Multi-blade CT thickness measurement layout optimization method

Abstract

The invention belongs to the field of CT thickness measurement layout optimization of an X-ray machine, and particularly relates to a multi-blade CT thickness measurement layout optimization method. According to the method, the maximum penetration thickness of a blade is determined, simulation transillumination is carried out on the position with the maximum penetration thickness, and a gray value corresponding to the position with the maximum penetration thickness is obtained; and then placing and adjusting the plurality of leaves, carrying out simulation transillumination to ensure that the valley value in the gray distribution map after simulation of different sections obtained by the simulation transillumination of the plurality of leaves is not lower than the gray value corresponding to the maximum penetration thickness, and taking the scheme when the number of the placed leaves is the maximum as the optimal scheme. According to the method, an effective optimization method and a judgment basis are provided, superposition interference of the maximum thickness of the blades on a ray passing path is avoided, and maximization of the number of the blades detected at a time can be realized, so that the blade thickness measurement efficiency is greatly improved, and the average energy consumption of equipment is reduced.

Description

Technical Field

[0001] The invention belongs to the field of X-ray machine CT thickness measurement layout optimization, and in particular relates to a multi-leaf CT thickness measurement layout optimization method. Background Art

[0002] Turbine blades are one of the most critical parts of aircraft engines. Ensuring that each part of the turbine blade has a suitable wall thickness can not only ensure that the blade has sufficient load-bearing capacity, but also reduce the blade's own weight and increase the blade's service life. The measurement of blade wall thickness is mainly carried out by ultrasonic testing and industrial CT. Due to the anisotropic characteristics of single-crystal blades, ultrasonic testing is no longer suitable for the wall thickness measurement of single-crystal blades. Industrial CT is increasingly widely used in blade thickness measurement. The X-ray machine carried by the current mainstream industrial CT system is mainly 450kV. Limited by the penetration capability of the X-ray machine carried, the existing turbine blades are close to the penetration limit of the X-ray machine. When CT thickness measurement is performed on multiple blades at the same time, if there is an overlap in the maximum thickness area where the rays pass through, it may cause the beam to fail to penetrate effectively, resulting in the failure of the test. However, if only one blade is tested at a time, not only is the efficiency of part detection low and cannot meet production needs, but the comprehensive depreciation loss of the equipment is large and the energy consumption is high.

[0003] Therefore, a method is needed to maximize the number of blades detected in a single test, thereby greatly improving the efficiency of blade thickness measurement and reducing the average energy consumption of the equipment. Summary of the invention

[0004] In view of the problems in the prior art, the present invention provides a multi-blade CT thickness measurement layout optimization method, which provides an effective optimization method and judgment basis, avoids the superposition interference of the maximum thickness of the blades on the ray passing path, and can maximize the number of blades detected in a single time, thereby greatly improving the blade thickness measurement efficiency and reducing the average energy consumption of the equipment.

[0005] The technical solution of the present invention is: A multi-blade CT thickness measurement layout optimization method comprises the following steps: Step (1) using a CT device to perform a CT thickness scan on the blade to be inspected, ensuring that the X-ray machine of the CT device can penetrate the blade from all directions of 360° to ensure the inspection of the blade, and solidifying the scanning arrangement; Step (2) Observe the grayscale image of the DR image of a single leaf or the grayscale image of the sinusoidal curve formed by CT scanning to determine the "maximum penetration thickness" of the leaf: When the gray value of the thickest area is equal to 5% of the maximum imaging gray value of the detector, the ray path corresponding to the thickest area at this time is considered to be the "maximum penetration thickness"; When the gray value of the thickest area is greater than 20% of the maximum gray value of the detector, a conical or truncated cone test block of the same or similar material as the blade is selected as a simulation block, and the simulation block is scanned to form a DR image grayscale or sinusoidal grayscale image. The diameter of the simulation block corresponding to 5% of the maximum imaging gray value of the detector is taken as the "maximum penetration thickness"; Step (3) simulates the “maximum penetration thickness” of a single blade or simulation block and obtains the grayscale value corresponding to the “maximum penetration thickness”; Step (4) multiple leaves are placed, and simulated transillumination is performed at different angles to obtain grayscale distribution diagrams after simulation of different cross-sections, ensuring that the valley value in each distribution diagram is not lower than the grayscale value corresponding to the "maximum penetration thickness". If the valley value is lower than the grayscale value corresponding to the "maximum penetration thickness", the number, spacing and orientation of the leaves are adjusted again. The solution with the largest number of leaves placed is the optimal solution.

[0006] Furthermore, in the above-mentioned multi-leaf CT thickness measurement layout optimization method, in step (1), the method for determining whether the X-ray machine of the CT equipment penetrates the leaf is: the grayscale value of the leaf in all DR irradiation directions within 360° is not less than 5% of the lower limit of the detector grayscale value, or the lowest grayscale value on the sinusoidal diagram of the CT scan is not less than 5% of the lower limit of the detector.

[0007] Furthermore, in the above-mentioned multi-leaf CT thickness measurement layout optimization method, in step (4), the multiple leaves are arranged in an equal-diameter and evenly distributed manner.

[0008] Furthermore, in the above-mentioned multi-leaf CT thickness measurement layout optimization method, the leaf CT thickness measurement mainly uses a linear array detector. When multiple leaves are scanned at the same time, the scattering artifacts near the leaf matrix will be superimposed. In order to obtain better detection image quality, the leaves cannot be close to each other or arranged too densely. The spacing between multiple leaves is that the grayscale value formed by the blank area between the leaves does not exceed 1200, and is not higher than 1 / 10 of the grayscale value of the matrix.

[0009] Advantages and beneficial effects of the present invention: The present invention adopts multi-leaf CT layout optimization technology to avoid the superposition interference of the maximum thickness of the blades on the path through which the rays pass, and can maximize the number of blades detected in a single time, greatly reducing the machine time of the CT detection equipment, significantly shortening the blade thickness measurement cycle, and reducing the average energy consumption of the equipment, which has significant economic benefits.

[0010] By adopting multi-blade CT layout optimization technology, taking the blade width of 35mm-45mm as an example, at least 5-10 blades can be CT-measured for thickness simultaneously, and the detection efficiency is improved by more than 3-5 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1It is a grayscale image of the simulation effect of a single blade at a certain angle; Figure 2 Grayscale images of multiple blades and their simulation effects. DETAILED DESCRIPTION

[0012] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but cannot be used to limit the scope of the present invention. Example 1

[0013] In this embodiment, the blade to be tested has a width of 35 mm to 45 mm. The CT thickness measurement layout optimization method for this type of blade includes the following steps: Step (1) Use CT equipment to perform CT thickness measurement scanning on the blade to be inspected. Assuming that the detector A / D conversion bit number is 16 bits, the maximum grayscale value of the DR image is 65535. It is determined that the X-ray machine of the CT equipment can penetrate the blade from all directions of 360° to ensure the inspection of the blade, and solidify the scanning arrangement.

[0014] Step (2) Determine the diameter of the stage scanning area according to the scanning arrangement solidified in step (1), and use 3D software to place a single blade within the scanning area diameter circle, such as Figure 1 As shown in Figure (a), the morphology of a single blade is shown in Figure 2. The dotted line is the cross-sectional position of the wall thickness to be tested. The three-dimensional model is simulated by ray transillumination to obtain the grayscale distribution of the cross-section at any transillumination angle. The line grayscale can be shown as Figure 1 As shown in (b), by adjusting different transillumination directions, a series of grayscale distribution maps can be obtained. In each grayscale distribution map, there are Figure 1 (b) The grayscale valley value is compared with each valley value and the minimum valley value GM is found. Min That is, corresponding to the "maximum penetration thickness" of the blade, its grayscale value should not be less than 5% of 65535, which is about 3276.

[0015] Step (3) determines the diameter of the stage scanning area according to the scanning arrangement solidified in step (1), and arranges 5 blades within this diameter, such as Figure 2 As shown in Figure (a), the placement of the five leaves should be arranged according to the equal diameter distribution scheme. The gray value formed by the blank area between adjacent leaves should not exceed 1200, and should not be higher than 1 / 10 of the gray value of the matrix. The gray distribution of the leaves is a 5-cycle distribution. By simulating the transillumination of the three-dimensional model, the gray distribution after cross-section simulation can be obtained. By adjusting different transillumination directions, a series of gray distribution diagrams can be obtained, such as Figure 2 The middle (b) figure shows the grayscale distribution diagram of a certain transillumination direction. Since the leaves are uniformly distributed with equal diameters, it is only necessary to analyze within the uniform distribution angle. Figure 2In the case shown, we only need to observe the grayscale changes of the image within 72°, and it is easier to find whether the grayscale extreme value exceeds GM. Min ,therefore Figure 2 The minimum valley value in each grayscale distribution diagram is not lower than the grayscale value GM at the "maximum penetration thickness" Min .

[0016] Step (4) Select other cross sections and repeat the method of step (3), and screen them based on the optimization results of each cross section to ensure that no cross section has a grayscale extreme value lower than GM. Min situation.

[0017] This embodiment can realize CT thickness measurement of 5 blades at the same time, and the detection efficiency is improved by more than 3 times, which can greatly reduce the machine time of CT detection equipment and significantly shorten the blade thickness measurement cycle.

Claims

1. A multi-blade CT thickness measurement layout optimization method, characterized in that: The following steps are involved: Step (1) using a CT device to perform a CT thickness scan on the blade to be inspected, ensuring that the X-ray machine of the CT device can penetrate the blade from all directions of 360° to ensure the inspection of the blade, and solidifying the scanning arrangement; Step (2) Observe the grayscale image of the DR image of a single leaf or the grayscale image of the sinusoidal curve formed by CT scanning to determine the "maximum penetration thickness" of the leaf: When the gray value of the thickest area is equal to 5% of the maximum imaging gray value of the detector, the ray path corresponding to the thickest area at this time is considered to be the "maximum penetration thickness"; When the gray value of the thickest area is greater than 20% of the maximum gray value of the detector, a conical or truncated cone-shaped test block of the same or similar material as the blade is selected as a simulation block, and the simulation block is scanned to form a DR image grayscale or sinusoidal grayscale image. The diameter of the simulation block corresponding to 5% of the maximum imaging gray value of the detector is taken as the "maximum penetration thickness"; Step (3) simulates the "maximum penetration thickness" of a single blade or simulation block to obtain the gray value corresponding to the "maximum penetration thickness"; Step (4) multiple leaves are placed, and simulated transillumination is performed at different angles to obtain grayscale distribution diagrams after simulation of different cross-sections, ensuring that the valley value in each distribution diagram is not lower than the grayscale value corresponding to the "maximum penetration thickness". If the valley value is lower than the grayscale value corresponding to the "maximum penetration thickness", the number, spacing and orientation of the leaves are adjusted again. The solution with the largest number of leaves placed is the optimal solution.

2. The multi-blade CT thickness measurement layout optimization method according to claim 1, characterized in that: A method for optimizing the thickness measurement layout of a multi-leaf CT device, wherein in step (1), the method for determining whether the X-ray machine of the CT device penetrates the leaf is that the grayscale value of the leaf in all DR transillumination directions within 360° is not less than 5% of the lower limit of the detector grayscale value, or the lowest grayscale value on the sinusoidal diagram of the CT scan is not less than 5% of the lower limit of the detector.

3. The multi-blade CT thickness measurement layout optimization method according to claim 1, characterized in that: In step (4), the plurality of blades are arranged in an equal diameter and evenly distributed manner.

4. The multi-blade CT thickness measurement layout optimization method according to claim 1, characterized in that: In step (4), the spacing between the multiple blades is such that the grayscale value formed by the blank areas between the blades does not exceed 1200 and is not higher than 1 / 10 of the grayscale value of the matrix.

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