Amplitude loading stress measuring device and method for aircraft engine blade

Abstract

The invention discloses an amplitude loading stress measuring device and method for an aircraft engine blade, and belongs to the technical field of aircraft engine blade tests. The device comprises a test rack; a blade clamp assembly and a loading assembly are arranged on the test rack; the blade clamp assembly is connected with a tenon of a test blade; and the loading assembly is used for applying a load to the test blade. According to the invention, a laboratory environment independent of an engine entity and a test bench is constructed, and the working state of the blade can be simulated and stress measurement can be carried out without any modification of the engine or complicated engine test. The device can be suitable for testing blades with different sizes and different load requirements, only the sensor needs to be replaced, and the universality and economical efficiency of the device are improved.

Description

Technical Field

[0001] This invention belongs to the field of aircraft engine blade testing technology, and relates to an amplitude loading stress measurement device and method for aircraft engine blades. Background Technology

[0002] As a core component, the structural strength and reliability of aircraft engine blades directly affect the overall performance and flight safety of the engine. Under operating conditions, blades are subjected to complex aerodynamic, centrifugal, and vibrational loads, making them susceptible to fracture due to high-cycle or low-cycle fatigue. Therefore, accurately measuring the stress levels of blades under different operating conditions is crucial during engine development and blade reliability verification.

[0003] Currently, the measurement of stress on aircraft engine blades under operating conditions mainly relies on two technical approaches. The first is the direct measurement method. This method typically involves attaching strain gauges to the blade surface and using slip ring actuators for dynamic signal transmission, directly acquiring strain data during engine testing. However, this method has significant limitations: it requires modification of the engine to install the measuring device, and the entire measurement process depends on actual engine testing. This not only leads to difficulties in engine modification, high technical barriers, and long implementation cycles, but also incurs high economic costs. More seriously, modified components may not be able to be restored to their original state, rendering them unusable and affecting subsequent engine testing and delivery. The second method is the indirect calculation method. This method uses blade dynamic amplitude measurement equipment to collect amplitude and frequency data of the blades during engine operation, and then indirectly determines the stress borne by the blades through theoretical formulas. Although this method reduces direct engine modification, the accuracy of its results heavily depends on the precision of the calculation model, making it difficult to accurately reflect the complex stress distribution on the blade surface, especially in stress concentration areas, and carries a certain risk of error. Similarly, this method cannot be separated from the prerequisite of engine testing.

[0004] In summary, there is an urgent need for a specialized tooling that can simulate the working state of blades and perform precise stress measurements under different amplitudes, angles, and even temperatures in the laboratory. This would enable convenient, accurate, and low-cost stress measurement of blades without the constraints of the engine and test environment. Summary of the Invention

[0005] The purpose of this invention is to provide an amplitude loading stress measurement device and method for aircraft engine blades, so as to solve the technical problem in the prior art that it is difficult to complete the stress measurement of blades under conditions that are separate from the engine body and test environment.

[0006] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides an amplitude loading stress measuring device for aircraft engine blades, comprising a test frame; a blade clamp assembly and a loading assembly are provided on the test frame; the blade clamp assembly is connected to the test blade by a tenon; and the loading assembly is used to apply a load to the test blade.

[0007] Furthermore, the blade clamp assembly includes an adapter plate and a mounting plate; one side of the mounting plate is detachably connected to the test frame via a vertically arranged adapter plate, and the other side of the mounting plate is provided with a dovetail groove, which engages with the tenon of the test blade.

[0008] Furthermore, the mounting plate has several threaded holes on the side where it connects to the adapter plate, and the mounting plate and the adapter plate are connected by bolts and nuts.

[0009] Furthermore, the loading assembly includes a loading head, a sensor, and a loading rod arranged sequentially from top to bottom; the upper end of the loading head contacts the bottom of the test blade; and the loading rod is connected to the test frame via a connector.

[0010] Furthermore, the two ends of the loading rod are respectively provided with threads of opposite directions to realize the extension and retraction of the loading rod.

[0011] Furthermore, the connecting component is a pressure plate and a base, the bottom of the loading rod is connected to the middle of the pressure plate through the base, and the two ends of the pressure plate are respectively connected to the test frames on both sides.

[0012] Furthermore, a groove is provided at the connection between the pressure plate and the base, allowing the base to move horizontally relative to the pressure plate through the groove.

[0013] Furthermore, a trolley assembly is provided at the bottom of the test frame, and the trolley assembly is provided with pulleys at the bottom.

[0014] Secondly, the present invention provides a method for measuring amplitude loading stress of aircraft engine blades, based on the aforementioned device for measuring amplitude loading stress of aircraft engine blades, comprising the following steps: Strain gauges were attached to the area of ​​maximum stress on the test blade. The test blade is fixed using a blade clamp assembly; Install and adjust the loading components, apply load to the test blade, and perform stress measurements.

[0015] Furthermore, the step of fixing the test blade using the blade clamp assembly specifically includes: Based on the preset loading posture of the test blade, different bolt holes on the mounting plate are selected to connect with the test frame in order to adjust the clamping posture of the test blade.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a device and method for measuring amplitude loading stress of aircraft engine blades. The device uses a blade clamping assembly on a test stand to fix and hold the test blade, and a loading assembly applies a load to the test blade to measure the amplitude loading stress of the engine blade. This invention constructs a laboratory environment independent of the actual engine and test bench, requiring no modification to the engine or complex engine testing to simulate the working state of the blade and perform stress measurements. It can adapt to testing blades of different sizes and with different load requirements; only the sensor needs to be replaced, improving the versatility and economy of the equipment.

[0017] Furthermore, the unique left- and right-hand threaded loading rod design in the loading assembly of this invention allows for precise and linear adjustment of the load applied to the blades through simple manual rotation. Combined with real-time feedback from the force sensor, the load can be easily and accurately controlled at specific values ​​corresponding to different blade amplitudes.

[0018] Furthermore, the multiple sets of bolt holes on the mounting plate allow for flexible adjustment of the blade's clamping posture as needed, enabling simulations of various operating conditions such as vertical blade sheath, vertical inlet edge, blade back loading, and blade head loading. This flexibility allows the device to be used to study the stress response of blades under different force directions and comprehensively evaluate their structural strength.

[0019] Furthermore, the grooves in the test stand base allow the loading point to be adjusted along the blade direction. This feature enables users to precisely apply loads at specific locations on the blade (such as the point of maximum stress or point of interest), or to study the stress distribution along the blade, further enriching the testing content. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a front view of the overall structure of an amplitude loading stress measuring device for aircraft engine blades according to the present invention. Figure 2 This is a top view of the overall structure of an amplitude loading stress measuring device for aircraft engine blades according to the present invention. Figure 3 This is a schematic diagram of the installation disk of the present invention; Figure 4 This is a schematic diagram of the base in the connector of the present invention.

[0022] Wherein: 1-Test frame; 2-Blade clamp assembly; 3-Bolt; 4-Nut; 5-Test blade; 6-Loading rod; 7-Loading top; 8-Sensor; 9-Pressure plate; 10-Trolley assembly; 11-Mounting plate. Detailed Implementation

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 This invention discloses an amplitude loading stress measurement device for aircraft engine blades, comprising a test frame 1; a blade clamp assembly 2 and a loading assembly are mounted on the test frame 1; the blade clamp assembly 2 is tenon-connected to a test blade 5; the loading assembly is used to apply a load to the test blade 5. The test blade 5 is fixedly clamped by the blade clamp assembly 2 on the test frame 1, and a load is applied to the test blade 5 by the loading assembly to measure the amplitude loading stress of the engine blade. This invention constructs a laboratory environment independent of the actual engine and test bench, requiring no modification to the engine or complex engine testing, to simulate the working state of the blade and perform stress measurement. It can adapt to the testing of blades of different sizes and with different load requirements; only the sensor needs to be replaced, improving the versatility and economy of the equipment.

[0030] In one feasible embodiment of the present invention, the test frame 1 is composed of two welded supports, and its rigidity is enhanced by reinforcing ribs. The test frame 1 and the blade clamp assembly 2 are positioned by a stop and connected by bolts to ensure installation and assembly accuracy. Preferably, the blade clamp assembly 2 includes an adapter plate and a mounting plate 11. One side of the mounting plate 11 is detachably connected to the test frame 1 via a vertically arranged adapter plate. The other side of the mounting plate 11 has a dovetail groove, which engages with the tenon of the test blade 5. The blade tenon is placed in the dovetail groove of the clamp and can be fixed and clamped by three bolts. The side of the mounting plate 11 connected to the adapter plate has several threaded holes, and the mounting plate 11 and the adapter plate are connected by bolts 3 and nuts 4. See also Figure 3 The mounting plate 11 has multiple sets of bolt holes, which allow for flexible adjustment of the blade clamping posture as needed, such as simulating various working conditions including vertical blade body, vertical inlet edge, blade back loading, and blade basin loading. This flexibility enables the device to be used to study the stress response of blades under different force directions and comprehensively evaluate their structural strength.

[0031] In one feasible embodiment of the present invention, the loading assembly includes a loading head 7, a sensor 8, and a loading rod 6 arranged sequentially from top to bottom; the upper end of the loading head 7 contacts the bottom of the test blade 5; the loading rod 6 is connected to the test frame 1 via a connector. The load is generated from the loading rod 6, passes sequentially through the sensor 8 and the loading head 7, and is finally transmitted to the bottom of the test blade 5. This series layout ensures that the applied force is completely transmitted, minimizes force diversion or loss caused by structural complexity, and guarantees the accuracy of loading. The two ends of the loading rod 6 are respectively provided with threads of opposite directions, forming a simple and efficient fine-tuning telescopic mechanism. The test load is adjusted by adjusting the extension and retraction of the left-hand and right-hand threads of the loading rod 6, with one end of the loading rod 6 having a left-hand thread and the other end having a right-hand thread. Specifically, during loading, the loading assembly is rotated with a wrench at one end of the loading rod 6. Based on the load value measured by the force sensor, the loading assembly is manually adjusted to achieve the load required for the test.

[0032] In one feasible embodiment of the present invention, see [link to relevant documentation]. Figure 4 The connecting components are a pressure plate 9 and a base. The bottom of the loading rod 6 is connected to the middle of the pressure plate 9 via the base, and both ends of the pressure plate 9 are connected to the test frames 1 on both sides. A groove is provided at the connection between the pressure plate 9 and the base, allowing the base to move horizontally relative to the pressure plate 9 through the groove. The load is generated from the loading rod 6, passes through the base and pressure plate 9, and is ultimately borne by the robust test frame 1. This fixed-end support method distributes the force to the two support points of the test frame 1, avoiding the torque and unstable sway that may occur with single-point support, forming a stable and highly rigid force transmission path. Furthermore, the groove structure allows the base to be adjusted horizontally, enabling the loading point to be adjusted along the blade direction, enhancing the versatility of the tooling.

[0033] In one feasible embodiment of the present invention, see [link to relevant documentation]. Figure 2 The test frame 1 is further equipped with a trolley assembly 10 at its bottom, and the trolley assembly 10 is equipped with casters at its bottom. In this embodiment, the entire test frame 1 is placed on the trolley assembly 10, allowing the entire measuring device to be easily moved between different workstations in the laboratory. When conducting high and low temperature tests, the operator can directly and smoothly push the entire fixture, with the blades and sensors installed, into the high and low temperature environment chamber as a complete "test unit," achieving overall chamber entry and overall testing. This avoids the difficulties of complex assembly within the confined space of the chamber.

[0034] This invention discloses a method for measuring amplitude loading stress in aircraft engine blades, characterized by comprising the following steps based on the aforementioned amplitude loading stress measuring device for aircraft engine blades: S1, Strain gauges are attached to the maximum stress zone of test blade 5; S2, the test blade 5 is fixed by the blade clamp assembly 2; According to the preset loading posture of the test blade 5, different bolt holes on the mounting plate 11 are selected to connect with the test frame 1 in order to adjust the clamping posture of the test blade 5.

[0035] S3, Install and adjust the loading assembly, apply load to the test blade 5, and perform stress measurement.

[0036] This invention constructs an independent and efficient laboratory simulation testing platform, eliminating the reliance on actual engine modifications and testing. It solves fundamental problems inherent in existing technologies, such as long implementation cycles, high modification difficulty, high costs, and the inability to reuse parts, achieving low-cost and high-safety testing. Technically, the design ensures data accuracy and comprehensiveness through highly simulated and flexibly adjustable structures. Adjustable clamping postures and movable loading bases significantly expand the coverage of test conditions, enabling systematic study of the stress response of blades under different angles and positions. Furthermore, the modular and integrated design of the tooling significantly improves its usability and functional expandability. The use of a left- or right-hand threaded loading rod 6 in conjunction with a force sensor achieves precise closed-loop load control; the design of the trolley assembly 10 allows the entire device to be easily moved into high and low temperature environmental chambers, seamlessly realizing the coupled testing of temperature fields and vibration loads.

[0037] The working process of this invention is as follows: Attach strain gauges to the maximum stress zone of test blade 5 and connect the data acquisition equipment. Determine the loading posture of test blade 5 (blade body or inlet edge) and select the mounting plate angle 11. Measure the minimum clamping torque at blade resonance on the electromagnetic vibration table, ensuring clamping without damaging the blade dovetail. After securing test blade 5, install the loading assembly, move the base left and right to confirm the blade body loading position. Adjust the loading rod 6 by turning the nut left and right, measure whether the blade tip amplitude reaches the required amplitude, and observe the force sensor value and strain gauge output strain.

[0038] When measuring with a temperature field, repeat the above steps and place the test piece and tooling together into the high and low temperature chamber. Adjust the furnace temperature according to the set temperature and the rate of rise and fall, and realize strain measurement through the acquisition equipment.

[0039] This invented fixture has been used to measure the temperature range of a certain engine fan blade, from -60℃ to 50℃; the force sensor's measurement range is no greater than 400 kg. This invention can not only measure the stress borne by the maximum stress zone of an aircraft engine blade under different amplitudes and torsional angles, but also measure the stress variation with temperature.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the 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 device for measuring amplitude loading stress in aircraft engine blades, characterized in that, The test frame (1) is provided with a blade clamp assembly (2) and a loading assembly. The blade clamp assembly (2) is connected to the tenon of the test blade (5). The loading assembly is used to apply a load to the test blade (5).

2. The amplitude loading stress measuring device for aircraft engine blades according to claim 1, characterized in that, The blade clamp assembly (2) includes a transition plate and a mounting plate (11); one side of the mounting plate (11) is detachably connected to the test frame (1) through the vertically arranged transition plate, and the other side of the mounting plate (11) is provided with a dovetail groove, which is engaged with the tenon of the test blade (5).

3. The amplitude loading stress measuring device for aircraft engine blades according to claim 2, characterized in that, The mounting plate (11) has several threaded holes on the side connected to the adapter plate. The mounting plate (11) and the adapter plate are connected by bolts (3) and nuts (4).

4. The amplitude loading stress measuring device for aircraft engine blades according to claim 1, characterized in that, The loading assembly includes a loading head (7), a sensor (8), and a loading rod (6) arranged sequentially from top to bottom; the upper end of the loading head (7) contacts the bottom of the test blade (5); the loading rod (6) is connected to the test frame (1) through a connector.

5. The amplitude loading stress measuring device for aircraft engine blades according to claim 4, characterized in that, The loading rod (6) has threads with opposite directions at both ends to enable the loading rod (6) to extend and retract.

6. The amplitude loading stress measuring device for aircraft engine blades according to claim 4, characterized in that, The connecting parts are a pressure plate (9) and a base. The bottom of the loading rod (6) is connected to the middle of the pressure plate (9) through the base. The two ends of the pressure plate (9) are connected to the test frames (1) on both sides respectively.

7. The amplitude loading stress measuring device for aircraft engine blades according to claim 6, characterized in that, A groove is provided at the connection between the pressure plate (9) and the base, and the base can move horizontally relative to the pressure plate (9) through the groove.

8. The amplitude loading stress measuring device for aircraft engine blades according to claim 1, characterized in that, The test frame (1) is also provided with a trolley assembly (10) at the bottom, and the trolley assembly (10) is provided with pulleys at the bottom.

9. A method for measuring amplitude-loaded stress in aircraft engine blades, characterized in that, An amplitude loading stress measuring device for aircraft engine blades according to any one of claims 1 to 8 includes the following steps: Strain gauges were attached to the maximum stress zone of the test blade (5); The test blade (5) is fixed by the blade clamp assembly (2); Install and adjust the loading components, apply load to the test blade (5), and perform stress measurement.

10. A method for measuring amplitude loading stress in aircraft engine blades according to claim 9, characterized in that, The step of fixing the test blade (5) using the blade clamp assembly (2) specifically includes: According to the preset loading posture of the test blade (5), different bolt holes on the mounting plate (11) are selected to connect with the test frame (1) in order to adjust the clamping posture of the test blade (5).

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