Tool and method for determining pasting coordinates of strain gauges of aero-engine turbine blades

Abstract

The invention discloses a tool and method for determining a strain gauge pasting coordinate of an aero-engine turbine blade, and belongs to the technical field of aero-engine blade fatigue tests. The tool comprises a body, an adjusting mechanism, a fixing mechanism and a plurality of functional surfaces, the body is of an L-shaped structure; the functional surface comprises a B1 surface and an A1 surface which are positioned on one side of the long edge of the L-shaped structure and are in a step shape in sequence; the functional surface further comprises a surface A2 and a surface B4 which are positioned on the other side of the long edge of the L-shaped structure and are arranged in parallel; the B1 surface and the A2 surface are positioned on the same horizontal plane; the functional surface further comprises a surface B3 and a surface B2 which are of a curved surface structure, and the surface B3 and the surface B2 are located on two orthogonal planes adjacent to the surface A1 respectively; the B2 surface is adjacent to the A3 surface; and the outer side of the short edge side of the L-shaped structure is an A3 surface parallel to the B1 surface. According to the method, an operator can quickly and accurately position the pasting coordinates of the strain gauge according to the relative position relation of the functional surfaces, tedious measurement and repeated adjustment which are carried out in a traditional method are not needed, and the time for determining the pasting coordinates is greatly saved.

Description

Technical Field

[0001] This invention belongs to the field of fatigue testing technology for aero-engine blades, and relates to a tooling and method for determining the coordinates of strain gauges on aero-engine turbine blades. Background Technology

[0002] As a core component of high-end equipment such as aero-engines and gas turbines, the fatigue strength of blades directly affects the operational reliability and service life of the entire equipment. Blade fatigue strength testing is a necessary step to verify the stability of blade manufacturing processes and plays a crucial role in ensuring blade quality. In blade fatigue strength testing, strain gauges are typically attached to the blade body for stress calibration and monitoring. Strain gauges can accurately sense the stress changes experienced by the blade during the test and convert these physical signals into electrical signals, providing crucial data for subsequent analysis. Currently, in the process of attaching strain gauges to turbine blades, the method of using calipers combined with pencil lines is commonly used to determine the attachment position. However, the airfoil structure of turbine blades is extremely complex, with numerous irregular curved surfaces and unique contour features. When using vernier calipers for line drawing, the process is not only cumbersome and time-consuming due to the need for frequent caliper adjustments to accommodate measurements at different locations, but it is also highly susceptible to measurement errors caused by human factors.

[0003] This traditional method severely impacts the consistency and accuracy of strain gauge placement. Deviations in placement prevent the stress data monitored by the strain gauges from accurately reflecting the actual stress on the blade, thus affecting the accurate assessment of the blade's fatigue strength. Furthermore, the inefficient operation significantly reduces work efficiency, prolongs the blade production cycle, and increases production costs. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem that the existing methods for determining the strain gauge bonding position of turbine blades are cumbersome and not accurate enough, and to provide a tooling for determining the bonding coordinates of strain gauges on aero-engine turbine blades.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention discloses a tooling for determining the coordinates of strain gauges for aero-engine turbine blades, comprising a body, an adjustment mechanism, a fixing mechanism, and several functional surfaces; the body is an L-shaped structure; the functional surfaces include a stepped B1 surface and an A1 surface located on one side of the long side of the L-shaped structure; the functional surfaces also include a parallel A2 surface and a B4 surface located on the other side of the long side of the L-shaped structure; the B1 surface and the A2 surface are located on the same horizontal plane; the functional surfaces also include a curved B3 surface and a B2 surface, located on two orthogonal planes adjacent to the A1 surface; the B2 surface is adjacent to the A3 surface; the outer side of the short side of the L-shaped structure is the A3 surface, which is parallel to the B1 surface.

[0006] Further improvements are made in the following aspects: The main body is an aviation aluminum alloy frame structure.

[0007] The adjustment mechanism includes hidden rollers arranged on several functional surfaces.

[0008] The fixing mechanism includes a magnetic fixing device.

[0009] The A1 surface is the positioning reference surface for the exhaust edge of the turbine blade, and its surface roughness Ra≤0.8μm; the A1 surface is subjected to induction hardening treatment.

[0010] The B1 surface is the first scribing reference surface on the blade back, and the B1 surface is coated with a zirconia ceramic coating using plasma spraying technology; the vertical distance between the A1 surface and the B1 surface is the abscissa of the strain gauge bonding coordinate on the blade back.

[0011] The B2 surface is the second scribing reference surface on the blade back. The B2 surface is a three-dimensional curved surface adapted to the blade back profile of the turbine blade, and the fitting error with the blade back profile is ≤0.1mm.

[0012] The A3 surface is the reference surface for the tooling plane, and the fitting gap between the A3 surface and the C1 surface of the fatigue test tooling is ≤0.03mm.

[0013] The B3 surface is the reference surface for blade basin marking, with a surface contour error ≤0.08mm; the A4 surface is the reference surface for air intake edge positioning, with a flatness error ≤0.02mm / 100mm.

[0014] Secondly, this invention discloses a method for determining the bonding coordinates of strain gauges on aero-engine turbine blades based on the aforementioned tooling, comprising: The coordinates of the strain gauges attached to the back of the turbine blade are determined. 1.1: Clamp the turbine blade with the back facing upwards onto the fatigue testing fixture to securely position the turbine blade; 1.2: Place the A1 surface of the strain gauge bonding coordinate determination fixture in contact with the exhaust edge of the turbine blade. Adjust the position of the strain gauge bonding coordinate determination fixture so that the lower edge of the B1 surface is in contact with the back of the turbine blade. Draw a line along the contact position between the B1 surface and the back of the blade, and record it as line x1. 1.3: Make the A1 surface of the strain gauge bonding coordinate determination fixture fit with the C1 surface of the fatigue test fixture, adjust the strain gauge bonding coordinate determination fixture so that the B2 surface fits with the back profile of the turbine blade, and draw a line along the fit position of the B2 surface and the back profile of the blade, and record it as the y1 line. 1.4: The intersection of line x1 and line y1 is the coordinate point where the strain gauge is pasted on the back of the turbine blade; The coordinates of the strain gauges attached to the turbine blade blade basin are determined. 2.1: Mount the turbine blade with the blade head facing upwards onto the fatigue test fixture to securely position the turbine blade; 2.2: Make the A1 surface of the strain gauge bonding coordinate determination fixture fit with the C1 surface of the fatigue test fixture, adjust the strain gauge bonding coordinate determination fixture so that the B3 surface fits with the blade basin surface of the turbine blade, and draw a line along the fit position of the B3 surface and the blade basin surface, and record it as the y2 line. 2.3: Adjust the strain gauge bonding coordinates to determine the fixture, so that surface A3 and the fatigue test fixture are placed on the same plane, press the inlet edge of the turbine blade against surface A4, and make the edge of surface B4 fit with the blade head of the turbine blade. Draw a line along the fit position of the edge of surface B4 and the blade head, and mark it as line x2. 2.4: The intersection of the y2 line and the x2 line is the coordinate of the strain gauge pasted on the turbine blade basin.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a fixture for determining the bonding coordinates of strain gauges on aero-engine turbine blades. The fixture body adopts an L-shaped structure and is equipped with multiple functional surfaces. Surfaces B1 and A1, B3 and B2, located on one side of the long side of the L-shaped structure, are arranged in a stepped pattern. This stepped design provides a clear and orderly reference for determining the bonding coordinates of the strain gauges. Simultaneously, surfaces A2 and B4, parallel to each other on the other side of the long side of the L-shaped structure, and surfaces B3 and B2, which are curved surfaces located on two orthogonal planes adjacent to surface A1 (surface B2 is adjacent to surface A3), along with surface A3 parallel to surface B1 on the outer side of the short side, work together to form a comprehensive, multi-angle coordinate reference system. Operators can quickly and accurately locate the bonding coordinates of the strain gauges based on the relative positions of these functional surfaces, eliminating the need for tedious measurements and repeated adjustments required by traditional methods, significantly saving time in determining bonding coordinates. Integrating multiple functional surfaces onto a single L-shaped structure makes the entire fixture an organic whole. When determining the coordinates for strain gauge bonding, multiple separate tools or equipment are unnecessary. Operators simply assemble the turbine blades with the fixture, utilizing the various functional surfaces of the fixture to quickly complete the coordinate positioning, further improving operational efficiency and achieving the goal of rapidly determining the strain gauge bonding coordinates. The various functional surfaces of the fixture form a standardized coordinate reference system, providing a unified standard for strain gauge bonding on all turbine blades. Whether bonding different turbine blades from the same batch or different batches, operators can determine the same bonding coordinates based on the functional surfaces of the fixture, ensuring the consistency of strain gauge bonding positions on all turbine blades. This consistency is crucial for blade fatigue testing because it ensures the comparability and reliability of test data, enabling researchers to accurately analyze the performance of different turbine blades under the same test conditions. The fixture of this invention has good durability and reusability. During multiple uses, as long as the functional surfaces of the fixture are not damaged or deformed, it can always provide a stable coordinate reference for strain gauge bonding. This means that the same fixture can be used to determine the strain gauge bonding coordinates in different production batches or test projects, further ensuring the consistency of bonding positions. At the same time, reusable tooling reduces production costs and improves resource utilization efficiency.

[0016] Furthermore, to ensure the accuracy of strain gauge bonding coordinates, each functional surface of the fixture underwent rigorous precision control during manufacturing. Surfaces B1 and A2 are on the same horizontal plane; this precise flatness requirement ensures a stable horizontal reference for strain gauge bonding, preventing coordinate deviations caused by uneven reference surfaces. Simultaneously, the relative positions of the functional surfaces, such as parallelism and perpendicularity, were precisely machined and tested. This allows operators to accurately determine strain gauge bonding coordinates using the fixture based on these precise geometric relationships, effectively reducing human error and improving the accuracy of coordinate determination. The L-shaped structure design gives the fixture high structural stability. During strain gauge bonding coordinate determination, the fixture can withstand certain external forces without deformation, ensuring the relative positions of the functional surfaces remain stable. This means that regardless of how the operator manipulates the fixture, the strain gauge bonding coordinates determined based on the functional surfaces are accurate and reliable, without deviations due to fixture deformation, thus providing a precise data basis for subsequent blade fatigue testing.

[0017] This invention discloses a method for determining the coordinates of strain gauges on aero-engine turbine blades. The determination of the coordinates of strain gauges on the blade back and blade base is broken down into clear steps of clamping, bonding, marking, and finding intersection points. Each step corresponds to a specific functional surface of the device (such as bonding the A1 surface to the exhaust edge and the A3 surface to the C1 surface of the tooling). It does not require the operator's experience and judgment, and solves the problems of cumbersome operation and reliance on manual skills in traditional caliper measurement and pencil drawing. Novices can quickly master the method and improve the standardization of operation. By employing the positioning logic of "double-line intersection finding," the blade back is marked with lines twice using the A1-B1 and A3-B2 surfaces, while the blade base is marked with lines twice using the A3-B3 and A4-B4 surfaces. With the help of high-precision machining of the device's functional surfaces (such as B1 surface perpendicularity error ≤0.015mm / 100mm and B3 surface contour error ≤0.08mm), the straightness error of the marking lines is ensured to be ≤0.03mm / 100mm and the intersection point position error is ≤0.08mm. Compared with traditional methods, this significantly reduces coordinate deviation, ensures that the strain gauge bonding position is consistent with the design coordinate height, and improves the reliability of stress monitoring data from blade fatigue tests. The process involves moving the device along the blade profile and adjusting its angle, adapting to the complex curved surfaces of turbine blades, such as the segmented hinge structure of the B2 surface to accommodate blades with different curvatures. This eliminates the need for designing separate positioning methods for specific blade profiles. It is also compatible with fatigue testing fixtures, requiring no additional tooling modifications. This makes it suitable for batch testing of aero-engine turbine blades, solving the problems of poor adaptability to complex blade profiles and the need for frequent adjustments in operation required by traditional methods. The process eliminates the need for repeated caliper measurements and position checks; the device's functional surfaces allow for rapid fitting and positioning, reducing the time required to determine the coordinates of each blade's blade back and face by more than 50%. Furthermore, standardized operation avoids the randomness of manual marking, ensuring that the repeatability error of strain gauge placement on different blades is ≤0.03mm, reducing test data deviations caused by inconsistencies in coordinates. This improves test preparation efficiency and ensures the accuracy of blade fatigue strength test results, providing reliable data support for verifying the stability of blade manufacturing processes. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a front view of a tooling for determining the coordinate bonding of strain gauges on an aero-engine turbine blade, according to an embodiment of the present invention. Figure 2 This is a view of a tooling for determining the coordinate bonding of strain gauges on a turbine blade of an aero-engine according to an embodiment of the present invention. Figure 3 This is a top view of a tooling for determining the coordinate bonding of strain gauges on an aero-engine turbine blade, according to an embodiment of the present invention. Figure 4 This is a front view of the fatigue testing fixture in an embodiment of the present invention; Figure 5 This is a side view of the fatigue testing fixture in an embodiment of the present invention; Figure 6 This is a schematic diagram of turbine blade clamping in an embodiment of the present invention.

[0020] Among them: 1- Fixture for determining coordinates; 2- Fixture for fatigue testing; 3- Turbine blade; 31- Blade back; 4- Patch position. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0027] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1This invention discloses a fixture for determining the bonding coordinates of strain gauges on aero-engine turbine blades, comprising a body, an adjustment mechanism, a fixing mechanism, and several functional surfaces. The body is an L-shaped aerospace aluminum alloy frame structure. The adjustment mechanism includes hidden rollers disposed on several functional surfaces. The fixing mechanism includes a magnetic fixing device. The functional surfaces include a stepped B1 surface and an A1 surface located on one side of the long side of the L-shaped structure. The A1 surface is the positioning reference surface for the exhaust edge of the turbine blade, with a surface roughness Ra≤0.8μm; the A1 surface is induction hardened. The B1 surface is the first scribing reference surface on the blade back, and the B1 surface is coated with a zirconia ceramic coating using plasma spraying technology. The vertical distance between the A1 surface and the B1 surface is the abscissa of the strain gauge bonding coordinates on the blade back. The functional surfaces also include surfaces A2 and B4, which are located on the other side of the long side of the L-shaped structure and are arranged parallel to each other; surfaces B1 and A2 are located on the same horizontal plane; the functional surfaces also include surfaces B3 and B2, which are curved surfaces, located on two orthogonal planes adjacent to surface A1; surface B2 is adjacent to surface A3; surface B2 is the second scribing reference surface on the blade back, and surface B2 is a three-dimensional curved surface adapted to the blade back profile, with a fitting error of ≤0.1mm. To ensure the accuracy of the strain gauge bonding coordinates, each functional surface on the tooling has undergone strict precision control during processing. Surfaces B1 and A2 are located on the same horizontal plane; this precise flatness requirement ensures that when these two surfaces are used as references, a stable horizontal reference can be provided for strain gauge bonding, avoiding coordinate deviations caused by uneven reference surfaces. Meanwhile, the relative positions of the various functional surfaces, such as parallelism and perpendicularity, have been precisely processed and tested. This allows operators to accurately determine the strain gauge bonding coordinates using the fixture based on these precise geometric relationships, effectively reducing human error and improving the accuracy of coordinate determination. The L-shaped structure design gives the fixture high structural stability. During the determination of strain gauge bonding coordinates, the fixture can withstand certain external forces without deformation, ensuring that the relative positions of the various functional surfaces remain stable. This means that regardless of how the operator manipulates the fixture, the strain gauge bonding coordinates determined based on the functional surfaces are accurate and reliable, and will not deviate due to deformation of the fixture itself, thus providing a precise data basis for subsequent blade fatigue tests. The outer side of the short side of the L-shaped structure is surface A3, which is parallel to surface B1. Surface A3 is the reference surface for the fixture's planar contact, and the contact gap between surface A3 and surface C1 of the fatigue test fixture is ≤0.03mm. The B3 surface is the reference surface for blade basin marking, with a surface contour error ≤0.08mm; the A4 surface is the reference surface for air intake edge positioning, with a flatness error ≤0.02mm / 100mm.

[0028] This invention discloses a fixture for determining the bonding coordinates of strain gauges on aero-engine turbine blades. The fixture body adopts an L-shaped structure and is carefully designed with multiple functional surfaces. Surfaces B1 and A1, B3 and B2, located on one side of the long side of the L-shaped structure, are arranged in a stepped pattern. This stepped design provides a clear and orderly reference for determining the bonding coordinates of the strain gauges. Simultaneously, surfaces A2 and B4, parallel to each other on the other side of the long side of the L-shaped structure, and surfaces B3 and B2, which are curved surfaces located on two orthogonal planes adjacent to surface A1, along with surface A3 parallel to surface B1 on the outer side of the short side, work together to form a comprehensive, multi-angle coordinate reference system. Operators can quickly and accurately locate the bonding coordinates of the strain gauges based on the relative positions of these functional surfaces, eliminating the need for tedious measurements and repeated adjustments required by traditional methods, significantly saving time in determining bonding coordinates. Integrating multiple functional surfaces onto a single L-shaped structure makes the entire fixture an organic whole. When determining the coordinates for strain gauge bonding, multiple separate tools or equipment are unnecessary. Operators simply assemble the turbine blades with the fixture, utilizing the various functional surfaces of the fixture to quickly complete the coordinate positioning, further improving operational efficiency and achieving the goal of rapidly determining the strain gauge bonding coordinates. The various functional surfaces of the fixture form a standardized coordinate reference system, providing a unified standard for strain gauge bonding on all turbine blades. Whether bonding different turbine blades from the same batch or different batches, operators can determine the same bonding coordinates based on the functional surfaces of the fixture, ensuring the consistency of strain gauge bonding positions on all turbine blades. This consistency is crucial for blade fatigue testing because it ensures the comparability and reliability of test data, enabling researchers to accurately analyze the performance of different turbine blades under the same test conditions. The fixture of this invention has good durability and reusability. During multiple uses, as long as the functional surfaces of the fixture are not damaged or deformed, it can always provide a stable coordinate reference for strain gauge bonding. This means that the same fixture can be used to determine the strain gauge bonding coordinates in different production batches or test projects, further ensuring the consistency of bonding positions. At the same time, reusable tooling reduces production costs and improves resource utilization efficiency.

[0029] See Figure 2 and Figure 3 This invention discloses a method for determining the bonding coordinates of strain gauges on aero-engine turbine blades based on the above-mentioned tooling, comprising: Step 1: Determine the coordinates by attaching strain gauges to the back of the turbine blade; 1.1: Clamp the turbine blade 3 with the back facing upward on the fatigue test fixture 2 to securely position the turbine blade 3; 1.2: Place the A1 surface of the strain gauge bonding coordinate determination fixture 1 in contact with the exhaust edge of the turbine blade 3, adjust the position of the strain gauge bonding coordinate determination fixture 1 so that the lower edge of the B1 surface is in contact with the back of the turbine blade 3, and draw a line along the contact position between the B1 surface and the back of the blade, which is recorded as line x1. 1.3: Make the A1 surface of the strain gauge bonding coordinate determination fixture 1 fit with the C1 surface of the fatigue test fixture 2, adjust the strain gauge bonding coordinate determination fixture 1 so that the B2 surface fits with the back profile of the turbine blade 3, and draw a line along the fit position of the B2 surface and the back profile of the blade, and record it as line y1. 1.4: The intersection of line x1 and line y1 is the coordinate point for the strain gauge pasted on the back of turbine blade 3; Step 2: Determine the coordinates by attaching strain gauges to the turbine blade basin; 2.1: Mount the turbine blade 3 with the blade facets facing upwards onto the fatigue test fixture 2 to securely position the turbine blade 3; 2.2: Make the A1 surface of the strain gauge bonding coordinate determination fixture 1 fit with the C1 surface of the fatigue test fixture 2, adjust the strain gauge bonding coordinate determination fixture 1 so that the B3 surface fits with the blade basin surface of the turbine blade 3, and draw a line along the fit position of the B3 surface and the blade basin surface, and record it as the y2 line. 2.3: Adjust the strain gauge bonding coordinates to determine fixture 1, so that surface A3 and fatigue test fixture 2 are placed on the same plane, press the air intake edge of turbine blade 3 against surface A4, and make the edge of surface B4 fit with the blade head of turbine blade 3. Draw a line along the fit position of the edge of surface B4 and the blade head, and record it as line x2. 2.4: The intersection of the y2 line and the x2 line is the coordinate of the strain gauge pasted on the turbine blade basin.

[0030] This invention discloses a method for determining the coordinates of strain gauges on aero-engine turbine blades. The determination of the coordinates of strain gauges on the blade back and blade base is broken down into clear steps of clamping, bonding, marking, and finding intersection points. Each step corresponds to a specific functional surface of the device (such as bonding the A1 surface to the exhaust edge and the A3 surface to the C1 surface of the tooling). It does not require the operator's experience and judgment, and solves the problems of cumbersome operation and reliance on manual skills in traditional caliper measurement and pencil drawing. Novices can quickly master the method and improve the standardization of operation. By employing the positioning logic of "double-line intersection finding," the blade back is marked with lines twice using the A1-B1 and A3-B2 surfaces, while the blade base is marked with lines twice using the A3-B3 and A4-B4 surfaces. With the help of high-precision machining of the device's functional surfaces (such as B1 surface perpendicularity error ≤0.015mm / 100mm and B3 surface contour error ≤0.08mm), the straightness error of the marking lines is ensured to be ≤0.03mm / 100mm and the intersection point position error is ≤0.08mm. Compared with traditional methods, this significantly reduces coordinate deviation, ensures that the strain gauge bonding position is consistent with the design coordinate height, and improves the reliability of stress monitoring data from blade fatigue tests. The process involves moving the device along the blade profile and adjusting its angle, adapting to the complex curved surfaces of turbine blades, such as the segmented hinge structure of the B2 surface to accommodate blades with different curvatures. This eliminates the need for designing separate positioning methods for specific blade profiles. It is also compatible with fatigue testing fixtures, requiring no additional tooling modifications. This makes it suitable for batch testing of aero-engine turbine blades, solving the problems of poor adaptability to complex blade profiles and the need for frequent adjustments in operation required by traditional methods. The process eliminates the need for repeated caliper measurements and position checks; the device's functional surfaces allow for rapid fitting and positioning, reducing the time required to determine the coordinates of each blade's blade back and face by more than 50%. Furthermore, standardized operation avoids the randomness of manual marking, ensuring that the repeatability error of strain gauge placement on different blades is ≤0.03mm, reducing test data deviations caused by inconsistencies in coordinates. This improves test preparation efficiency and ensures the accuracy of blade fatigue strength test results, providing reliable data support for verifying the stability of blade manufacturing processes.

[0031] The working principle of this invention is as follows: This invention mainly uses the eight surfaces and four dimensions of the strain gauge bonding coordinate determination fixture 1, which works in conjunction with the turbine blade 3 and the fatigue testing special fixture 2, to bond strain gauges at one position point each on the back and base of the aero-engine turbine blade.

[0032] One location point needs to be located on the back of the turbine blade 3 and one on the blade base, for a total of four dimensional locations.

[0033] With the turbine blade 3 facing upwards, place the strain gauge bonding coordinate determination fixture 1 along the exhaust edge of blade 3. Press the exhaust edge of turbine blade 3 against the A1 surface of the strain gauge bonding coordinate determination fixture 1. Adjust the position so that the lower edge of the B1 surface of the strain gauge bonding coordinate determination fixture 1 is in contact with the back of turbine blade 3. Draw a line along the contact position, x1=a2.

[0034] Turbine blade 3 is clamped in fatigue test fixture 2 with the blade back facing upward. Strain gauge bonding coordinate determination fixture 1 is placed on fatigue test fixture 2, keeping surface A1 of strain gauge bonding coordinate determination fixture 1 in contact with surface C1 of fatigue test fixture 2. Move strain gauge bonding coordinate determination fixture 1 so that surface B2 is in contact with the blade back profile of turbine blade 3. Draw a line along the contact position, y1=a1+a0.

[0035] The intersection of the two lines on the back of the blade is the coordinate of the strain gauge attached to the back of the blade.

[0036] Turbine blade 3 is clamped in fatigue test fixture 2 with the blade head facing upward. Strain gauge bonding coordinate determination fixture 1 is placed on fatigue test fixture 2. The A1 surface of strain gauge bonding coordinate determination fixture 1 is kept in contact with the C1 surface of fatigue test fixture 2. The strain gauge bonding coordinate determination fixture 1 is moved so that B3 is in contact with the blade head surface of turbine blade 3. A line is drawn along the contact position, y2=a1+a0.

[0037] Turbine blade 3 is clamped in fatigue test fixture 2 with the blade head facing upward. The A3 surface of strain gauge bonding coordinate determination fixture 1 is placed on the same plane as fatigue test fixture 2. The air inlet edge of turbine blade 3 is pressed against the A4 surface of strain gauge bonding coordinate determination fixture 1. The position is adjusted so that the edge of the B4 surface of strain gauge bonding coordinate determination fixture 1 is in contact with the blade head of turbine blade 3. A line is drawn along the contact position, x2=a3.

[0038] The intersection of the two lines on the blade basin is the coordinate of the strain gauge attached to the blade basin.

[0039] This invention enables rapid and accurate determination of strain gauge bonding coordinates during blade fatigue testing of aero-engine turbine blades, improving work efficiency and ensuring consistency of bonding positions and test accuracy.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., 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 tooling for determining the coordinates of strain gauges on aero-engine turbine blades, characterized in that, The device includes a main body, an adjustment mechanism, a fixing mechanism, and several functional surfaces. The main body has an L-shaped structure. The functional surfaces include a stepped B1 surface and an A1 surface located on one side of the long side of the L-shaped structure. The functional surfaces also include a parallel A2 surface and a B4 surface located on the other side of the long side of the L-shaped structure. The B1 surface and the A2 surface are on the same horizontal plane. The functional surfaces also include a curved B3 surface and a B2 surface, located on two orthogonal planes adjacent to the A1 surface. The B2 surface is adjacent to the A3 surface. The A3 surface is parallel to the B1 surface on the outer side of the short side of the L-shaped structure.

2. The fixture for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 1, characterized in that, The main body is an aviation aluminum alloy frame structure.

3. The fixture for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 1, characterized in that, The adjustment mechanism includes hidden rollers arranged on several functional surfaces.

4. The fixture for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 1, characterized in that, The fixing mechanism includes a magnetic fixing device.

5. The fixture for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 1, characterized in that, The A1 surface is the positioning reference surface for the exhaust edge of the turbine blade, and its surface roughness Ra≤0.8μm; the A1 surface is subjected to induction hardening treatment.

6. The fixture for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 5, characterized in that, The B1 surface is the first scribing reference surface on the blade back, and the B1 surface is coated with a zirconia ceramic coating using plasma spraying technology; the vertical distance between the A1 surface and the B1 surface is the abscissa of the strain gauge bonding coordinate on the blade back.

7. The tooling for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 6, characterized in that, The B2 surface is the second scribing reference surface on the blade back. The B2 surface is a three-dimensional curved surface adapted to the blade back profile of the turbine blade, and the fitting error with the blade back profile is ≤0.1mm.

8. The fixture for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 1, characterized in that, The A3 surface is the reference surface for the tooling plane, and the fitting gap between the A3 surface and the C1 surface of the fatigue test tooling is ≤0.03mm.

9. The fixture for determining the coordinate bonding of strain gauges for aero-engine turbine blades according to claim 1, characterized in that, The B3 surface is the reference surface for blade basin marking, with a surface contour error ≤0.08mm; the A4 surface is the reference surface for air intake edge positioning, with a flatness error ≤0.02mm / 100mm.

10. A method for determining the coordinates of strain gauge bonding on an aero-engine turbine blade based on the tooling described in any one of claims 1-9, characterized in that, include: The coordinates of the strain gauges attached to the back of the turbine blade are determined. 1.1: The turbine blade (3) is clamped on the fatigue test fixture (2) with the blade back facing upward, so that the turbine blade (3) is stably positioned; 1.2: Place the A1 surface of the strain gauge bonding coordinate determination tool (1) in contact with the exhaust edge of the turbine blade (3), adjust the position of the strain gauge bonding coordinate determination tool (1) so that the lower edge of the B1 surface is in contact with the back of the turbine blade (3), and draw a line along the contact position between the B1 surface and the back of the blade, which is recorded as line x1. 1.3: Make the A1 surface of the strain gauge bonding coordinate determination fixture (1) fit with the C1 surface of the fatigue test fixture (2), adjust the strain gauge bonding coordinate determination fixture (1) so that the B2 surface fits with the blade back profile of the turbine blade (3), and draw a line along the fit position of the B2 surface and the blade back profile, which is recorded as line y1. 1.4: The intersection of line x1 and line y1 is the coordinate of the strain gauge pasted on the back of the turbine blade (3); The coordinates of the strain gauges attached to the turbine blade blade basin are determined. 2.1: The turbine blade (3) is clamped upward on the fatigue test fixture (2) to secure the turbine blade (3) in place; 2.2: Make the A1 surface of the strain gauge bonding coordinate determination fixture (1) fit with the C1 surface of the fatigue test fixture (2), adjust the strain gauge bonding coordinate determination fixture (1) so that the B3 surface fits with the blade basin surface of the turbine blade (3), and draw a line along the fitting position of the B3 surface and the blade basin surface, which is recorded as line y2. 2.3: Adjust the strain gauge bonding coordinates to determine the fixture (1), so that surface A3 and fatigue test fixture (2) are placed on the same plane, press the inlet edge of turbine blade (3) against surface A4, and make the edge of surface B4 fit with the blade head of turbine blade (3). Draw a line along the fit position of the edge of surface B4 and the blade head, and record it as line x2. 2.4: The intersection of the y2 line and the x2 line is the coordinate of the strain gauge pasted on the turbine blade basin.

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