A composite blade tenon sampling piece tensile test clamp and test method

Abstract

The present application relates to a kind of composite material blade tenon sampling piece tensile test fixture and test method.The tensile test fixture is used to clamp the two ends of tenon sampling piece and carry out tensile test, specifically includes ear piece adapter, mortise simulation piece, pin, a pair of clamping plate and several clamping plate bolts.The upper end of ear piece adapter is connected with the upper clamp of testing machine, and the lower end of mortise simulation piece is connected with the lower clamp of testing machine.The lower end of ear piece adapter is connected with the upper end of two clamping plates by pin penetration, and pin shaft connection pair is formed.Two clamping plates are oppositely arranged and clamp tenon sampling piece by clamping plate bolt in array compression mode.The inner side of clamping plate and tenon sampling piece contact is provided with tooth groove structure, and the inner cavity profile of mortise simulation piece is adapted to the shape of the outer surface of tenus sampling piece.Compared with prior art, the present application is suitable for static strength test under 0~250 kN large load range, and significantly improves the stability and success rate of composite material special-shaped sampling piece test.

Description

Technical Field

[0001] This invention relates to the field of mechanical property testing and evaluation technology, and in particular to a tensile testing fixture and method for sampling tenons of composite material blades. Background Technology

[0002] Carbon fiber reinforced resin matrix composites (CFRP) have become the preferred material for modern aero-engine fan blades due to their high specific strength, high specific modulus, and excellent fatigue resistance. In actual aero-engine operation, under twice the centrifugal force, the dovetail joint structure at the root of the fan blade is prone to delamination and cracking, directly affecting operational safety. The tenon joint, as the core area for load transfer, experiences extremely complex stress states and is a critical weak point in structural design. To ensure the safety of composite blades during actual service, tensile load tests must be conducted on the tenon structure in a laboratory environment to obtain its true strength data and evaluate its mechanical properties.

[0003] Traditional composite material mechanical property tests often use regular straight tenon simulation parts, whose clamping ends are usually designed as straight planes to facilitate clamping using general-purpose wedge clamps, drilled dowels, or threads. However, for real tenon samples cut directly from finished blades, their geometric features are significantly complex and asymmetrical. Existing clamps designed for straight tenons are difficult to load directly, and are prone to causing clamping position failure or introducing eccentric bending moments during loading, thus failing to accurately reflect the load-bearing capacity of the blade tenon structure. In addition, commonly used dowel clamping requires drilling holes in the clamping section of the specimen, which breaks continuous fibers and causes serious damage, significantly reducing the load-bearing capacity of the clamping section and causing the specimen to fracture prematurely in non-test areas.

[0004] CN115436161A discloses a tensile fatigue testing fixture and method for tenon joint structures of ceramic matrix composites. The fixture uses round bar clamps for both the upper and lower sections, which are connected to a fatigue testing machine. Both the upper and lower round bars are threaded to other parts. The upper part includes an upper round bar, a U-shaped plate, a pin, a clamping plate, clamping plate bolts, and washers; the lower part consists of transverse clamping plates, longitudinal clamping plates, a transition section, and a lower round bar. This fixture can flexibly adapt to ceramic matrix composite tenon specimens of different sizes, while avoiding the problem of test failure caused by fracture of the clamping section due to dovetail, pin, or threaded clamping. It can be used for tensile load tests on composite tenon joints from 0 N to 100 kN. However, due to its structural limitations, the clamping plate design of this fixture is only suitable for geometrically regular straight tenon simulation parts, making it difficult to accommodate real tenon samples with complex irregular shapes cut from finished blades. Furthermore, the design load of this fixture is relatively small, which cannot meet the ultra-large load loading requirements of composite fan blades under twice the centrifugal force test requirements.

[0005] In summary, existing technologies mostly focus on testing simulated parts with regular shapes, and lack a simple and reliable test fixture and matching tensile testing method for directly clamping real blade irregularly shaped samples. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art by providing a tensile testing fixture and method for sampling composite material blade tenons.

[0007] The objective of this invention can be achieved through the following technical solutions: The present invention first provides a tensile test fixture for a composite material blade tenon sample, which is used to clamp both ends of the tenon sample and perform a tensile test. The tensile test fixture includes an ear adapter, a tenon simulation part, a pin, a pair of clamping plates and several clamping plate bolts. The upper end of the ear adapter is connected to the upper clamp of the testing machine, and the lower end of the tenon and groove simulation part is connected to the lower clamp of the testing machine. The lower end of the ear-shaped adapter is connected to the upper end of the two clamping plates by a pin, forming a pin connection pair that can be finely adjusted and aligned; the two clamping plates are arranged opposite to each other and clamp the upper end of the tenon sample piece by an array of clamping bolts. The inner surface of the clamping plate that contacts the tenon sample is provided with a toothed groove structure for constraining the tenon sample; the inner cavity surface of the tenon groove simulation part is adapted to the outer surface shape of the tenon sample to form a geometric constraint.

[0008] Furthermore, the ear adapter includes a cylindrical connector and an ear piece.

[0009] Furthermore, the cylindrical connector is used to connect to the upper clamp of the testing machine.

[0010] Furthermore, the ear piece is provided with a through hole for the pin to pass through.

[0011] Furthermore, the cylindrical connector is integrally connected to or detachably connected to the lug.

[0012] Furthermore, the clamping plate includes a clamping plate body and an ear plate integrally connected to the upper end of the clamping plate body.

[0013] Furthermore, the ear plate has a through hole for the pin to pass through, and the ear plate adapter is clamped between the two clamping plates.

[0014] Furthermore, the clamp body has ≥3 connecting holes for pins to pass through on both sides along its length direction, and the corresponding connecting holes on both sides are at the same horizontal height.

[0015] Furthermore, washers are provided between the nut of the clamping bolt and the clamping plate to even out the preload of the clamping bolt and prevent the nut of the clamping bolt from loosening.

[0016] Furthermore, the mortise and tenon simulation component includes a clamping body and a connecting piece integrally connected to the clamping body.

[0017] Furthermore, the inner cavity surface of the clamping body is adapted to the outer surface shape of the tenon sampling piece.

[0018] Furthermore, the connecting piece is used to connect with the lower clamp of the testing machine.

[0019] Furthermore, the ear-shaped adapter, pin, clamp, and tenon groove simulation parts are all made of 45 steel that has undergone tempering and high-frequency quenching processes.

[0020] Furthermore, the load transfer path of the tensile testing fixture is as follows: The ear-shaped adapter receives the axial tensile force applied by the testing machine and transmits it to the clamps on both sides through pins. The ear-shaped adapter and the clamps are connected by pins to achieve automatic alignment of the force direction. The toothed clamp is fastened to the tenon sample by the normal preload provided by the clamp bolts and washers; the load is transmitted through the mechanical locking force between the toothed structure on the inner side of the clamp and the surface of the tenon sample, as well as the resultant force of friction, to ensure that no relative slippage occurs. The axial tensile force at the bottom of the tenon sample acts directly on the inner cavity surface of the tenon-groove simulation part through its geometric surface; the load is directly transmitted downward from the lower end of the tenon-groove simulation part to the lower clamp of the testing machine.

[0021] This invention also provides a method for tensile testing of composite material blade tenon samples, using the tensile testing fixture described in any of the above-mentioned embodiments. The testing method includes the following steps: S1: Place the lower end of the tenon sample in the inner cavity of the mortise simulation part, and use the inner cavity surface of the mortise simulation part to precisely fit and position the tenon sample. Place the two clamping plates symmetrically on both sides of the clamping section above the tenon sample, so that the inner toothed grooves of the clamping plates are in contact with the surface of the sample. Insert the clamping bolts in sequence and place the washers. Tighten the clamping bolts in an array according to the pre-tightening torque. Clamp the tenon sample piece by mechanical locking force. Align the ear adapter with the upper ends of the two clamping plates, and connect them by passing pins through the pin holes to complete the clamp assembly; S2: Move the assembled fixture to the testing machine, insert the top of the lug adapter into the upper chuck of the testing machine and lock it; insert the lower end of the tenon and groove simulation part into the lower chuck of the testing machine and lock it, ensuring that the axis is perpendicular; Strain gauges or displacement monitoring sensors are installed on the test section and key parts of the tenon sample to monitor the deformation and damage status in real time during the tensile process. S3: Set the loading parameters through the load controller of the testing machine and apply an increasing axial tensile load according to the test requirements; During the loading process, observe the self-alignment adjustment of the lug adapter and the pin to ensure that the load is smoothly transferred to the target range of 250 kN. The load-displacement curve is continuously monitored. When the tenon sample fails due to structural fracture or reaches the predetermined load value, the testing machine stops loading and the test data is recorded.

[0022] Furthermore, the tensile testing method is applicable to static strength tests under a large load range of 0~250 kN.

[0023] Furthermore, the tenon sample is a carbon fiber reinforced resin matrix composite material.

[0024] Compared with the prior art, the present invention has the following technical advantages: (1) This invention provides a tensile testing fixture for composite blade tenon sampling parts with excellent shape compatibility and high reliability, and a matching testing method. Its structure is simple and low-cost, and it can flexibly adapt to the tenon sampling requirements at different positions on the blade. Through conformal fitting and pin alignment design, it ensures precise alignment of the loading axis and can bear extremely large loads, providing an effective testing method for the strength evaluation of real composite blade structures. The testing fixture of this invention is suitable for static strength testing under a large load range of 0N to 250kN, significantly improving the stability and success rate of composite irregular-shaped sampling part testing.

[0025] (2) The tensile test fixture of the present invention has good shape compatibility and positioning accuracy. By designing a conformal fitting tenon groove simulation part for real blade irregular sample parts, it solves the problem that traditional straight tenon fixtures cannot adapt to asymmetrical geometric features and provides reliable support and positioning.

[0026] (3) The tensile test fixture of the present invention achieves reliable transmission of large loads through mechanical locking of toothed clamp plate and bolt array, avoids continuous fiber breakage caused by drilling holes in the specimen, and protects the integrity of composite material specimen.

[0027] (4) The tensile test fixture of the present invention uses the pin pair formed by the lug and the pin to release the rotational degree of freedom, automatically compensate for the eccentric bending moment when the irregular specimen is loaded, and ensure that the stress state conforms to the pure tensile working condition.

[0028] (5) The tensile test fixture of the present invention has a clear structure and is made of commonly used high-performance steel, which significantly reduces the evaluation cost of complex irregular parts tests while ensuring high reliability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the tensile test fixture for the composite material blade tenon sample of the present invention.

[0030] Figure 2 This is an exploded view of the tensile test fixture for the composite material blade tenon sample of the present invention.

[0031] Figure 3 This is a physical image of the tensile test fixture for the composite material blade tenon sampling part of the present invention.

[0032] Figure 4 This is the load-displacement curve of the testing machine obtained in Embodiment 2 of the present invention.

[0033] Explanation of markings in the diagram: 1-Ear adapter, 1.1-Cylindrical connector, 1.2-Ear; 2-Pin; 3-Clamping plate, 3.1-Clamping plate body, 3.2-Ear plate, 3.3-Connecting hole; 4-Clamping bolts; 5-Gasket; 6-Tenon sample; 7-Tongue and groove simulation part, 7.1-Clamping body, 7.2-Connecting piece. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0035] In this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the 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 invention; the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; they can be internal connections between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] 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.

[0037] Example 1: This invention first provides a tensile testing fixture for a composite material blade tenon sample, used to clamp both ends of the tenon sample 6 and perform a tensile test. The tensile testing fixture in this embodiment includes an ear-shaped adapter 1, a tenon-groove simulation component 7, a pin 2, a pair of clamping plates 3, and several clamping plate bolts 4. The ear-shaped adapter 1, pin 2, clamping plates 3, and tenon-groove simulation component 7 are all made of 45# steel that has undergone tempering and high-frequency quenching processes, while the remaining components are made of high-strength alloy steel to ensure the reliability of the overall structure.

[0038] The lug adapter 1 in this embodiment includes a cylindrical connector 1.1 and a lug 1.2. The cylindrical connector 1.1 is used to connect with the upper clamp of the testing machine. The lug 1.2 has a through hole for the pin 2 to pass through. The lug 1.2 is connected to the upper ends of the two clamping plates 3 through the pin 2, forming a pin-shaft connection pair that can be finely adjusted for alignment. The cylindrical connector 1.1 and the lug 1.2 are either integrally connected or detachably connected.

[0039] In this embodiment, two clamping plates 3 are arranged opposite each other and clamped to the upper end of the tenon sampling piece 6 by an array of clamping bolts 4. The clamping plate 3 in this embodiment includes a clamping plate body 3.1 and an ear plate 3.2 integrally connected to the upper end of the clamping plate body 3.2. The ear plate 3.2 has a through hole for the pin 2 to pass through, and the ear plate adapter 1 is clamped between the two clamping plates 3. The clamping plate body 3.1 has ≥3 connecting holes 3.3 for the pin 2 to pass through on both sides along the length direction from top to bottom, and the corresponding connecting holes 3.3 on both sides are at the same horizontal height.

[0040] In addition, the inner side of the clamping plate 3 in contact with the tenon sampling piece 6 in this embodiment is provided with a toothed groove structure for constraining the tenon sampling piece 6.

[0041] In this embodiment, a washer 5 is provided between the nut of the clamp bolt 4 and the clamp 3 to even out the preload of the clamp bolt 4 and prevent the nut of the clamp bolt 4 from loosening.

[0042] The mortise and tenon simulation component 7 in this embodiment includes a clamping body 7.1 and a connecting piece 7.2 integrally connected to the clamping body 7.1, wherein the connecting piece 7.2 is used to connect to the lower clamp of the testing machine. The inner cavity surface of the clamping body 7.1 is adapted to the outer surface shape of the tenon sampling component 6, forming a geometric constraint.

[0043] Example 2: This embodiment provides a tensile test fixture and test method for composite blade tenon sample parts, which aims to meet the high load static strength loading requirements of carbon fiber reinforced resin matrix composite (CFRP) fan blade sample parts under the test requirement of twice the centrifugal force at room temperature.

[0044] Carbon fiber reinforced resin matrix composites (CFRPs) possess high specific strength, high specific modulus, and excellent fatigue resistance; however, they are highly susceptible to interlaminar cracking under complex stress conditions. In actual operation of aero-engines, fan blades subjected to twice the centrifugal force are prone to delamination cracking at their root dovetail structure, directly impacting operational safety. Therefore, accurate assessment of the cracking load and bearing limit of this area is urgently needed.

[0045] To balance the cost-effectiveness and data accuracy of testing, actual blade samples are often used instead of full-size blades for tensile performance verification. Because the samples retain the true structural features (irregular shape of the upper clamping area and a standard dovetail tenon at the lower end), the testing process faces higher requirements: firstly, the direction of the tensile load must be precisely through the centerline of the tenon; secondly, additional stress concentration or secondary damage must be avoided due to clamping treatments (such as drilling). This test aims to determine the load-bearing limit of the dovetail tenon structure, significantly reducing the cost of full-size blade testing while providing crucial data support for blade structural optimization design and molding process verification. This has significant practical engineering implications for ensuring the assembly reliability of aero-engine blades, successfully passing airworthiness certification, and promoting the research and development of aero-engine composite material equipment.

[0046] This embodiment uses a fan blade tenon sample 6 made of carbon fiber reinforced resin matrix composite (CFRP). The upper clamping assembly and the lower support assembly are made of 45# steel and have undergone tempering and high-frequency quenching treatment. The maximum load designed for the experiment is 250 kN (25 t), mainly used for static strength testing at room temperature.

[0047] like Figure 1-3 As shown, the tensile test fixture for the composite blade tenon sample in this embodiment includes a lug adapter 1, a pin 2, a toothed clamping plate 3, clamping plate bolts 4, a washer 5, a tenon sample 6, and a tenon simulation component 7. The lug adapter 1, pin 2, toothed clamping plate 3, and tenon simulation component 7 are all made of 45# steel and have undergone tempering and high-frequency quenching treatment to achieve high strength and high toughness, ensuring no plastic deformation occurs during the high-load static strength test and guaranteeing the service life of the fixture.

[0048] In this embodiment, the upper chuck of the tensile testing machine clamps the cylindrical section at the top of the lug adapter 1. The lower end of the lug adapter 1 is connected to the upper ends of the two clamping plates 3 by a pin 2, forming a pin-shaft connection pair that can be finely adjusted for alignment. The lower ends of the two clamping plates 3 are clamped to the upper clamping section of the tenon sample 6 by eight clamping bolts 4. A washer 5 is provided between the nut and the clamping plate 3. The inner surface of the clamping plate 3 in contact with the tenon sample 6 has a toothed structure, which constrains the sample through mechanical locking to prevent slippage under heavy loads. The lower end of the tenon sample 6 mates with the mortise and tenon simulation part 7. The outer surface of the machined layer of the tenon sample 6 conforms to the inner cavity of the mortise and tenon simulation part 7, which restricts displacement and rotation through geometric constraints. The bottom of the mortise and tenon simulation part 7 has a sheet structure that is directly clamped in the lower chuck of the testing machine.

[0049] In this embodiment, the ear-shaped adapter 1 and the clamping plate 3 are connected by a pin 2. This pin-shaft connection automatically compensates for the eccentric moment caused by the geometric asymmetry of the tenon sample 6 by releasing the rotational degree of freedom of the tenon sample 6 in the direction of the pin axis, so that the tensile load is always transmitted along the centerline of the test section of the tenon sample 6.

[0050] In this embodiment, the clamping plate 3, under the normal preload provided by the eight clamping bolts 4, generates a restraining force through the mechanical locking and friction interface between the toothed structure and the surface of the tenon sample 6. This clamping method, combining friction and mechanical locking, avoids fiber breakage caused by drilling holes in the composite material specimen, thus protecting the specimen's integrity. The distance between the two clamping plates 3 can be freely adjusted according to the thickness of the clamping section of the tenon sample 6.

[0051] In this embodiment, the gasket 5 is located between the clamping plate 3 and the fastening nut of the clamping plate bolt 4. Its function is to uniformly distribute the bolt preload and prevent vibration and loosening during the test, while increasing the contact area to optimize the clamping effect.

[0052] In this embodiment, the inner cavity surface of the mortise and tenon simulation part 7 is completely fitted with the machined layer surface of the tenon sample part 6. The axial sliding, lateral displacement and rotation around the axis of the tenon sample part 6 are restricted by the geometric limit in three-dimensional space, thereby ensuring the stability of the sample part's posture during loading and facilitating experimental observation of the failure location.

[0053] In this embodiment, the precise positioning function of the mortise and tenon simulation part 7, together with the pin connection pair formed by the upper ear piece 1 and the pin 2, can automatically compensate for the eccentric moment caused by the geometric asymmetry of the sample part, so that the tensile load is always transmitted along the center line of the test section of the tenon sample part 6.

[0054] The tensile testing fixture of this embodiment is suitable for the temperature and static strength testing of tenon samples 6 at different positions and with different geometric dimensions on the blade. By adjusting the distance between the two clamping plates 3 and replacing the corresponding conformal fitting tenon groove simulation part 7, stable testing of tenon samples 6 of different specifications can be achieved, which has significant versatility and flexibility.

[0055] The specific load transfer path of the tensile testing fixture in this embodiment is as follows: 1. The load transfer route on the upper side of the test fixture is as follows: the axial tensile force applied by the testing machine is received by the lug adapter 1 and transferred to the toothed clamping plates 3 on both sides through the pin 2; during this process, the pin 2 mainly bears the shear force, and the lug adapter 1 and the clamping plate 3 are connected by the pin to achieve automatic centering of the force direction.

[0056] 2. Load transfer path of clamping section: The toothed clamping plate 3 is fastened to the tenon sample 6 by the normal preload provided by the clamping plate bolts 4 and the washer 5; the load is transferred through the mechanical locking force and friction force between the inner toothed groove of the clamping plate 3 and the surface of the tenon sample 6, ensuring that the tenon sample 6 does not slip relative to the test load.

[0057] 3. Load transfer path on the lower side: The axial tensile force at the bottom of the tenon sample 6 acts directly on the inner cavity mating surface of the tenon simulation part 7 through its geometric surface; the load is directly transferred downward from the lower end piece of the tenon simulation part 7 to the lower clamp of the testing machine.

[0058] 4. Stress characteristics: In the overall structure, pin 2 is subjected to shear force, ear adapter 1 and clamping plate 3 mainly bear axial tensile stress, and the internal surface of the tenon simulation part 7 bears normal compressive stress from the tenon sample part 6.

[0059] The tensile testing method in this embodiment includes the following steps: (1) Assembly of test pieces: First, the inner cavity shape of the tenon groove simulation piece 7 is designed according to the sampling position of the blade. The lower end of the tenon sample piece 6 is placed in the inner cavity of the tenon groove simulation piece 7 to achieve conformal fitting and positioning.

[0060] (2) Installation of the upper clamp: Place the two toothed clamping plates 3 on both sides of the clamping section of the tenon sample 6, insert eight clamping plate bolts 4 and use washers 5, and tighten them according to the specified force matrix to ensure that the toothed grooves are embedded in the surface of the tenon sample 6. Then connect the ear adapter 1 to the clamping plate 3 by pins 2.

[0061] (3) Positioning of the testing machine: Insert the cylindrical section at the top of the ear adapter 1 and the plate at the bottom of the tenon simulation part 7 into the upper and lower clamps of the testing machine respectively, and ensure that the axis of the whole set of devices is vertically aligned.

[0062] (4) Monitoring setup: Based on the characteristics of CFRP material, strain gauges are attached to the test section of tenon sample 6, and displacement sensors are set up to monitor the deformation and damage evolution during the tensile process in real time.

[0063] (5) Loading Test: The loading parameters are set using the load controller of the testing machine, and a monotonically increasing axial tensile load is applied according to the test requirements. During loading, the self-alignment adjustment of the lug adapter 1 and pin 2 is observed to ensure that the load is smoothly transferred to the target range of 250 kN. The load-displacement curve is continuously monitored. When the tenon sample 6 experiences structural fracture failure or reaches the predetermined load value, the testing machine stops loading, the test data is recorded, and the test ends. The final result is as follows: Figure 4 The load-displacement curve of the testing machine is shown.

[0064] The tensile testing fixture of this invention can flexibly adapt to tenon sampling parts with different positions and bending shapes on blades, while avoiding the need for drilling holes in composite material specimens or the risk of fracture due to abrupt changes in cross-section, as required by traditional fixtures, ensuring that the specimen does not fail prematurely in the clamping section. The tensile testing fixture of this invention is suitable for static strength testing under a large load range of 0~250kN, significantly improving the stability and success rate of testing irregularly shaped composite material sampling parts.

[0065] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A tensile testing fixture for a composite material blade tenon sample, used to clamp both ends of a tenon sample (6) and perform a tensile test, characterized in that, The tensile test fixture includes an ear-shaped adapter (1), a tenon-groove simulation piece (7), a pin (2), a pair of clamping plates (3), and several clamping plate bolts (4). The upper end of the ear adapter (1) is connected to the upper clamp of the testing machine, and the lower end of the tenon and groove simulation part (7) is connected to the lower clamp of the testing machine. The lower end of the ear adapter (1) is connected to the upper end of the two clamping plates (3) by a pin (2) to form a pin connection pair that can be finely adjusted and aligned; the two clamping plates (3) are arranged opposite to each other and clamp the upper end of the tenon sample (6) by an array of clamping bolts (4); The inner side of the clamping plate (3) that contacts the tenon sample (6) is provided with a toothed groove structure for constraining the tenon sample (6); the inner cavity surface of the tenon groove simulation part (7) is adapted to the outer surface shape of the tenon sample (6) to form a geometric constraint.

2. The tensile test fixture for a composite material blade tenon sample as described in claim 1, characterized in that, The ear adapter (1) includes a cylindrical connector (1.1) and an ear piece (1.2). The cylindrical connector (1.1) is used to connect with the upper clamp of the testing machine; The ear piece (1.2) has a through hole for the pin (2) to pass through; The cylindrical connector (1.1) is integrally connected to the lug (1.2) or can be detachably connected.

3. The tensile test fixture for a composite material blade tenon sample as described in claim 1, characterized in that, The clamp (3) includes a clamp body (3.1) and an ear plate (3.2) integrally connected to the upper end of the clamp body (3.1). The ear plate (3.2) has a through hole for passing through the pin (2), and the ear plate adapter (1) is clamped between two clamping plates (3).

4. A tensile test fixture for a composite material blade tenon sample as described in claim 3, characterized in that, The clamp body (3.1) has ≥3 connecting holes (3.3) for pins (2) to pass through on both sides along the length direction from top to bottom, and the corresponding connecting holes (3.3) on both sides are at the same horizontal height.

5. A tensile test fixture for a composite material blade tenon sample as described in claim 1, characterized in that, Washers (5) are provided between the nut of the clamp bolt (4) and the clamp plate (3) to even out the preload of the clamp bolt (4) and prevent the nut of the clamp bolt (4) from loosening.

6. A tensile test fixture for a composite material blade tenon sample as described in claim 1, characterized in that, The mortise and tenon simulation component (7) includes a clamping body (7.1) and a connecting piece (7.2) integrally connected to the clamping body (7.1). The inner cavity surface of the clamping body (7.1) is adapted to the outer surface shape of the tenon sampling part (6); The connecting piece (7.2) is used to connect with the lower clamp of the testing machine.

7. A tensile test fixture for a composite material blade tenon sample as described in claim 1, characterized in that, The ear-shaped adapter (1), pin (2), clamp (3) and tenon groove simulation part (7) are all made of No. 45 steel that has been treated with tempering and high frequency quenching process.

8. The tensile test fixture for composite blade tenon sampling parts according to any one of claims 1-7, characterized in that, The load transfer path of the tensile test fixture is as follows: The ear-shaped adapter (1) receives the axial tensile force applied by the testing machine and transmits it to the clamps (3) on both sides through the pin (2). The ear-shaped adapter (1) and the clamps (3) are connected by the pin to achieve automatic alignment of the force direction. The toothed clamp (3) is fastened to the tenon sample (6) by the normal preload provided by the clamp bolt (4) and the washer (5); the load is transmitted through the mechanical locking force and friction force between the toothed structure on the inner side of the clamp (3) and the surface of the tenon sample (6), ensuring that no relative slippage occurs. The axial tensile force at the bottom of the tenon sample (6) acts directly on the inner cavity surface of the tenon simulation part (7) through its geometric surface; the load is directly transmitted downward from the lower end of the tenon simulation part (7) to the lower clamp of the testing machine.

9. A method for tensile testing of composite blade tenon samples, characterized in that, The tensile testing fixture according to any one of claims 1-8 is used; The experimental method includes the following steps: S1: Place the lower end of the tenon sample (6) into the inner cavity of the mortise simulation part (7), and use the inner cavity surface of the mortise simulation part (7) to precisely fit and position the outer surface of the tenon sample (6). Place the two clamping plates (3) symmetrically on both sides of the clamping section above the tenon sample (6), so that the inner tooth groove of the clamping plate (3) contacts the surface of the sample; Insert the clamping bolts (4) in sequence and place the washers (5). Tighten the clamping bolts (4) in an array according to the pre-tightening torque. Clamp the tenon sample (6) by mechanical locking force. Align the upper ends of the ear-shaped adapter (1) with the two clamp plates (3), and connect them by passing the pin (2) through the pin hole to complete the fixture assembly; S2: Move the assembled fixture to the testing machine, insert the top of the ear adapter (1) into the upper chuck of the testing machine and lock it; insert the lower end of the tenon simulation part (7) into the lower chuck of the testing machine and lock it to ensure that the axis is perpendicular; Strain gauges or displacement monitoring sensors are installed on the test section and key parts of the tenon sample (6) to monitor the deformation and damage status during the tensile process in real time. S3: Set the loading parameters through the load controller of the testing machine and apply an increasing axial tensile load according to the test requirements; During the loading process, observe the self-alignment adjustment of the ear adapter (1) and the pin (2) to ensure that the load is smoothly transferred to the target range of 250 kN; The load-displacement curve is continuously monitored. When the tenon sample (6) experiences structural fracture failure or reaches the predetermined load value, the testing machine stops loading and records the test data.

10. The method for tensile testing of composite blade tenon samples according to claim 9, characterized in that, The tensile testing method described herein is applicable to static strength testing under a large load range of 0~250 kN. The tenon sample (6) is a carbon fiber reinforced resin matrix composite material.

Images