Blind hole method residual stress testing device and operation method thereof
By designing a multifunctional blind hole method residual stress testing device, the problems of fixing and drilling offset of complex structural parts were solved, and accurate residual stress measurement was achieved, improving test efficiency and accuracy.
Patent Information
- Application Number
- CN202511655681.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-12
- Publication Date
- 2026-01-09
AI Technical Summary
Traditional blind hole residual stress testing devices are difficult to effectively fix engine parts with complex surface profiles, resulting in hole position deviation, large measurement error, significant influence from operator subjectivity, and low test efficiency and accuracy.
A testing device was designed, comprising a base, a semi-circular bracket, a stage, a sleeve, a sight glass, and a drilling device. Through multi-angle adjustment and precise fixing, the drill bit is ensured to be perpendicular to the surface of the component. The test piece is fixed by a multi-functional stage and bracket, and a combination of universal joint and drill bit is used for precise drilling.
It enables precise residual stress testing of complex structural components, reduces the influence of human factors, improves test efficiency and measurement accuracy, and ensures the stability and accuracy of test results.
Smart Images
Figure CN121298088A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of aero-engine technology, and specifically relates to a blind hole method residual stress testing device and its operation method. Background Technology
[0002] Residual stress refers to the elastic-plastic deformation that occurs within a certain distance from the material surface when a material is subjected to an external load. After the load is removed, the elastic deformation recovers, while the plastic deformation remains, thus forming residual stress. Studies have shown that residual stress has a significant impact on the fatigue performance, wear resistance, corrosion resistance, and service life of engine components. Currently, the demand for residual stress testing of key engine components is continuously increasing in aero-engine development.
[0003] Blind hole testing is a widely used method for residual stress measurement, and it has also been applied to some extent in aero-engine development. However, due to the diverse structures and complex surface profiles of engine components, most of the parts requiring testing are not flat surfaces. Conventional blind hole testing equipment struggles to meet the testing requirements for these components with complex profiles, leading to difficulties in ensuring drilling accuracy and resulting in low measurement accuracy.
[0004] To address the challenge of performing blind-hole residual stress testing on components with complex surface contours, this project has developed a simple, stable, and powerful blind-hole residual stress testing device and method. This device allows for multi-angle and omnidirectional adjustment of components with complex structures, enabling precise testing and characterization of residual stress in areas with complex surface contours, thus providing technical support for residual stress characterization and service life assessment of engine components.
[0005] Traditional blind hole residual stress testing devices cannot effectively fix engine parts with complex surface profiles, which can easily cause the drilling position to shift or make it impossible to drill.
[0006] 2. For components with complex structures, the traditional method of drilling blind holes cannot guarantee that the drilling direction is perpendicular to the surface of the component, which increases the error in subsequent residual stress measurement.
[0007] 3. Most existing drilling devices are handheld devices, and the subjective behavior of the operator has a significant impact on the test results, resulting in low test efficiency, low accuracy, and poor stability. Summary of the Invention
[0008] To address the aforementioned problems, this application provides a blind hole method residual stress testing device, comprising:
[0009] Base;
[0010] The first and second brackets are both semi-circular structures, and are rotatably and positionably hinged to the base by the lugs at both ends, forming a hemispherical space with the base; both the first and second brackets have guide grooves, and the guide grooves of the first and second brackets form a rectangular hole for mounting sleeves at the intersection.
[0011] The sleeve can be slidably installed along the guide groove or positioned in the rectangular hole;
[0012] The stage is rotatable and positionable on the base and located within the hemispherical space. The stage is equipped with a clamp for holding the test piece.
[0013] The eyepiece is detachably mounted on the sleeve and is used to observe the test piece and position the sleeve.
[0014] The drilling device is installed in the positioned sleeve to drill blind holes in the test piece.
[0015] Preferably, the first bracket and the second bracket are respectively locked to the base by bolts. When the bolts are loose, the first bracket and the second bracket have a degree of freedom to rotate 180 degrees around the line connecting the two lugs. When the bolts are tightened, the positions of the first bracket and the second bracket are fixed.
[0016] Preferably, the stage has multiple radially distributed guide rails, each guide rail has a slidable and lockable fixture, and each guide rail has distance scales; multiple fixtures together hold the test piece.
[0017] Preferably, the sleeve portion can be divided into an upper sleeve and a lower sleeve. The outer surfaces of the upper sleeve and the lower sleeve respectively have retaining edges that limit the first bracket and the second bracket. The upper sleeve and the lower sleeve are connected by threads. They are locked onto the first bracket and the second bracket by the retaining edges, or the axial position of the sleeve is adjusted by setting a pad on the retaining edge.
[0018] Preferably, the lower outlet of the sleeve has a retaining ring with a reduced diameter, and a gasket is fitted inside the sleeve. The gasket is axially limited by the retaining ring to adjust the axial installation position of the eyepiece or drilling device.
[0019] Preferably, the drilling device includes: a hand drill, a universal joint, and a drill bit;
[0020] The universal joint includes an upper section, a lower section, and a drive bearing. The upper and lower sections are connected by the drive bearing. A hand drill is connected to the upper section to provide rotational power. The lower section has a clamping device that can clamp drill bits of different sizes to drill holes in the test piece. The lower section is inserted into a sleeve and has a limiting ring on its outer side that limits the spacer.
[0021] A method for operating a blind hole residual stress testing device, wherein strain gauges are attached to test points on the surface of the test piece using the blind hole residual stress testing device.
[0022] The test piece is fixed on the stage by adjusting the clamps so that the test point is facing upwards;
[0023] Install a sight glass inside the sleeve;
[0024] By adjusting the rotation angle of the stage and the orientation angle of the first and second supports, and observing through the eyepiece, ensure that the normal of the test point coincides with the axis of the sleeve, and fix the first and second supports.
[0025] Remove the eyepiece and, as needed, install a gasket of the appropriate thickness inside the sleeve;
[0026] Install the hand drill on the sleeve, adjust the drilling device and the sleeve, and ensure that the drill tip makes slight contact with the test point.
[0027] Remove the gasket of the appropriate thickness from inside the sleeve as needed;
[0028] Start the drilling device to drill blind holes of the corresponding depth and size at the test point;
[0029] Subsequent tests were conducted, and the residual stress in the test area was calculated.
[0030] 1. The present invention features a self-designed multifunctional stage that effectively fixes the tested parts and ensures accurate drilling positions.
[0031] 2. The present invention independently designs a multi-functional bracket to ensure that the drilling direction of the drill bit is perpendicular to the surface of the component, thereby improving the accuracy of testing.
[0032] 3. Precisely control the drilling size and depth to avoid the influence of human factors, further improve test efficiency, and ensure the accuracy of test results. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of the residual stress testing device.
[0034] Figure 2a This is a schematic diagram of the support structure;
[0035] Figure 2b This is a schematic diagram of the support structure;
[0036] Figure 3 This is a schematic diagram of the stage structure;
[0037] Figure 4 This is a schematic diagram of the sleeve structure;
[0038] Figure 5This is an exploded view of a universal joint. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0040] like Figures 1-5 As shown, this application provides a blind hole residual stress testing device and its operation method. The blind hole residual stress testing device includes: a first bracket (4) and a second bracket (7) are both hollow metal semi-circular structures. Angle scales are set on the outer surfaces of the two semicircles. The two ends are hinged to the base (5) by bolts and lugs (41) and are perpendicular to each other. Each bracket has a degree of freedom to rotate 180 degrees around the line connecting the two lugs. A sleeve (3) can be installed at the intersection of the first bracket (4) and the second bracket (7) to fix the hand drill (1). This structure can realize the adjustment of the hand drill (1) at any angle above the base (5). After the angle is adjusted, the first bracket (4) and the second bracket (7) can be locked by the lugs (41) and bolts to fix the angle of the hand drill (1) for subsequent operation.
[0041] The lower stage (9) is placed on the base (5) and can achieve horizontal rotation and locking functions. Angle scales are set on the surface of the stage (9) and the base (5). A motor can be added to this part to realize the electric horizontal rotation and positioning of the stage (9). Eight guide rails (81) are pre-set on the stage (9). The clamp can realize the horizontal movement and locking functions on the guide rails (81). Distance scales are set on the eight guide rails (81). A motor can be added to each guide rail (81) at the bottom of the stage (9) to realize the electric control of the clamp opening, closing and locking. By adjusting the position of the clamp, the spatial position adjustment and fixing functions of the irregularly shaped test piece (10) can be realized. Match the spatial position between the test piece (10) and the hand drill (1) to ensure that the drill bit (8) is perpendicular to the test point of the test piece (10) to facilitate the subsequent work of drilling to test the residual stress.
[0042] A shim (31) is placed inside the sleeve (3) to control the depth of the blind hole drilled by the hand drill (1). The sleeve (3) can move up and down and be positioned at the intersection of the support to ensure a reasonable distance between the hand drill (1) and the test piece (10). The sleeve (3) can be divided into an upper sleeve (32) and a lower sleeve (33). The shim (31) can be prefabricated in various thicknesses ranging from 0.5 mm to 5 mm to facilitate accurate control of the drilling depth.
[0043] The drilling section includes: a hand drill (1), a universal joint (2), and a drill bit (8). The universal joint (2) includes an upper section (21), a lower section (22), and a drive bearing (23). The upper section (21) and the lower section (22) are connected by the drive bearing (23) to ensure smooth rotation and maintain the same rotation angle even if the angle changes during drilling. The hand drill (1) is connected to the upper section (21) to provide rotational power. The lower section (22) has a clamping device that can hold drill bits (8) of different sizes for drilling on the test piece (10). Drill bits (8) can be selected from various diameter sizes. The lower section (22) is inserted into the sleeve (3) for positioning.
[0044] A method for operating a blind hole method residual stress testing device, characterized by the following steps:
[0045] Strain gauges are attached to the test points on the surface of the test piece (10);
[0046] By adjusting the clamps, the test piece (10) is fixed on the stage (9) to ensure that the test point is located above the test piece (10) and that the test piece (10) is firm and stable.
[0047] Install a sight glass inside the sleeve (3);
[0048] By adjusting the rotation angle of the stage (9) and the orientation angle of the first bracket (4) and the second bracket (7), and observing through the eyepiece, ensure that the normal of the test point coincides with the axis of the sleeve (3), and fix the first bracket (4) and the second bracket (7).
[0049] Take out the eyepiece and install a gasket (31) of appropriate thickness inside the sleeve (3) as needed.
[0050] Install the hand drill (1) on the sleeve (3), adjust the hand drill (1) and the sleeve (3) to ensure that the tip of the drill bit (1) is in slight contact with the test point;
[0051] According to the requirements, remove the gasket (31) of the corresponding thickness from the inside of the sleeve (3).
[0052] Start the hand drill (1) to drill blind holes of the corresponding depth and size at the test point;
[0053] Subsequent tests were conducted, and the residual stress in the test area was calculated.
[0054] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A blind-hole method residual stress testing device, characterized in that, include: Base (5); The first bracket (4) and the second bracket (7) are both semi-circular structures. They are hinged to the base (5) through the lugs (41) at both ends, which are perpendicular to each other, rotatable and positionable, forming a hemispherical space with the base (5). The first bracket (4) and the second bracket (7) both have guide grooves. The guide grooves of the first bracket (4) and the second bracket (7) form a rectangular hole for mounting the sleeve (3) at the intersection. The sleeve (3) can be slidably installed along the guide groove or positioned in the rectangular hole; The stage (9) is rotatably and positionably mounted on the base (5) and located within the hemispherical space. The stage (9) is provided with a clamp for holding the test piece. A visual sight is detachably mounted on the sleeve (3) for observing the test piece and positioning the sleeve (3); The drilling device is installed in the positioned sleeve (3) to drill blind holes in the test piece.
2. The blind hole method residual stress testing device as described in claim 1, characterized in that, The first bracket (4) and the second bracket (7) are respectively locked to the base (5) by bolts. When the bolts are loose, the first bracket (4) and the second bracket (7) have a degree of freedom to rotate 180 degrees around the line connecting the two lugs. When the bolts are tightened, the positions of the first bracket (4) and the second bracket (7) are fixed.
3. The blind hole method residual stress testing device as described in claim 1, characterized in that, Multiple radially distributed guide rails (81) are pre-installed on the stage (9). Each guide rail (81) can be slidably and lockably fitted with a clamp. Distance scales are set on each guide rail (81). Multiple clamps together hold the test piece.
4. The blind hole method residual stress testing device as described in claim 1, characterized in that, The sleeve (3) part can be divided into an upper sleeve (32) and a lower sleeve (33). The outer surfaces of the upper sleeve (32) and the lower sleeve (33) have retaining edges that limit the first bracket (4) and the second bracket (7), respectively. The upper sleeve (32) and the lower sleeve (33) are connected by threads; and are locked to the first bracket (4) and the second bracket (7) by the retaining edges, or the axial position of the sleeve (3) is adjusted by setting a pad on the retaining edge.
5. The blind hole method residual stress testing device as described in claim 1, characterized in that, The lower outlet of the sleeve (3) has a retaining ring formed by a smaller diameter. A gasket (31) is fitted inside the sleeve (3). The gasket (31) is axially limited by the retaining ring to adjust the axial installation position of the eyepiece or drilling device.
6. The blind hole method residual stress testing device as described in claim 1, characterized in that, The drilling device includes: a hand drill (1), a universal joint (2), and a drill bit (8); Among them: the universal joint (2) includes an upper section (21), a lower section (22) and a transmission bearing (23). The upper section (21) and the lower section (22) are connected by the transmission bearing (23). The hand drill (1) is connected to the upper section (21) to provide rotational power. The lower section (22) is provided with a clamping device to clamp drill bits (8) of different sizes to drill holes in the test piece (10). The lower section (22) is inserted into the sleeve (3) and has a limiting ring on the outside that limits the gasket.
7. An operating method for a blind hole method residual stress testing device, characterized in that, Using the blind hole method residual stress testing device as described in any one of claims 1-6, strain gauges are attached to the test points on the surface of the test piece (10); The test piece (10) is fixed on the stage (9) by adjusting the clamps so that the test point is facing upwards; Install a sight glass inside the sleeve (3); By adjusting the rotation angle of the stage (9) and the orientation angle of the first bracket (4) and the second bracket (7), and observing through the eyepiece, ensure that the normal of the test point coincides with the axis of the sleeve (3), and fix the first bracket (4) and the second bracket (7). Take out the eyepiece and install a gasket (31) of appropriate thickness inside the sleeve (3) as needed. Install the hand drill (1) on the sleeve (3), adjust the drilling device and the sleeve (3) to ensure that the tip of the drill bit (1) is in slight contact with the test point; According to the requirements, remove the gasket (31) of the corresponding thickness from the inside of the sleeve (3). Start the drilling device to drill blind holes of the corresponding depth and size at the test point; Subsequent tests were conducted, and the residual stress in the test area was calculated.