Blade of wind driven generator and wind driven generator set

Abstract

The invention provides a blade of a wind driven generator and a wind driven generator set, the blade comprises a trailing edge beam and a core material of the blade combined with the trailing edge beam in the chord direction of the blade, and the blade is characterized in that the trailing edge beam and the core material are combined with each other in a combination area of the blade; one of the trailing edge beam and the core material includes a protrusion, the other of the trailing edge beam and the core material includes a recess, and the protrusion is inserted into the recess. According to the blade, due to the fact that the protrusions and the concave parts which are basically symmetrical are formed in the combination area of the trailing edge beam and the core material, stress concentration generated when the local part is subjected to the coupling shearing force effect can be effectively avoided, the local stress condition is obviously improved under the same external load effect, and therefore the reliability of the blade is improved.

Description

Technical Field

[0001] The present invention relates to a blade of a wind turbine and a wind power generation set, and particularly to a blade of a wind turbine and a wind power generation set with improved reliability. Background Art

[0002] The blade is the main component of a wind power generation set for absorbing wind energy. Figure 1 The schematic diagram of a traditional blade is shown. The length direction of the blade 100 is defined as the span direction, and the width direction of the blade is defined as the chord direction. The blade 100 mainly includes an upper shell, a lower shell and a web. The upper shell and the lower shell may respectively include an inner skin laminate, an internal structure (core structure) and an outer skin laminate. The internal structure mainly includes a main beam, a trailing edge beam, a leading edge beam, a composite material composed of fibers and resin, and a core material. The core material mainly includes foam (such as PVC, PET foam core materials) or wood (Balsa wood) materials. There is a bonding area between the main beam, the trailing edge beam and the leading edge beam and the core material. Figure 2 The cross-sectional view of the traditional blade in the chord direction is shown; Figure 3 It is a schematic enlarged view of the bonding area A between the main beam and the core material; Figure 4 It is a schematic enlarged view of the bonding area B between the trailing edge beam and the core material. As Figure 2 and Figure 3 shown, the bonding area between the main beam and the core material adopts a direct transition bonding method; as Figure 2 and Figure 4 shown, the trailing edge beam and the core material adopt a single-sided triangular transition bonding form; although the enlarged view of the bonding area C between the leading edge beam and the core material is not shown, the bonding area C between the leading edge beam and the core material also adopts a direct transition or a single-sided triangular transition bonding method. Whether it is a direct transition or a single-sided triangular transition bonding method, stress concentration is likely to occur, resulting in local failure of the bonding area. Summary of the Invention

[0003] The blade of the wind turbine and the wind power generation set of the present invention are provided to improve the problem of low reliability of the existing blade of the wind turbine.

[0004] According to one aspect of the present invention, a blade of a wind turbine is provided. The blade includes a trailing edge beam and a core material of the blade bonded to the trailing edge beam in the chord direction of the blade. Wherein, the trailing edge beam and the core material are bonded to each other in the bonding area of the blade. One of the trailing edge beam and the core material includes a protrusion, and the other of the trailing edge beam and the core material includes a recess, and the protrusion is inserted into the recess.

[0005] According to the present invention, the protrusion may be formed on the trailing edge beam, and the protrusion may be formed by a preformed laminate or a fiber-reinforced material layup.

[0006] According to the present invention, in the cross-sectional view of the blade in the chord direction, the protrusion may be substantially in an isosceles triangle shape.

[0007] According to the present invention, there may be at least one protrusion, and the number of the recesses may correspond to the number of the protrusions.

[0008] According to the present invention, in the cross-sectional view of the blade in the chord direction, the protrusion may be rectangular, and the distance between the first edge of the protrusion close to the inner skin of the blade and the inner skin is substantially equal to the distance between the second edge of the protrusion close to the outer skin of the blade and the outer skin.

[0009] According to the present invention, the protrusion may be formed by two preformed laminates of right-angled triangles.

[0010] According to the present invention, the protrusion may be formed on the core material.

[0011] According to the present invention, the trailing edge beam may further include a main body portion connected to the protrusion, and the protrusion and the main body portion may be integrally formed.

[0012] According to the present invention, the trailing edge beam and the core material are only subjected to in-plane shear flow and not to out-of-plane shear.

[0013] On the other hand, the present invention provides a wind turbine generator set, which includes: a tower; a nacelle disposed at the top of the tower; a hub rotatably connected to the nacelle; and the above-mentioned blade rotatably connected to the hub.

[0014] According to the blade of the present invention, in the bonding region between the trailing edge beam and the core material, since the trailing edge beam and the core material are bonded in an occluding manner such as a dovetail, a sawtooth or a square tooth as symmetrically as possible, substantially symmetric protrusions and recesses are formed. Therefore, it is possible to effectively avoid the coupling of out-of-plane shear under the action of in-plane shear flow in the inner skin laminate or the outer skin laminate of the sandwich structure including the trailing edge beam and the core material, prevent the sandwich structure from bearing forces of non-designed loads, prevent or significantly improve the stress concentration of the sandwich structure, and significantly improve the local stress condition under the action of the same external load, thereby improving the reliability of the blade. According to the blade of the present invention, in the bonding region between the trailing edge beam and the core material, by forming an occluding structure between the core material and the laminate forming the trailing edge beam, the problem that the local core material is prone to protrusion can be improved. In addition, the locally prefabricated chamfer of the core material is also easier to adjust than the overall chamfered core material. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Through the description of the embodiments in conjunction with the accompanying drawings below, the above and / or other objects and advantages of the present invention will become clearer, wherein:

[0016] Figure 1 Shows a schematic diagram of a conventional blade;

[0017] Figure 2 Shows a cross-sectional view of a conventional blade in the chordwise direction;

[0018] Figure 3 Is a schematic enlarged view of the bonding area A between the main beam and the core material;

[0019] Figure 4 Is a schematic enlarged view of the bonding area B between the trailing edge beam and the core material, where the stress condition of the bonding area B between the trailing edge beam and the core material is shown;

[0020] Figure 5 Shows a cross-sectional view of the part where the trailing edge beam of the blade according to an exemplary embodiment of the present invention is bonded to the core material;

[0021] Figure 6 Is a cross-sectional view showing a variant example of the part where the trailing edge beam of the blade according to an exemplary embodiment of the present invention is bonded to the core material, where protrusions are formed on the core material;

[0022] Figure 7 Is a cross-sectional view showing a variant example of the part where the trailing edge beam of the blade according to an exemplary embodiment of the present invention is bonded to the core material, where there are two protrusions;

[0023] Figure 8 Is a cross-sectional view showing a variant example of the part where the trailing edge beam of the blade according to an exemplary embodiment of the present invention is bonded to the core material, where the protrusions are rectangular;

[0024] Figures 9A to 9F Shows a process diagram of the manufacturing process of the part where the trailing edge beam is bonded to the core material according to an exemplary embodiment of the present invention.

[0025] Figure 10A Is a schematic enlarged view of the bonding area between the trailing edge beam and the core material according to an exemplary embodiment of the present invention, where the stress condition of the bonding area between the trailing edge beam and the core material is shown;

[0026] Figure 10B Is a schematic diagram showing Figure 4 The principal stress nephogram of the core material in;

[0027] Figure 10C Is a schematic diagram showing Figure 10A The principal stress nephogram of the core material in. Detailed implementation mode

[0028] Exemplary embodiments of the present invention will now be described more fully with reference to the accompanying drawings. However, the embodiments of the present invention should not be construed as being limited to the embodiments set forth herein. Identical reference numerals in the figures denote identical or similar structures, and thus their detailed description will be omitted.

[0029] Figure 5 A cross-sectional view of a portion where a trailing edge beam of a blade is joined to a core material according to an exemplary embodiment of the present invention is shown.

[0030] As Figure 5 shown, a blade of a wind turbine according to an exemplary embodiment of the present invention includes a trailing edge beam 1 and a core material 2 of the blade joined to the trailing edge beam 1 in the chord direction of the blade. Among them, the trailing edge beam 1 and the core material 2 are joined to each other in a joining region 3 of the blade. One of the trailing edge beam 1 and the core material 2 includes a protrusion 11, and the other of the trailing edge beam 1 and the core material 2 includes a recess 21, where the protrusion 11 is inserted into the recess 21.

[0031] As Figure 5 shown, the portion where the trailing edge beam 1 of the blade is joined to the core material 2 mainly includes an inner skin laminate 4, an internal structure (a sandwich structure), and an outer skin laminate 5. The internal structure is sandwiched between the inner skin laminate 4 and the outer skin laminate 5 and mainly includes the trailing edge beam 1 and the core material 2. The trailing edge beam 1 includes a protrusion 11 and a main body portion 12, and the protrusion 11 protrudes from the main body portion 12. Optionally, the protrusion 11 and the main body portion 12 may be integrally formed.

[0032] Optionally, as Figure 5 shown, the core material 2 may include a recess 21, and the shape of the recess 21 corresponds to the shape of the protrusion 11, and the protrusion 11 is inserted into the recess 21.

[0033] Optionally, the joining region 3 is defined as a region that includes both the trailing edge beam 1 and the core material 2 in the chord direction of the blade, that is, the region where the trailing edge beam 1 and the core material 2 are joined to each other. The joining region 3 is located between the inner skin laminate 4 and the outer skin laminate 5 of the blade, and the ratio of the length in the chord direction of the blade to its thickness (the dimension of the joining region in the direction from the inner skin laminate 4 to the outer skin laminate 5) is 0.5 to 20.

[0034] The center line D-D of the joining region 3 is defined as the line located at the center of the inner skin laminate 4 and the outer skin laminate 5 in the cross-section of the blade in the chord direction.

[0035] As Figure 5 shown, the protrusion 11 may be in the shape of an isosceles triangle, and the vertex of the isosceles triangle is located on the center line D-D. In this case, the protrusion 11 is axisymmetric with respect to the center line D-D of the joining region 3. Correspondingly, the shape of the recess 21 corresponds to the shape of the protrusion 11 and is also axisymmetric with respect to the center line D-D of the joining region 3.

[0036] As Figure 5 shown, when the protrusion 11 is in the shape of an isosceles triangle, the protrusion 11 can be formed by two right-angled triangular preformed laminates. The right-angled sides of the two right-angled triangles face each other, and the other right-angled sides are located on a straight line, thus forming the protrusion 11. The two right-angled triangles are mutually combined through a fabric with good flow guiding effect.

[0037] Optionally, Figure 5 the trailing edge beam 1 including the protrusion 11 and the main body portion 12 shown in can be bisected into upper and lower parts along the center line D-D, and the two parts are mutually combined through a fabric with good flow guiding effect.

[0038] Although Figure 5 the protrusion 11 is shown in the shape of an isosceles triangle, the present invention is not limited thereto. The apex angle of the triangle can deviate upward or downward from the center line D-D in the thickness direction of the blade (the direction from the inner skin laminate 4 to the outer skin laminate 5), as long as the protrusion 11 can be inserted into the recess 21.

[0039] Optionally, although Figure 5 the protrusion 11 is shown in the shape of an isosceles triangle, the present invention is not limited thereto. The protrusion 11 can also be in the shape of an isosceles trapezoid, and the midpoint of the upper base of the isosceles trapezoid is located on the center line D-D, or the protrusion 11 is in the shape of a trapezoid, and the midpoint of the upper base of the trapezoid can deviate upward or downward from the center line D-D in the thickness direction of the blade, as long as the protrusion 11 can be inserted into the recess 21.

[0040] Returning to Figure 3 and Figure 4 , for the bonding area between the beam body (main beam, trailing edge beam or leading edge beam) of a traditional blade and the core material, a direct transition or a unilateral triangular transition bonding method is adopted, resulting in extremely asymmetric inside and outside of the overall sandwich structure. The inner skin laminate or the outer skin laminate of the blade is prone to couple out-of-plane shear force under the action of in-plane shear flow, resulting in the sandwich structure bearing forces other than the designed load, and there is stress concentration due to local structural mutation. For example, as Figure 4 shown, the bonding area between the beam body and the core material is subjected to the action of in-plane shear flow F1. Due to the structural asymmetry between the beam body and the core material in the bonding area, it is easy to couple out-of-plane shear force F2, resulting in stress concentration and crack generation at the chamfer termination position of the beam body. As the blade becomes longer, the breathing effect in the area near the maximum chord length of the blade exacerbates the local stress, making the bonding area prone to local failure.

[0041] However, according to an exemplary embodiment of the present invention, the joining area between the beam and the core material of the blade is designed symmetrically, so that the local structure is subjected to uniform force, avoiding the sandwich structure from coupling out-of-plane shear force under the action of in-plane shear flow of the inner skin laminate or the outer skin laminate, preventing the sandwich structure from being subjected to forces other than design loads, preventing or significantly improving stress concentration in the sandwich structure, significantly improving the bearing capacity of the sandwich structure, and ultimately improving the reliability of the blade.

[0042] In the present invention, "laminate" refers to a composite material composed of unidirectional or multidirectional fibers and resin, and the fibers may include glass fibers, carbon fibers, aramid fibers, basalt fibers, plant fibers, etc. "Core material" may be a porous material formed by foaming artificial synthetic polymers such as PVC, PET, PU, ​​or balsa, bamboo or other natural lightweight materials.

[0043] Optionally, the protrusions 11 are formed from preformed laminates or layups of fiber reinforced material.

[0044] Figure 6 2 is a cross-sectional view showing a modified example of a portion where a trailing edge beam of a blade is combined with a core material according to an exemplary embodiment of the present invention, wherein a protrusion is formed on the core material 2 and a recess is formed on the trailing edge beam 1 accordingly, and the protrusion is inserted into the recess. Figure 5 The description of the protrusions and recesses of the exemplary embodiments also applies to Figure 6 The protrusions and recesses of the exemplary embodiment of the present invention are different from those of the present invention. Figure 5 The configuration of the exemplary embodiments is similar and will not be described in detail here.

[0045] Figure 7 1 is a cross-sectional view showing a modified example of a portion where the trailing edge beam of a blade is combined with a core material according to an exemplary embodiment of the present invention, wherein there are two protrusions and correspondingly, there are also two recesses, and the corresponding protrusions are inserted into the corresponding recesses. Figure 7 As shown, the two protrusions formed on the trailing edge beam 1 can be axially symmetrical with respect to the center line of the bonding area, that is, the two protrusions can be formed according to the same size. Each protrusion can be in the shape of an isosceles triangle, and accordingly, the shape of each recess corresponds to the shape of the protrusion.

[0046] like Figure 7 As shown, in the case where the protrusion is in the shape of an isosceles triangle, each protrusion can be formed by two right-angled triangle preformed laminates, the right-angled sides of the two right-angled triangles are opposite to each other, and the other right-angled sides are located on a straight line, thereby forming a protrusion, and the two right-angled triangles are connected to each other by a fabric with a better flow-guiding effect.

[0047] Although Figure 7The protrusions are shown as being in an isosceles triangle shape in [reference], but the present invention is not limited thereto. The protrusions may also be in a non-isosceles triangle shape, as long as the protrusions can be inserted into the recesses.

[0048] Optionally, although Figure 7 each protrusion is shown as being in an isosceles triangle shape in [reference], the present invention is not limited thereto. The protrusions may also be in an isosceles trapezoid shape, or the protrusions may also be in other trapezoid shapes that are non-isosceles trapezoids, as long as the protrusions can be inserted into the recesses.

[0049] Although Figure 7 it is shown that the number of protrusions is two, but according to the thickness of the shell of the blade, more than two protrusions and corresponding numbers of recesses may be formed. As long as the local stress of the sandwich structure can be made uniform, preventing the sandwich structure from bearing forces of non-designed loads, significantly improving the stress concentration of the sandwich structure, enhancing the load-bearing capacity of the sandwich structure, and improving the reliability of the blade.

[0050] Although Figure 7 it is shown that the protrusions are formed on the trailing edge beam 1 and the recesses are formed on the core material 2, the present invention is not limited thereto. The protrusions may also be formed on the core material 2, and correspondingly, the recesses may be formed on the trailing edge beam 1.

[0051] Figure 8 A cross-sectional view of a variant example of the portion where the trailing edge beam and the core material of the blade according to an exemplary embodiment of the present invention are combined is shown, wherein the protrusions are rectangular.

[0052] As Figure 8 shown, in the cross-sectional view of the blade in the chord direction, the protrusion 11 is rectangular, and the distance between the first edge 111 of the protrusion 11 close to the inner skin laminate 4 of the blade and the inner skin laminate 4 is substantially equal to the distance between the second edge 112 of the protrusion 11 close to the outer skin laminate 5 of the blade and the outer skin laminate 5. The protrusion 11 is rectangular, and the shape of the recess 21 corresponds to the shape of the protrusion 11. Except for the different shapes of the protrusions and the recesses, other structures are similar to those of the exemplary embodiment of Figure 5 and will not be described in detail herein.

[0053] Although Figure 8 it is shown that the protrusions are formed on the trailing edge beam 1 and the recesses are formed on the core material 2, the present invention is not limited thereto. The protrusions may also be formed on the core material 2, and correspondingly, the recesses may be formed on the trailing edge beam 1.

[0054] Although Figure 8 it is shown that the number of rectangular protrusions is two, but according to the thickness of the shell of the blade, more than two protrusions and corresponding numbers of recesses may be formed. As long as the local stress of the sandwich structure can be made uniform, preventing the sandwich structure from bearing forces of non-designed loads, significantly improving the stress concentration of the sandwich structure, enhancing the load-bearing capacity of the sandwich structure, and improving the reliability of the blade.

[0055] The present invention also provides a wind turbine generator, which includes: a tower; a nacelle disposed at the top of the tower; a hub rotatably connected to the nacelle; and the above-mentioned blades rotatably connected to the hub.

[0056] Figures 9A to 9F A process diagram of the manufacturing process of the bonded part of the trailing edge beam and the core material according to an exemplary embodiment of the present invention is shown.

[0057] The following refers to Figures 9A to 9F Briefly describe the manufacturing process of the bonded part of the trailing edge beam and the core material according to an exemplary embodiment of the present invention. As Figures 9A to 9F shown, in the first step, lay the outer skin ply; in the second step, lay the core material; in the third step, lay the chamfer of the core material on the outer skin side; in the fourth step, lay the preformed laminate or lay the fiber reinforced material ply; in the fifth step, lay the chamfer of the core material on the inner skin side; in the sixth step, lay the inner skin ply to complete the laying of the bonded part of the trailing edge beam and the core material.

[0058] Although Figure 9D showing the overall laying of the preformed laminate or the overall laying of the fiber reinforced material ply, the present invention is not limited thereto, and the overall laying of the preformed laminate or the overall laying of the fiber reinforced material ply can also be replaced by ply-by-ply gradually staggered laying to meet the requirements of different processes. In addition, it can also be replaced by, for example, laying a part of the prefabricated laminate and a part of the ply Figure 9D of the overall laying of the preformed laminate or the overall laying of the fiber reinforced material ply.

[0059] Figure 10A is a schematic enlarged view showing the bonded area of the trailing edge beam and the core material according to an exemplary embodiment of the present invention, in which the stress condition of the bonded area of the trailing edge beam and the core material is shown; Figure 10B is showing Figure 4 the principal stress nephogram of the core material in Figure 10C is showing Figure 10A the principal stress nephogram of the core material in

[0060] As Figure 10A shown, the bonded area of the trailing edge beam and the core material is only subjected to the in-plane shear flow F1. Due to the structural symmetry of the trailing edge beam and the core material in the bonded area, there is no coupled out-of-plane shear force caused by structural asymmetry in the prior art, that is, the stress in the bonded area of the trailing edge beam and the core material is uniform and cracks are not likely to occur.

[0061] In Figure 10B for the core material according to the prior art, under the action of the out-of-plane shear force of the local structure, due to the structural mutation and obvious cross-sectional asymmetry, there is serious stress concentration in the chamfer area of the core material ( Figure 10Bas shown by the red circle in), which causes the local core material to start to fail first and ultimately leads to the failure of the structure.

[0062] However, for the blade of the wind turbine according to the present invention, the core materials are symmetrically distributed on both sides of the trailing edge beam. The principal stress nephogram of the core material is shown in Figure 10C , it can be seen that the stress concentration phenomenon of the core material is significantly improved ( Figure 10C in the nephogram of, the red range is more widely distributed), there is no stress concentration at the chamfer termination position of the trailing edge beam, and the maximum principal stress of the core material is significantly reduced.

[0063] In the present invention, it is not necessary for the protrusions or recesses to be completely symmetric, and only the bonding area needs to be in the form of dovetail, serrated or square-tooth bonding that is as symmetric as possible.

[0064] For the blade according to the present invention, in the bonding area between the trailing edge beam and the core material, since the trailing edge beam and the core material are bonded in the form of dovetail, serrated or square-tooth biting that is as symmetric as possible, so as to form substantially symmetric protrusions and recesses, it is possible to effectively avoid the coupling of out-of-plane shear force under the action of in-plane shear flow in the sandwich structure including the trailing edge beam and the core material, prevent the sandwich structure from bearing the force of non-designed load, prevent or significantly improve the stress concentration of the sandwich structure, and under the action of the same external load, the local stress condition is significantly improved, thereby improving the reliability of the blade.

[0065] For the blade according to the present invention, in the bonding area between the trailing edge beam and the core material, by forming a biting structure between the core material and the laminate forming the trailing edge beam, the problem that the local core material is prone to protrusion can be improved. In addition, the locally prefabricated chamfer of the core material is also easier to adjust than the overall chamfered core material.

[0066] In the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0067] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0068] For the sake of convenience in description, terms such as front, back, top, bottom, horizontal, and vertical are used to describe the structure and operation method of the device. However, the installation direction of the device is not limited thereto, and the device can be turned over front and back, turned over up and down, or positioned at other angular orientations.

[0069] The features, structures, or characteristics described in the present invention may be combined in one or more embodiments in any suitable manner. In the above description, numerous specific details are provided to give a thorough understanding of the embodiments of the present invention. However, those skilled in the art will realize that the technical solutions of the present invention can be practiced without one or more of the specific details, or other methods, components, materials, etc. may be adopted. In other cases, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring various aspects of the present invention.

Claims

1. A blade of a wind turbine, the blade comprising a trailing edge beam (1) and a core material (2) of the blade joined to the trailing edge beam (1) in the chord direction of the blade, characterized in that, The trailing edge beam (1) and the core material (2) are joined to each other in the joining region (3) of the blade. One of the trailing edge beam (1) and the core material (2) includes a protrusion (11), and the other of the trailing edge beam (1) and the core material (2) includes a recess (21), wherein the protrusion (11) is inserted into the recess (21).

2. The blade of a wind turbine as claimed in claim 1, wherein, The protrusion (11) is formed on the trailing edge beam (1), and the protrusion (11) is formed by laminating a preformed laminate or a fiber-reinforced material.

3. The blade of a wind turbine according to claim 2, characterized in that, In the cross-sectional view of the blade in the chordwise direction, the protrusion (11) is substantially in an isosceles triangle shape.

4. The blade of the wind turbine according to claim 3, characterized in that, There is at least one protrusion (11), and the number of the recesses (21) corresponds to the number of the protrusions (11).

5. The blade of the wind turbine according to claim 2, characterized in that, In the cross-sectional view of the blade in the chordwise direction, the protrusion (11) is rectangular, and the distance between the first edge (111) of the protrusion (11) close to the inner skin (4) of the blade and the inner skin (4) is substantially equal to the distance between the second edge (112) of the protrusion (11) close to the outer skin (5) of the blade and the outer skin (5).

6. The blade of a wind turbine according to claim 3, characterized in that, The protrusion (11) is formed by laminating two right-angled triangular preformed laminates.

7. The blade of a wind turbine as claimed in claim 1, characterized in that, The protrusion (11) is formed on the core material (2).

8. The blade of the wind turbine according to any one of claims 1 to 6, characterized in that, The trailing edge beam (1) further includes a main body portion (12) connected to the protrusion (11), and the protrusion (11) and the main body portion (12) are integrally formed.

9. The blade of a wind turbine according to any one of claims 3, 5, and 6, characterized in that The trailing edge beam (1) and the core material (2) are only subjected to in-plane shear flow and not subjected to out-of-plane shear force.

10. A wind turbine generator, characterized in that, Comprising: A tower; A nacelle provided at the top end of the tower; A hub rotatably connected to the nacelle; The blade as claimed in claims 1-9, rotatably connected to the hub.

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