Blade fatigue testing device, system and method

Abstract

The invention relates to the technical field of blade fatigue testing, and discloses a blade fatigue testing device, system and method. According to the blade fatigue testing device provided by the invention, the loading unit is used, so that the blade fatigue testing device has the capability of applying a torsional reciprocating load to the blade to be tested, and the loading unit can independently or jointly apply loads in flapping, shimmy and torsional directions; therefore, a user can formulate a test scheme according to the blade type, the test standard or the actual load working condition, and various loading modes can be realized without replacing equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of blade fatigue testing, and in particular to a blade fatigue testing device, system and method. Background Art

[0002] As the global wind power industry rapidly develops towards high power and long blades, the size and structural complexity of blades have increased significantly.

[0003] Full-size blade testing primarily involves static and fatigue testing. Static blade testing involves applying static loads (such as bending and torsion) to the blades, typically to 150%-200% of the design value to test safety margins. Blade strain, displacement, and local deformation are monitored, as well as the presence of cracks or delamination, to determine the structural reliability of the blades. Blade fatigue testing involves cyclic loading to simulate the alternating stresses experienced in long-term blade operation. Under the influence of a resonant excitation system, the blades undergo millions of flapping and shimmying motions to verify their structural reliability. Fatigue testing typically lasts several months or even a year.

[0004] Among them, the fatigue testing content of blades mainly includes flapping fatigue testing, shimmy fatigue testing, and torsional fatigue testing. The flapping fatigue test is to make the blade complete millions of reciprocating deformation movements in the up and down (pressure side-suction side) bending direction; the shimmy fatigue test is to make the blade complete millions of reciprocating deformation movements in the front and back (leading edge-trailing edge) bending direction. The current standards do not require the implementation of torsional fatigue testing, and there are currently few related testing equipment and supporting methods in the industry. The fatigue testing types of blades mainly include uniaxial fatigue testing and biaxial fatigue testing. The uniaxial fatigue test often uses the resonant excitation method: an eccentric hammer exciter is installed at the appropriate position of the blade, and the excitation frequency is adjusted to be close to the natural frequency of the blade to induce large vibrations in the blade; the biaxial fatigue test test machine is equipped with two independent excitation units. The servo motor repeatedly pushes the connecting rod connected to the blade to achieve forced vibration loading of the blade in two directions. Uniaxial and biaxial fatigue tests each have their applicable boundaries. Uniaxial testing is simple and reliable, but it proves insufficient when blades are larger and subjected to complex loads. Biaxial testing is realistic and efficient, but requires overcoming equipment complexity and control challenges. In the current industry, uniaxial testing is still the dominant method for blades.

[0005] However, both uniaxial and multi-axial tests verify the fatigue reliability of the blade in the flapping and swing directions, while neither of these two types of testing equipment has the ability to verify the torsional fatigue reliability of the blade. Summary of the Invention

[0006] In view of this, the present invention provides a blade fatigue testing device, system and method to solve the problem of simultaneously verifying the reliability of blade flapping, shimmy and torsional fatigue.

[0007] In a first aspect, the present invention provides a blade fatigue testing device comprising a blade fixing base and a loading assembly. The blade fixing base fixes the root of the blade to be tested; the loading assembly comprises a blade fixture and a loading unit. The blade fixture fixes the blade to be tested; the loading unit is mounted on the blade fixture and is configured to apply at least one of an up-and-down reciprocating load in the swing direction, a back-and-forth reciprocating load in the swing direction, and a torsional reciprocating load in the torsional direction to the blade fixture.

[0008] Beneficial Effects: The use of loading units enables blade fatigue testing equipment to apply torsional reciprocating loads to the blades under test. These loading units can independently or in combination apply loads in the swing, shimmy, and torsional directions. This allows users to develop test plans based on blade type, test standard, or actual load conditions, enabling multiple loading modes without changing equipment. Furthermore, by integrating multiple loading functions during the test process, multi-directional fatigue testing can be completed quickly, eliminating multiple installation and commissioning steps and shortening the test cycle.

[0009] In an optional embodiment, the blade clamp has a first loading part and a second loading part; the loading unit includes a first loading component and a second loading component, the first loading component acts on the first loading part, and the second loading component acts on the second loading part; the first loading component and the second loading component are configured to drive the first loading part and the second loading part to have the same horizontal displacement, or the same vertical displacement, or different horizontal and vertical displacements.

[0010] Beneficial effects: Through the independent configuration of the first loading part and the second loading part, combined with the displacement difference control of the loading component in the horizontal / vertical direction (such as horizontal and vertical asynchronous), the complex coupling loads (such as flapping-swing-torsion three-way coupled vibration) caused by wind field dynamics, yaw deflection, etc. in the actual operation of the blade can be accurately reproduced, solving the problem of the lack of torsional fatigue testing in the existing technology and realizing the reliability verification of the blade throughout its life cycle. At the same time, the first loading part and the second loading part can also simulate flapping or swing fatigue through synchronous loading (such as synchronous displacement in the horizontal or vertical direction), retaining the simple reliability of traditional uniaxial testing. In addition, the independent configuration of the loading component allows for quick switching of test modes without changing equipment or adjusting fixtures, reducing test preparation time and cost.

[0011] In an optional embodiment, the first loading assembly includes a connecting rod and a drive motor. The connecting rod has a first end along its length that is rotatably mounted to the first loading portion of the blade clamp; the drive motor has a drive shaft that is drivingly connected to a second end along its length, the drive shaft being configured to drive the second end of the connecting rod to rotate about the first end.

[0012] Beneficial effects: By setting up a drive motor, a stable and controllable driving force can be provided to drive the first end of the connecting rod to rotate around the second end. Through the setting of the connecting rod, a stable mechanical support structure can be formed to ensure the smoothness and accuracy of the first loading part along the expected movement, and provide a reliable direction adjustment basis for realizing complex load loading of blades with multiple degrees of freedom and multi-axis coupling, effectively improving the flexibility and accuracy of the loading device in simulating the actual force scenarios of the blades.

[0013] In an optional embodiment, the first loading assembly further comprises a rocker, wherein one end of the rocker along its length direction serves as a movable end connected to the second end of the connecting rod, and the other end serves as a connecting end and rotates coaxially with the drive shaft of the drive motor.

[0014] Beneficial effects: The rocker serves as a lever structure, which is connected to the connecting rod through the connecting end. The connecting end of the rocker is connected to the coaxial rotation of the drive shaft, so that the coaxial rotation of the drive shaft is directly and without offset transmitted to the movable end of the rocker. In the process of the connecting end driving the movable end to move, it can drive the connecting rod to swing linearly. There is no need for a complex gear set or transmission chain. Motion conversion can be achieved through a simple articulated joint, reducing the number of parts.

[0015] In an optional embodiment, the first loading assembly further includes a first telescopic member. The first telescopic member includes a first telescopic portion and a first fixed portion, wherein one end portion of the first telescopic portion along its telescopic direction is rotatably mounted on the connecting rod and is located between the first end portion and the second end portion, and one end portion of the first fixed portion along its length direction is used to constrain the other end portion of the first telescopic portion along its telescopic direction to move along the telescopic direction, and the other end portion of the first fixed portion along its length direction is movably mounted on the drive shaft of the drive motor.

[0016] Beneficial effect: Through the setting of the first telescopic member, the length of the force arm from the drive shaft to the connecting rod connection point can be actively adjusted by controlling the telescopic degree of the first telescopic part, thereby adjusting the swing amplitude of the connecting rod to adapt to different working conditions.

[0017] In an optional embodiment, the second loading assembly includes a second telescopic member and a mounting seat. The second telescopic member has a second telescopic portion and a second fixed portion, wherein one end of the second telescopic portion along its telescopic direction is rotatably mounted to the second loading position, and one end of the second fixed portion along its length direction is used to constrain the other end of the second telescopic portion along its telescopic direction; and the mounting seat is rotatably mounted to the other end of the second fixed portion along its length direction.

[0018] Beneficial effect: The second telescopic part is installed at the second loading part by rotation, ensuring that the push or pull of the second loading component is accurately transmitted to the second loading part, and the mounting seat can support the second fixed part to rotate slightly to avoid jamming.

[0019] In an optional embodiment, the second loading portion and the first loading portion are spaced apart in the horizontal direction and / or vertical direction.

[0020] Beneficial Effects: In actual operation, blades are subject to a combination of multi-directional loads, including flapping (vertical), oscillation (horizontal), and torsion (axial). By spacing the loading locations horizontally and vertically, varying degrees of load can be applied independently or simultaneously, fully simulating the blade's stress state under complex operating conditions such as wind loads and gravity. Furthermore, spacing the loading components horizontally and / or vertically avoids physical interference between them, reducing the risk of collisions between moving parts and extending the equipment's service life.

[0021] In an optional embodiment, the blade fatigue testing device further comprises a positioning flange, which is mounted on a blade fixing base; and the root of the blade to be tested is mounted on the blade fixing base via the positioning flange.

[0022] Beneficial effects: The positioning flange cooperates with the blade root and the blade fixing base through standardized interfaces (such as threaded holes, positioning pins, etc.), so that the flange surface and the blade root are in surface contact, making the constraint force transmitted from the blade fixing base to the blade more evenly distributed, and improving the phenomenon of additional loads in non-target directions interfering with test data.

[0023] In a second aspect, the present invention further provides a blade fatigue testing system, comprising a blade to be tested and the blade fatigue testing device of the first aspect, wherein the blade fatigue testing device is used to fix the blade to be tested and perform fatigue testing on the blade to be tested.

[0024] Beneficial effects: Since the blade fatigue testing system includes the blade fatigue testing device, it has the same effects as the blade fatigue testing device and will not be described in detail here.

[0025] In a third aspect, the present invention also provides a blade fatigue testing method, applicable to the blade fatigue testing system of the second aspect. The blade fatigue testing method comprises: periodically applying at least one of a reciprocating load, a shimmying load, and a torsional load to the blade under test via the blade fatigue testing system; adjusting loading parameters to match the loading frequency of the blade fatigue testing device with the blade's natural frequency; continuing resonant loading until a preset fatigue damage threshold is reached; and collecting dynamic response data of the blade under test and analyzing fatigue characteristics.

[0026] Beneficial effects: By periodically applying at least one of reciprocating loads, oscillating loads and torsional loads, the alternating stress state in different working conditions is simulated, the loading parameters are adjusted to make the system loading frequency accurately match the natural frequency of the blade, and the load amplitude is amplified by the resonance effect, which significantly accelerates the accumulation process of fatigue damage; continuous resonant loading is applied to the preset fatigue damage threshold, and the strain distribution, crack initiation and expansion behavior of the blade under different load amplitudes and frequencies are recorded through real-time collection of dynamic response data; fatigue life curves are constructed based on the collected data, and the stiffness degradation law and failure mode of the blade are analyzed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A three-dimensional view of a blade fatigue testing system provided by an embodiment of the present invention;

[0029] Figure 2 A three-dimensional view of the installed loading unit and blade fixture in the blade fatigue testing system provided by an embodiment of the present invention;

[0030] Figure 3 An exploded view of the installation of a loading unit and a blade fixture in a blade fatigue testing system provided by an embodiment of the present invention;

[0031] Figure 4 This is a front view of the installed loading unit and blade fixture in the blade fatigue testing system provided by an embodiment of the present invention.

[0032] Description of reference numerals:

[0033] 1. Blade fixing base;

[0034] 2. Loading unit; 211. Connecting rod; 2111. First end portion; 2112. Second end portion; 212. Driving motor; 2121. Driving shaft; 213. Rocker; 214. First telescopic member; 2141. First telescopic portion; 2142. First fixed portion; 215. Second telescopic member; 2151. Second telescopic portion; 2152. Second fixed portion; 216. Mounting base; 217. Speed ​​regulating box; 218. Connector;

[0035] 3. Blade fixture; 301. First loading position; 302. Second loading position;

[0036] 4. Positioning flange;

[0037] a. Blade to be tested. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0039] As the global wind power industry rapidly develops towards high power and long blades, the size and structural complexity of blades have increased significantly.

[0040] Full-size blade testing primarily involves static and fatigue testing. Static blade testing involves applying static loads (such as bending and torsion) to the blades, typically to 150%-200% of the design value to test safety margins. Blade strain, displacement, and local deformation are monitored, as well as the presence of cracks or delamination, to determine the structural reliability of the blades. Blade fatigue testing involves cyclic loading to simulate the alternating stresses experienced in long-term blade operation. Under the influence of a resonant excitation system, the blades undergo millions of flapping and shimmying motions to verify their structural reliability. Fatigue testing typically lasts several months or even a year.

[0041] Among them, the fatigue testing content of blades mainly includes flapping fatigue testing, shimmy fatigue testing, and torsional fatigue testing. The flapping fatigue test is to make the blade complete millions of reciprocating deformation movements in the up and down (pressure side-suction side) bending direction; the shimmy fatigue test is to make the blade complete millions of reciprocating deformation movements in the front and back (leading edge-trailing edge) bending direction. The current standards do not require the implementation of torsional fatigue testing, and there are currently few related testing equipment and supporting methods in the industry. The fatigue testing types of blades mainly include uniaxial fatigue testing and biaxial fatigue testing. The uniaxial fatigue test often uses the resonant excitation method: an eccentric hammer exciter is installed at the appropriate position of the blade, and the excitation frequency is adjusted to be close to the natural frequency of the blade to induce large vibrations in the blade; the biaxial fatigue test test machine is equipped with two independent excitation units. The servo motor repeatedly pushes the connecting rod connected to the blade to achieve forced vibration loading of the blade in two directions. Uniaxial and biaxial fatigue tests each have their applicable boundaries. Uniaxial testing is simple and reliable, but it proves insufficient when blades are larger and subjected to complex loads. Biaxial testing is realistic and efficient, but requires overcoming equipment complexity and control challenges. In the current industry, uniaxial testing is still the dominant method for blades.

[0042] However, both uniaxial and multi-axial tests verify the fatigue reliability of the blade in the flapping and swing directions, while neither of these two types of testing equipment has the ability to verify the torsional fatigue reliability of the blade.

[0043] To this end, the present application provides a blade fatigue testing device, system, and method to solve the problem of simultaneously verifying the reliability of blade flapping, shimmy, and torsional fatigue.

[0044] The following combination Figures 1 to 4 , describing embodiments of the present invention.

[0045] According to an embodiment of the present invention, on the one hand, a blade fatigue testing device is provided, comprising a blade fixing base 1 and a loading assembly.

[0046] The blade fixing base 1 fixes the root of the blade a to be tested; the loading assembly includes a blade clamp 3 and a loading unit 2, the blade clamp 3 fixes the blade a to be tested; the loading unit 2 is installed on the blade clamp 3, and the loading unit 2 is configured to apply at least one of the up and down reciprocating load in the swing direction, the front and back reciprocating load in the swing direction, and the torsional reciprocating load in the torsional direction to the blade clamp 3.

[0047] This configuration, through the use of loading unit 2, enables the blade fatigue test apparatus to apply torsional reciprocating loads to the blade under test (a). Loading unit 2 can independently or in combination apply loads in the flapping, shimmying, and torsional directions. This allows users to develop test plans based on blade type, test standard, or actual load conditions, enabling multiple loading modes without having to change equipment. Furthermore, by integrating multiple loading functions during the test process, multi-directional fatigue testing can be completed quickly, avoiding multiple installation and commissioning steps and shortening the test cycle.

[0048] In one embodiment, the blade clamp 3 has a first loading portion 301 and a second loading portion 302 .

[0049] The loading unit 2 includes a first loading component and a second loading component, the first loading component acts on the first loading part 301, and the second loading component acts on the second loading part 302; the first loading component and the second loading component are configured to drive the first loading part 301 and the second loading part 302 to have the same horizontal displacement, or the same vertical displacement, or different horizontal and vertical displacements.

[0050] With this arrangement, through the independent configuration of the first loading part 301 and the second loading part 302, combined with the differential control of the displacement of the two loading components in the horizontal / vertical directions (such as horizontal and vertical asynchronous), the complex coupled loads (such as flapping-sway-torsion three-way coupled vibration) caused by wind field dynamics, yaw deflection, etc. in actual operation of the blade can be accurately reproduced, solving the problem of the lack of torsional fatigue testing in the prior art and realizing the reliability verification of the blade throughout its life cycle. At the same time, the first loading part 301 and the second loading part 302 can also simulate flapping or sway fatigue through synchronous loading (such as synchronous displacement in the horizontal or vertical direction), retaining the simple reliability of traditional uniaxial testing. In addition, the independent configuration of the loading components allows for rapid switching of test modes without the need to replace equipment or adjust fixtures, reducing test preparation time and cost.

[0051] In one embodiment, the first loading assembly includes a connecting rod 211 and a driving motor 212 .

[0052] The first end 2111 of the connecting rod 211 along its length direction is rotatably mounted on the first loading portion 301 of the blade clamp 3; the driving motor 212 has a driving shaft 2121, which is transmission-connected to the second end 2112 of the connecting rod 211 along its length direction, and the driving shaft 2121 is configured to drive the second end 2112 of the connecting rod 211 to rotate around the first end 2111.

[0053] In this embodiment, the working mode of the connecting rod 211 is: after the driving motor 212 is energized, its driving shaft 2121 rotates and drives the second end 2112 connected to it to rotate. Since the first end 2111 is rotatably installed on the first loading part 301 of the blade clamp 3, the second end 2112 will rotate around the first end 2111 during the rotation process.

[0054] In this way, by setting up a drive motor 212, a stable and controllable driving force can be provided to drive the second end 2112 of the connecting rod 211 to rotate around the first end 2111, and through the setting of the connecting rod 211, a stable mechanical support structure can be formed to ensure the smoothness and accuracy of the first loading part 301 along the expected movement, providing a reliable direction adjustment basis for realizing complex load loading of blades with multiple degrees of freedom and multi-axis coupling, and effectively improving the flexibility and accuracy of the loading device in simulating the actual force scenario of the blade.

[0055] It can be explained that the driving motor 212 is selected as a servo motor.

[0056] It can be explained that the first loading assembly further includes a speed regulating box 217 . In this case, the speed regulating box 217 is installed on the driving shaft 2121 of the driving motor 212 , and adjusts the speed output by the driving shaft 2121 before transmitting it to the second end 2112 .

[0057] Preferably, the speed regulating box 217 is a gear box.

[0058] In one embodiment, the first loading assembly further includes a rocker 213. One end of the rocker 213 along its length direction is connected to the second end 2112 of the connecting rod 211 as a movable end, and the other end is connected to the driving shaft 2121 of the driving motor 212 as a connecting end to rotate coaxially.

[0059] In this arrangement, the rocker 213 serves as a lever structure, which is connected to the connecting rod 211 through the connecting end. The connecting end of the rocker 213 is connected to the coaxial rotation of the drive shaft 2121, so that the coaxial rotation of the drive shaft 2121 is directly and without offset transmitted to the movable end of the rocker 213. In the process of the connecting end driving the movable end to move, it can drive the connecting rod 211 to swing linearly, and drive the first loading part 301 to move during the swing of the connecting rod 211, so that the blade clamp 3 completes planar motion, thereby adjusting the posture of the blade clamp 3. In the process of transmitting power, no complex gear set or transmission chain is required, and motion conversion can be achieved only through simple articulated joints, thereby reducing the number of parts.

[0060] In one embodiment, the first loading assembly further includes a first telescopic member 214. The first telescopic member 214 has a first telescopic portion 2141 and a first fixed portion 2142. One end of the first telescopic portion 2141 along its telescopic direction is rotatably mounted on the connecting rod 211 and is located between the first end 2111 and the second end 2112. One end of the first fixed portion 2142 along its length direction is used to constrain the other end of the first telescopic portion 2141 along its telescopic direction to move along its telescopic direction. The other end of the first fixed portion 2142 along its length direction is movably mounted on the drive shaft 2121 of the drive motor 212.

[0061] In this way, through the setting of the first telescopic member 214, the angle between the rocker 213 and the connecting rod 211 can be adjusted by controlling the telescopic degree of the first telescopic part 2141, so that the first end 2111 of the connecting rod 211 is controlled by biaxial motion in the plane, thereby adjusting the swing amplitude of the connecting rod 211 to adapt to different working conditions.

[0062] It can be explained that the first telescopic member 214 is a hydraulic rod, the first telescopic portion 2141 is a piston rod, and the first fixed portion 2142 is a hydraulic cylinder.

[0063] Furthermore, the first loading assembly further includes a joint 218 , which is installed between the first end 2111 and the second end 2112 of the connecting rod 211 , and the end of the piston rod facing away from the hydraulic cylinder is installed on the joint 218 .

[0064] In one embodiment, the second loading assembly includes a second telescopic member 215 and a mounting base 216. The second telescopic member 215 has a second telescopic portion 2151 and a second fixed portion 2152. One end of the second telescopic portion 2151 along its telescopic direction is rotatably mounted on the second loading portion 302, and one end of the second fixed portion 2152 along its length direction is used to constrain the other end of the second telescopic portion 2151 along its telescopic direction to move along its telescopic direction; the mounting base 216 is rotatably mounted with the other end of the second fixed portion 2152 along its length direction.

[0065] With this arrangement, the second telescopic portion 2151 is mounted on the second loading portion 302 by rotation, ensuring that the push or pull of the second loading assembly is accurately transmitted to the second loading portion 302, and the mounting seat 216 can support the second fixed portion 2152 to rotate slightly to avoid jamming.

[0066] At the same time, the second telescopic member 215 can adjust the angle between the blade clamp 3 and the horizontal plane when used in conjunction with the connecting rod 211, thereby applying a torsional load to the blade.

[0067] It can be explained that the second telescopic member 215 is a hydraulic rod, the second telescopic portion 2151 thereof is a piston rod, the second fixed portion 2152 is a hydraulic cylinder, and the mounting seat 216 serves as a hydraulic rod seat.

[0068] Furthermore, the first telescopic member 214 and the second telescopic member 215 are selected as electric hydraulic rods, and their respective electrical connection ends are connected to the control terminal through wires. When in use, the control terminal controls the extension and retraction degree of each telescopic member.

[0069] In one embodiment, the second loading portion 302 and the first loading portion 301 are spaced apart in the horizontal direction and / or the vertical direction.

[0070] With this configuration, the blades are subject to a combination of multi-directional loads during actual operation, including flapping (vertical), oscillation (horizontal), and torsion (axial). By spacing the loading locations horizontally and vertically, varying degrees of load can be applied independently or simultaneously, fully simulating the blade's stress state under complex operating conditions such as wind loads and gravity. Furthermore, spacing the loading components horizontally and / or vertically avoids physical interference between them, reducing the risk of collisions between moving parts and extending the equipment's service life.

[0071] In one embodiment, the blade fatigue testing device further comprises a positioning flange 4. The positioning flange 4 is mounted on the blade fixing base 1; the root of the blade a to be tested is mounted on the blade fixing base 1 through the positioning flange 4.

[0072] With this arrangement, the positioning flange 4 cooperates with the blade root and the blade fixing base 1 through standardized interfaces (such as threaded holes, positioning pins, etc.), so that the flange surface and the blade root are in surface contact, making the constraint force transmitted from the blade fixing base 1 to the blade more evenly distributed, and improving the phenomenon of additional loads in non-target directions interfering with test data.

[0073] According to an embodiment of the present invention, in a second aspect, the present invention further provides a blade fatigue testing system, comprising a blade a to be tested and a blade fatigue testing device according to the first aspect, wherein the blade fatigue testing device is used to fix the blade a to be tested and perform fatigue testing on the blade a to be tested.

[0074] Such arrangement, because the blade fatigue testing system includes the blade fatigue testing device, has the same effect as the blade fatigue testing device, and is not described in detail here.

[0075] According to an embodiment of the present invention, in a third aspect, the present invention further provides a blade fatigue testing method, which is applied to the blade fatigue testing system of the second aspect.

[0076] The blade fatigue testing method includes: periodically applying at least one of a flapping load, a swing load, and a torsional load to a blade to be tested through a blade fatigue testing system; adjusting loading parameters so that the loading frequency of the blade fatigue testing device matches the blade's natural frequency; continuing resonant loading until a preset fatigue damage threshold is reached; and collecting dynamic response data of the blade to be tested and analyzing fatigue characteristics.

[0077] In this way, by periodically applying at least one of the flapping load, swing load and torsional load, the alternating stress state in different working conditions is simulated, the loading parameters are adjusted to make the system loading frequency accurately match the natural frequency of the blade, and the load amplitude is amplified by the resonance effect, which significantly accelerates the accumulation process of fatigue damage; continuous resonant loading is applied to the preset fatigue damage threshold, and the strain distribution, crack initiation and expansion behavior of the blade under different load amplitudes and frequencies are recorded through real-time collection of dynamic response data; fatigue life curves are constructed based on the collected data, and the stiffness degradation law and failure mode of the blade are analyzed.

[0078] Among them, the loading frequency matching mechanism maximizes the energy input efficiency, compressing the test cycle of several months of traditional methods to several weeks; the synergistic effect of periodic load and natural frequency accurately reproduces the dynamic response of the blade under actual working conditions, improving the accuracy of fatigue characteristics analysis; quantitative control of preset fatigue damage thresholds avoids test deviations caused by overload or underload, ensuring the reliability of results; multi-dimensional acquisition of dynamic response data provides high-precision input for blade structure optimization design, shortens the R&D iteration cycle, and reduces the overall cost of full-scale testing.

[0079] In this fatigue testing method, the working method is as follows: the first loading assembly and the second loading assembly are assembled, and the connecting rod 211 and the second telescopic member 215 are installed at the first loading part 301 and the second loading part 302 respectively. By adjusting the positions of the connecting rod 211 and the second telescopic member 215, the traction direction of the first loading assembly and the second loading assembly is in the expected direction and matches the required load angle in the actual working condition of the blade. Then, a periodic traction force is applied through the control terminal. For example, when the first loading assembly and the second loading assembly respectively drive the first loading part 301 and the second loading part 302 to move synchronously in the vertical direction, the blade produces a flapping motion; when the first loading assembly and the second loading assembly respectively drive the first loading part 301 and the second loading part 302 to move synchronously in the horizontal direction, the blade produces a shimmying motion; and when the displacement difference of the two loading assemblies in the horizontal / vertical direction is controlled, the blade produces a torsional motion.

[0080] This simulates the up-and-down reciprocating load in the flapping direction (vertical direction), the back-and-forth reciprocating load in the swing direction (horizontal direction), or the torsional reciprocating load in the torsional direction (around the axis) applied to the blade.

[0081] The effect is that through the coordinated loading of the first loading component and the second loading component, the multi-axial composite stress state that the blade is subjected to during actual operation can be accurately simulated. Compared with the traditional uniaxial test mode that requires loading in different directions in stages, this method can realize the simultaneous application of multi-directional loads at one time, significantly shortening the test cycle.

[0082] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A blade fatigue testing device, characterized in that: include: A blade fixing base (1) fixes the root of the blade to be measured (a); Load components, including: A blade fixture (3) for fixing the blade to be tested (a); A loading unit (2) is installed on the blade fixture (3), and the loading unit (2) is configured to apply at least one of an up-and-down reciprocating load in a swinging direction, a front-and-back reciprocating load in a swinging direction, and a torsional reciprocating load in a torsional direction to the blade fixture (3).

2. The blade fatigue testing device according to claim 1, characterized in that: The blade clamp (3) has a first loading portion (301) and a second loading portion (302); The loading unit (2) comprises a first loading component and a second loading component, the first loading component acts on a first loading portion (301), and the second loading component acts on a second loading portion (302); The first loading assembly and the second loading assembly are configured to drive the first loading part (301) and the second loading part (302) to have the same displacement in the horizontal direction, or the same displacement in the vertical direction, or different displacements in both the horizontal and vertical directions.

3. The blade fatigue testing device according to claim 2, characterized in that: The first loading component includes: A connecting rod (211), a first end portion (2111) along a length direction of the connecting rod being rotatably mounted on a first loading portion (301) of the blade clamp (3); The driving motor (212) has a driving shaft (2121), the driving shaft (2121) being in transmission connection with the second end (2112) of the connecting rod (211) along its length direction, and the driving shaft (2121) being configured to drive the second end (2112) of the connecting rod (211) to rotate around the first end (2111).

4. The blade fatigue testing device according to claim 3, characterized in that: The first loading component further includes: The rocker (213) has one end portion along its length direction connected to the second end portion (2112) of the connecting rod (211) as a movable end portion, and the other end portion as a connecting end portion coaxially rotating with the driving shaft (2121) of the driving motor (212).

5. The blade fatigue testing device according to claim 4, characterized in that: The first loading component further includes: The first telescopic member (214) comprises a first telescopic portion (2141) and a first fixed portion (2142); one end portion of the first telescopic portion (2141) along its telescopic direction is rotatably mounted on the connecting rod (211) and is located between the first end portion (2111) and the second end portion (2112); one end portion of the first fixed portion (2142) along its length direction is used to constrain the other end portion of the first telescopic portion (2141) along its telescopic direction to move along its telescopic direction; the other end portion of the first fixed portion (2142) along its length direction is movably mounted on the drive shaft (2121) of the drive motor (212).

6. The blade fatigue testing device according to any one of claims 2 to 5, characterized in that: The second loading component includes: The second telescopic member (215) comprises a second telescopic portion (2151) and a second fixed portion (2152), wherein one end portion of the second telescopic portion (2151) along its telescopic direction is rotatably mounted on the second loading portion (302), and one end portion of the second fixed portion (2152) along its length direction is used to constrain the other end portion of the second telescopic portion (2151) along its telescopic direction to move along its telescopic direction; The mounting seat (216) is rotatably mounted with the other end portion of the second fixing portion (2152) along its length direction.

7. The blade fatigue testing device according to any one of claims 2 to 5, characterized in that: The second loading portion (302) and the first loading portion (301) are spaced apart in the horizontal direction and / or the vertical direction.

8. The blade fatigue testing device according to any one of claims 1 to 5, characterized in that: The blade fatigue test rig also includes: A positioning flange (4) is mounted on the blade fixing base (1); The root of the blade to be measured (a) is mounted on the blade fixing base (1) via a positioning flange (4).

9. A blade fatigue testing system, characterized in that: include: The blade to be tested (a); A blade fatigue testing device is the blade fatigue testing device according to any one of claims 1 to 8, used for fixing the blade to be tested (a) and performing fatigue testing on the blade to be tested (a).

10. A blade fatigue testing method, applied to the blade fatigue testing device according to claim 9, characterized in that: Blade fatigue testing methods include: Periodically applying at least one of a reciprocating load, a shimmying load, and a torsional load to the blade to be tested (a) through a blade fatigue testing system; Adjust the loading parameters so that the loading frequency of the blade fatigue test device matches the blade natural frequency; Continue resonant loading until the preset fatigue damage threshold is reached; Collect dynamic response data of the blade to be tested and analyze fatigue characteristics.

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