A large blade fatigue test device

Abstract

This invention discloses a fatigue testing device for large blades. The device includes: two moment application components, two movable hinge components, two centrifugal force application components, and a test specimen. The two moment application components are fixedly clamped onto the test specimen and arranged along its spanwise direction. Each moment application component has a waving moment connector for applying waving moment in the waving direction and a shimmy moment connector for applying shimmy moment in the shimmy direction. Both ends of the test specimen are fixedly connected to the inner ends of one movable hinge component, and the outer ends of the two movable hinge components are connected to the centrifugal force application components. The end of the centrifugal force application component away from the test specimen is fixedly connected to a centrifugal force connector for applying centrifugal force. This large blade fatigue testing device is used to simultaneously apply waving moment and shimmy moment through the two moment application components clamped onto the test specimen. Using this fatigue testing device, centrifugal force, waving moment, and shimmy moment can be applied independently simultaneously, meeting the requirements of fatigue testing for large blades.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of helicopter blade fatigue testing technology, and specifically to a large-scale blade fatigue testing device. Background Technology

[0002] Large rotor blade fatigue testing is an important test in helicopter rotor blade fatigue testing technology. It has important guiding significance for the life and safety of helicopter rotor blades. The loads that need to be applied in the entire test area for large rotor blade fatigue testing include flapping moment, oscillation moment and centrifugal force.

[0003] For fatigue testing of the airfoil section of a medium-sized helicopter main rotor blade, the common testing method is to apply flapping and tessellation loads by exciting vibration under pre-applied centrifugal force. The load control accuracy of this loading method is relatively low, and the risk of applying loads to large helicopter rotor blades is too high, so it is generally not used. Chinese patent application number 201210570656.8 proposes a device for applying equal bending moment in the test area, using a single actuator for equal bending moment loading; Chinese patent application number 201410727507.7 proposes an equal bending moment loading mechanism for anti-icing and de-icing main rotor blades; and Chinese patent application number 201610149355.6 proposes an implementation scheme for simultaneously applying torque to anti-icing and de-icing main rotor blades. However, none of these existing patents can apply centrifugal force loads.

[0004] In summary, there is currently no implementation scheme in the existing technology for simultaneously applying flapping moment, oscillation moment and centrifugal force load to large blades. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems. This invention provides a fatigue testing device for large blades to address the issue that conventional loading methods for fatigue testing of large blades involve equal moment loading of flapping moment and oscillation moment. In other words, the existing technology lacks a fatigue testing scheme that simultaneously applies flapping moment, oscillation moment, and centrifugal force loads to large blades.

[0006] The technical solution of the present invention: The present invention provides a large blade fatigue testing device, comprising: two bending moment application components 1, two movable hinge support components 2, two centrifugal force application components 3, and a test piece 4;

[0007] Two moment application components 1 are fixedly clamped on the test specimen 4 and arranged along the span of the test specimen 4; each moment application component 1 is provided with a swing moment joint for applying swing moment in the swing direction and a sway moment joint for applying sway moment in the sway direction.

[0008] Both ends of the test piece 4 are fixedly connected to the inner end of a movable hinge assembly 2, and the outer ends of the two movable hinge assemblies 2 are respectively connected to a centrifugal force application assembly 3. The centrifugal force application assembly 3 is fixedly connected to a centrifugal force connector for applying centrifugal force at the end away from the test piece 4.

[0009] The large blade fatigue testing device is used to simultaneously apply wagging moment and oscillation moment through two moment application components 1 clamped on the test piece 4.

[0010] Optionally, in the large blade fatigue testing apparatus described above,

[0011] Each of the movable hinge components 2 includes: a linear guide mechanism 2a, a horizontal axis 2b, a connector 2c, and a limiting mechanism 2d;

[0012] One end of the connector 2c is fixedly connected to the test piece 4, and the shaft hole of the other end is nested in the centrifugal force double-ear connector 3b of the centrifugal force application component 3. The connector 2c and the centrifugal force double-ear connector 3b are hinged by a horizontal shaft 2b. The two ends of the horizontal shaft 2b are respectively installed on the symmetrically arranged linear guide mechanism 2a, so that the horizontal shaft 2b slides along the direction of the linear guide mechanism 2a. A limit mechanism 2d is installed at the end of the guide rail of the linear guide mechanism 2a that is close to the test piece 4.

[0013] The movable hinge assembly 2 connected to both sides of the test piece 4 is used to ensure that the test piece 4 does not deviate from the central installation position during the test loading process through the combined action of the limiting mechanism 2d on the linear guide rail mechanism 2a on both sides.

[0014] Optionally, in the large blade fatigue testing apparatus described above,

[0015] A radial bearing is installed in the shaft hole of the connector 2c, so that the hinge between it and the horizontal shaft 2b has the ability to rotate in the swinging direction and to swing in the oscillation direction.

[0016] Optionally, in the large blade fatigue testing apparatus described above,

[0017] In the structure of each of the movable hinge components 2, the connector 2c includes: a cross joint 2e, a vertical shaft 2f, a transition piece 2g, a flange 2h, and a blade joint 2j;

[0018] The cross joint 2e has a vertical shaft hole at its inner end and a horizontal shaft hole at its outer end. It is fitted into the middle of the horizontal shaft 2b through the horizontal shaft hole at its outer end. The vertical shaft hole at its inner end is hinged to the double-ear end of the transition piece 2g through the vertical shaft 2f. The other end of the transition piece 2g is connected to one end of the blade joint 2j through the flange 2h, and the other end of the blade joint 2j is fixedly connected to one end of the test piece 4.

[0019] Optionally, in the large blade fatigue testing apparatus described above,

[0020] In each of the connecting members 2c of the movable hinge assembly 2

[0021] A hinge mechanism with free rotation capability in the swinging direction is formed by the horizontal axis 2b and the cross joint 2e.

[0022] A hinge mechanism with free rotation capability in the oscillation direction is formed by the cross joint 2e, the vertical shaft 2f, and the transition piece 2g.

[0023] The installation angle adjustment mechanism of test piece 4 is formed by transition piece 2g, flange 2h and blade joint 2j to adapt to the installation requirements when test piece 4 has a self-torsion angle.

[0024] Optionally, in the large blade fatigue testing apparatus described above,

[0025] Each of the bending moment application components 1 includes: a clamping mechanism 1a, a waving linear actuator 1b, and a oscillating linear actuator 1c;

[0026] The two clamping mechanisms 1a are fixedly clamped on the test piece 4 along the spanwise direction. The waving linear actuator 1b is hinged to the waving moment joint of the clamping mechanism 1a in the waving direction. The swinging linear actuator 1c is hinged to the swinging moment joint of the clamping mechanism 1a in the swinging direction.

[0027] Optionally, in the large blade fatigue testing apparatus described above,

[0028] The two moment application components 2 are respectively arranged asymmetrically on the test specimen 4 from the center to both ends; or...

[0029] The two moment application components 2 are positioned on the test piece 4 such that the two moment application components 2 are equidistant from the center of the test piece 4, which is a symmetrical arrangement.

[0030] Optionally, in the large blade fatigue testing apparatus described above,

[0031] Each of the centrifugal force application components 3 includes a centrifugal force linear actuator 3a and a centrifugal force double-ear connector 3b. One end of the centrifugal force double-ear connector 3b is hinged to the horizontal axis 2b of the same-side movable hinge component 2, and the other end is connected to the centrifugal force linear actuator 3a.

[0032] Optionally, in the large blade fatigue testing apparatus described above,

[0033] Each of the centrifugal force application components 3 includes a centrifugal force linear actuator 3a, two sets of pulleys 3c and steel cables 3d; wherein, the two pulleys 3c are respectively installed at both ends of the horizontal shaft 2b extending out of the horizontal shaft hole in the cross joint 2e, and one end of each steel cable 3d is wrapped around the pulley 3c at the corresponding position, and the other end is connected to the centrifugal force linear actuator 3a.

[0034] The beneficial effects of the present invention are as follows: The present invention provides a large blade fatigue testing device. Two bending moment application components 1 in the fatigue testing device are fixedly clamped on the test piece 4 and arranged along the spanwise direction of the test piece 4. Each bending moment application component 1 is provided with a swinging bending moment joint for applying swinging bending moment in the swinging direction and a swaying bending moment joint for applying swaying bending moment in the swaying direction. Both ends of the test piece 4 are respectively fixedly connected to the inner end of a movable hinge component 2, and the outer ends of the two movable hinge components 2 are respectively connected to a centrifugal force application component 3. The end of the centrifugal force application component 3 away from the test piece 4 is fixedly connected to a centrifugal force joint for applying centrifugal force. The internal structure of the two movable hinge components 2 enables them to have rotational motion capability in the swinging direction and oscillating motion capability in the swaying direction. The large blade fatigue testing device provided in this embodiment of the invention can simultaneously apply flapping moment and oscillation moment through two moment application components 1 clamped on the test piece 4. In addition, the large blade fatigue testing device provided in this embodiment of the invention has a compact structure and high loading accuracy, and can simultaneously achieve independent application of flapping moment, oscillation moment and centrifugal force load, which can meet the requirements of large blade fatigue testing. Attached Figure Description

[0035] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0036] Figure 1 This is a schematic diagram of the overall structure of a large blade fatigue testing device provided in an embodiment of the present invention;

[0037] Figure 2 This is another structural schematic diagram of the movable hinge component in the large blade fatigue testing device provided in this embodiment of the invention.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1-Moment application assembly, 1a-Clamping mechanism, 1b-Waving linear actuator, 1c-Swinging linear actuator, 2-Moving hinge assembly, 2a-Linear guide mechanism, 2b-Horizontal axis, 2c-Connector, 2d-Limiting mechanism, 2e-Cross joint, 2f-Vertical axis, 2g-Transition piece, 2h-Flange, 2j-Paddle joint, 3-Centrifugal force application assembly, 3a-Centrifugal force linear actuator, 3b-Centrifugal force double-ear joint, 3c-Pulley, 3d-Steel cable, 4-Test piece. Detailed Implementation Plan

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0041] As explained in the background section, the conventional loading method for fatigue testing of large blades is equal-moment loading of flapping moment and tessellation moment, as illustrated in the several Chinese patents listed in the background section. In summary, the existing technology currently lacks a fatigue testing scheme that simultaneously applies flapping moment, tessellation moment, and centrifugal force loads to large blades.

[0042] To address the problem of fatigue testing for large propeller blades, this invention provides a fatigue testing device for large propeller blades.

[0043] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0044] Figure 1 This is a schematic diagram of the overall structure of a large blade fatigue testing device provided in an embodiment of the present invention. Figure 1 As shown, the large blade fatigue testing device provided in this embodiment of the invention may include: two bending moment application components 1, two movable hinge support components 2, two centrifugal force application components 3, and a test piece 4.

[0045] like Figure 1 In the structure of the large blade fatigue testing device shown, two moment application components 1 are fixedly clamped onto the test specimen 4 and arranged along the spanwise direction of the test specimen 4. Each moment application component 1 is provided with a waving moment joint for applying waving moment in the waving direction and a shimmy moment joint for applying shimmy moment in the shimmy direction. It should be noted that the two moment application components 1 can be symmetrically clamped onto the test specimen 4, for example, and this clamping method can be used to apply equal moments; and the embodiment of the present invention does not limit the symmetrical clamping method.

[0046] In this embodiment of the invention, the two ends of the test piece 4 are respectively fixedly connected to the inner end of a movable hinge assembly 2, the outer ends of the two movable hinge assemblies 2 are respectively connected to a centrifugal force application assembly 3, and the end of the centrifugal force application assembly 3 away from the test piece 4 is fixedly connected to a centrifugal force connector for applying centrifugal force.

[0047] The large blade fatigue testing device provided in this embodiment of the invention can simultaneously apply flapping bending moment and oscillation bending moment through two bending moment application components 1 clamped on the test piece 4.

[0048] In one optional implementation of this invention, a structural implementation of the movable hinge assembly 2 is provided, such as... Figure 1 As shown, each movable hinge assembly 2 includes: a linear guide mechanism 2a, a horizontal shaft 2b, a connector 2c, and a limiting mechanism 2d.

[0049] Reference Figure 1 and Figure 2 As shown, one end of the connector 2c is fixedly connected to the test piece 4, and the shaft hole of the other end is nested in the centrifugal force double-ear connector 3b of the centrifugal force application component 3. The shaft hole of the connector 2c and the centrifugal force double-ear connector 3b are hinged by the horizontal shaft 2b. In addition, the two ends of the horizontal shaft 2b are respectively installed on the symmetrically arranged linear guide mechanism 2a, so that the horizontal shaft 2b slides along the direction of the linear guide mechanism 2a. The end of the guide rail in the linear guide mechanism 2a that is close to the test piece 4 is equipped with a limit mechanism 2d.

[0050] In this implementation, the movable hinge support assembly 2 connected to both sides of the test piece 4 is used to ensure that the test piece 4 does not deviate from the central installation position during the test loading process through the combined action of the limiting mechanism 2d on the linear guide rail mechanism 2a on both sides.

[0051] It should be noted that in this implementation, the hinge between the connecting piece 2c and the horizontal shaft 2b allows for free rotation in both the swinging and oscillating directions. This is achieved by installing a radial bearing within the shaft hole of the connecting piece 2c, enabling the hinge between it and the horizontal shaft 2b to have rotational movement capability in the swinging direction and oscillating movement capability in the oscillating direction.

[0052] In another optional implementation of this invention, a different implementation structure of the movable hinge component 2 is provided, such as... Figure 2 The diagram shown is a schematic representation of another structure of the movable hinge assembly in the large blade fatigue testing device provided in an embodiment of the present invention. Figure 1 Based on the structure of the movable hinge assembly 2 shown, the connecting member 2c includes: a cross joint 2e, a vertical shaft 2f, a transition member 2g, a flange 2h, and a blade joint 2j.

[0053] In this implementation, the inner end of the cross joint 2e has a vertical shaft hole, and the outer end has a horizontal shaft hole. It is fitted into the middle of the horizontal shaft 2b through the horizontal shaft hole at its outer end. The vertical shaft hole at its inner end is hinged to the double-ear end of the transition piece 2g through the vertical shaft 2f. The other end of the transition piece 2g is connected to one end of the blade joint 2j through the flange 2h, and the other end of the blade joint 2j is fixedly connected to one end of the test piece 4.

[0054] In the implementation, the connecting member 2c structure of the movable hinge assembly 2 includes, on the one hand, a hinge mechanism that can rotate freely in the swing direction, specifically formed by the horizontal shaft 2b and the cross joint 2e. On the other hand, it also includes a hinge mechanism that can rotate freely in the swing direction, specifically formed by the cross joint 2e, the vertical shaft 2f, and the transition member 2g. Furthermore, the connecting member 2c includes a test piece mounting angle adjustment mechanism, specifically formed by the transition member 2g, the flange 2h, and the blade joint 2j to adjust the mounting angle of the test piece 4, which is used to adapt to the installation requirements when the test piece 4 has a self-torsion angle.

[0055] In one implementation of this invention, such as Figure 1 As shown, each moment application component 1 includes: a clamping mechanism 1a, a swinging linear actuator 1b, and a oscillating linear actuator 1c.

[0056] In this implementation, two clamping mechanisms 1a are fixedly clamped on the test piece 4 along the spanwise direction, the swinging linear actuator 1b is hinged to the swinging moment joint of the clamping mechanism 1a in the swinging direction, and the oscillating linear actuator 1c is hinged to the oscillating moment joint of the clamping mechanism 1a in the oscillating direction.

[0057] The large blade fatigue testing device provided by this implementation can simultaneously apply flapping moment and oscillation moment through two moment application components 1 clamped on the test piece 4.

[0058] In practical implementation, the positions of the two moment application components 2 can be:

[0059] Example 1: Two moment application components 2 are respectively set on the test specimen 4 from the center position to both ends, and are arranged asymmetrically.

[0060] Example 2: The two moment application components 2 are positioned on the test specimen 4 such that the two moment application components 2 are equidistant from the center of the test specimen 4, which is a symmetrical arrangement.

[0061] In one optional implementation of this invention, such as Figure 1As shown, each of the centrifugal force application components 3 includes a centrifugal force linear actuator 3a and a centrifugal force double-ear connector 3b. One end of the centrifugal force double-ear connector 3b is hinged to the horizontal axis 2b of the same-side movable hinge component 2, and the other end is connected to the centrifugal force linear actuator 3a.

[0062] In another optional implementation of the present invention, in the above... Figure 2 Based on the structure of the movable hinge assembly 2 shown, the centrifugal force double-ear joint 3b includes: a centrifugal force linear actuator 3a, and two sets of pulleys 3c and steel cables 3d; wherein, the two pulleys 3c are respectively installed at both ends of the horizontal shaft 2b extending out of the horizontal shaft hole in the cross joint 2e, and one end of each steel cable 3d is wrapped around the pulley 3c at the corresponding position, and the other end is connected to the centrifugal force linear actuator 3a.

[0063] The large blade fatigue testing device provided in this embodiment of the invention has two bending moment application components 1 fixedly clamped on the test piece 4 and arranged along the spanwise direction of the test piece 4. Each bending moment application component 1 is provided with a swinging bending moment joint for applying swinging bending moment in the swinging direction and a swaying bending moment joint for applying swaying bending moment in the swaying direction. Both ends of the test piece 4 are respectively fixedly connected to the inner ends of a movable hinge component 2, and the outer ends of the two movable hinge components 2 are respectively connected to a centrifugal force application component 3. The end of the centrifugal force application component 3 away from the test piece 4 is fixedly connected to a centrifugal force joint for applying centrifugal force. The internal structure of the two movable hinge components 2 enables them to rotate in the swinging direction and swing in the swaying direction. The large blade fatigue testing device provided in this embodiment of the invention can simultaneously apply flapping moment and oscillation moment through two moment application components 1 clamped on the test piece 4. In addition, the large blade fatigue testing device provided in this embodiment of the invention has a compact structure and high loading accuracy, and can simultaneously achieve independent application of flapping moment, oscillation moment and centrifugal force load, which can meet the requirements of large blade fatigue testing.

[0064] The following are schematic illustrations of the implementation of the large blade fatigue testing device provided by the present invention through several specific embodiments.

[0065] Example 1:

[0066] like Figure 1 As shown, in this embodiment, test piece 4 is the main blade, with its center as the origin, the short side as the X-axis, the upward direction as the Z-axis, and the direction perpendicular to the X and Z axes as the Y-axis. This is a schematic illustration of a large blade fatigue testing device. In this embodiment 1, the flapping moment is the bending moment rotating about the X-axis, the oscillation moment is the bending moment rotating about the Z-axis, and the centrifugal force is the tensile load in the Y-axis direction.

[0067] refer to Figure 1Two moment application components 1 are symmetrically distributed along the Y-axis, respectively positioned on the test specimen 4 from the center to both ends, with the two moment application components 1 being equidistant from the center of the test specimen 4. Each moment application component 1 includes a clamping mechanism 1a, a swinging linear actuator 1b, and a oscillating linear actuator 1c. The clamping mechanism 1a is fixed to the test specimen 4. The swinging linear actuator 1b is hinged to the clamping mechanism 1a along the Z-axis, and the oscillating linear actuator 1c is hinged to the clamping mechanism 1a along the X-axis. The ends of the swinging linear actuator 1b and the oscillating linear actuator 1c furthest from the clamping mechanism 1a are connected and fixed in a conventional manner. In this embodiment, both the swinging linear actuator 1b and the oscillating linear actuator 1c are actuator cylinders, but other load application methods, such as electric motors or electromagnetic actuators, can also be used.

[0068] Two movable hinge components 2 are symmetrically distributed left and right along the Y-axis, and each movable hinge component 2 is symmetrical front and back along the X-axis. Each component includes a linear guide mechanism 2a, a horizontal shaft 2b, a connecting piece 2c, and a limiting mechanism 2d. The two ends of the horizontal shaft 2b are fixedly mounted on the sliders of the linear guide mechanisms 2a on both sides. It is understood that if there are two sliders on a single linear guide mechanism 2a, a transition plate can be added to achieve a fixed connection between the horizontal shaft 2b and multiple sliders. One end of the connecting piece 2c is fixedly connected to the test piece, and the other end is hinged to the middle of the horizontal shaft 2b. It is understood that to reduce frictional resistance, a bearing can be installed between the connecting piece 2c and the horizontal shaft 2b. In this embodiment, to achieve free rotation of the connecting piece 2c relative to the horizontal shaft 2b in the swinging and oscillating directions, a radial bearing or a spherical bearing must be selected. The limiting mechanism 2d is located on the guide rail of the linear guide mechanism 2a on the side close to the test piece 4. The purpose of setting the limiting mechanism 2d is to prevent the test piece from gradually deviating to one side while ensuring that the test piece can move freely in the Y-axis direction during the fatigue test.

[0069] Two centrifugal force application components 3 are symmetrically distributed along the Y-axis on the side of the movable hinge assembly 2 away from the test piece 4, and include a centrifugal force linear actuator 3a and a centrifugal force double-ear connector 3b. One end of the centrifugal force double-ear connector 3b is hinged to the outside of the connector 2c on the horizontal shaft 2b, and the other end is connected to the centrifugal force linear actuator 3a. The end of the centrifugal force linear actuator 3a away from the centrifugal force double-ear connector 3b is connected and fixed in a conventional manner. It is understood that, in order to reduce frictional resistance, a rolling bearing can also be installed between the centrifugal force double-ear connector 3b and the horizontal shaft 2b.

[0070] Example 2:

[0071] Similar in principle to Example 1, the difference lies in that: the connecting member 2c includes a hinge mechanism that can rotate freely in the direction of oscillation and a test piece mounting angle adjustment mechanism. (Reference) Figure 2, Figure 1 In Embodiment 1, the connector 2c is replaced by: a cross joint 2e, a vertical shaft 2f, a transition piece 2g, a flange 2h, and a blade connector 2j. One end of the cross joint 2e is hinged to the middle of the horizontal shaft 2b, and the other end is hinged to the double-eared end of the transition piece 2g via the vertical shaft 2f. The other end of the transition piece 2g is connected to one end of the blade connector 2j via the flange 2h, and the other end of the blade connector 2j is fixedly connected to the test piece. In this Embodiment 2, the horizontal shaft 2b and the cross joint 2e form a hinge mechanism with free rotation capability in the swing direction; the cross joint 2e, the vertical shaft 2f, and the transition piece 2g form a hinge mechanism that can rotate freely in the oscillation direction. The presence of this hinge mechanism reduces the frictional resistance and bearing load of the entire moving hinge assembly 2; the transition piece 2g, the flange 2h, and the blade connector 2j form a test piece installation angle adjustment mechanism, which can adapt to the installation requirements when the test piece 4 has a self-torsion angle. In addition, in this embodiment 2, in order to improve the load-bearing capacity of the linear guide mechanism 2a, the number of guide rails and sliders is increased; in order to prevent the centrifugal force linear actuator 3a from pushing and causing damage to the test piece 4, the centrifugal force double-ear joint 3b is replaced by a combination of pulley 3c and steel cable 3d. The pulley 3c is installed at both ends of the horizontal shaft 2b extending out of the horizontal shaft hole in the cross joint 2e. One end of each steel cable 3d is wrapped around the pulley 3c, and the other end is connected to the centrifugal force linear actuator 3a.

[0072] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A large-scale blade fatigue test apparatus characterized by comprising: Includes: two moment application assemblies (1), two movable hinge support assemblies (2), two centrifugal force application assemblies (3), and a test specimen (4); Two moment application components (1) are fixedly clamped on the test piece (4) and arranged along the span of the test piece (4); each moment application component (1) is provided with a swing moment joint for applying swing moment in the swing direction and a swing moment joint for applying swing moment in the swing direction. The two ends of the test piece (4) are respectively fixedly connected to the inner end of a movable hinge assembly (2), and the outer ends of the two movable hinge assemblies (2) are respectively connected to a centrifugal force application assembly (3). The centrifugal force application assembly (3) is fixedly connected to a centrifugal force connector for applying centrifugal force at the end away from the test piece (4). The internal structure of the two movable hinge assemblies (2) enables them to rotate in the swinging direction and swing in the oscillation direction. The large blade fatigue testing device is used to simultaneously apply flapping moment and oscillation moment through two moment application components (1) clamped on the test piece (4), and simultaneously realize the independent application of flapping moment, oscillation moment and centrifugal force load. Each of the bending moment application components (1) includes: a clamping mechanism (1a), a swinging linear actuator (1b), and a oscillating linear actuator (1c); wherein, the two clamping mechanisms (1a) are fixedly clamped on the test piece (4) along the spanwise direction, the swinging linear actuator (1b) is hinged to the swinging bending moment joint provided in the swinging direction of the clamping mechanism (1a), and the oscillating linear actuator (1c) is hinged to the oscillating bending moment joint provided in the oscillating direction of the clamping mechanism (1a); Each of the movable hinge components (2) includes: a linear guide mechanism (2a), a horizontal shaft (2b), a connector (2c), and a limiting mechanism (2d); wherein, one end of the connector (2c) is fixedly connected to the test piece (4), and the shaft hole of the other end is nested in the centrifugal force double-ear joint (3b) of the centrifugal force application component (3), and the horizontal shaft (2b) is used to hinge the connector (2c) and the centrifugal force double-ear joint (3b); the two ends of the horizontal shaft (2b) are respectively installed on the symmetrically arranged linear guide mechanism (2a), so that the horizontal shaft (2b) slides along the direction of the linear guide mechanism (2a); the limiting mechanism (2d) is installed at the end of the guide rail of the linear guide mechanism (2a) that is close to the test piece (4); In each of the movable hinge components (2), the connecting member (2c) includes: a cross joint (2e), a vertical shaft (2f), a transition member (2g), a flange (2h), and a blade joint (2j); wherein, the inner end of the cross joint (2e) is provided with a vertical shaft hole, and the outer end is provided with a horizontal shaft hole; it is integrally fitted into the middle of the horizontal shaft (2b) through the horizontal shaft hole at its outer end, the vertical shaft hole at its inner end is hinged to the double-ear end of the transition member (2g) through the vertical shaft (2f), the other end of the transition member (2g) is connected to one end of the blade joint (2j) through the flange (2h), and the other end of the blade joint (2j) is fixedly connected to one end of the test piece (4); A hinge mechanism with free rotation capability in the swinging direction is formed by the horizontal axis (2b) and the cross joint (2e); a hinge mechanism with free rotation capability in the oscillation direction is formed by the cross joint (2e), the vertical axis (2f), and the transition piece (2g). In each of the connecting parts (2c) of the movable hinge assembly (2), the installation angle adjustment mechanism of the test piece (4) is formed by the transition part (2g), the flange (2h) and the blade joint (2j) to adapt to the installation requirements when the test piece (4) has a self-torsion angle.

2. The large blade fatigue testing device according to claim 1, characterized in that, The movable hinge assembly (2) connected to both sides of the test piece (4) is used to ensure that the test piece (4) does not deviate from the central installation position during the test loading process through the combined action of the limiting mechanism (2d) on the linear guide rail mechanism (2a) on both sides.

3. The large blade fatigue testing device according to claim 2, characterized in that, A radial bearing is installed in the shaft hole of the connector (2c), so that the hinge between it and the horizontal shaft (2b) has the ability to rotate in the swinging direction and to swing in the oscillation direction.

4. The large blade fatigue testing device according to claim 1, characterized in that, The two moment application components (2) are respectively arranged asymmetrically on the test piece (4) from the center to both ends; or, The two moment application components (2) are positioned on the test piece (4) such that the two moment application components (2) are equidistant from the center of the test piece (4), and are symmetrically arranged.

5. The large blade fatigue testing device according to any one of claims 1 to 4, characterized in that, Each of the centrifugal force application components (3) includes a centrifugal force linear actuator (3a) and a centrifugal force double-ear connector (3b), one end of which is hinged to the horizontal axis (2b) of the same-side movable hinge assembly (2), and the other end is connected to the centrifugal force linear actuator (3a).

6. The large blade fatigue testing device according to any one of claims 1 to 4, characterized in that, Each of the centrifugal force application components (3) includes a centrifugal force linear actuator (3a), two sets of pulleys (3c) and steel cables (3d); wherein, the two pulleys (3c) are respectively installed at both ends of the horizontal shaft (2b) extending out of the horizontal shaft hole in the cross joint (2e), and one end of each steel cable (3d) is wound around the corresponding pulley (3c), and the other end is connected to the centrifugal force linear actuator (3a).

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