Large-scale component residual stress testing platform and test method based on neutron diffraction

Abstract

The present invention discloses a large-scale component residual stress testing platform and test method based on neutron diffraction. The test platform includes a component support, a rotating spindle, a first thrust cylindrical roller bearing, a first cylindrical roller bearing, a bearing clearance cylinder, a second cylindrical roller bearing, a sleeve, and a first fixed baffle, which are arranged on a neutron spectrometer sample stage. The component support is fixedly mounted on the neutron spectrometer sample stage, and the rotating spindle is mounted on the component support via a fixed spindle and a second fixed baffle. The first thrust cylindrical roller bearing, the first cylindrical roller bearing, the bearing clearance cylinder, and the second cylindrical roller bearing are sequentially mounted on the rotating spindle from the inside out. The sleeve is mounted on the outside of the first cylindrical roller bearing, the bearing clearance cylinder, and the second cylindrical roller bearing. The large component is mounted on the sleeve, and the first fixed baffle is used to laterally limit the large component. The present invention can achieve the support, movement, rotation, tilting, and rotation of large components during residual stress testing.

Description

Technical Field

[0001] The present invention relates to the technical field of residual stress detection, and in particular to a large-scale component residual stress testing platform based on neutron diffraction and a testing method thereof. Background Art

[0002] Residual stress is a stress system that exists inside an object and maintains its own equilibrium in the absence of external forces. During the solidification, deformation and heat treatment processes of large components, not only does the microstructure evolve, but local changes in the stress field also occur, leading to the emergence of multi-scale residual stress fields. During the processing and assembly process, the multi-scale stress field may be redistributed and deformed. During service, under the action of external alternating loads, the complex stress state superimposed on the multi-scale residual stress field can cause local damage to large components, ultimately leading to component failure and catastrophic accidents. It can be seen that residual stress runs through the entire industrial manufacturing and use chain of large component preparation, processing, assembly and service, and its detection and evaluation are crucial.

[0003] Residual stress testing techniques fall into two categories: destructive testing and non-destructive testing. Destructive testing techniques include drilling, slicing, profiling, and deep-hole methods. These techniques typically require partial or complete removal of component material. The strain in the surrounding area resulting from the local stress release after material removal is recorded, thereby inferring the residual stress at that location before the release. According to the European standard BS EN 13262:2020, residual stress testing in the rim of large high-speed rail wheel components utilizes a strain gauge-attached slicing method. The wheel is gradually cut according to a specific procedure, and the strain gauges are used to obtain the distribution of the gradually released stress. These destructive techniques require the destruction of the high-speed rail wheel, making it difficult to monitor the evolution of residual stress during the component's service life. Furthermore, the residual stress obtained by these methods is discontinuous, making it difficult to accurately obtain a three-dimensional stress distribution. Non-destructive testing techniques include ultrasonic testing, X-ray diffraction, and neutron diffraction. Ultrasonic residual stress detection relies on the difference in the speed of ultrasonic waves propagating through a material under different stress states. This technique can detect stress at depths ranging from millimeters to meters. However, it only obtains average stress, has poor spatial resolution, and is susceptible to structural interference. Diffraction is the most widely used and mature nondestructive residual stress detection technique. X-ray diffraction and neutron diffraction methods share the same principle: measuring changes in lattice spacing to calculate interatomic strain, and then inferring stress from strain according to Hooke's law. Due to the limited penetration depth of X-rays into materials, X-ray diffraction can only detect residual stress at the surface of metal materials at tens to hundreds of microns. Neutron beams, on the other hand, can penetrate tens of millimeters of steel and can detect residual stress deep within large components. By controlling the neutron beam sampling volume to the millimeter level, it is possible to nondestructively obtain three-dimensional residual stress distributions deep within large components with millimeter-level spatial resolution. Therefore, the development of neutron diffraction-based residual stress detection technology for large components is crucial for component design, development, and in-service safety monitoring.

[0004] Currently, devices capable of performing neutron diffraction-based residual stress testing include neutron diffractometers at reactor neutron sources and spallation neutron sources. Residual stress testing of small-scale specimens and partially cut engineering parts has been reported. However, large components such as high-speed rail wheels and aircraft turbine disks often contain residual stress, and after cutting, these internal residual stresses are released, leading to deviations in test results. The installation, fixturing, and residual stress testing of these full-scale components using neutron diffraction remain difficult, and no relevant reports have been published. Therefore, there is an urgent need to develop a neutron diffraction-based residual stress testing platform and test methods for large-scale components. Summary of the Invention

[0005] The purpose of the present invention is to provide a large-scale component residual stress testing platform and test method based on neutron diffraction, and to develop a dedicated large-scale component testing platform based on the neutron spectrometer of the existing reactor neutron source and spallation neutron source, so as to facilitate the installation and debugging of large components and meet the requirements of non-destructive testing of the deep residual stress distribution of large components.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A large-scale component residual stress test platform based on neutron diffraction, the test platform comprising: a neutron spectrometer sample stage and a large-scale component residual stress test bench arranged on the neutron spectrometer sample stage, the large-scale component residual stress test bench comprising a component support, a rotating spindle, a first thrust cylindrical roller bearing, a first cylindrical roller bearing, a bearing clearance cylinder, a second cylindrical roller bearing, a sleeve and a first fixed baffle, the component support being fixedly mounted on the neutron spectrometer sample stage, the rotating spindle being mounted on the component support via a fixed spindle and a second fixed baffle, the rotating spindle and the component support being provided with matching axial holes, the fixed spindle passing through the axial hole to connect the rotating spindle and the component support together, and the second fixed baffle being arranged at the end of the fixed spindle;

[0008] The first thrust cylindrical roller bearing, the first cylindrical roller bearing, the bearing clearance cylinder and the second cylindrical roller bearing are sequentially mounted on the rotating main shaft from the inside to the outside. The bearing clearance cylinder is arranged between the first cylindrical roller bearing and the second cylindrical roller bearing for adjusting the distance between the two bearings. The sleeve is mounted on the outside of the first cylindrical roller bearing, the bearing clearance cylinder and the second cylindrical roller bearing. A large component is mounted on the sleeve. The first fixed baffle is used for lateral limitation of the large component. The second thrust cylindrical roller bearing is embedded in the center of the first fixed baffle. The second thrust cylindrical roller bearing is fixedly mounted on the rotating main shaft through a connecting piece.

[0009] Furthermore, two auxiliary rotating devices are provided on the sample stage of the neutron spectrometer, namely a first auxiliary rotating device and a second auxiliary rotating device. The first auxiliary rotating device and the second auxiliary rotating device are symmetrically arranged on both sides of the rotating main shaft and located below the large component.

[0010] Furthermore, the first auxiliary rotation device and the second auxiliary rotation device have the same structure, both including a base gasket and an auxiliary bearing arranged on the base gasket. The auxiliary bearing can be rotatably mounted on the base gasket, and the rotation direction is consistent with the large component, which is used to assist in the support and rotation of the large component.

[0011] Furthermore, the connecting member includes a screw and a screw ring, the screw passes through the center of the second thrust cylindrical roller bearing and is fixed to the center of the rotating main shaft, and the screw ring is arranged between the nut of the screw and the second thrust cylindrical roller bearing.

[0012] Furthermore, the thickness of the sleeve ranges from 5 to 50 mm.

[0013] Furthermore, the rotating main shaft can rotate around the fixed main shaft, and the angle formed with the horizontal plane where the neutron spectrometer sample stage is located ranges from 0 to 90 degrees.

[0014] The present invention also provides a test method for a large-scale component residual stress test platform based on neutron diffraction, which is applied to the above-mentioned large-scale component residual stress test platform based on neutron diffraction, and includes the following steps:

[0015] S1, preparation of stress-free specimens;

[0016] S2, determine the neutron diffraction measurement parameters and measure the stress-free sample;

[0017] S3, fix the large component to the test bench and install it on the neutron spectrometer sample table;

[0018] S4, setting up a large component test path and measuring large components using neutron diffraction;

[0019] S5, based on the change in lattice spacing between large components and stress-free specimens, derive elastic strain and calculate residual stress.

[0020] Furthermore, the step S3 of fixing the large component on the test bench and installing it on the neutron spectrometer sample table specifically includes:

[0021] According to the inner diameter of the large component, select a sleeve of appropriate thickness and put the large component on the sleeve;

[0022] Then, the large component is laterally limited on the rotating main shaft by the first fixed baffle and the second thrust cylindrical roller bearing, ensuring that the large component can rotate freely around the rotating main shaft while being laterally fixed.

[0023] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the present invention provides a large-component residual stress testing platform based on neutron diffraction and a testing method thereof, a large-component residual stress testing bench is set on the neutron spectrometer sample table, the large-component residual stress testing bench includes a component support, a rotating spindle, a first thrust cylindrical roller bearing, a first cylindrical roller bearing, a bearing clearance cylinder, a second cylindrical roller bearing, a sleeve and a first fixed baffle, which can realize the support, movement, rotation, tilting and rotation of the large component during the residual stress test, has a simple structure and is easy to install and operate; by selecting sleeves of different thicknesses, large components of different inner diameters can be installed, and the measurement of components of various sizes of the same device can be realized, which is conducive to the development of large-component residual stress detection test methods and meets the requirements of non-destructive testing of deep residual stress distribution of large components. 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 following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is an exploded view of the large-scale component residual stress testing platform based on neutron diffraction of the present invention;

[0026] Figure 2 Axonometric measurement of the residual stress test platform for large components based on neutron diffraction Figure 1 ;

[0027] Figure 3 Axonometric measurement of the residual stress test platform for large components based on neutron diffraction Figure 2 ;

[0028] Figure 4 This is a cross-sectional view of a large-scale component residual stress testing platform based on neutron diffraction according to the present invention;

[0029] Figure 5 This is a right view of the large-scale component residual stress testing platform based on neutron diffraction of the present invention;

[0030] Figure 6 This is an overall top view of the large-scale component residual stress testing platform based on neutron diffraction of the present invention;

[0031] Figure 7 Schematic diagram of the stress-free specimen of the present invention.

[0032] In the figure: 1. Neutron spectrometer sample stage; 2. Large component; 3. Screw; 4. Screw ring; 5. Second thrust cylindrical roller bearing; 6. First fixed baffle; 7. Sleeve; 8. Second cylindrical roller bearing; 9. Bearing clearance cylinder; 10. First cylindrical roller bearing; 11. First thrust cylindrical roller bearing; 12. Rotating spindle; 13. Second fixed baffle; 14. Component bracket; 15. Fixed spindle; 16. Bracket mounting seat; 17. First auxiliary rotating device; 18. Second auxiliary rotating device. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0034] The purpose of the present invention is to provide a large-scale component residual stress testing platform and test method based on neutron diffraction, and to develop a dedicated large-scale component testing platform based on the neutron spectrometer of the existing reactor neutron source and spallation neutron source, so as to facilitate the installation and debugging of large components and meet the requirements of non-destructive testing of the deep residual stress distribution of large components.

[0035] 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.

[0036] like Figure 1-6 As shown, the large-scale component residual stress test platform based on neutron diffraction provided by the present invention includes: a neutron spectrometer sample stage 1 and a large-scale component residual stress test bench arranged on the neutron spectrometer sample stage 1, the large-scale component residual stress test bench includes a component support 14, a rotating spindle 12, a first thrust cylindrical roller bearing 11, a first cylindrical roller bearing 10, a bearing clearance cylinder 9, a second cylindrical roller bearing 8, a sleeve 7 and a first fixed baffle 6, the component support 14 is fixedly installed on the neutron spectrometer sample stage 1, the rotating spindle 12 is installed on the component support 14 through a fixed spindle 15 and a second fixed baffle 13, the rotating spindle 12 and the component support 14 are provided with matching axial holes, the fixed spindle 15 passes through the axial hole to connect the rotating spindle 12 and the component support 14 together, and the second fixed baffle 13 is provided at the end of the fixed spindle 15;

[0037] The first thrust cylindrical roller bearing 11, the first cylindrical roller bearing 10, the bearing clearance tube 9 and the second cylindrical roller bearing 8 are sequentially mounted on the rotating main shaft 12 from the inside to the outside. The bearing clearance tube 9 is arranged between the first cylindrical roller bearing 10 and the second cylindrical roller bearing 8 for adjusting the distance between the two bearings; the sleeve 7 is mounted on the outside of the first cylindrical roller bearing 10, the bearing clearance tube 9 and the second cylindrical roller bearing 8, and the large component 2 is mounted on the sleeve 7. The first fixed baffle 6 is used for the lateral limitation of the large component 2. The second thrust cylindrical roller bearing 5 is embedded in the center of the first fixed baffle 6, and the second thrust cylindrical roller bearing 5 is fixedly mounted on the rotating main shaft 12 through a connecting piece.

[0038] The neutron spectrometer sample stage 1 is also provided with two auxiliary rotation devices, namely a first auxiliary rotation device 17 and a second auxiliary rotation device 18. The first auxiliary rotation device 17 and the second auxiliary rotation device 18 are symmetrically arranged on both sides of the rotating main shaft 12 and are located directly below the large component 2. The first auxiliary rotation device 17 and the second auxiliary rotation device 18 have the same structure, both including a base gasket and an auxiliary bearing provided on the base gasket. The auxiliary bearing is rotatably mounted on the base gasket, and the rotation direction is consistent with the large component 2, which is used to assist in the support and rotation of the large component 2. The bottom of the large component 2 presses on the two auxiliary rotation devices, so that the weight of the entire test platform and components is pressed on the sample stage from three sides, so that the sample stage is subjected to a relatively uniform force and prevents the sample stage from being deformed by torsional forces.

[0039] The connecting member includes a screw 3 and a screw collar 4. The screw 3 passes through the center of the second thrust cylindrical roller bearing 5 and is fixed to the center of the rotating main shaft 12. The screw collar 4 is arranged between the nut of the screw 3 and the second thrust cylindrical roller bearing 5. The second thrust cylindrical roller bearing 5 and the first fixed baffle 6 ensure that the large component 2 can rotate freely about the main shaft 12 while being laterally fixed.

[0040] The thickness of the sleeve 7 ranges from 5 to 50 mm, and can be mounted with large components 2 of different inner diameters, thereby enabling the measurement of components of various sizes of the same device.

[0041] The rotating main shaft 12 can rotate around the fixed main shaft 15 , and the angle formed with the horizontal plane where the neutron spectrometer sample stage 1 is located ranges from 0° to 90°.

[0042] During the specific implementation process, the neutron spectrometer sample stage 1 is automatically controlled by a stepper motor and software to achieve up and down, left and right movement and rotation. When the test bench is installed on the neutron spectrometer sample stage, it can support, move, rotate, tilt and rotate the component during the residual stress test, meeting the requirements of residual stress testing in different directions. After the component bracket 14 is installed on the neutron spectrometer sample stage 1, it can fix and support the component and move up and down, left and right, and rotate with the sample stage; the rotating spindle 12, after being fixed to the component bracket 14 at different angles, can achieve component tilt; the rolling bearing 11 and the combined rolling kit can achieve component fixation and rotation; the first auxiliary rotation device 17 and the second auxiliary rotation device 18 can achieve component support and rotation.

[0043] In this embodiment, the variable thickness sleeve 7 is 5 mm according to the inner diameter of the large component to be tested. According to the component test position, the angle between the rotating spindle 12 and the horizontal plane of the sample stage is fixed at 0°, so that the large component is placed perpendicular to the sample stage along the radial direction.

[0044] The present invention also provides a test method for a large-scale component residual stress test platform based on neutron diffraction, which is applied to the above-mentioned large-scale component residual stress test platform based on neutron diffraction, and includes the following steps:

[0045] S1, preparation of stress-free specimens;

[0046] S2, determine the neutron diffraction measurement parameters and measure the stress-free sample;

[0047] S3, fix the large component to the test bench and install it on the neutron spectrometer sample table; specifically include:

[0048] According to the inner diameter of the large component, select a sleeve of appropriate thickness and put the large component on the sleeve;

[0049] Then, the large component is laterally restrained on the rotating main shaft by the first fixed baffle and the second thrust cylindrical roller bearing, ensuring that the large component can rotate freely around the rotating main shaft while being laterally fixed;

[0050] S4, by moving or rotating the sample stage, setting the test path of the large component and measuring the large component using neutron diffraction;

[0051] S5, based on the change in lattice spacing between large components and stress-free specimens, derive elastic strain and calculate residual stress.

[0052] The stress-free specimens prepared in step S1 are obtained from the same test position of the same batch of large components to be tested by wire cutting, with a thickness of 5 to 10 mm, and are processed into comb shapes with equal intervals by wire cutting, such as Figure 7The intervals between the equally spaced comb-shaped stress-free specimens should be 2 to 15 mm. In a specific embodiment, the thickness can be 5 mm and the specimens can be processed into a comb shape with equal intervals of 5 mm by wire cutting.

[0053] The neutron diffraction measurement parameters in step S2 include the diffraction peak (spectrum) of the sample to be measured, the sampling volume, the test direction and the measurement time. These parameters are consistent for stress-free samples and large components to be measured.

[0054] The diffraction peak (spectrum) of the sample to be measured in the neutron diffraction measurement parameter of step S2 is the characteristic crystal plane diffraction peak when a reactor neutron source is used, and is the diffraction spectrum when a spallation neutron source is used; the sampling volume is determined according to the incident slit and the exit slit of the neutron spectrometer, and the range is 1×1×1 to 10×10×10 mm 3 , for example, the sampling volume is 3×3×3mm 3 ; The test directions include circumferential, radial and transverse directions, the circumferential direction is the rolling direction of the large component, the radial direction is along the radius of the component, and the transverse direction is perpendicular to the thickness of the component; the measurement time is determined according to the sample size, diffraction peak intensity and background intensity, ranging from tens to thousands of seconds, for example, in the range of 50 to 3000 seconds.

[0055] In step S4, a large component test path is set, which is a distributed test at different positions, different depths, and different directions.

[0056] The calculation formula of the elastic strain in step S5 is:

[0057]

[0058] Among them, ε hkl represents the elastic strain, d 0,hkl represents the lattice spacing of the stress-free specimen, d hkl Represents the lattice spacing of the large component sample to be tested, θ 0,hkl represents the Bragg angle of the stress-free specimen, θ hkl Indicates the Bragg angle of the large component specimen to be tested.

[0059] The calculation formula of the residual stress in step S5 is:

[0060]

[0061]

[0062]

[0063] Among them, σ xx , σ yy , σ zz is the stress in three orthogonal directions, ε xx, ε yy , ε zz is the stress in three orthogonal directions, E hkl is the elastic modulus associated with the (hkl) diffraction plane, ν hkl is the Poisson's ratio associated with the (hkl) diffraction plane.

[0064] In a specific embodiment, the large component is a high-speed railway wheel, an aviation turbine disc, etc.

[0065] The present invention provides a large-scale component residual stress testing platform and test method based on neutron diffraction. A large-scale component residual stress testing bench is set on a neutron spectrometer sample table. The large-scale component residual stress testing bench includes a component support, a rotating spindle, a first thrust cylindrical roller bearing, a first cylindrical roller bearing, a bearing clearance cylinder, a second cylindrical roller bearing, a sleeve, and a first fixed baffle. It can realize the support, movement, rotation, tilting and rotation of the large-scale component during the residual stress testing process. It has a simple structure and is easy to install and operate. By selecting sleeves of different thicknesses, large components of different inner diameters can be installed, and the measurement of components of multiple sizes with the same device can be realized. This is conducive to the development of large-scale component residual stress detection test methods and meets the requirements of non-destructive testing of deep residual stress distribution of large components. The test platform and test method described in the present invention can realize the support, movement, rotation, tilting and rotation during the residual stress testing of large components, and can non-destructively obtain the three-dimensional and deep residual stress distribution of large components with a spatial resolution of several millimeters, overcoming the limitations of traditional evaluation technology such as loss, limited penetration and low spatial resolution.

[0066] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A large-scale component residual stress testing platform based on neutron diffraction, characterized in that: include: A neutron spectrometer sample stage (1) and a large-scale component residual stress test bench arranged on the neutron spectrometer sample stage (1), wherein the large-scale component residual stress test bench comprises a component support (14), a rotating spindle (12), a first thrust cylindrical roller bearing (11), a first cylindrical roller bearing (10), a bearing clearance cylinder (9), a second cylindrical roller bearing (8), a sleeve (7) and a first fixed baffle (6); the component support (14) is fixedly mounted on the neutron spectrometer sample stage (1); the rotating spindle (12) is mounted on the component support (14) through a fixed spindle (15) and a second fixed baffle (13); the rotating spindle (12) and the component support (14) are provided with matching axial holes; the fixed spindle (15) passes through the axial hole to connect the rotating spindle (12) and the component support (14); and the second fixed baffle (13) is arranged at the end of the fixed spindle (15); The first thrust cylindrical roller bearing (11), the first cylindrical roller bearing (10), the bearing gap cylinder (9) and the second cylindrical roller bearing (8) are sequentially sleeved and installed on the rotating main shaft (12) from the inside to the outside, and the bearing gap cylinder (9) is arranged between the first cylindrical roller bearing (10) and the second cylindrical roller bearing (8) for adjusting the distance between the two bearings; the sleeve (7) is sleeved on the outside of the first cylindrical roller bearing (10), the bearing gap cylinder (9) and the second cylindrical roller bearing (8); the large component (2) is sleeved and installed on the sleeve (7); the first fixed baffle (6) is used for lateral limitation of the large component (2); the center of the first fixed baffle (6) is embedded with the second thrust cylindrical roller bearing (5); the second thrust cylindrical roller bearing (5) is fixedly installed on the rotating main shaft (12) through a connecting piece; The thickness of the sleeve (7) ranges from 5 to 50 mm; The neutron spectrometer sample stage (1) is further provided with two auxiliary rotating devices, namely a first auxiliary rotating device (17) and a second auxiliary rotating device (18). The first auxiliary rotating device (17) and the second auxiliary rotating device (18) are symmetrically arranged on both sides of the rotating main shaft (12) and are located below the large component (2). The first auxiliary rotating device (17) and the second auxiliary rotating device (18) have the same structure, and both include a base gasket and an auxiliary bearing arranged on the base gasket. The auxiliary bearing can be rotatably mounted on the base gasket, and the rotation direction is consistent with that of the large component (2), and is used to assist in achieving the support and rotation of the large component (2).

2. The large-scale component residual stress testing platform based on neutron diffraction according to claim 1 is characterized in that: The connecting member comprises a screw (3) and a screw ring (4); the screw (3) passes through the center of the second thrust cylindrical roller bearing (5) and is fixed to the center of the rotating main shaft (12); the screw ring (4) is arranged between the nut of the screw (3) and the second thrust cylindrical roller bearing (5).

3. The large-scale component residual stress testing platform based on neutron diffraction according to claim 1 is characterized in that: The rotating main shaft (12) can rotate around the fixed main shaft (15), and the angle formed with the horizontal plane where the neutron spectrometer sample stage (1) is located ranges from 0 to 90 degrees.

4. A test method for a large-scale component residual stress test platform based on neutron diffraction, applied to the large-scale component residual stress test platform based on neutron diffraction according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, preparation of stress-free specimens; S2, determine the neutron diffraction measurement parameters and measure the stress-free sample; S3, fix the large component to the test bench and install it on the neutron spectrometer sample table; S4, setting up a large component test path and measuring large components using neutron diffraction; S5, based on the change in lattice spacing between large components and stress-free specimens, derive elastic strain and calculate residual stress.

5. The test method of the large-scale component residual stress test platform based on neutron diffraction according to claim 4 is characterized in that: The step S3, fixing the large component on the test bench and installing it on the neutron spectrometer sample table, specifically includes: According to the inner diameter of the large component, select a sleeve of appropriate thickness and put the large component on the sleeve; Then, the large component is laterally limited on the rotating main shaft by the first fixed baffle and the second thrust cylindrical roller bearing, ensuring that the large component can rotate freely around the rotating main shaft while being laterally fixed.

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