Detector data processing method and system for residual stress measurement by X-ray diffraction method

Abstract

The invention belongs to the technical field of X-ray method residual stress detection, and discloses a method and system for processing data collected by a detector in the X-ray method residual stress measurement process, and the method comprises the steps: building a coordinate mapping relation between a detector coordinate system and a world coordinate system; according to the coordinate mapping relation, converting the coordinate and intensity information of each pixel point collected by the detector from a detector coordinate system to a world coordinate system to obtain an intensity data point set under the world coordinate system; and calculating a diffraction angle corresponding to each data point according to a spatial vector relationship on the basis of the obtained intensity data point set under the world coordinate system in combination with the position and the incident direction of an X-ray light source, converting detector data into a diffraction curve form set, and performing centralized processing to generate continuous X-ray diffraction spectral lines. According to the invention, through coordinate system unified mapping, diffraction angle accurate derivation and data centralization processing, the accuracy of data conversion and the repeatability of stress measurement are significantly improved.

Description

Technical Field

[0001] This invention belongs to the technical field of X-ray residual stress detection, and more specifically, relates to a data processing method and system for detector acquisition during X-ray residual stress measurement. Background Technology X-ray diffraction, a widely used non-destructive testing technique for residual stress measurement, operates on the principle that residual stress within a material causes changes in interplanar spacing. When X-rays irradiate a crystalline material, Bragg diffraction occurs, and the change in interplanar spacing manifests as a shift in the diffraction angle. By measuring this shift and combining it with elasticity theory, the residual stress can be calculated. This method has been widely applied in aerospace, welding, heavy machinery, and other fields.

[0002] During the measurement process, X-ray detectors are used to receive diffraction signals. Commonly used photon counting detectors consist of a regularly arranged array of pixels, with each pixel recording the number or intensity of received X-ray photons, ultimately outputting pixel data expressed in matrix form. According to the measurement principle, the Debye ring data acquired by the detector must be converted into an XRD curve with diffraction angle as the abscissa and intensity as the ordinate before subsequent analysis can be performed. This conversion process is the core of detector data processing.

[0003] However, current technologies for detector data processing in X-ray stress measurement are relatively lacking. For example, although patent CN119278377A mentions a data processing device, it does not elaborate on the specific method; patent CN114972287A proposes a two-dimensional detector data processing method, but it is mainly aimed at component measurement and has limited applicability.

[0004] Therefore, there is an urgent need to propose a data processing method and system for detector acquisition during X-ray residual stress measurement, in order to overcome the limitations of existing detector data processing methods in terms of versatility and accuracy, and ultimately improve the accuracy of X-ray stress measurement. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a data processing method and system for detector acquisition during X-ray residual stress measurement. The purpose is to construct a complete data processing workflow to ensure that detector data can be accurately converted into diffraction curves that can be used for peak position analysis. This solves the limitations of existing detector data processing methods in terms of versatility and accuracy, and ultimately improves the accuracy of X-ray stress measurement.

[0006] To achieve the above objectives, according to one aspect of the present invention, a detector data processing system for X-ray diffraction residual stress measurement is provided, comprising: X-ray source, used to generate and emit X-rays; At least one detector is used to receive X-ray signals diffracted by the material under test and convert them into pixel data; the pixel data includes the position index of the pixel and its corresponding X-ray intensity characterization value; The computer is equipped with data processing software to convert the pixel data into diffraction curve data with the diffraction angle as the abscissa and the intensity characterization quantity as the ordinate, and to perform stress analysis. The data processing software includes: The detector data acquisition module is used to acquire pixel data collected by the detector; The detector data conversion module maps pixel data to a unified world coordinate system, calculates the diffraction angle for each pixel, and generates a diffraction curve. Point set; The diffraction curve generation module is used to generate the diffraction curve form. The point set is centrally integrated to generate diffraction curves for analysis; The diffraction curve analysis module is used to perform peak shape fitting and peak position extraction on the diffraction curve.

[0007] Preferably, the pixel data is in the form of a two-dimensional matrix.

[0008] According to another aspect of the present invention, a detector data processing method for residual stress measurement by X-ray diffraction is provided, comprising the following steps: S1: Establish the coordinate mapping relationship between the detector coordinate system and the world coordinate system; S2: Based on the coordinate mapping relationship, the coordinates and intensity information of each pixel collected by the detector are transformed from the detector coordinate system to the world coordinate system to obtain the intensity data point set in the world coordinate system; S3: Based on the intensity data point set in the world coordinate system obtained from S2, and combined with the position and incident direction of the X-ray source, the diffraction angle corresponding to each data point is calculated according to the spatial vector relationship, and the detector data is converted into diffraction curve form. Point set; S4: The diffraction curve form obtained from S3 The point set is centralized to generate continuous X-ray diffraction lines.

[0009] Preferably, the step of establishing the coordinate mapping relationship in step S1 specifically includes: taking the intersection of the X-ray source outlet and the test sample as the origin. Establish a world coordinate system {W}, where The axis is in the opposite direction to the X-ray incident direction; a detector coordinate system {D} is established with the center of the detector measurement plane as the origin; The detector coordinate system {D} describes the position of each point in the pixel plane, while the world coordinate system {W} uniformly represents the spatial layout of the detector, X-ray source, and the component under test. The expression for the mapping relationship is as follows:

[0010] in, This represents a pixel in world coordinates {W}. This represents the pixel in the detector coordinate system {D}. To measure the rotation transformation matrix from the planar coordinate system {D} to the world coordinate system {W} for the detector. The expression of the origin of the plane coordinate system {D} for the detector in the world coordinate system {W}.

[0011] Preferably, step S2 specifically includes: calculating the coordinates of the center of each pixel in the detector coordinate system {D} based on the pixel's position index, pixel size, and the origin of the detector coordinate system. Using the coordinate mapping relationship established by S1, the coordinates of the center of each pixel are... Convert to its coordinates in the world coordinate system {W} Thus, the intensity data point set in the world coordinate system is obtained. ,in, This is the X-ray intensity characterization value corresponding to this pixel.

[0012] Preferably, the diffraction angle is calculated in step S3. The specific method is as follows: based on the intensity data point set obtained from S2 By combining the position of the X-ray source exit port and the position of the measured point, the incident direction of the X-rays is determined, and the diffraction angle corresponding to each pixel is calculated. ; Calculate the diffraction angle of a pixel. The specific method is as follows: based on the position of the pixel in the world coordinate system {W} Calculate the diffracted X-ray vector based on the position of the measured point in the world coordinate system {W}; calculate the incident X-ray vector based on the position of the X-ray exit port in the world coordinate system {W} and the position of the measured point in the world coordinate system {W}; calculate the angle between the incident X-ray vector and the diffracted X-ray vector, which is the diffraction angle corresponding to that pixel. .

[0013] Preferably, when the measured point is selected as the origin of the world coordinate system {W}, and the direction opposite to the X-ray incident direction is taken as the positive direction of the Z-axis of the world coordinate system, the diffraction angle is... The calculation formula is as follows:

[0014] in, , , These are the coordinates of a pixel 'a' along the x, y, and z axes in the world coordinate system.

[0015] Preferably, the centralized processing in S4 employs interval merging, weighted accumulation, or integration strategies to merge intensity values ​​within the same angular interval into new data points. ,in This is the sum or integral of the intensity values ​​of all pixels within this angular range; finally, X-ray diffraction lines are plotted based on the integrated data for subsequent stress analysis.

[0016] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the detector data processing method for X-ray diffraction residual stress measurement described above.

[0017] In summary, compared with the prior art, the detector data processing method and system for X-ray diffraction residual stress measurement provided by the present invention have the following advantages: 1. This invention constructs a complete data conversion architecture from detector to diffraction curve, and clarifies the geometric modeling and conversion path from pixel data to XRD spectral lines.

[0018] 2. This invention significantly improves the accuracy of data conversion and the repeatability of stress measurement through coordinate system mapping, accurate derivation of diffraction angles, and centralized data processing.

[0019] 3. The method of the present invention has good versatility and is applicable to various types of detectors such as one-dimensional and two-dimensional detectors. It can be integrated into the corresponding system to achieve efficient diffraction line generation and analysis. Attached Figure Description

[0020] Figure 1 This is a schematic flowchart of a detector data processing method for residual stress measurement by X-ray diffraction provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the composition of a detector data processing system for X-ray diffraction residual stress measurement provided in an embodiment of the present invention; Figure 3 This is a schematic diagram from different angles of a detector data processing system for residual stress measurement using X-ray diffraction, a specific method according to the present invention. Figure 4 This is a schematic diagram illustrating the process of constructing a transformation relationship and describing detector data in the detector measurement plane coordinate system according to an embodiment of the present invention. Figure 5This is an example diagram of the diffraction curve generated by the detector in an embodiment of the present invention, and also a schematic diagram of the coordinate mapping from the detector plane pixel to the diffraction angle.

[0021] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-X-ray source; 1'-X-ray source exit port; 2, 2'-detector; 3-computer; 20-detector measurement plane; 21-detector dustproof device; 4-detector data acquisition module; 5-detector data conversion module; 6-diffraction curve generation module; 7-diffraction curve analysis module. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Please see Figure 2 and 3 This paper provides a detector data processing system for residual stress measurement using X-ray diffraction. Specifically, it is a dual-detector X-ray stress measurement structure, consisting of an X-ray source exit port 1', detectors 2 and 2', and other mechanical structures. 20 is the detector measurement plane; 21 is the detector dust collector. During stress measurement, X-rays are emitted through the X-ray source exit port 1' and pass through a point... After the test sample is diffracted, the diffracted X-rays reaching detectors 2 and 2' are recorded, forming detector pixel data.

[0024] In this embodiment, a detector data processing system for X-ray diffraction residual stress measurement is provided, comprising: X-ray source 1, used to generate and emit X-rays; Two detectors, 2 and 2', are used to receive the X-ray signals diffracted by the material under test and convert them into pixel data; the pixel data includes the position index of the pixel and its corresponding X-ray intensity characterization value; The computer is equipped with data processing software to convert the pixel data into diffraction curve data with the diffraction angle as the abscissa and the intensity characterization quantity as the ordinate, and to perform stress analysis. The data processing software includes: Detector data acquisition module 4 is used to acquire pixel data collected by the detector; The detector data conversion module 5 is used to map pixel data to a unified world coordinate system and calculate the diffraction angle corresponding to each pixel to generate a (diffraction angle, intensity) data point set. The diffraction curve generation module 6 is used to centrally integrate the (diffraction angle, intensity) data point set and generate a diffraction curve for analysis. The diffraction curve analysis module 7 is used to perform peak shape fitting and peak position extraction on the diffraction curve.

[0025] Please see Figure 1 The following describes this embodiment in detail according to the method steps proposed in this invention: This embodiment provides a detector data processing method for residual stress measurement using X-ray diffraction, including the following steps: S1: Establish the coordinate mapping relationship between the detector coordinate system and the world coordinate system; The steps for establishing the coordinate mapping relationship in S1 specifically include: taking the intersection of the X-ray source outlet and the test sample as the origin. Establish a world coordinate system {W}, where The axis is in the opposite direction to the X-ray incident direction; a detector coordinate system {D} is established with the center of the detector measurement plane as the origin; The detector coordinate system {D} describes the position of each point in the pixel plane, while the world coordinate system {W} uniformly represents the spatial layout of the detector, X-ray source, and the component under test. The expression for the mapping relationship is as follows:

[0026] in, This represents a pixel in world coordinates {W}. This represents the pixel in the detector coordinate system {D}. To measure the rotation transformation matrix from the planar coordinate system {D} to the world coordinate system {W} for the detector. The expression of the origin of the plane coordinate system {D} for the detector in the world coordinate system {W}.

[0027] In one implementation, appendix Figure 3 The relative positions of the X-ray source exit port 1' and detectors 2 and 2' are fixed by a mechanical structure. The detectors are two-dimensional area array detectors, and their measurement planes are rectangular. Let the center points of the measurement planes of the two detectors be... and The line connecting them intersects the X-ray exit at a single point. And distance size The angles of deviation from the central axis of the light output port are respectively .

[0028] by Establish a world coordinate system {W} with the origin: The axis is opposite to the incident direction of the X-rays. The axis is parallel to the length direction of the detector's measurement plane. The axis is determined according to the right-hand rule.

[0029] by Establish a coordinate system {A} for the measurement plane of detector 2 with the origin: The axis is parallel to , The axis is parallel to the width direction of the detector. shaft edge The direction points inward into the detector plane. Similarly, establish the coordinate system {B} of the detector 2' measurement plane.

[0030] Based on the above settings, the measurement plane coordinate system {A} of detector 2 can be considered as being revolved around {W}. Axis rotation Corner back edge Directional translation distance d The resulting coordinate system {B} is then a revolving coordinate system. Axis rotation Corner back edge Directional translation distance d The results show that coordinate transformation relationships from {A} to {W} and from {B} to {W} can be constructed respectively, enabling the coordinate representation of any point on the detector plane in the world coordinate system.

[0031] For the transformation of the detector 2 from the plane coordinate system {A} to the world coordinate system {W}:

[0032]

[0033]

[0034] in, Let W be the representation of a point on the detector in world coordinates {W} (i.e., spatial coordinates). Measure the rotation transformation matrix from the planar coordinate system {A} to the world coordinate system {W} for detector 2. Let {A} be the representation of the same point in the coordinate system {A} of the measurement plane of detector 2. Measure the origin of the planar coordinate system {A} for detector 2. Representation in the world coordinate system {W}.

[0035] The transformation from the measurement plane coordinate system {B} to the world coordinate system {W} of detector 2' is basically the same as the above form.

[0036] S2: Based on the coordinate mapping relationship, the coordinates and intensity information of each pixel collected by the detector are transformed from the detector coordinate system to the world coordinate system to obtain the intensity data point set in the world coordinate system; Step S2 specifically includes: calculating the coordinates of the center of each pixel in the detector coordinate system {D} based on the pixel's position index, pixel size, and the origin of the detector coordinate system. Using the coordinate mapping relationship established by S1, the coordinates of the center of each pixel are... Convert to its coordinates in the world coordinate system {W} Thus, the intensity data point set in the world coordinate system is obtained. ,in, This is the X-ray intensity characterization value corresponding to this pixel.

[0037] In one implementation, such as Figure 4 As shown, the detector's measurement plane consists of a regular pixel array, with each pixel recording its position. and intensity information In this embodiment, the planar pixels are arranged in a 256×256 layout, and the center pixel is located at index (128, 128).

[0038] In the {A} coordinate system of the measurement plane of detector 2, with the center of the central pixel as the origin, the coordinates of any pixel center can be calculated based on the pixel size, index position, and pixel size. Then, using the coordinate transformation relationship established in step (I), the pixel center coordinates are transformed to the world coordinate system, thereby converting the original data points... Data points mapped to world coordinates .

[0039] For coordinate system {B} and appended Figure 3 The same applies to the 2' detector.

[0040] S3: Based on the intensity data point set in the world coordinate system obtained from S2, and combined with the position and incident direction of the X-ray source, the diffraction angle corresponding to each data point is calculated according to the spatial vector relationship, and the detector data is converted into diffraction curve form. Point set; Calculate the diffraction angle in step S3. The specific method is as follows: based on the intensity data point set obtained from S2 By combining the position of the X-ray source exit port and the position of the measured point, the incident direction of the X-rays is determined, and the diffraction angle corresponding to each pixel is calculated. ; Calculate the diffraction angle of a pixel. The specific method is as follows: based on the position of the pixel in the world coordinate system {W} Calculate the diffracted X-ray vector based on the position of the measured point in the world coordinate system {W}; calculate the incident X-ray vector based on the position of the X-ray exit port in the world coordinate system {W} and the position of the measured point in the world coordinate system {W}; calculate the angle between the incident X-ray vector and the diffracted X-ray vector, which is the diffraction angle corresponding to that pixel. .

[0041] In one implementation, in the world coordinate system {W}, The negative axis is the direction of the X-ray incident vector. The diffracted X-ray vector is at the origin. The direction vector pointing to the detector pixel. Based on the diffraction angle. The definition of the angle between the incident and diffracted X-ray vectors can be obtained by performing spatial vector operations based on the pixel's coordinates in the world coordinate system. Values, thereby further converting data points into form.

[0042] As attached Figure 5 As shown, a point The corresponding formula for calculating the diffraction angle is as follows:

[0043] in, , , These are the coordinates of a pixel 'a' along the x, y, and z axes in the world coordinate system.

[0044] S4: The diffraction curve form obtained from S3 The point set is centralized to generate continuous X-ray diffraction lines.

[0045] The centralized processing described in S4 employs interval merging, weighted accumulation, or integration strategies to combine intensity values ​​within the same angular interval into new data points. ,in This is the sum or integral of the intensity values ​​of all pixels within this angular range; finally, X-ray diffraction lines are plotted based on the integrated data for subsequent stress analysis.

[0046] In one implementation, since each pixel generates a The data points are numerous and densely distributed; directly plotting them would result in discrete diffraction peaks, hindering subsequent analysis. Therefore, this embodiment employs a strategy of angle interval division and intensity accumulation: [The remaining text appears to be incomplete and requires further context.] The range is set according to the preset interval. Divide the data into several consecutive intervals, and accumulate the intensity values ​​of data points falling into the same interval to generate new data points. ,in IThis is the cumulative intensity.

[0047] After this centralized processing, the diffraction peak shapes are highlighted, facilitating peak position identification and fitting analysis. Ultimately, with... Plot X-ray diffraction lines with I as the x-axis and I as the y-axis, completing the full conversion from detector data to analyzable diffraction curves.

[0048] Practice has shown that multiple sets of detector data acquired at different azimuth angles can all obtain ideal diffraction spectra after being processed by the method described in this invention, providing a reliable basis for achieving high-precision stress measurement.

[0049] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A detector data processing system for residual stress measurement using X-ray diffraction, characterized in that: include: X-ray source, used to generate and emit X-rays; At least one detector is used to receive X-ray signals diffracted by the material under test and convert them into pixel data; the pixel data includes the position index of the pixel and its corresponding X-ray intensity characterization value; The computer is equipped with data processing software to convert the pixel data into diffraction curve data with the diffraction angle as the abscissa and the intensity characterization quantity as the ordinate, and to perform stress analysis. The data processing software includes: The detector data acquisition module is used to acquire pixel data collected by the detector; The detector data conversion module maps pixel data to a unified world coordinate system, calculates the diffraction angle for each pixel, and generates a diffraction curve. Point set; The diffraction curve generation module is used to generate the diffraction curve form. The point set is centrally integrated to generate diffraction curves for analysis; The diffraction curve analysis module is used to perform peak shape fitting and peak position extraction on the diffraction curve.

2. The detector data processing system for residual stress measurement by X-ray diffraction as described in claim 1, characterized in that: The pixel data is in the form of a two-dimensional matrix.

3. A data processing method for an X-ray residual stress measurement detector based on the system described in claim 1 or 2, characterized in that, Includes the following steps: S1: Establish the coordinate mapping relationship between the detector coordinate system and the world coordinate system; S2: Based on the coordinate mapping relationship, the coordinates and intensity information of each pixel collected by the detector are transformed from the detector coordinate system to the world coordinate system to obtain the intensity data point set in the world coordinate system; S3: Based on the intensity data point set in the world coordinate system obtained from S2, and combined with the position and incident direction of the X-ray source, the diffraction angle corresponding to each data point is calculated according to the spatial vector relationship, and the detector data is converted into diffraction curve form. Point set; S4: The diffraction curve form obtained from S3 The point set is centralized to generate continuous X-ray diffraction lines.

4. The detector data processing method for residual stress measurement by X-ray diffraction as described in claim 3, characterized in that, The specific steps in step S1 for establishing the coordinate mapping relationship include: taking the intersection of the X-ray source outlet and the test sample as the origin. Establish a world coordinate system {W}, where The axis is in the opposite direction to the X-ray incident direction; a detector coordinate system {D} is established with the center of the detector measurement plane as the origin; The detector coordinate system {D} describes the position of each point in the pixel plane, while the world coordinate system {W} uniformly represents the spatial layout of the detector, X-ray source, and the component under test. The expression for the mapping relationship is as follows: in, This represents a pixel in world coordinates {W}. This represents the pixel in the detector coordinate system {D}. To measure the rotation transformation matrix from the planar coordinate system {D} to the world coordinate system {W} for the detector. The expression of the origin of the plane coordinate system {D} for the detector in the world coordinate system {W}.

5. The detector data processing method for residual stress measurement by X-ray diffraction as described in claim 3, characterized in that, Step S2 specifically includes: calculating the coordinates of the center of each pixel in the detector coordinate system {D} based on the pixel's position index, pixel size, and the origin of the detector coordinate system. Using the coordinate mapping relationship established by S1, the coordinates of the center of each pixel are... Convert to its coordinates in the world coordinate system {W} Thus, the intensity data point set in the world coordinate system is obtained. ,in, This is the X-ray intensity characterization value corresponding to this pixel.

6. The detector data processing method for residual stress measurement by X-ray diffraction as described in claim 3, characterized in that, Calculate the diffraction angle in step S3. The specific method is as follows: based on the intensity data point set obtained from S2 By combining the position of the X-ray source exit port and the position of the measured point, the incident direction of the X-rays is determined, and the diffraction angle corresponding to each pixel is calculated. ; Calculate the diffraction angle of a pixel. The specific method is as follows: based on the position of the pixel in the world coordinate system {W} Calculate the diffracted X-ray vector based on the position of the measured point in the world coordinate system {W}; calculate the incident X-ray vector based on the position of the X-ray exit port in the world coordinate system {W} and the position of the measured point in the world coordinate system {W}. Calculate the angle between the incident X-ray vector and the diffracted X-ray vector; this angle is the diffraction angle corresponding to that pixel. .

7. The detector data processing method for residual stress measurement by X-ray diffraction as described in claim 6, characterized in that, When the measured point is selected as the origin of the world coordinate system {W}, and the direction opposite to the incident direction of the X-ray is taken as the positive direction of the Z-axis of the world coordinate system, the diffraction angle is... The calculation formula is as follows: in, , , These are the coordinates of a pixel 'a' along the x, y, and z axes in the world coordinate system.

8. The detector data processing method for residual stress measurement by X-ray diffraction as described in claim 3, characterized in that, The centralized processing described in S4 employs interval merging, weighted accumulation, or integration strategies to combine intensity values ​​within the same angular interval into new data points. ,in This is the sum or integral of the intensity values ​​of all pixels within this angular range; finally, X-ray diffraction lines are plotted based on the integrated data for subsequent stress analysis.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 3 to 8.

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