Torsional stiffness and shear center test method for a blade, adjustment fixture

Abstract

The embodiment of the application provides a kind of blade torsional rigidity and shear core test method, adjusting clamp, blade torsional rigidity test method includes: the blade root is fixed, and blade is in suspended state;Fixed clamp is set in the first position and the second position of blade, adjusting clamp is set in the loading position of blade, first position, second position and loading position are spaced apart along the length direction of blade, and loading position is located on the side of first position and second position away from blade root;Test load is applied to loading position by adjusting clamp;Test load and the rotation angle of loading position under test load are obtained;The torsional rigidity of blade is determined according to test load and rotation angle.In the test method provided in the application, not only the torsional rigidity of blade can be determined, but also the accuracy of test result can be ensured due to the setting of two fixed positions.

Description

Technical Field

[0001] This application relates to the field of wind power equipment technology, and in particular to a method for testing the torsional stiffness and shear core of a blade, and an adjustment fixture. Background Technology

[0002] With the depletion of traditional fossil fuels such as coal, oil, and natural gas drawing ever closer, the development and utilization of wind energy are receiving increasing attention, making wind, nuclear, and solar energy the three major clean energy sources. Among these, the blade is a core component of wind power generation equipment. Driven by market demands, blade designs are being updated very rapidly. Therefore, the ability to quickly and accurately test blades to determine their mechanical properties is crucial for the development of wind power. Summary of the Invention

[0003] This application provides a method and adjustment fixture for testing the torsional stiffness and shear core of a blade, with the aim of determining the torsional stiffness of the blade.

[0004] An embodiment of the first aspect of this application provides a method for testing the torsional stiffness of a blade, comprising:

[0005] Fix the leaf base so that the leaf is in a hanging state;

[0006] Fixing clamps are set at the first and second positions of the blade, and adjusting clamps are set at the loading position of the blade. The first, second, and loading positions are distributed at intervals along the length of the blade, and the loading position is located on the side of the first and second positions away from the blade root.

[0007] The test load is applied to the loading position by adjusting the clamp;

[0008] Obtain the test load and the rotation angle at the loading position under the test load;

[0009] The torsional stiffness of the blade is determined based on the test load and rotation angle.

[0010] According to the first aspect of this application, in the step of fixing the leaf root and suspending the leaf: the chord direction of the leaf is made perpendicular to the horizontal plane.

[0011] According to any of the foregoing embodiments of the first aspect of this application, in the step of applying a test load to the loading position by adjusting the clamp: the test loads of opposite directions and equal magnitudes are applied to the loading position on both sides of the chord direction of the loading position by adjusting the clamp, and the force direction of the test load is perpendicular to the chord direction.

[0012] According to any of the foregoing embodiments of the first aspect of this application, in the steps of obtaining the test load and the rotation angle of the loading position under the test load: the rotation angle is determined as the chordal rotation angle of the loading position under the test load.

[0013] According to any of the foregoing embodiments of the first aspect of this application, before the step of determining the torsional stiffness of the blade based on the test load and rotation angle, the method further includes: obtaining the flapping stiffness of the blade and the flapping displacement of the loading position in the flapping direction under the test load.

[0014] In the step of determining the torsional stiffness of the blade based on the test load and rotation angle: the torsional stiffness is determined based on the test load, rotation angle, flapping stiffness, and flapping displacement.

[0015] According to any of the foregoing embodiments of the first aspect of this application, before the step of determining the torsional stiffness of the blade based on the test load and rotation angle, the method further includes: obtaining the swing stiffness of the blade and the swing displacement of the loading position in the swing direction under the test load.

[0016] In the step of determining the torsional stiffness of the blade based on the test load and rotation angle: the torsional stiffness is determined based on the test load, rotation angle, swing stiffness, and swing displacement.

[0017] According to any of the foregoing embodiments of the first aspect of this application, before the step of determining the torsional stiffness of the blade based on the test load and rotation angle, the method further includes: obtaining the flapping stiffness, swing stiffness, and flapping displacement in the flapping direction and swing displacement in the swing direction of the blade at the loading position under the test load.

[0018] In the step of determining the torsional stiffness of the blade based on the test load and rotation angle: the torsional stiffness is determined based on the test load, rotation angle, flapping stiffness, flapping displacement, swing stiffness, and swing displacement.

[0019] According to any of the foregoing embodiments of the first aspect of this application, in the step of determining the torsional stiffness based on the test load, rotation angle, swing stiffness, swing angle, swing array stiffness and swing array angle: the torsional stiffness is determined based on the relationship between the applied load potential energy and the bending elastic potential energy and the torsional elastic potential energy.

[0020] Load potential energy E load The following relationship must be satisfied:

[0021] E load = F×d×△ψ (1)

[0022] Where F is the test load, d is the lever arm, and Δψ is the rotation angle;

[0023] Bending elastic potential energy E b The following relationship must be satisfied:

[0024] E b = 1 / 2×K x ×△x 2 +1 / 2×K y×△y 2 (2)

[0025] Among them, K x For swing stiffness, K y Let Δx be the swing stiffness, Δy be the swing displacement, and Δy be the swing displacement.

[0026] Torsional elastic potential energy E t The following relationship must be satisfied:

[0027] E t = 1 / 2×K t ×△ψ 2 (3)

[0028] Among them, K t For torsional stiffness;

[0029] Based on the law of conservation of energy, the following relationship can be obtained:

[0030] E load = E b + E t (4)

[0031] The torsional stiffness can be determined based on the above relationship (4).

[0032] According to any of the foregoing embodiments of the first aspect of this application, before the step of setting the adjusting clamp at the loading position of the blade, the method further includes: obtaining the first rotation angle of the blade at the loading position;

[0033] In the step of setting the adjustment clamp at the loading position of the blade:

[0034] Set the adjustment fixture at the loading position of the blade and obtain the second rotation angle of the loading position after setting the adjustment fixture;

[0035] By adjusting the clamp to apply a counterweight to the loading position, the first rotation angle is made equal to the second rotation angle.

[0036] According to any of the foregoing embodiments of the first aspect of this application, in the step of applying a test load to the loading position by adjusting the clamp:

[0037] Different test loads are applied to the loading position by adjusting the clamps;

[0038] In the steps of obtaining the test load and the rotation angle of the loading position under the test load: obtain different test loads and different rotation angles of the loading position under different test loads;

[0039] In the step of determining the torsional stiffness of the blade based on the test load and rotation angle: multiple torsional stiffnesses are determined based on different test loads and different rotation angles, and the final torsional stiffness is determined based on the multiple torsional stiffnesses.

[0040] According to any of the foregoing embodiments of the first aspect of this application, the first position is located on the side of the second position close to the leaf root, the first distance between the first position and the leaf root is 1m to 3m, the distance between the first position and the second position is 1m to 3m, and the distance between the second position and the loading position is 8m to 12m.

[0041] An embodiment of the second aspect of this application also provides a method for testing the core shearing of a blade, comprising:

[0042] According to any of the embodiments of the first aspect above, multiple sets of torsional stiffness are determined under different force application positions based on multiple sets of test loads.

[0043] The shear center position of the blade is determined based on multiple sets of torsional stiffness.

[0044] In the step of applying the test load to the loading position by adjusting the fixture:

[0045] By adjusting the clamp at different force application points on both sides of the loading position in the chord direction, test loads of opposite directions and equal magnitudes are applied to the loading position. The force direction of the test load is perpendicular to the chord direction.

[0046] The midpoint of the line connecting the force application points of the two test loads located on both sides of the chordal direction at the loading position is determined as the measuring point. The measuring points corresponding to multiple sets of test loads do not overlap.

[0047] In the step of determining the shear center position of the blade based on multiple sets of torsional stiffness:

[0048] The shear center position is determined based on multiple sets of torsional stiffness and their corresponding multiple measuring point positions.

[0049] According to the second aspect of this application, in the step of determining the shear center position of the blade based on multiple sets of torsional stiffness:

[0050] When multiple sets of torsional stiffness are linearly related, the multiple measuring points corresponding to the multiple sets of torsional stiffness are located on the same side of the shear center in the chord direction.

[0051] According to the second aspect of this application, in the step of determining the shear center position of the blade based on multiple sets of torsional stiffness:

[0052] When multiple sets of torsional stiffnesses exhibit a curvilinear relationship, the measuring points corresponding to these multiple sets of torsional stiffnesses are located on both sides of the shear center in the chord direction.

[0053] According to any of the foregoing embodiments of the second aspect of this application, in the step of determining the shear center position of the blade based on multiple sets of torsional stiffness:

[0054] Plot curves based on multiple sets of torsional stiffness, and the measuring point corresponding to the torsional stiffness at the inflection point of the curve is the shear center position.

[0055] Alternatively, the measuring point corresponding to the maximum torsional stiffness among multiple sets of torsional stiffness can be determined as the shear center position.

[0056] An embodiment of the third aspect of this application also provides an adjustment fixture for testing the torsional stiffness of a blade, the adjustment fixture comprising:

[0057] The body has a receiving cavity for accommodating at least a portion of the blades;

[0058] The loading section, at least two loading sections are provided on both sides of the body section in the first direction, and the loading section is provided with a force-applying member to apply a load to the loading section through the force-applying member. At least one force-applying member on the loading section is movably provided along the first direction.

[0059] According to an embodiment of the third aspect of this application, it further includes: a counterweight portion disposed on at least one side of the main body portion in the second direction, the counterweight portion being provided with a counterweight member, the counterweight member being movably disposed along the first direction.

[0060] According to any of the foregoing embodiments of the third aspect of this application, the body includes an upper half-shell and a lower half-shell distributed in a second direction, and the upper half-shell and the lower half-shell are joined together to form a receiving cavity.

[0061] The loading unit includes an upper part and a lower part. The upper part and the upper shell are fixedly connected to each other, and the lower part and the lower shell are fixedly connected to each other. The force-applying component connects the upper part and the lower part.

[0062] According to any of the foregoing embodiments of the third aspect of this application, the first direction is parallel to the chord direction of the blade located in the receiving cavity, so that a test load perpendicular to the chord direction can be applied to the blade located in the receiving cavity by the force-applying member.

[0063] According to any of the foregoing embodiments of the third aspect of this application, the number of loading parts is three or more, and at least one loading part is disposed on one side of the body part in the second direction.

[0064] In the testing method provided in this application embodiment, the blade is first fixed in a suspended state, with the blade root fixed and the blade tip freely suspended, facilitating the twisting operation of the blade. Then, the blade is fixed at a first position and a second position. Fixing the blade at two positions mitigates the problem of easy movement during twisting, ensuring the accuracy of the twisting test results. Next, an adjusting clamp is set at the loading position. By adjusting the clamp, a test load can be applied. The torsional stiffness of the blade can be determined based on the magnitude of the test load and the rotation angle of the blade. Therefore, the testing method provided in this application not only determines the torsional stiffness of the blade but also ensures the accuracy of the test results due to the two fixed positions. Attached Figure Description

[0065] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar features.

[0066] Figure 1 This is a flowchart illustrating a method for testing the torsional stiffness of a blade according to an embodiment of this application.

[0067] Figure 2 This is a schematic diagram of the state of a blade during torsional stiffness testing, provided in an embodiment of this application.

[0068] Figure 3 This is a schematic diagram of the force analysis of a blade in a blade torsional stiffness testing method provided in an embodiment of this application;

[0069] Figure 4 This is a schematic diagram of the leaf shearing test method provided in the second aspect embodiment of this application;

[0070] Figure 5 yes Figure 4 A flowchart illustrating a specific step in the process;

[0071] Figure 6 This is a schematic diagram of the stress analysis of the blade in the blade shearing test method provided in the second aspect embodiment of this application;

[0072] Figure 7 This is a schematic diagram of the structure of an adjusting clamp provided in the third aspect embodiment of this application;

[0073] Figure 8 This is a schematic diagram of the structure of an adjustment clamp provided in another embodiment of the third aspect of this application.

[0074] Explanation of reference numerals in the attached figures:

[0075] 10. Leaf blade; 11. Leaf root; 12. Leaf tip; 13. Leading edge; 14. Trailing edge; 15. Windward side; 16. Leeward side; 10a. First position; 10b. Second position; 10c. Loading position; 10d. Target position;

[0076] 20. Fixtures;

[0077] 30. Adjusting clamp; 31. Body; 311. Receiving cavity; 312. Upper shell; 313. Lower shell; 32. Loading part; 321. Force-applying component; 321a. Sliding component; 321b. Flexible component; 322. Upper split; 323. Lower split; 324. Slide rail; 325. Nut; 33. Counterweight;

[0078] X, chord direction; Y, length direction; Z, swing direction. Detailed Implementation

[0079] The features and exemplary embodiments of various aspects of this application will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this application by illustrating examples. In the accompanying drawings and the following description, at least some well-known structures and techniques are not shown to avoid unnecessarily obscuring the application; and, for clarity, the dimensions of some structures may be exaggerated. Furthermore, the features, structures, or characteristics described below can be combined in any suitable manner in one or more embodiments.

[0080] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0081] The directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0082] To better understand this application, the following will be combined with... Figures 1 to 8 The torsional stiffness and shear core testing method of the blade 10 and the adjustment fixture 30 of the embodiments of this application are described in detail.

[0083] Please see Figure 1 and Figure 2 , Figure 1 This is a flowchart illustrating a method for testing the torsional stiffness of a blade 10 provided in an embodiment of this application. Figure 2 This is a schematic diagram of the state of a blade 10 during a torsional stiffness test, provided in an embodiment of this application.

[0084] like Figure 1 and Figure 2As shown, the torsional stiffness test method for blade 10 includes:

[0085] Step S01: Fix the leaf root 11 of the leaf 10 so that the leaf 10 is in a suspended state.

[0086] Step S02: Set a fixing clamp 20 at the first position 10a and the second position 10b of the blade 10, and set an adjusting clamp 30 at the loading position 10c of the blade 10.

[0087] Fixtures 20 are provided at the first position 10a and the second position 10b of the blade 10 to fix the blade 10 at the first position 10a and the second position 10b, so as to prevent the blade 10 from shaking at the first position 10a and the second position 10b during the test. The first position 10a, the second position 10b and the loading position 10c are distributed at intervals along the length direction Y of the blade 10, and the loading position 10c is located on the side of the first position 10a and the second position 10b away from the blade root 11.

[0088] Step S03: Apply test load F to loading position 10c by adjusting clamp 30.

[0089] Step S04: Obtain the test load F and the rotation angle of the loading position 10c under the test load F.

[0090] Step S05: Determine the torsional stiffness of blade 10 based on the test load F and rotation angle.

[0091] In the testing method provided in this application embodiment, the blade 10 is first fixed in a suspended state, with the blade root 11 fixed and the blade tip 12 freely suspended, facilitating the torsion operation of the blade 10. Then, the blade 10 is fixed at a first position 10a and a second position 10b. Fixing the blade 10 at two positions improves the problem of easy movement during torsion and improves the transmission of the test load F to the blade root 11, ensuring the accuracy of the torsion test results. Next, an adjusting clamp 30 is set at the loading position 10c. By adjusting the clamp 30, the test load F can be applied. The torsional stiffness of the blade 10 can be determined based on the magnitude of the test load F and the rotation angle of the blade 10. Therefore, in the testing method provided in this application, not only can the torsional stiffness of the blade 10 be determined, but also the accuracy of the test results can be guaranteed due to the two fixed positions.

[0092] Optionally, the blade 10 also includes a target position 10d, which is located between the first position 10a and the loading position 10c. Alternatively, the target position 10d may be located between the first position 10a and the loading position 10c. When testing the torsional stiffness of the blade 10 using the torsional stiffness test method provided in this application, the torsional stiffness of the blade 10 at the target position 10d can be determined. By reasonably setting the first position 10a and the loading position 10c, the torsional stiffness of the blade 10 at different target positions 10d can be tested.

[0093] In some optional embodiments, the first position 10a is located on the side of the second position 10b close to the leaf root 11, the first distance between the first position 10a and the leaf root 11 is 1m to 3m, the distance between the first position 10a and the second position 10b is 1m to 3m, and the distance between the second position 10b and the loading position 10c is 8m to 12m.

[0094] Optionally, when the target position 10d is determined, a first position 10a, a second position 10b, and a loading position 10c can be determined based on the target position 10d. For example, the loading position 10c is set on the side of the target position 10d facing the blade tip 12, and the distance between the loading position 10c and the target position 10d is 4m to 6m. The first position 10a is set on the side of the target position 10d facing the blade root 11, and the distance between the first position 10a and the target position 10d is 4m to 6m. The second position 10b is set on the side of the first position 10a facing the blade root 11, and the distance between the first position 10a and the second position 10b is 1m to 3m.

[0095] Optionally, in step S01, the chordal direction X of the blade 10 is made perpendicular to the horizontal plane, that is, the swing direction of the blade 10 is perpendicular to the horizontal plane, and the flapping direction Z of the blade 10 is parallel to the horizontal plane. The extension dimension of the blade 10 in the chordal direction X is larger, while the extension dimension of the blade 10 in the flapping direction Z is smaller. When the chordal direction X of the blade 10 is perpendicular to the horizontal plane, the influence of the self-weight of the blade 10 on the torsional stiffness test results can be reduced, further improving the accuracy of the torsional stiffness test results. The swing stiffness of the blade 10 is 3-5 times the flapping stiffness. Under the same gravity, the displacement in the swing direction is smaller. Therefore, in this application, the swing direction is perpendicular to the ground, and the leading edge 13 faces the ground, which can reduce the influence of the gravity of the blade 10 on the test results.

[0096] Optionally, in step S02, the fixing clamp 20 can be set first and then the adjusting clamp 30 can be set, or the adjusting clamp 30 can be set first and then the fixing clamp 20 can be set.

[0097] Please see Figure 3 , Figure 3This is a schematic diagram of the force analysis of the blade 10 in a torsional stiffness test method provided in an embodiment of this application.

[0098] There are multiple, selectable directions for applying the test load F, such as... Figure 3 As shown, in step S03: by adjusting the clamp 30, test loads F of opposite directions and equal magnitudes are applied to the loading position 10c on both sides along the chordal X direction, and the direction of the test loads F is perpendicular to the chordal X direction. Applying test loads F of opposite directions and equal magnitudes at the loading position 10c can accelerate the torsion of the blade 10 while ensuring the accuracy of the test results. Applying test loads F perpendicular to the chordal X direction can further accelerate the torsion of the blade 10.

[0099] Optionally, in step S04: the rotation angle of the chordal direction X of the loading position 10c under the test load F is determined as the rotation angle. Since the test load F is perpendicular to the chordal direction X, the chordal direction X of the blade 10 is most easily rotated under the action of the test load F.

[0100] There are several ways to determine the rotation angle. For example, before applying the test load F, you can obtain the first line connecting a specified position to the center point of the chord X direction, and after applying the load, you can obtain the second line connecting the specified position to the center point of the chord X direction. The angle between the first line and the second line is the rotation angle.

[0101] There are several ways to obtain the rotation angle. For example, the rotation angle can be obtained through an angle measuring instrument. Optionally, the blade 10 includes a housing and a web disposed within the housing. The housing includes a windward side 15 and a leeward side 16. The angle measuring instrument can be set at the midpoint of the web at the trailing edge 14 of the loading position 10c and at the connection point between the web at the trailing edge 14 of the windward side 15 and the target position 10d.

[0102] When a test load F is applied to the blade 10, the blade 10 may undergo displacement in the flapping direction Z, giving the blade 10 flapping potential energy. According to the law of conservation of energy, the potential energy of the test load F is converted into the torsional potential energy and flapping potential energy of the blade 10.

[0103] To further improve the accuracy of the torsional stiffness test results, in some optional embodiments, the method further includes, before step S05: obtaining the flapping stiffness of the blade 10 and the flapping displacement of the loading position 10c under the test load F in the flapping direction Z. Then, in step S05, the torsional stiffness is determined based on the test load F, rotation angle, flapping stiffness, and flapping displacement.

[0104] In these alternative embodiments, the load potential energy applied to the blade 10 can be determined by the test load F, and the flapping potential energy of the blade 10 under the test load F can be determined by the flapping stiffness and flapping displacement. The difference between the load potential energy and the flapping potential energy is the torsional potential energy. The torsional stiffness can be determined based on the torsional potential energy and the rotation angle, which can further improve the accuracy of the torsional stiffness test results.

[0105] There are several ways to obtain the waving displacement. For example, a rangefinder can be set on the blade 10 to obtain the waving displacement. The rangefinder can be set at the target position 10d, for example, the rangefinder can be set at the trailing edge 14 of the target position 10d. The rangefinder obtains the displacement of the target position 10d in the waving direction Z as the waving displacement.

[0106] In other embodiments, the inventors also discovered that when a test load F is applied to the blade 10, the blade 10 may undergo displacement in the swing direction, thereby giving the blade 10 swing potential energy. According to the law of conservation of energy, the potential energy of the test load F is converted into the torsional potential energy and swing potential energy of the blade 10.

[0107] To further improve the accuracy of the torsional stiffness test results, in some optional embodiments, the method further includes, before step S05: obtaining the swing stiffness of the blade 10 and the swing displacement of the loading position 10c in the swing direction under the test load F. Then, in step S05, the torsional stiffness is determined based on the test load F, rotation angle, swing stiffness, and swing displacement.

[0108] In these alternative embodiments, the load potential energy applied to the blade 10 can be determined by the test load F, and the swing potential energy of the blade 10 under the test load F can be determined by the swing stiffness and swing displacement. The difference between the load potential energy and the swing potential energy is the torsional potential energy. The torsional stiffness can be determined based on the torsional potential energy and the rotation angle, which can further improve the accuracy of the torsional stiffness test results.

[0109] There are several ways to obtain the swing displacement. For example, a rangefinder can be set on the blade 10 to obtain the swing displacement. The rangefinder can be set at the target position 10d, for example, the rangefinder can be set at the trailing edge 14 of the target position 10d. The rangefinder obtains the displacement of the target position 10d in the swing direction as the swing displacement.

[0110] The inventors discovered that when a test load F is applied to the blade 10, the blade 10 may undergo displacement in the flapping direction Z and the swing direction, giving the blade 10 flapping potential energy and swing potential energy. According to the law of conservation of energy, the potential energy of the test load F is converted into the torsional potential energy, flapping potential energy and swing potential energy of the blade 10.

[0111] To further improve the accuracy of the torsional stiffness test results, in some optional embodiments, the method further includes, before step S05: acquiring the flapping stiffness, swing stiffness, and flapping displacement in the flapping direction Z and swing displacement in the swing direction of the blade 10 at the loading position 10c under the test load F. In step S05, the torsional stiffness is determined based on the test load F, rotation angle, flapping stiffness, flapping displacement, swing stiffness, and swing displacement.

[0112] In these alternative embodiments, the load potential energy applied to the blade 10 can be determined by the test load F, the flapping potential energy of the blade 10 under the test load F can be determined by the flapping stiffness and flapping displacement, and the swing potential energy of the blade 10 under the test load F can be determined by the swing stiffness and swing displacement. The load potential energy minus the flapping potential energy and the swing potential energy is the torsional potential energy. The torsional stiffness can be determined based on the torsional potential energy and the rotation angle, which can further improve the accuracy of the torsional stiffness test results.

[0113] The flapping potential energy and the swing potential energy together constitute the flexural elastic potential energy of the blade 10. Optionally, the torsional stiffness is determined based on the relationship between the applied load potential energy and the flexural elastic potential energy and the torsional elastic potential energy.

[0114] Load potential energy E load The following relationship must be satisfied:

[0115] E load = F×d×△ψ (1)

[0116] Where F is the test load F, d is the lever arm, and Δψ is the rotation angle. When test loads F of opposite directions and equal magnitude are applied to the blade 10 from both ends of the chord X direction of the loading position 10c, the lever arm d is half the distance between the two test load F application positions at both ends of the chord X direction of the loading position 10c.

[0117] Bending elastic potential energy E b The following relationship must be satisfied:

[0118] E b = 1 / 2×K x ×△x 2 +1 / 2×K y ×△y 2 (2)

[0119] Among them, K x For swing stiffness, K y Let be the swing stiffness, Δx be the swing displacement, and Δy be the swing displacement. Optional, the swing stiffness K... x and the stiffness K of the array y It can be measured based on other experiments.

[0120] Torsional elastic potential energy Et The following relationship must be satisfied:

[0121] E t = 1 / 2×K t ×△ψ 2 (3)

[0122] Among them, K t For torsional stiffness;

[0123] Based on the law of conservation of energy, the following relationship can be obtained:

[0124] E load = E b + E t (4)

[0125] The torsional stiffness can be determined based on the above relationship (4).

[0126] During the torsional stiffness test of the blade 10, before the step of setting the adjusting clamp 30 at the loading position 10c of the blade 10 in step S02, the method further includes: obtaining the first rotation angle of the blade 10 at the loading position 10c; in the step of setting the adjusting clamp 30 at the loading position 10c of the blade 10 in step S02: setting the adjusting clamp 30 at the loading position 10c of the blade 10 and obtaining the second rotation angle of the loading position 10c after setting the adjusting clamp 30; applying a counterweight to the loading position 10c by adjusting the clamp 30 so that the first rotation angle is equal to the second rotation angle.

[0127] When the adjusting fixture 30 is set at loading position 10c, the blade 10 may rotate under its own weight. This application improves the accuracy of the torsional stiffness test results by comparing the first rotation angle at loading position 10c before setting the adjusting fixture 30 with the second rotation angle after setting the adjusting fixture 30, and adjusting the counterweight so that the first rotation angle equals the second rotation angle.

[0128] There are several ways to obtain the first rotation angle. For example, before setting the adjustment fixture 30, you can obtain the third line connecting a specified point on the loading position 10c to its chordal X-center point, and use the angle between the third line and the chordal X-line as the first rotation angle. Then, after setting the adjustment fixture 30, you can obtain the fourth line connecting the specified point to the chordal X-center point on the loading position 10c, and use the angle between the fourth line and the chordal X-line as the second rotation angle.

[0129] There are multiple ways to obtain the first rotation angle and the second rotation angle. For example, the rotation angle can be obtained by using an angle measuring instrument. Optionally, the angle measuring instrument can be set at the connection position between the middle position of the web of the rear edge 14 of the loading position 10c and the web of the rear edge 14 of the windward side of the target position 10d.

[0130] Optionally, an angle measuring instrument set at the same location can be used to obtain the first rotation angle, the second rotation angle, and the aforementioned rotation angle.

[0131] In some optional embodiments, in step S03, different test loads F can be applied to the loading position 10c by the adjusting clamp 30. Then, in step S04, different test loads F and different rotation angles of the loading position 10c under different test loads F can be obtained. In step S05, multiple torsional stiffnesses are determined based on the different test loads F and the different rotation angles, and a final torsional stiffness is determined based on the multiple torsional stiffnesses.

[0132] In these alternative embodiments, multiple torsional stiffnesses can be obtained by performing multiple sets of tests, avoiding the bias that may exist in test results obtained from only one side of the test data.

[0133] In step S03, when different test loads F can be applied to the loading position 10c by the adjusting fixture 30, the multiple test loads F increase in a gradient.

[0134] Optionally, during the torsional stiffness test of blade 10, a trial load can also be performed, i.e., through steps S03 and S04. Based on the trial load, the maximum load that blade 10 can withstand is determined. Then, during the final test, in step S03, the test load F can be adjusted according to the maximum load. For example, when multiple sets of test loads F need to be applied, 30%, 60%, and 90% of the maximum load can be applied in stages. Alternatively, 20%, 40%, 60%, 80%, and 100% of the maximum load can be applied in stages.

[0135] Optionally, when determining the maximum load, the maximum rotation angle of blade 10 can also be determined first, so that the test load F at which blade 10 can rotate to the maximum rotation angle is the maximum load. There are several ways to set the maximum rotation angle; optionally, the maximum rotation angle is between 2 degrees and 10 degrees.

[0136] Optionally, a simulation model for testing the torsional stiffness of blade 10 can be constructed. Through finite element simulation calculations, the simulated values ​​at target location 10d under various loads can be determined, such as determining the maximum load based on the simulation model. Optionally, during the torsional stiffness test of blade 10, the tensile strain and shear strain at target location 10d can also be obtained. The simulated values ​​in the simulation model can be adjusted based on the actually obtained tensile and shear strains, making the simulation model closer to the actual test. For example, shear strain gauges and tensile strain gauges can be attached to the centerline of the main beam on the windward side 15 and the leeward side 16 at target location 10d to obtain the tensile and shear strains at target location 10d.

[0137] When applying multiple sets of test loads F to the blade 10, it should be ensured that multiple sets of test loads F are applied to the blade 10 at the same location. Furthermore, the direction of the test load F should be perpendicular to the chordal X direction of the blade 10, that is, the direction of the test load F should be parallel to the spanwise direction of the blade 10.

[0138] Optionally, in step S03, the test is stopped when the first position 10a and / or the second position 10b are displaced. When the first position 10a and the second position 10b are displaced, it indicates that the first position 10a and the second position 10b are not securely fixed and need to be re-fixed and the test repeated.

[0139] Optionally, in step S03, when the test load F is applied to the loading position 10c by adjusting the clamp 30: the test is stopped when the bending displacement of the loading position 10c in the swinging direction Z is greater than or equal to 0.5m. Alternatively, the test is stopped when the bending displacement of the loading position 10c in the swinging direction is greater than or equal to 0.5m. When the loading position 10c has a large displacement in the swinging direction Z or the swinging direction, it indicates that more of the loading potential energy has been converted into swinging potential energy or swinging potential energy, rather than torsional potential energy, which may lead to inaccurate test results. Therefore, the test is stopped, and the clamp 30 and other devices are adjusted before the test is repeated.

[0140] Optionally, after the installation of the fixed clamp 20, the adjusting clamp 30, and measuring instruments such as the angle measuring instrument and the rangefinder is completed, the humidity of the environment can also be measured, and the angle measuring instrument, the laser rangefinder, the force gauge and other instruments can be calibrated and verified according to the usage specifications of each instrument. Then, the test load F is applied through the adjusting clamp 30.

[0141] To ensure the accuracy of the test results, the wind speed in the test environment should be less than 3 m / s during the test.

[0142] Please see Figures 4 to 6 , Figure 4 This is a schematic flowchart of the core-cutting test method for the blade 10 provided in the second aspect embodiment of this application. Figure 5 yes Figure 4 A flowchart of a certain step in the process. Figure 6 This is a schematic diagram of the force analysis of the blade 10 in the core shearing test method provided in the second aspect embodiment of this application.

[0143] like Figures 4 to 6 As shown, the core-cutting test method provided by the embodiment of the second aspect of this application includes:

[0144] Step S1: Determine multiple sets of torsional stiffness under different force application positions by determining multiple sets of test loads F.

[0145] The torsional stiffness can be determined by selecting any of the embodiments of the first aspect described above.

[0146] Step S2: Determine the shear center position of blade 10 based on multiple sets of torsional stiffness.

[0147] In determining the torsional stiffness using the embodiment of the first aspect, step S03 includes:

[0148] Step S031: By adjusting the clamp 30, test loads F with opposite directions and equal magnitudes are applied to the loading position 10c at different force application points on both sides of the chord X direction. The force direction of the test load F is perpendicular to the chord X direction.

[0149] like Figure 6 As shown, it is possible to Figure 6 The test load F is applied to three different force application points on both sides of the middle chord X.

[0150] Step S032: Determine the midpoint of the line connecting the force application points of the two test loads F on both sides of the chord X direction at the loading position 10c as the measuring point. The measuring points corresponding to multiple sets of test loads F do not overlap.

[0151] In step S2, the shear center position is determined based on multiple sets of torsional stiffness and their corresponding multiple measuring point positions.

[0152] In the shear core testing method provided in this application embodiment, the measuring point is the assumed shear core position when performing torsional stiffness testing. The shear core position can be determined based on the variation law of torsional stiffness corresponding to multiple sets of measuring points.

[0153] In some alternative embodiments, in step S2: when multiple sets of torsional stiffness are linearly related, it is determined that multiple measuring points corresponding to the multiple sets of torsional stiffness are located on the same side of the shear center position in the chord X direction.

[0154] In some alternative embodiments, in step S2: when multiple sets of torsional stiffness are in a curvilinear relationship, the measuring points corresponding to the multiple sets of torsional stiffness are determined to be located on both sides of the shear center position in the chord X direction.

[0155] When multiple measuring points are located on both sides of the shear center in the chordal X direction, a curve is plotted based on multiple sets of torsional stiffness. The measuring point corresponding to the torsional stiffness at the inflection point of the curve is the shear center position. For example, multiple sets of tests can be performed to obtain multiple measuring points and torsional stiffness, and a curve can be plotted based on the multiple torsional stiffness. The measuring point corresponding to the torsional stiffness at the inflection point of the curve is the shear center position.

[0156] Alternatively, the measuring point corresponding to the maximum torsional stiffness among multiple sets of torsional stiffness can be determined as the shear center position. The torsional stiffness is greatest at the shear center position, therefore, the measuring point corresponding to the maximum torsional stiffness can be directly determined as the shear center position based on the measured multiple sets of torsional stiffness.

[0157] Therefore, in the test method provided in this application, the shear center position of the blade 10 can be obtained based on multiple sets of torsional stiffness and their corresponding measuring points.

[0158] like Figure 6 As shown, in the shearing test method of blade 10, in step S03, among a set of test loads F of the same size and opposite direction, one test load F can be applied to any one of the force application points P1, P2 and P3, and another test load F can be applied to P4, P5 and P6 respectively, so that three different test loads F can be obtained, and three non-overlapping test points can be determined.

[0159] When the three torsional stiffness values ​​obtained from the three sets of test loads F are linearly related, the shear center position is determined to be on the same side of the three measuring points in the chord X direction.

[0160] When the three torsional stiffness values ​​obtained from the three sets of test loads F are not linearly related, the shear center position is determined to be located between the three measuring points.

[0161] Please see Figure 7 , Figure 7 This is a schematic diagram of the structure of an adjustment fixture 30 provided in the third aspect embodiment of this application. The adjustment fixture 30 provided in the third aspect embodiment of this application is used for the torsional stiffness test and the shearing test of the blade 10 described above.

[0162] like Figure 7 As shown, the adjusting clamp 30 includes: a body part 31 having a receiving cavity 311 for accommodating at least a portion of the blades 10; a loading part 32, at least two loading parts 32 being disposed on both sides of the body part 31 in a first direction, and a force-applying member 321 being provided on the loading part 32 to apply a load to the loading part 32 through the force-applying member 321, and at least one force-applying member 321 on the loading part 32 being movably disposed along the first direction.

[0163] In the adjusting clamp 30 provided in this embodiment, the adjusting clamp 30 is clamped onto the blade 10 via a body portion 31. A loading portion 32 is provided on the body portion 31. A test load F can be applied to the adjusting clamp 30 via a force-applying member 321 on the loading portion 32, that is, a test load F is applied to the blade 10 via the force-applying member 321. The force-applying member 321 is movable along a first direction, allowing the test load F to be applied to the blade 10 from different positions on the loading portion 32.

[0164] For example, in the test method for shearing the blade 10, multiple sets of torsional stiffness tests can be completed under different force application positions by moving the position of the force application member 321.

[0165] There are various ways to set up the force-applying component 321. For example, the force-applying component 321 includes a sliding component 321a and a flexible component 321b. The flexible component 321b is, for example, a steel cable. The steel cable is fixed to one end of the sliding component 321a, and the test load F can be applied through the steel cable. The sliding component 321a is moved along the first direction.

[0166] Optionally, the loading unit 32 may further include a slide rail 324 extending in a first direction, and the slider is movable within the slide rail 324 in the first direction.

[0167] In the shear core test method of blade 10, the position of the slider is the force application position. By moving the slider, the force application position can be changed, thereby obtaining the torsional stiffness of different test loads F under different force application positions.

[0168] In some optional embodiments, the body portion 31 includes an upper half-shell 312 and a lower half-shell 313 distributed in a second direction, which are joined together to form a receiving cavity 311; the loading portion 32 includes an upper half-segment 322 and a lower half-segment 323, which are fixedly connected to each other, and the lower half-segment 323 and the lower half-shell 313 are fixedly connected to each other, and the force-applying member 321 connects the upper half-segment 322 and the lower half-segment 323. By configuring the body portion 31 as an upper half-shell 312 and a lower half-shell 313, it is convenient to install the body portion 31 onto the blade 10.

[0169] Optionally, the slider extends along the second direction, and nuts 325 are provided at both ends of the slider. The slider can reuse the connecting parts of the upper half 322 and the lower half 323, and connect the upper half 322 and the lower half 323 together through the slider.

[0170] In some alternative embodiments, the first direction is parallel to the chordal X of the blade 10 located within the receiving cavity 311, so that a test load F perpendicular to the chordal X can be applied to the blade 10 located within the receiving cavity 311 by the force-applying member 321.

[0171] Optionally, the adjusting clamp 30 further includes a counterweight 33 disposed on at least one side of the main body 31 in the second direction, wherein a counterweight member is disposed on the counterweight 33 and is movably disposed along the first direction. In these optional embodiments, the counterweight 33 can be used to adjust the counterweight of the blade 10. In the torsional stiffness testing method of the blade 10 provided in the first aspect embodiment above, the position of the counterweight member in the first direction can be adjusted to make the first rotation angle and the second rotation angle equal.

[0172] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of an adjusting clamp 30 provided in another embodiment of the third aspect of this application. (See attached diagram.) Figure 8 As shown, optionally, the outer contour of the adjusting clamp 30 is cylindrical, and three or more loading portions 32 can be provided on the periphery of the body portion 31, with at least one loading portion 32 provided on one side of the body portion 31 in the second direction. By applying a counterweight force to the loading portion 32 on one side of the body portion 31 in the second direction, the first rotation angle and the second rotation angle are made equal.

[0173] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for testing the torsional stiffness of a blade (10), characterized in that, include: Fix the leaf root (11) of the leaf (10) so that the leaf (10) is in a suspended state, and the leaf includes the target position (10d). Fixing clamps (20) are provided at the first position (10a) and the second position (10b) of the blade (10) to fix the first position (10a) and the second position (10b) of the blade (10). Adjusting clamps (30) are provided at the loading position (10c) of the blade (10). The first position (10a), the second position (10b) and the loading position (10c) are distributed at intervals along the length direction of the blade (10), and the loading position (10c) is located on the side of the first position (10a) and the second position (10b) away from the leaf root (11). The target position (10d) is located between the first position (10a) and the loading position (10c). The adjusting clamp (30) applies test loads of opposite directions and equal magnitudes to the loading position (10c) on both sides of the chord-up direction at the loading position (10c); Obtain the test load and the rotation angle of the loading position (10c) under the test load; The torsional stiffness of the blade (10) at the target position (10d) is determined based on the test load and the rotation angle.

2. The method according to claim 1, characterized in that, In the step of fixing the leaf root (11) of the blade (10) and suspending the blade (10): the chord direction of the blade (10) is perpendicular to the horizontal plane.

3. The method according to claim 1, characterized in that, The direction of the applied force of the test load is perpendicular to the chord direction.

4. The method according to claim 3, characterized in that, In the step of obtaining the test load and the rotation angle of the loading position (10c) under the test load: the chordal rotation angle of the loading position (10c) under the test load is determined as the rotation angle.

5. The method according to claim 1, characterized in that, Before the step of determining the torsional stiffness of the blade (10) based on the test load and the rotation angle, the method further includes: obtaining the flapping stiffness of the blade (10) and the flapping displacement of the loading position (10c) in the flapping direction under the test load; In the step of determining the torsional stiffness of the blade (10) based on the test load and the rotation angle: the torsional stiffness is determined based on the test load, the rotation angle, the flapping stiffness and the flapping displacement.

6. The method according to any one of claims 1-5, characterized in that, Before the step of determining the torsional stiffness of the blade (10) based on the test load and the rotation angle, the method further includes: obtaining the swing stiffness of the blade (10) and the swing displacement of the loading position (10c) in the swing direction under the test load; In the step of determining the torsional stiffness of the blade (10) based on the test load and the rotation angle: the torsional stiffness is determined based on the test load, the rotation angle, the swing stiffness and the swing displacement.

7. The method according to claim 6, characterized in that, Before the step of determining the torsional stiffness of the blade (10) based on the test load and the rotation angle, the method further includes: obtaining the flapping stiffness, swing stiffness, and flapping displacement and swing displacement in the swing direction of the loading position (10c) under the test load; In the step of determining the torsional stiffness of the blade (10) based on the test load and the rotation angle: the torsional stiffness is determined based on the test load, the rotation angle, the flapping stiffness, the flapping displacement, the swing stiffness, and the swing displacement.

8. The method according to claim 7, characterized in that, In the step of determining the torsional stiffness based on the test load, the rotation angle, the swing stiffness, the swing displacement, the swing array stiffness, and the swing array displacement: the torsional stiffness is determined based on the relationship between the applied load potential energy and the bending elastic potential energy and the torsional elastic potential energy. The load potential energy E load The following relationship must be satisfied: AND load = F×d×△ψ (1) Where F is the test load, d is the lever arm, and Δψ is the rotation angle; The bending elastic potential energy E b The following relationship must be satisfied: AND b = 1 / 2×K x ×△x 2 +1 / 2×K y ×△y 2 (2) Among them, K x For the swing stiffness, K y Let Δx be the swing stiffness, Δy be the swing displacement, and Δy be the swing displacement. The torsional elastic potential energy E t The following relationship must be satisfied: AND t = 1 / 2×K t ×△ψ 2 (3) Among them, K t The torsional stiffness is mentioned above; Based on the law of conservation of energy, the following relationship can be obtained: AND load = And b + E t (4) The torsional stiffness can be determined based on the above relationship (4).

9. The method according to claim 1, characterized in that, Before the step of setting the adjusting clamp (30) at the loading position (10c) of the blade (10), the method further includes: obtaining the first rotation angle of the blade (10) at the loading position (10c); In the step of setting the adjusting clamp (30) at the loading position (10c) of the blade (10): An adjusting clamp (30) is set at the loading position (10c) of the blade (10) and a second rotation angle of the loading position (10c) is obtained after the adjusting clamp (30) is set; The adjustment clamp (30) applies a counterweight to the loading position (10c) so that the first rotation angle is equal to the second rotation angle.

10. The method according to claim 1, characterized in that, In the step of applying the test load to the loading position (10c) via the adjusting clamp (30): Different test loads are applied to the loading position (10c) by means of the adjusting fixture (30); In the step of obtaining the test load and the rotation angle of the loading position (10c) under the test load: obtaining different test loads and different rotation angles of the loading position (10c) under different test loads; In the step of determining the torsional stiffness of the blade (10) based on the test load and the rotation angle: multiple torsional stiffnesses are determined based on different test loads and different rotation angles, and a final torsional stiffness is determined based on the multiple torsional stiffnesses.

11. The method according to claim 1, characterized in that, The first position (10a) is located on the side of the second position (10b) close to the leaf root (11). The first distance between the first position (10a) and the leaf root (11) is 1m to 3m. The distance between the first position (10a) and the second position (10b) is 1m to 3m. The distance between the second position (10b) and the loading position (10c) is 8m to 12m.

12. A method for testing the core shearing of a blade (10), characterized in that, include: The method according to any one of claims 1-11 determines multiple sets of torsional stiffnesses under different applied force positions for multiple sets of test loads; The shear center position of the blade (10) is determined based on the multiple sets of torsional stiffness. In the step of applying the test load to the loading position (10c) through the adjusting clamp (30): The adjusting clamp (30) applies test loads of opposite directions and equal magnitudes to the loading position (10c) at different force application points on both sides of the chord direction. The force application direction of the test loads is perpendicular to the chord direction. The midpoint of the line connecting the two test load application points on both sides of the chord-up direction at the loading position (10c) is determined as the measuring point, and the measuring points corresponding to multiple sets of test loads do not overlap; In the step of determining the shear center position of the blade (10) based on multiple sets of torsional stiffness: The shear center position is determined based on the multiple sets of torsional stiffness and the corresponding multiple measuring point positions.

13. The method according to claim 12, characterized in that, In the step of determining the shear center position of the blade (10) based on multiple sets of torsional stiffness: When multiple sets of torsional stiffness are linearly related, it is determined that multiple measuring points corresponding to the multiple sets of torsional stiffness are located on the same side of the shear center position in the chord direction.

14. The method according to claim 12, characterized in that, In the step of determining the shear center position of the blade (10) based on multiple sets of torsional stiffness: When multiple sets of torsional stiffnesses exhibit a curvilinear relationship, the measuring points corresponding to the multiple sets of torsional stiffnesses are determined to be located on both sides of the shear center position in the chord direction.

15. The method according to claim 14, characterized in that, In the step of determining the shear center position of the blade (10) based on multiple sets of torsional stiffness: Plot a curve based on the multiple sets of torsional stiffness, and the measuring point corresponding to the torsional stiffness at the inflection point of the curve is the shear center position. Alternatively, the measuring point corresponding to the maximum torsional stiffness among multiple sets of torsional stiffness can be determined as the shear center position.

16. An adjusting clamp (30) for testing the torsional stiffness of the blade (10) according to any one of claims 1-11, characterized in that, The adjusting clamp (30) includes: The body part (31) has a receiving cavity (311) for accommodating at least part of the blade (10). Loading part (32), at least two loading parts (32) are respectively disposed on both sides of the body part (31) in the first direction, and a force-applying member (321) is provided on the loading part (32) to apply a load to the loading part (32) through the force-applying member (321), and at least one of the force-applying members (321) on the loading part (32) is movably disposed along the first direction.

17. The adjusting clamp (30) according to claim 16, characterized in that, Also includes: A counterweight (33) is disposed on at least one side of the main body (31) in the second direction. A counterweight member is disposed on the counterweight (33) and the counterweight member is movably disposed along the first direction.

18. The adjusting clamp (30) according to claim 16, characterized in that, The main body (31) includes an upper shell (312) and a lower shell (313) distributed in a second direction, which are joined together to form the receiving cavity (311). The loading part (32) includes an upper half (322) and a lower half (323). The upper half (322) and the upper shell (312) are fixedly connected to each other, and the lower half (323) and the lower shell (313) are fixedly connected to each other. The force-applying member (321) connects the upper half (322) and the lower half (323).

19. The adjusting clamp (30) according to claim 18, characterized in that, The loading part (32) further includes a slide rail (324) extending along the first direction. The force-applying member (321) includes a slider. The slider is movably disposed within the slide rail (324) along the first direction. The slider is reused as a connecting member between the upper half (322) and the lower half (323). The upper half (322) and the lower half (323) are connected together by the slider.

20. The adjusting clamp (30) according to claim 16, characterized in that, The first direction is parallel to the chord of the blade (10) located in the receiving cavity (311) so that a test load perpendicular to the chord can be applied to the blade (10) located in the receiving cavity (311) by the force-applying member (321).

21. The adjusting clamp (30) according to claim 16, characterized in that, The number of loading parts (32) is three or more, and at least one of the loading parts (32) is disposed on one side of the body part (31) in the second direction.

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