blade crown. These thorny problems have undoubtedly become the most prominent and critical problems that seriously affect the quality of related technologies, posing a great threat and challenge to the safety of the entire mechanical system.

[0003] In the non-destructive testing of residual stress, common methods include X-ray diffraction, neutron diffraction, and hard X-ray diffraction of high-energy synchrotron radiation, but these methods have disadvantages such as high cost, small detection thickness, and difficulty in commercial use. Short-wavelength characteristic X-ray diffraction technology has the characteristics of low cost, high detection accuracy, and large detection thickness. However, in the actual measurement process, the detector probe cannot be perpendicular to the detection point of the detected surface, resulting in low accuracy of residual stress detection data. Therefore, a multi-directional residual stress test method and a normal adjustment device suitable for complex surfaces are urgently needed to solve the problem. Summary of the invention

[0004] The purpose of the present invention is to provide a multi-directional residual stress testing method and a normal adjustment device suitable for complex curved surfaces to solve the above problems.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The multi-directional residual stress test method applicable to complex curved surfaces includes the following steps:

[0007] The first step is to establish the three-dimensional model and absolute coordinate system of the specimen and determine the absolute coordinates of the measured points;

[0008] The second step is to determine the normal line of the measured point so that the direction of the normal line of the measured point is collinear with the probe direction of the X-ray stress detector;

[0009] The third step is to detect the residual stress of the measured point.

[0010] Preferably, the test piece is mounted on a surface test point normal angle adjustment device, and the X-axis angle, Y-axis angle and Z-axis angle of the surface test point normal angle adjustment device are reset to zero, and the test piece and the surface test point normal angle adjustment device are modeled using a three-dimensional coordinate measuring machine to form the three-dimensional model and the absolute coordinate system.

[0011] Preferably, the absolute coordinate position of the measured point is found in the three-dimensional model, the normal of the measured point is generated, the deviation angles between the normal and the X-axis, Y-axis and Z-axis of the absolute coordinate system are calculated, and the angle of the test piece is adjusted so that the normal of the measured point is collinear with the probe direction of the X-ray stress detector.

[0012] Preferably, the X-axis deviation angle of the normal line and the absolute coordinate system is recorded as the X-direction deviation angle, the Y-axis deviation angle of the normal line and the absolute coordinate system is recorded as the Y-direction deviation angle, and the Z-axis deviation angle of the normal line and the absolute coordinate system is recorded as the Z-direction deviation angle. According to the X-direction deviation angle, the Y-direction deviation angle and the Z-direction deviation angle, the normal deviation adjustment device of the curved surface test point is adjusted so that the X-axis rotation angle of the test piece is the same as the X-direction deviation angle, the Y-axis rotation angle is the same as the Y-direction deviation angle, and the Z-axis rotation angle is the same as the Z-direction deviation angle, so that the normal line is collinear with the probe direction of the X-ray stress detector.

[0013] Preferably, after moving the probe of the X-ray stress detector to the measured point, the residual stress of the measured point is detected.

[0014] Preferably, in the process of determining the normal, four adjacent nodes on the same section as the measured point are found in the three-dimensional model, the absolute coordinates of the measured point and the four nodes are recorded, the plane where the measured point is located is fitted, and the normal of the plane is taken as the normal direction of the measured point.

[0015] Preferably, the three-dimensional model and the absolute coordinates are generated by ABAQUS software, the three-dimensional model is meshed using the C3D8R mesh type, and the relative coordinate positions of the measured points are found in ABAQUS.

[0016] Preferably, Matlab is used to fit the plane where the measured point is located, and Matlab is used to calculate the X-direction deflection angle, the Y-direction deflection angle and the Z-direction deflection angle.

[0017] A device for adjusting the normal angle of a curved surface test point, using the above-mentioned multi-directional residual stress test method applicable to complex curved surfaces, comprises:

[0018] A Z-axis rotation adjustment device, used to adjust the Z-axis rotation angle of the test piece;

[0019] An X-axis rotation adjustment device, installed at the movable end of the Z-axis rotation adjustment device, used to adjust the inclination angle of the specimen in the X-axis direction;

[0020] The Y-axis rotation adjustment device is installed on the movable end of the X-axis rotation adjustment device through a 90° inclined block, and is used to adjust the Y-axis direction angle of the test piece.

[0021] Preferably, a 30° bevel block for increasing the adjustment range of the inclination angle in the X-axis direction is provided between the X-axis rotation adjustment device and the 90° bevel block.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] The present invention realizes precise positioning of the measured point and determination of the normal direction through three-dimensional modeling and establishment of the same absolute coordinate system between the model and the real object, combined with the point coordination between simulation and the real object. Compared with the traditional method of detecting residual stress on curved surfaces by X-ray, the present invention improves the accuracy of residual stress detection data by making the normal direction of the measured point collinear with the probe direction of the X-ray stress detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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 are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0025] Figure 1 This is a schematic structural diagram of a device for adjusting the normal angle of a curved surface test point according to the present invention;

[0026] Figure 2 It is a structural schematic diagram of another device for adjusting the normal deflection angle of a test point on an angled surface according to the present invention;

[0027] Figure 3 This is an exploded view of the structure of the device for adjusting the normal angle of the curved surface test point of the present invention;

[0028] Figure 4 This is a schematic diagram of the 90° inclined block structure of the present invention;

[0029] Figure 5 This is a schematic diagram of the 30° inclined block structure of the present invention;

[0030] Figure 6 Establishing a grid schematic diagram for the measured surface of the present invention;

[0031] Figure 7 is the position of the measured point in the grid of the present invention;

[0032] Figure 8 It is a coordinate data diagram of four nodes near the measured point of the present invention;

[0033] Fig. 9 The normal direction of the plane after fitting in the present invention;

[0034] Fig.10 It is a schematic diagram of the structure of the Y-axis rotation adjustment device of the present invention;

[0035] Fig.11 This is an internal structure diagram of the Y-axis rotation adjustment device of the present invention;

[0036] Fig.12 This is a schematic diagram of the structure of the X-axis rotation adjustment device of the present invention;

[0037] Fig.13 This is a schematic diagram of the interior of the X-axis rotation adjustment device of the present invention;

[0038] Fig.14 This is a schematic diagram of the structure of the Z-axis rotation adjustment device of the present invention;

[0039] Among them, 1. Y-axis rotation adjustment device; 2. 90° bevel block; 3. 30° bevel block; 4. X-axis rotation adjustment device; 5. Z-axis rotation adjustment device; 101. first base; 102. locking device; 103. first micrometer adjustment assembly; 104. first support assembly; 401. second base; 402. rotating part; 403. second micrometer adjustment assembly; 501. third base; 502. third locking device; 503. third micrometer adjustment assembly; 504. third support assembly. DETAILED DESCRIPTION

[0040] 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.

[0041] 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.

[0042] Reference Figures 1 to 4 The present invention discloses a method for testing multi-directional residual stress on complex curved surfaces, comprising the following steps:

[0043] The multi-directional residual stress test method applicable to complex curved surfaces includes the following steps:

[0044] The first step is to establish the three-dimensional model and absolute coordinate system of the specimen and determine the absolute coordinates of the measured points;

[0045] The second step is to determine the normal line of the measured point so that the direction of the normal line of the measured point is collinear with the probe direction of the X-ray stress detector;

[0046] The third step is to detect the residual stress at the measured point.

[0047] The present invention realizes precise positioning of the measured point and determination of the normal direction through three-dimensional modeling and establishment of the same absolute coordinate system between the model and the real object, combined with the point coordination between simulation and the real object. Compared with the traditional method of detecting residual stress on curved surfaces by X-ray, the present invention improves the accuracy of residual stress detection data by making the normal direction of the measured point collinear with the probe direction of the X-ray stress detector.

[0048] To further optimize the plan, the test piece was installed on the normal angle adjustment device for the surface test point, and the X-axis angle, Y-axis angle and Z-axis angle of the normal angle adjustment device for the surface test point were reset to zero. The test piece and the normal angle adjustment device for the surface test point were modeled using a three-dimensional model and an absolute coordinate system.

[0049] After the test piece is installed on the surface test point normal deflection adjustment device, the deflection angles of the surface test point normal deflection adjustment device in the three directions of X, Y, and Z are adjusted to zero, and then the surface test point normal deflection adjustment device and the test piece are placed under a three-dimensional coordinate measuring machine. The three-dimensional coordinate measuring machine (CMM) is a device used to accurately measure the geometric shape of an object. It is mainly composed of a measuring head, X, Y, and Z axis guides, a drive motor, and a base. The measuring head is the core component of the three-dimensional coordinate measuring machine, which is responsible for contact or non-contact measurement of the surface of the workpiece. It can be equipped with different types of probes (such as stylus, laser, etc.) to meet different measurement needs. The function of the X, Y, and Z axis guides is to allow the measuring head to move in three dimensions to ensure that each measuring point of the workpiece can be accurately located. The drive motor controls the movement of the measuring head on each axis to ensure that it can reach the specified position quickly and accurately. The base provides stable support to ensure the rigidity and stability of the entire measurement system and reduce measurement errors.

[0050] To further optimize the scheme, the absolute coordinate position of the measured point is found in the three-dimensional model, the normal of the measured point is generated, the deviation angle between the normal and the X-axis, Y-axis and Z-axis of the absolute coordinate system is calculated, and the angle of the test piece is adjusted so that the normal of the measured point is collinear with the probe direction of the X-ray stress detector.

[0051] To further optimize the scheme, the X-axis deviation angle of the normal line and the absolute coordinate system is recorded as the X-direction deviation angle, the Y-axis deviation angle of the normal line and the absolute coordinate system is recorded as the Y-direction deviation angle, and the Z-axis deviation angle of the normal line and the absolute coordinate system is recorded as the Z-direction deviation angle. According to the X-direction deviation angle, the Y-direction deviation angle and the Z-direction deviation angle, the normal deviation adjustment device of the curved surface test point is adjusted to make the X-axis rotation angle of the test piece the same as the X-direction deviation angle, the Y-axis rotation angle and the Y-direction deviation angle, and the Z-axis rotation angle and the Z-direction deviation angle, so that the normal line is collinear with the probe direction of the X-ray stress detector.

[0052] The solution is further optimized by moving the probe of the X-ray stress detector to the measured point to detect the residual stress at the measured point.

[0053] To further optimize the solution and determine the normal line, find four adjacent nodes on the same section as the measured point in the three-dimensional model, record the absolute coordinates of the measured point and the four nodes, fit the plane where the measured point is located, and take the normal of the plane as the normal direction of the measured point.

[0054] To further optimize the scheme, the three-dimensional model and absolute coordinates were generated by ABAQUS software, the three-dimensional model was meshed using the C3D8R mesh type, and the relative coordinate positions of the measured points were found in ABAQUS.

[0055] To further optimize the scheme, Matlab was used to fit the plane where the measured points were located, and Matlab was used to calculate the deflection angles in the X, Y and Z directions.

[0056] Taking the impeller as an example, this method is used to measure the residual stress at the measured point on the impeller.

[0057] The test process and case test results are as follows:

[0058] 1. Install the impeller to be measured on the normal angle adjustment device of the curved surface test point. Place it under the three-coordinate measuring instrument. After determining the measured point, establish an absolute coordinate system for the blade where the measured point is located.

[0059] 2. Based on the three-dimensional coordinate measuring instrument, the normal angle adjustment device of the blade and surface test points is 3D modeled and the absolute coordinate system is established in ABAQUS. The C3D8R grid type is used to divide the grid, and the relative coordinate position of the measured point is found in ABAQUS to achieve the goal of coordination between simulation and physical point positions, which is convenient for subsequent measurements.

[0060] 3. Find four adjacent nodes on the same section as the measured point, record the absolute coordinates of the target point and these four points, and then fit the plane where the measured point is located through the absolute coordinates of the four nodes in Matlab, and then calculate the normal direction of the plane. It can be approximately considered that the normal direction of the plane is the normal direction of the measured point.

[0061] 4. Calculate the deviation angle between the normal direction and the three absolute coordinate axes in Matlab, and adjust the deflection angles of the normal deflection adjustment device of the surface test point in the X, Y, and Z directions according to the deviation angle, so that the normal direction of the measured point on the blade is collinear with the probe direction of the X-ray stress detector, so as to achieve the function of detecting residual stress along the normal direction of the surface, thereby improving the accuracy.

[0062] 5. Use an X-ray stress detector to measure the residual stress at the measured point.

[0063] 6. Based on the above detection process, five target points on the aluminum alloy impeller are selected, and the detection results are shown in the following table:

[0064] Table 1 Residual stress measurement values ​​in X and Y directions

[0065]

[0066] Based on the above table, the measured residual stress values ​​are:

[0067] X direction (processing direction): 190MPa; 185MPa; 178MPa; 192MPa; 188MPa;

[0068] Y direction (vertical processing direction): 135MPa; 142MPa; 130MPa; 128MPa; 139MPa;

[0069] Since the processing parameters of the five test points are the same and the residual stress detection is performed immediately after processing, the residual stress values ​​between the five points should not differ much. From the results, this rule is also confirmed, thus indirectly ensuring the reliability of this method.

[0070] It can be seen that this method has the following advantages compared with the traditional method:

[0071] 1) Combining simulation and physical point coordination: Using a three-coordinate measuring instrument and professional software to coordinate the physical and simulated points, the precise positioning of the measured points and the determination of the normal direction are achieved. This combination of multiple technical means improves the accuracy and reliability of detection.

[0072] 2) Intelligent angle deviation display: The angle of deviation between the normal direction and the absolute coordinate can be displayed in Matlab, allowing users to intuitively understand and make precise adjustments, improving the convenience and visualization of operation.

[0073] A device for adjusting the normal angle of a curved surface test point, using the above-mentioned multi-directional residual stress test method applicable to complex curved surfaces, comprises:

[0074] The Z-axis rotation adjustment device 5 is used to adjust the rotation angle of the specimen in the Z-axis direction;

[0075] An X-axis rotation adjustment device 4 is installed at the movable end of the Z-axis rotation adjustment device 5 and is used to adjust the inclination angle of the specimen in the X-axis direction;

[0076] The Y-axis rotation adjustment device 1 is installed on the movable end of the X-axis rotation adjustment device 4 through a 90° inclined block 2, and is used to adjust the rotation angle of the specimen in the Y-axis direction.

[0077] As a further optimization solution, a 30° bevel block 3 for increasing the adjustment range of the inclination angle in the X-axis direction is provided between the X-axis rotation adjustment device 4 and the 90° bevel block 2.

[0078] A surface test point normal angle adjustment device includes three rotation adjustment devices, an impeller connecting plate and two inclined blocks. With the help of bolt connection and coordinated spiral slide grooves, the impeller can rotate freely in the X, Y and Z directions, thereby ensuring that the probe of the X-ray stress detector can always be along the normal direction of the surface, so as to more accurately detect the residual stress of the surface.

[0079] The workpiece to be measured is connected to the supporting component below by an M5 hexagon socket bolt to ensure that it is firmly fixed. The Y-axis rotation adjustment device 1 can make the blade rotate in the Y-axis direction as the rotation axis through the upper adjustment knob, and is connected to the lower bevel block through an M2.5 hexagon socket bolt; the bevel block can be selected as a 90° bevel block 2 and a 30° bevel block 3, which can increase the angle adjustment range. Usually, the Y-axis rotation adjustment device 1 is connected to the X-axis rotation adjustment device 4 through the 90° bevel block 2. When the angle adjustment range needs to be increased, the angle adjustment range can be increased by using the 90° bevel block 2 and the 30° bevel block 3 together. The X-axis rotation adjustment device 4 and the Z-axis rotation adjustment device 5 rotate the blade through the upper adjustment knob, wherein the X-axis rotation adjustment device 4 is connected to the bottom of the 90° bevel block 2 through an M4 hexagon socket bolt, and the X-axis rotation adjustment device 4 and the Z-axis rotation adjustment device 5 are connected through an M14 hexagon socket bolt, allowing the platform to rotate. Ultimately, the function of determining the normal direction of any point on the blade in space is realized. These connection methods ensure the overall stability and functionality of the device, enabling it to rotate and adjust smoothly.

[0080] The Y-axis rotation adjustment device 1, the X-axis rotation adjustment device 4 and the Z-axis rotation adjustment device 5 are all provided with a micrometer scale for displaying and adjusting the rotation angle, which can accurately control the rotation angle of the workpiece. The user can align the rotation axis with the micrometer by adjusting the knob on the platform, thereby ensuring that each rotation reaches a precise angle. In addition, the user only needs to rotate the knob on the axis to accurately control the rotation angle of the workpiece, which can be easily achieved whether clockwise or counterclockwise, and the operation is simple and convenient.

[0081] As the core intermediate force transmission parts, the design and material selection of 90° and 30° bevel blocks are aimed at ensuring the highest stability and load-bearing capacity. The 90° and 30° bevel blocks are made of high-strength alloy steel, and the optimal balance of mechanical strength and corrosion resistance is achieved through precision processing, thus ensuring that the shape remains accurate and long-term durability when bearing complex curved components.

[0082] The adjustable tilt angle of the bevel block allows the device to adapt to complex workpieces of different curvatures and shapes. By simply adjusting the angle of the bevel block, users can quickly respond to various inspection needs, whether it is for high-precision parts in the aerospace field or complex components in the automotive industry, accurate positioning and efficient inspection can be achieved. The interchangeable design further reduces manufacturing costs and simplifies the maintenance process. Users do not need to configure special equipment for different workpieces, which significantly improves resource utilization and economic benefits.

[0083] The Y-axis rotation adjustment device 1 includes a first base 101 , a first locking screw 102 , a first micrometer 103 , a first turntable 104 , a first elastic rod 105 , a translation thread block 106 and an extrusion block 107 .

[0084] The first rotating disk 104 is rotatably arranged in the first base 101, and the translation thread block 106 and the extrusion block 107 are movably arranged in the first base 101. An active groove for horizontal movement of the translation thread block 106 and the extrusion block 107 is opened in the first base 101, and the cross-section of the active groove is runway-shaped. The translation thread block 106 is internally threadedly connected with the first locking screw 102, and one end of the first locking screw 102 is located outside the first base 101, and the other end of the first locking screw 102 is rotatably connected with the extrusion block 107, and the end of the extrusion block 107 away from the first locking screw 102 contacts the side wall of the first rotating disk 104, which is used to rub the first rotating disk 104 to rotate. The first locking screw 102 can drive the extrusion block 107 to contact or separate with the side wall of the first rotating disk 104 under the action of the thread of the translation thread block 106. One side of the translation thread block 106 The movable end of the first elastic rod 105 is in contact with the first base 101, and the fixed end of the first elastic rod 105 is fixedly connected to the first base 101. The other side of the translation thread block 106 is in contact with the movable end of the first micrometer 103, and the fixed end of the first micrometer 103 is fixedly connected to the first base 101. By adjusting the extension of the movable end of the first micrometer 103, the translation thread block 106 can be pushed to move in the horizontal direction in the slide groove opened in the first base 101, and its moving direction is parallel to the tangential direction of the side wall of the first turntable 104, and then the extrusion block 107 is driven to move through the first locking screw 102. The end face of the extrusion block 107 is in contact with the side wall of the first turntable 104, and the end face of the extrusion block 107 is colinear with the tangential direction of the side wall of the first turntable 104. Therefore, the first turntable 104 can be rotated by rubbing the extrusion block 107 to achieve precise angle adjustment. In addition, when the extrusion block 107 is separated from the first rotating disk 104 under the threaded action of the first locking screw 102 and the translation thread block 106, the first rotating disk 104 can rotate freely and the rotation angle can be quickly and roughly adjusted.

[0085] The X-axis rotation adjustment device 4 includes a second base 401, a sliding block 402, a worm 403, a worm gear block 404, and a second locking screw 405. The worm 403 is rotatably arranged in the second base 401, the worm 403 is meshed with the worm gear block 404, the worm gear block 404 is movably arranged on the second base 401, the sliding block 402 is fixed to the worm gear block 404, the second locking screw 405 is threadedly connected to one side of the sliding block 402, and the second locking screw 405 is used to lock the sliding block 402 with the second base 401. The worm 403 is rotated to drive the worm gear block 404 to slide relative to the second base 401, so that the inclination angle of the sliding block 402 can be changed.

[0086] Among them, the Z-axis rotation adjustment device 5 includes a third base 501, a pushing rod 502, a third elastic rod 503, a third turntable 504, a third micrometer 505, a rotating seat 506 and a third locking screw 507. The rotating seat 506 is rotatably set on the third base 501, and the pushing rod 502 is fixedly connected to the side wall of the rotating seat 506. The pushing rod 502 is located between the movable end of the third elastic rod 503 and the movable end of the third micrometer 505. The two sides of the pushing rod 502 are respectively in contact with the movable end of the third elastic rod 503 and the movable end of the third micrometer 505. The fixed end of the third elastic rod 503 and the fixed end of the third micrometer 505 are fixedly connected to the third base 501. The third turntable 504 is rotatably connected to the rotating seat 506. The third turntable 504 is locked with the rotating seat 506 by the third locking screw 507, and the third locking screw 507 is threadedly connected to the third turntable 504. The third turntable 504 is rotated to an approximate angle by loosening the third locking screw 507, and then the third turntable 504 and the rotating seat 506 are locked. The push rod 502 is pushed by the third micrometer 505 to rotate the rotating seat 506 for fine adjustment. The rotating seat 506 can be fixed to the third base 501 by another locking screw.

[0087] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0088] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. It is applicable to the multi-directional residual stress test method of complex curved surfaces, characterized by: The steps include: The first step is to establish the three-dimensional model and absolute coordinate system of the specimen and determine the absolute coordinates of the measured points; The second step is to determine the normal line of the measured point so that the direction of the normal line of the measured point is collinear with the probe direction of the X-ray stress detector; The third step is to detect the residual stress of the measured point.

2. The multi-directional residual stress testing method for complex curved surfaces according to claim 1, characterized in that: The test piece is mounted on the device for adjusting the normal angle of the curved surface test point, and the X-axis angle, Y-axis angle and Z-axis angle of the device for adjusting the normal angle of the curved surface test point are reset to zero. The test piece and the device for adjusting the normal angle of the curved surface test point are modeled using a three-dimensional coordinate measuring machine to form the three-dimensional model and the absolute coordinate system.

3. The multi-directional residual stress testing method for complex curved surfaces according to claim 2 is characterized in that: The absolute coordinate position of the measured point is found in the three-dimensional model, a normal line of the measured point is generated, the deviation angles between the normal line and the X-axis, Y-axis and Z-axis of the absolute coordinate system are calculated, and the angle of the test piece is adjusted so that the normal line of the measured point is collinear with the probe direction of the X-ray stress detector.

4. The multi-directional residual stress testing method for complex curved surfaces according to claim 3 is characterized in that: The deflection angle between the normal line and the absolute coordinate system is recorded as the X-direction deflection angle, the deflection angle between the normal line and the absolute coordinate system is recorded as the Y-direction deflection angle, and the deflection angle between the normal line and the absolute coordinate system is recorded as the Z-direction deflection angle. According to the X-direction deflection angle, the Y-direction deflection angle and the Z-direction deflection angle, the normal deflection angle adjustment device of the curved surface test point is adjusted so that the X-axis rotation angle of the test piece is the same as the X-direction deflection angle, the Y-axis rotation angle is the same as the Y-direction deflection angle, and the Z-axis rotation angle is the same as the Z-direction deflection angle, so that the normal line is collinear with the probe direction of the X-ray stress detector.

5. The multi-directional residual stress testing method for complex curved surfaces according to claim 4 is characterized in that: After the probe of the X-ray stress detector is moved to the measured point, the residual stress of the measured point is detected.

6. The multi-directional residual stress testing method for complex curved surfaces according to claim 5, characterized in that: In the process of determining the normal line, four adjacent nodes on the same section as the measured point are found in the three-dimensional model, the absolute coordinates of the measured point and the four nodes are recorded, the plane where the measured point is located is fitted, and the normal of the plane is taken as the normal direction of the measured point.

7. The multi-directional residual stress testing method for complex curved surfaces according to claim 6, characterized in that: The three-dimensional model and the absolute coordinates are generated by ABAQUS software, the three-dimensional model is meshed using the C3D8R mesh type, and the relative coordinate positions of the measured points are found in ABAQUS.

8. The multi-directional residual stress testing method for complex curved surfaces according to claim 7, characterized in that: The plane where the measured point is located is fitted using Matlab, and the X-direction deflection angle, the Y-direction deflection angle and the Z-direction deflection angle are calculated using Matlab.

9. A device for adjusting the normal angle of a curved surface test point, using the multi-directional residual stress test method for complex curved surfaces as described in any one of claims 2 to 8, characterized in that: include: A Z-axis rotation adjustment device (5), used for adjusting the rotation angle of the test piece in the Z-axis direction; An X-axis rotation adjustment device (4), mounted on the movable end of the Z-axis rotation adjustment device (5), for adjusting the inclination angle of the specimen in the X-axis direction; The Y-axis rotation adjustment device (1) is installed on the movable end of the X-axis rotation adjustment device (4) via a 90° inclined block (2) and is used to adjust the rotation angle of the specimen in the Y-axis direction.

10. The device for adjusting the normal angle of a curved surface test point according to claim 9, characterized in that: A 30° inclined block (3) for increasing the adjustment range of the inclination angle in the X-axis direction is provided between the X-axis rotation adjustment device (4) and the 90° inclined block (2).

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