A vibration excitation device for wind turbine blade fatigue testing

Abstract

The present application relates to a kind of exciting device for wind power blade fatigue test, be provided on loading assembly, the device includes blade assembly and exciting assembly, the blade assembly includes blade, clamp and counterweight, the root of the blade is mounted on the loading support of loading assembly, the clamp is mounted on blade, and is connected exciting assembly, the counterweight is arranged on clamp;The exciting assembly includes motor, reel and cable, the motor driving connection reel is used to drive reel rotation, one end of the cable is fixed and is wound on reel, and the other end is connected clamp;The cable is in tension state, the included angle of the cable and the chord line plane of blade is less than 90 degrees.Compared with prior art, the present application excites the biaxial vibration of blade by cable inclined pull blade, has the advantages such as simple structure, low test cost and avoid the influence of gravity on result.

Description

Technical Field

[0001] The present invention relates to the technical field of fatigue testing of wind turbine blades, and particularly to an excitation device for fatigue testing of wind turbine blades. Background Art

[0002] Since wind turbines need to operate in harsh natural conditions for a long time, the blades, as key components, must be subjected to fatigue tests to verify their durability. With the development of blades towards large sizes, resonance-type test schemes are generally adopted to reduce energy consumption. Biaxial testing can not only simulate combined loads but also shorten the test time. Currently, the optional excitation devices for biaxial testing shakers include pendulum type, linear motor type, hydraulic cylinder type, etc.

[0003] The invention with the publication number CN109185244A discloses a hydraulic system supporting a biaxial fatigue test bench for wind turbine blades. The motor drives a constant-pressure variable pump to send the hydraulic oil in the oil tank to the integrated block, and then after being split by the large oil distribution block and regulated by the proportional servo valve, it is sent to the double-rod hydraulic cylinder assembly through the small oil distribution block, driving the mass block to reciprocate, forcing the wind turbine blade to achieve biaxial fatigue loading in the flap and pitch directions. The liquid level, temperature, and pressure are monitored by means of a liquid level gauge, an electric contact thermometer, and a pressure gauge, the oil is filtered by means of a pressure pipeline filter and a return oil filter, and the pipeline pressure is regulated and maintained by means of an accumulator, an overflow valve, and a flow control valve. The double-rod hydraulic cylinder assembly is firmly fixed to the wind turbine blade by means of a frame and adjusting bolts, having the advantages of easy profiling, adjustable position, and no damage to the blade. However, this hydraulic system is relatively complex in installation and maintenance, difficult to control, and the loading process needs to overcome the self-weight of the mass block.

[0004] Therefore, the above existing fatigue excitation systems have the following problems:

[0005] 1. Using an inertial exciter will impose a gravity effect on the blade, causing a large shear load; 2. The excitation system for completing biaxial testing is relatively complex in structure, with high test costs, and does not balance the requirements of resonance-type testing and control difficulty; 3. The influence of gravity load is not fully considered during the fatigue test process. [[ID=I8]] Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above existing technologies where an inertial oscillator is installed on the blade, imposing a gravity effect on the blade, causing a large shear load, and the structure of the inertial exciter is complex, and to provide an excitation device for fatigue testing of wind turbine blades.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A vibration excitation device for fatigue testing of wind turbine blades is mounted on a loading assembly. The device includes a blade assembly and a vibration excitation assembly. The blade assembly includes a blade, a clamp, and a counterweight. The root of the blade is mounted on a loading support of the loading assembly. The clamp is mounted on the blade and connected to the vibration excitation assembly. The counterweight is mounted on the clamp.

[0009] The excitation assembly includes a motor, a drum, and a cable. The motor drives the drum to rotate. One end of the cable is fixed and wound around the drum, and the other end is connected to a clamp. The cable is in a tensioned state, and the angle between the cable and the chord plane of the blade is less than 90 degrees.

[0010] Preferably, the device includes a first excitation component and a second excitation component, the chord plane of the blade is horizontally arranged, the clamp is provided with mounting holes, the cables of the first excitation component and the second excitation component are respectively connected to the mounting holes, and the angle between the axis of the cable of the first excitation component and the axis of the cable of the second excitation component is greater than 0 degrees.

[0011] Preferably, the cable axis of the first excitation component and the cable axis of the second excitation component are both located within the vertical cross-section of the blade passing through the mounting hole, and the angle between the cable axis of the first excitation component and the chord plane of the blade is equal to the angle between the cable axis of the second excitation component and the chord plane of the blade.

[0012] Preferably, the blade has a first resonant frequency in the vertical flapping direction and a second resonant frequency in the horizontal oscillation direction, the fundamental frequency of the tension on the cable of the first excitation component is the same as that of the first excitation component, and the fundamental frequency of the tension on the cable of the second excitation component is the same as that of the second resonant frequency.

[0013] Preferably, the device has an excitation assembly, the chord plane of the blade is horizontally arranged, the clamp is provided with mounting holes, and the excitation assembly has cable connection mounting holes.

[0014] Preferably, the blade has a first resonant frequency in the vertical waving direction and a second resonant frequency in the horizontal oscillation direction, and the tension on the cable of the excitation assembly has a first fundamental frequency and a second fundamental frequency, wherein the first fundamental frequency is the same as the first resonant frequency, and the second fundamental frequency is the same as the second resonant frequency.

[0015] Preferably, there is a phase difference between the first fundamental frequency and the second fundamental frequency.

[0016] Preferably, the device has an excitation assembly, the angle between the chord plane of the blade and the horizontal plane is greater than 0 degrees and less than 90 degrees, the clamp is provided with a mounting hole, the cable of the excitation assembly is connected to the mounting hole, and the cable is set vertically.

[0017] Preferably, the device further includes a support and a torsion spring. The support is set on the ground, the drum is rotatably fixed on the support and placed horizontally, and one end of the torsion spring is fixed on the ground, while the other end is connected to the end of the drum away from the motor.

[0018] When the blade is at its lowest vibration point, the torsion spring is at its original length.

[0019] When the blade is at its highest vibration point, the torsion spring is in a compressed state.

[0020] Preferably, the clamp is a detachable structure, the clamp is provided with bolts, the clamp is detachably fixed to the blade by the bolts, and the blade is provided with multiple clamps.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) In this scheme, the root of the blade is installed on the loading support, the clamp is installed on the blade, the clamp is used to set the counterweight and connect the cable of the excitation component to complete the assembly of the excitation device; then the motor drives the drum to reciprocate to realize the periodic winding and unwinding of the cable, which drives the clamp and the blade to move, thereby applying excitation force to the blade and conducting fatigue testing of the blade.

[0023] By fixing the blades to a loading support, a motor drives a drum to reciprocate, causing the cable to periodically wind up and down. A clamp connected to the cable and fixed to the blades applies an excitation force, driving the blades to flap vertically and oscillate horizontally. Compared to inertial exciters mounted on the blades, this excitation device is simpler to install, and its weight does not affect the blade testing, does not change the blade system's resonant frequency, and results in more accurate test results.

[0024] (2) In this scheme, the clamp is connected to two excitation components by cables. The angle between the axis of the cables on both sides and the vertical direction is adjustable. There is an adjustable phase difference between the fundamental frequency components of the tension in the cables on both sides, which can control the combined load during the biaxial test of the blade. The constant components of the tension in the cables on both sides cancel each other out in the swing direction, thereby improving the vibration trajectory deviation phenomenon in the biaxial test.

[0025] (3) In this scheme, an excitation component can be set to deflect the cable axis at an angle to the vertical direction. The tension in the cable has two fundamental frequency components, which are applied to the flapping and oscillating directions of the blades through the load angle. Adjusting the cable deflection angle and the phase difference of the fundamental frequency components can control the vibration trajectory and test energy consumption, thus completing the biaxial test. Moreover, the actual form of the tension in the cable can be smoothed and filtered based on the target form, thereby improving the operability in actual testing, making full use of equipment conditions, and reducing testing costs.

[0026] (4) In this scheme, an excitation component can also be set up so that the axis of the cable is vertical and the plane of the chord at the root of the blade is at an angle to the horizontal direction. The unidirectional load applied to the blade by the cable pull and the gravity of the counterweight will affect the fatigue damage during the test, especially when it only acts in the flapping direction; however, the unidirectional load after the cable is set vertically is decomposed into the flapping and oscillation directions, which can weaken this effect. Furthermore, changing the amplitude of the tension in the cable can further compensate for this, correct the effect of the superposition effect of the unidirectional load, and improve the test accuracy and reliability.

[0027] (5) In this scheme, a torsion spring is installed on the output shaft at the end of the drum away from the motor. Under the premise that the cable is always taut, the torsion spring is in its original length when the blade is at the lowest vibration point. When the blade vibrates from the lowest point to the highest point, the motor does positive work on the torsion spring through the drum, and the torsion spring rotates through a certain angle to store elastic potential energy. When the blade vibrates from the highest point to the lowest point, the motor and the torsion spring do positive work on the drum at the same time, and the torsion spring releases elastic potential energy. The energy output by the motor during the blade rebound process is fully utilized, the peak load of the motor when it reaches full load is reduced, and the power capacity of the motor is fully utilized. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the excitation device provided by the present invention;

[0029] Figure 2 This is a schematic diagram of the structure including two excitation components provided in Embodiment 1 of the present invention;

[0030] Figure 3 This is a schematic diagram of a vibration assembly with horizontally arranged blades provided in Embodiment 2 of the present invention;

[0031] Figure 4 This is a schematic diagram of a vibration excitation assembly provided in Embodiment 3 of the present invention, with the cable arranged vertically;

[0032] Figure 5 This is a schematic diagram of a torsion spring provided at the output end of a drum according to Embodiment 4 of the present invention;

[0033] In the figure: 1. Blade, 2. Bolt, 3. Clamp, 4. Counterweight, 5. Loading support, 6. String plane, 7. First excitation assembly, 8. Second excitation assembly, 11. Cable, 12. Support, 13. Drum, 14. Motor, 21. Torsion spring. Detailed Implementation

[0034] 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.

[0035] 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.

[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] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0038] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they 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.

[0040] Example 1

[0041] like Figure 1 and Figure 2As shown, this embodiment provides a vibration device for fatigue testing of wind turbine blades, which is mounted on a loading assembly. The device includes a blade assembly and a vibration assembly. The blade assembly includes a blade 1, a clamp 3, and a counterweight 4. The root of the blade 1 is mounted on the loading support 5 of the loading assembly. The clamp 3 is mounted on the blade 1 and connected to the vibration assembly. The counterweight 4 is mounted on the clamp 3.

[0042] The vibration excitation assembly includes a motor 14, a drum 13, and a cable 11. The motor 14 drives the drum 13 to rotate. One end of the cable 11 is fixed and wound on the drum 13, and the other end is connected to the clamp 3. The cable 11 is in a tensioned state, and the angle between the cable 11 and the chord plane 6 of the blade 1 is less than 90 degrees.

[0043] Working principle: The root of blade 1 is installed on the loading support 5, and the clamp 3 is installed on blade 1. The clamp 3 is used to set the counterweight 4 and connect the cable 11 of the excitation assembly to complete the assembly of the excitation device. Then, the motor 14 drives the drum 13 to reciprocate, realizing the periodic winding and unwinding action of the cable 11, which drives the clamp 3 and blade 1 to move, thereby applying excitation force to blade 1 and conducting fatigue test on blade 1.

[0044] By fixing the blade 1 to the loading support 5, the motor 14 drives the drum 13 to reciprocate, causing the cable 11 to periodically wind up and down. The clamp 3, connected to the cable 11 and fixed to the blade 1, applies an excitation force to the blade, driving it to flap vertically and oscillate horizontally. Compared to inertial exciters mounted on the blade, this excitation device is simpler to install, and its weight does not affect the blade testing, does not change the resonant frequency of the blade system, and results in higher accuracy.

[0045] The excitation assembly includes a first excitation assembly 7 and a second excitation assembly 8. The chord plane 6 of the blade 1 is horizontally set. The clamp 3 is provided with mounting holes. The cables 11 of the first excitation assembly 7 and the second excitation assembly 8 are respectively connected to the mounting holes. The angle between the axis of the cable 11 of the first excitation assembly 7 and the axis of the cable 11 of the second excitation assembly 8 is greater than 0 degrees.

[0046] The axis of cable 11 of the first excitation assembly 7 and the axis of cable 11 of the second excitation assembly 8 are both located within the vertical section of the blade passing through the mounting hole. The angle between the axis of cable 11 of the first excitation assembly 7 and the chord plane 6 of the blade 1 is equal to the angle between the axis of cable 11 of the second excitation assembly 8 and the chord plane 6 of the blade 1.

[0047] The blade 1 has a first resonant frequency in the vertical flapping direction and a second resonant frequency in the horizontal oscillation direction. The fundamental frequency of the tension on the cable 11 of the first excitation assembly 7 is the same as that of the first excitation assembly 7, and the fundamental frequency of the tension on the cable 11 of the second excitation assembly 8 is the same as the second resonant frequency. An adjustable phase difference is provided between the fundamental frequency of the tension on the cable 11 of the first excitation assembly 7 and the fundamental frequency of the tension on the cable 11 of the second excitation assembly 8.

[0048] Furthermore, the clamp 3 is a detachable structure, and the clamp 3 is provided with bolts 2. The clamp 3 is detachably fixed to the blade 1 by the bolts 2, and the blade 1 is provided with multiple clamps 3.

[0049] Specifically, in this embodiment, the root of the blade 1 is fixedly mounted on the loading support, with the root chord plane 6 aligned with the horizontal direction, and one end of the cable 11 is bound to the mounting hole of the clamp 3. Two sets of excitation components are respectively arranged on the ground on both sides of the vertical plane where the axis of the blade 1 is located. The motor 14 drives the drum 13 to reciprocate to realize the winding and unwinding action of the cable 11, thereby applying excitation force to the blade 1.

[0050] The fundamental frequency of the tension in cable 11 of the first excitation assembly 7 is the same as the resonant frequency of the system's swing direction, and the fundamental frequency of the tension in cable 11 of the second excitation assembly 8 is the same as the resonant frequency of the system's oscillation direction. The angle between the axis of the two ropes 11 and the vertical direction is variable, and there is an adjustable phase difference between the fundamental frequency components of the tension in the two cables 11, thus allowing control of the combined load during biaxial testing. The constant components of the tension in the two cables 11 cancel each other out in the oscillation direction, thereby improving the vibration trajectory deviation phenomenon in biaxial testing.

[0051] Specifically, two symmetrically arranged excitation components excite the blade for horizontal flapping and vertical oscillation. When the excitation forces of the first excitation component 7 and the second excitation component 8 are different, the blade exhibits horizontal flapping and vertical oscillation. Adjusting the excitation forces of the first excitation component 7 and the second excitation component 8 allows for the regulation of the blade's excitation force. When the excitation forces of the first excitation component 7 and the second excitation component 8 are the same, and their excitation timing (phase) is completely synchronized, the blade can achieve pure motion only in the flapping or oscillation direction. If the phases of 7 and 8 are different, even if their magnitudes are equal, it will still cause the blade to perform biaxial motion in space. By adjusting the excitation force or excitation timing of the two excitation components, various forms of blade motion can be excited.

[0052] The system resonant frequency can be obtained by real-time spectral analysis of the strain signal of blade 1, thereby adjusting the fundamental frequency of the tension in cable 11. The system resonant frequency is not only related to the inherent properties of blade 1, but also affected by clamp 3 and counterweight 4. For the actual loading force in the flapping and oscillating directions, a frequency domain weighting index is established, and the tension form in cables 11 on both sides is adjusted to reduce test energy consumption.

[0053] The inherent amplitude-frequency characteristics of a mechanical system manifest as a more prominent vibration in a certain frequency band. Therefore, the frequency components of the actual applied force that are outside the resonance zone can be filtered out during vibration. Thus, the tension in the ropes 11 on both sides does not need to be too complex, thereby reducing the control cost.

[0054] Example 2

[0055] like Figure 3 As shown, this embodiment is basically the same as embodiment 1, except that the device has an excitation component, the chord plane 6 of the blade 1 is set horizontally, the clamp 3 is provided with mounting holes, and the cable 11 of the excitation component is connected to the mounting holes.

[0056] The blade 1 has a first resonant frequency in the vertical flapping direction and a second resonant frequency in the horizontal oscillation direction. The tension on the cable 11 of the excitation assembly has a first fundamental frequency and a second fundamental frequency. The first fundamental frequency is the same as the first resonant frequency, and the second fundamental frequency is the same as the second resonant frequency. There is a phase difference between the first fundamental frequency and the second fundamental frequency.

[0057] Specifically, only one set of excitation components is retained, and the axis of cable 11 is deflected at an angle to the vertical direction. The tension in cable 11 has two fundamental frequency components, which are applied to the flapping and oscillating directions of blade 1 via the load angle. Adjusting the deflection angle and the phase difference of the fundamental frequency components of cable 11 can control the vibration trajectory and test energy consumption, completing the biaxial test. The actual form of tension in cable 11 can be smoothed and filtered based on the target form, thereby improving the operability in actual testing. This embodiment can make full use of equipment conditions and reduce testing costs.

[0058] Example 3

[0059] like Figure 4 As shown, this embodiment is basically the same as embodiment 2, except that the device has an excitation component, the angle between the chord plane 6 of the blade 1 and the horizontal plane is greater than 0 degrees and less than 90 degrees, the clamp 3 is provided with a mounting hole, the cable 11 of the excitation component is connected to the mounting hole, and the cable 11 is set vertically.

[0060] Specifically, the excitation component is positioned directly below blade 1, with the axis of cable 11 located in a vertical plane, and the chord line of the root section of blade 1 forming an angle with the horizontal direction. By rotating the blade's installation angle from the purely flapping (horizontal) direction by a certain angle, such as 45 degrees, even a single vertical excitation force can induce biaxial motion of the entire blade in both flapping and oscillating directions. The unidirectional load applied to blade 1 by the downward pull of cable 11 and gravity can affect fatigue damage during the test, especially when it acts only in the flapping direction. Decomposing the unidirectional load into the flapping and oscillating directions can weaken this effect, and further compensation can be achieved by changing the tension amplitude in cable 11. This embodiment corrects the effect of the superposition effect of unidirectional loads, improving test accuracy. Changing the blade installation form to adjust the direction of gravity relative to the blade coordinate system and modifying the loading force amplitude can compensate for the influence of unidirectional loads on structural damage and improve the reliability of test results.

[0061] Example 4

[0062] like Figure 5 As shown, this embodiment is basically the same as embodiment 1, except that the device also includes a support 12 and a torsion spring 21. The support 12 is set on the ground, the drum 13 is rotatably fixed on the support 12 and placed horizontally, one end of the torsion spring 21 is fixed on the ground, and the other end is connected to the end of the drum 13 away from the motor 14.

[0063] When blade 1 is at its lowest vibration point, torsion spring 21 is at its original length.

[0064] When blade 1 is at its highest vibration point, torsion spring 21 is in a compressed state.

[0065] Specifically, a torsion spring 21 is installed on the output shaft at the other end of the drum 13. With the cable 11 always taut, the torsion spring 21 is at its original length when the blade 1 is at its lowest vibration point. As the blade 1 vibrates from its lowest point to its highest point, the motor 14 performs positive work on the torsion spring 21 through the drum 13, and the torsion spring 21 rotates through a certain angle to store elastic potential energy. As the blade 1 vibrates from its highest point to its lowest point, the motor 14 and the torsion spring 21 simultaneously perform positive work on the drum 13, and the torsion spring 21 releases its elastic potential energy.

[0066] In this embodiment, energy is stored during the half-cycle when the motor 14 does no work on the blade 1, and then released during the half-cycle when the motor 14 does work on the blade 1. This reduces the demand on the output torque of the motor 1 during this stage and makes full use of the power of the motor 1. The torsion spring, as an energy storage element, makes full use of the energy output by the motor during the blade rebound process, reduces the peak load of the motor when it reaches full load, and makes full use of the motor's power capacity.

[0067] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A vibration excitation device for fatigue testing of wind turbine blades, mounted on a loading assembly, characterized in that, The device includes a blade assembly and an excitation assembly. The blade assembly includes a blade (1), a clamp (3), and a counterweight (4). The root of the blade (1) is mounted on the loading support (5) of the loading assembly. The clamp (3) is mounted on the blade (1) and connected to the excitation assembly. The counterweight (4) is mounted on the clamp (3). The excitation assembly includes a motor (14), a drum (13), and a cable (11). The motor (14) drives the drum (13) to rotate. One end of the cable (11) is fixed and wound on the drum (13), and the other end is connected to a clamp (3). The cable (11) is in a tensioned state, and the angle between the cable (11) and the chord plane (6) of the blade (1) is less than 90 degrees. The device has two excitation components, including a first excitation component (7) and a second excitation component (8). The chord plane (6) of the blade (1) is set horizontally. The clamp (3) is provided with mounting holes. The cables of the first excitation component (7) and the second excitation component (8) are respectively connected to the mounting holes. The angle between the axis of the cable of the first excitation component (7) and the axis of the cable of the second excitation component (8) is greater than 0 degrees. The cable axis of the first excitation component (7) and the cable axis of the second excitation component (8) are both located within the vertical section of the blade through the mounting hole. The angle between the cable axis of the first excitation component (7) and the chord plane (6) of the blade (1) is equal to the angle between the cable axis of the second excitation component (8) and the chord plane (6) of the blade (1). The blade (1) has a first resonant frequency in the vertical waving direction and a second resonant frequency in the horizontal oscillation direction. The fundamental frequency of the tension on the cable of the first excitation component (7) is the same as that of the first excitation component (7), and the fundamental frequency of the tension on the cable of the second excitation component (8) is the same as that of the second resonant frequency. Alternatively, the device may have an excitation assembly, with the chord plane (6) of the blade (1) set horizontally, the clamp (3) having mounting holes, and the cable (11) of the excitation assembly connected to the mounting holes; The blade (1) has a first resonant frequency in the vertical flapping direction and a second resonant frequency in the horizontal oscillation direction. The tension on the cable (11) of the excitation assembly has a first fundamental frequency and a second fundamental frequency. The first fundamental frequency is the same as the first resonant frequency, and the second fundamental frequency is the same as the second resonant frequency. There is a phase difference between the first fundamental frequency and the second fundamental frequency.

2. The vibration excitation device for fatigue testing of wind turbine blades according to claim 1, characterized in that, The device has an excitation assembly, the angle between the chord plane (6) of the blade (1) and the horizontal plane is greater than 0 degrees and less than 90 degrees, the clamp (3) is provided with a mounting hole, the cable (11) of the excitation assembly is connected to the mounting hole, and the cable (11) is set vertically.

3. The excitation device for fatigue testing of wind turbine blades according to claim 1, characterized in that, The device also includes a support (12) and a torsion spring (21). The support (12) is set on the ground. The drum (13) is rotatably fixed on the support (12) and placed horizontally. One end of the torsion spring (21) is fixed on the ground, and the other end is connected to the end of the drum (13) away from the motor (14). When the blade (1) is at its lowest vibration point, the torsion spring (21) is in its original length state; When the blade (1) is at its highest vibration point, the torsion spring (21) is in a compressed state.

4. A vibration excitation device for fatigue testing of wind turbine blades according to claim 1, characterized in that, The clamp (3) is a detachable structure. The clamp (3) is provided with bolts (2). The clamp (3) is detachably fixed to the blade (1) by bolts (2). The blade (1) is provided with multiple clamps (3).

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