Wind power blade girder layering damage failure analysis method based on body-shell coupling

Abstract

The invention provides a wind power blade girder layering damage failure analysis method based on body-shell coupling. The method comprises the steps that a full-size blade geometric model and a full-size blade shell finite element analysis model are established; selecting a full-size blade from a blade root pitch circle to a 1 / 3 blade length section as a shell analysis model; embedding the prefabricated layered defect into the full-size blade girder area by adopting a body-shell coupling method to obtain a body-shell coupling model for blade girder damage failure analysis; blade root fixing constraint is adopted, equivalent fatigue load is applied to the end of the shell analysis model through a multi-point constraint method, out-of-plane displacement of the center point of the upper surface of a sub-plate and the center point of the lower surface of the sub-plate is extracted, and a layered expansion failure process along with load action time is extracted; and carrying out layering failure research on the layering damage of the full-size blade. The method can solve the problem that there is no effective analysis method for the main beam layering failure mode and the expansion path of the wind power blade.

Description

Technical Field

[0001] The invention relates to a wind turbine blade main beam damage identification technology, and in particular to a wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling. Background Art

[0002] With the continuous growth of global energy demand and the increasing awareness of environmental protection, wind energy, as a clean, renewable and pollution-free energy source, has received widespread attention. As one of the main ways to utilize wind energy, wind power generation has been continuously developing and expanding in scale of application. The performance, reliability and safety of wind turbines are directly related to the operating efficiency and economic benefits of the entire wind farm. However, wind turbines are exposed to complex and changeable natural environments for a long time and are subjected to various loads, especially the blades, which are directly faced with the challenges of wind and other environmental factors. Therefore, the prediction of delamination failure of wind turbine blade main beams is particularly important.

[0003] Wind turbine blades are one of the core components of wind turbine generator sets. They have a complex structure and are composed of multiple materials. The blade main beam is the main load-bearing component of the blade. Its structural design and material selection have a decisive influence on the performance and life of the blade. The blade main beam is usually made of composite materials. These materials have the advantages of high strength, high modulus, and light weight, but they also have some potential defects, such as delamination, lack of glue, wrinkles, etc. These defects will gradually accumulate and develop under long-term loads, and eventually lead to damage and failure of the blade main beam structure. Delamination failure is one of the common failure modes of wind turbine blade main beams. It is mainly caused by insufficient bonding strength between the composite layers of the blade main beam or excessive shear load. Delamination failure will lead to a decrease in the overall stiffness and strength of the blade main beam structure, thereby affecting the vibration characteristics and aerodynamic performance of the blade. In severe cases, delamination failure may even cause the blade to break or fall off, posing a serious threat to the normal operation and safety of the wind turbine generator set. Therefore, in order to effectively predict the delamination failure of the wind turbine blade main beam, the present invention proposes a delamination damage failure analysis method for the wind turbine blade main beam based on body-shell coupling. Summary of the invention

[0004] In view of the lack of effective analysis methods for the delamination failure modes and extension paths of the main beams of wind turbine blades, the present invention proposes a delamination damage failure analysis method for the main beams of wind turbine blades based on body-shell coupling.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A method for analyzing delamination damage failure of a wind turbine blade main beam based on body-shell coupling, the method comprising the following steps:

[0007] Step 1: Geometrically model the shape of the blade body-shell coupling structure to be analyzed. The aerodynamic centers of all airfoil sections of the established full-size blade geometric model are located on the same straight line, and all aerodynamic centers are located at 1 / 3 of the blade chord length. The blade airfoil data is transformed into three-dimensional coordinates according to the aerodynamic shape;

[0008] Step 2: Create a full-size blade shell finite element analysis model based on the full-size blade geometry model;

[0009] Step 3: Based on the full-size blade shell finite element analysis model, the full-size blade from the blade root pitch circle to 1 / 3 of the blade length is selected as the shell analysis model, and the main beam ply thickness increases from 0 to the maximum thickness; a prefabricated layered body model is created based on the laminate theory and cohesive force model, and the prefabricated layering defects are embedded in the full-size blade main beam area using the body-shell coupling method to obtain a body-shell coupling model for blade main beam damage failure analysis;

[0010] Step 4: Based on the body-shell coupling model, the blade root is fixedly constrained, and the equivalent fatigue load is applied at the end of the shell analysis model using the multi-point constraint method. The out-of-plane displacements of the center points of the upper and lower surfaces of the sub-plates and the failure history of the layered expansion with the load action time are extracted. The distribution trend of the out-of-plane displacements of the upper and lower sub-plates and the damage factor cloud diagrams at different load action times are obtained respectively;

[0011] Step 5: According to the distribution trend of the out-of-plane displacements of the upper and lower sub-plates, determine whether the failure mode of the delamination damage is local buckling, global buckling or mixed buckling;

[0012] Step 6: Based on the damage factor cloud diagram at different load action times, the expansion path of delamination failure under continuous loading is analyzed.

[0013] Furthermore, in step 1, the process of performing three-dimensional coordinate transformation on the blade airfoil data according to the aerodynamic shape includes the following steps:

[0014] Retrieve the original two-dimensional plane coordinates (X, Y) of the blade element airfoil, and solve the two-dimensional coordinates (X 1, Y 1 ):

[0015] (X 1 ,Y 1 )=(X,YX 0 ,Y 0 )

[0016] In the formula, (X 0 ,Y 0 ) is the aerodynamic center coordinate; the coordinates of each blade element are calculated in combination with the chord length:

[0017] (X2 ,Y 2 )=C(X 1 ,Y 1 )

[0018] Where C is the cross-sectional chord length;

[0019] Rotate the blade element to get the actual space coordinates:

[0020]

[0021] Where θ is the twist angle and r is the position of the airfoil section. Combining the above two formulas, we get:

[0022]

[0023] Step 2 further includes:

[0024] The full-size blade geometry model is imported into the commercial finite element software ABAQUS in the form of a STEP file. According to the structural layout, layup design, and material selection, the chord-wise and span-wise structural partitions and layup planning are performed to create a full-size blade shell finite element analysis model.

[0025] Furthermore, in step 3, a full-size blade from the blade root pitch circle to 1 / 3 of the blade length is selected as the shell analysis model, and delamination defects are preset at different main beam thickness positions of the blade segment;

[0026] Among them, the main beam partition in the blade segment geometry model adopts a design of equal width and unequal thickness, and the inner width of the double web edge strip is used as the width of the main beam delamination failure model; the layered size blade segment grid of the embedded layer is divided into three areas: the first area is the blade shell part, which adopts the four-node S4R unit; the second area is the main beam area, which adopts the eight-node continuous unit SC8R; the third area is the embedded layer area and the layered peripheral extension area, which adopts the three-dimensional cohesive unit COH3D8; the SC4R unit in the first area is connected with the SC8R unit in the second area by body-shell coupling, and contact constraints are set to avoid mutual penetration between units.

[0027] Furthermore, in step 3, the process of connecting the SC4R unit in the first region and the SC8R unit in the second region by body-shell coupling includes the following steps:

[0028] An internal distributed coupling constraint set is created using reference nodes at the shell edges and coupling nodes on the solid surface to make the SC4R and SC8R elements compatible with displacement and stress equilibrium at the connection; specifically, the nodal displacements of the shell elements at the connection are equal to the displacements of the corresponding nodes in the thickness direction of the solid element:

[0029]

[0030] In the formula, w i Based on the multi-point constraint type and the location of the nodes, is the displacement of the i-th multi-point constraint node, n is the total number of multi-point constraint nodes, u x is the displacement of the entity node; the rotational freedom of the shell element node at the connection is consistent with the node in the thickness direction of the entity element. Assuming that the nodes on the entity remain on a line, the normalized direction N of the undeformed configuration and the normalized direction m of the deformed configuration represent the line. The rotation of the node is represented by the finite rotation vector Φ. The rotation constraint formula is:

[0031] A·N=m

[0032] in, is the skew-symmetric matrix form of Φ.

[0033] Step 4 further includes:

[0034] Based on the body-shell coupling model, a fixed constraint is set at the root of the blade to limit all degrees of freedom (U1, U2, U3, UR1, UR2, UR3), where U1, U2, U3 are the translational degrees of freedom along the three directions of the coordinate axis x, y, and z, respectively, and UR1, UR2, UR3 are the rotational degrees of freedom along the three directions of the coordinate axis x, y, and z, respectively, so that the degrees of freedom of each node in the root section in each direction are 0;

[0035] MPC multi-point constraints are set at the ends of the analysis model to constrain the motion coupling of the main beam nodes to a reference node, which is used to load equivalent fatigue loads and select different multiples of load coefficients for loading;

[0036] The buckling modes of the main beams are distinguished by the central nodes of the upper and lower sub-plate surfaces where the layers are located. The node sets are defined at the central point L on the upper surface of the sub-plate and the central point U on the lower surface of the sub-plate, and the out-of-plane displacements of each key point in the node set are extracted.

[0037] Step 5 further includes:

[0038] When the displacement paths of the two nodes are the same and the upper and lower sub-plates move in the same direction, the delamination gap is closed, and the failure mode of the delamination damage is judged to be global buckling; when the node of the lower sub-plate where the delamination is located remains horizontally displaced and the center node of the upper sub-plate moves upward, causing the delamination gap to open, the failure mode of the delamination damage is judged to be local buckling; when the center nodes of the upper and lower sub-plates are both away from the starting position to varying degrees and the delamination gap is in an open state, the failure mode of the delamination damage is judged to be a mixed buckling mode.

[0039] Step 6 further comprises:

[0040] Extract the damage factor of the layered interface, make the output step consistent with the loading step, and draw a damage factor cloud map;

[0041] At different load action time points, observe and record the changes in the damage factor cloud map, analyze the distribution and change trend of the damage factor in the damage factor cloud map, and determine the expansion path of delamination failure based on the accumulation and expansion of the damage factor in the damage factor cloud map.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The delamination damage failure analysis method for the main beam of a wind turbine blade based on body-shell coupling proposed in the present invention can systematically analyze and judge the delamination expansion failure history of a wind turbine blade model containing prefabricated delamination defects under the action of equivalent fatigue load, providing a scientific basis for the structural design and maintenance of wind turbine blades, and is of great significance for reducing the operation and maintenance costs of wind turbine blades and ensuring the healthy and stable operation of wind turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of a method for analyzing delamination damage failure of a wind turbine blade main beam based on body-shell coupling according to an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of delamination damage on the main beam of a wind turbine blade;

[0046] Figure 3 Model dimension diagram for layered analysis;

[0047] Figure 4 It is a full-scale blade shell model and a schematic diagram of the body model of delamination damage;

[0048] Figure 5 It is the body-shell coupling schematic diagram of the body-shell coupling section;

[0049] Figure 6 is the equivalent fatigue load distribution diagram;

[0050] Figure 7 It is the loading diagram of equivalent fatigue load for blade segment;

[0051] Figure 8 is a schematic diagram of out-of-plane displacement;

[0052] Fig. 9 It is a schematic diagram for judging the failure mode;

[0053] Fig.10 It is the damage factor cloud diagram. DETAILED DESCRIPTION

[0054] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0055] The present invention discloses a method for analyzing the delamination damage failure of a wind turbine blade main beam based on body-shell coupling (the specific process is as follows Figure 1 As shown), specifically including the following steps:

[0056] Step 1: Use Solid Works software to geometrically model the shape of the blade body shell coupling structure to be analyzed, transform the blade airfoil data into three-dimensional coordinates according to the aerodynamic shape, and obtain a solid model of prefabricated delamination defects and a full-size blade shell model; specifically including:

[0057] During geometric modeling, a blade geometric model is established in the solids work software. The aerodynamic centers of all airfoil sections of the blade geometric model are located on the same straight line, and these aerodynamic centers are located at 1 / 3 of the blade chord length. The blade airfoil data is transformed into three-dimensional coordinates according to the aerodynamic shape.

[0058] Retrieve the original two-dimensional plane coordinates (X, Y) of the blade element airfoil, and solve the two-dimensional coordinates (X 1, Y 1 ). Assume the aerodynamic center coordinates are (X 0 ,Y 0 ), C is the section chord length, θ is the twist angle, and r is the position of the airfoil section.

[0059] (X 1 ,Y 1 )=(X,YX 0 ,Y 0 )

[0060] Calculate the coordinates of each blade element based on the chord length:

[0061] (X 2 ,Y 2 )=C(X 1 ,Y 2 )

[0062] Rotate the blade element to get the actual space coordinates:

[0063]

[0064] Combining the above two formulas, we get:

[0065]

[0066] Step 2: Based on the full-size blade geometry model, create a full-size blade shell finite element analysis model; specifically including:

[0067] The full-size blade geometry model is imported into the commercial finite element software ABAQUS in the form of a STEP file. According to the structural layout, layer design, and material selection, the chord-wise and span-wise structural partitions and layer planning are performed to create a full-size blade shell finite element analysis model.

[0068] Step 3: Select the full-size blade from the blade root pitch circle to 1 / 3 of the blade length as the shell analysis model. At this time, the main beam ply thickness increases rapidly from 0 to the maximum thickness. Create a prefabricated layered body model based on the laminate theory and cohesive force model, and use the body-shell coupling method to embed the prefabricated layers into the full-size blade main beam area, thereby realizing the body-shell coupling model for blade main beam damage failure analysis. Specifically include:

[0069] In this embodiment, the full-size blade from the blade root pitch circle to 1 / 3 of the blade length is selected as the shell analysis model (eg Figure 2 As shown in the figure), delamination defects are preset at different main beam thickness positions of the blade segment, and the size of the delamination analysis model is 80*60mm (as shown in the figure). Figure 3 ). A prefabricated layered model is created based on the laminate theory and cohesive force model (as shown in Figure 4 shown).

[0070] In this embodiment, the main beam partition in the blade segment geometry model adopts a design of equal width and unequal thickness. The span of the main beam with the same thickness is about 1600mm, the width of the main beam is 400mm, and the inner width of the double web edge strip of 130mm is adopted as the width of the main beam delamination failure model.

[0071] The pre-embedded layered blade segment grid is divided into three areas. Area 1 is the blade shell part, which uses the four-node S4R unit suitable for thick shell units, with a grid unit size of 50mm×50mm and about 35,000 shell units in the blade segment. Area 2 is the main beam area, which uses the eight-node continuous unit SC8R that can represent the three-directional force state, with a grid size of 5mm×5mm. Area 3 is the pre-embedded layer area and the layered peripheral extension area, using the three-dimensional cohesive unit COH3D8, with a grid size of 5mm×5mm, and the analysis model includes a total of 754 cohesive units.

[0072] Among them, the SC4R unit in area 1 and the SC8R unit in the main beam area of ​​area 2 are connected by body-shell coupling (such as Figure 5 and set contact constraints to prevent mutual penetration between units.

[0073] Preferably, in the body-shell coupling method, an internal distributed coupling constraint set is created by using the reference nodes at the shell edge and the coupling nodes at the solid surface to achieve compatibility of displacement and stress balance at the connection between the two unit types. The node displacement of the shell element at the connection is equal to the displacement of the corresponding node in the thickness direction of the solid element, as shown in the formula:

[0074]

[0075] Among them, w i Based on the multi-point constraint type and the location of the nodes, is the displacement of the i-th multi-point constraint node, n is the total number of multi-point constraint nodes, u x is the entity node displacement.

[0076] At the same time, the rotational freedom of the shell element nodes at the connection must be consistent with the nodes in the thickness direction of the solid element. Assuming that the nodes on the solid are kept on a line, the normalized direction N of the undeformed configuration and the normalized direction m of the deformed configuration are used to represent the line. The rotation of the node is represented by the finite rotation vector Φ. The rotation constraint formula is:

[0077] A·N=m

[0078] in, is the skew-symmetric matrix form of Φ.

[0079] Step 4: Based on the body-shell coupling model, the blade root is fixedly constrained, and the equivalent fatigue load is applied at the end of the analysis model using a multi-point constraint method. The out-of-plane displacement of the center point of the upper surface of the sub-plate and the center point of the lower surface of the sub-plate of the sub-model of the model with prefabricated delamination defects, as well as the delamination extension failure history with the load action time are extracted; specifically, it includes:

[0080] On the basis of the body-shell coupling model, a fixed constraint is set at the root of the blade to limit all degrees of freedom (U1, U2, U3, UR1, UR2, UR3), where U1, U2, U3 are the translational degrees of freedom along the three directions of the coordinate axes x, y, and z, respectively, and UR1, UR2, UR3 are the rotational degrees of freedom along the three directions of the coordinate axes x, y, and z, respectively, so that the degrees of freedom of each node in the root section in each direction are 0. MPC multi-point constraints are set at the end of the analysis model to constrain the motion coupling of the main beam node to a reference node, which is used to load equivalent fatigue loads (such as Figure 6 and Figure 7 As shown), select different multiples of load factors for loading.

[0081] The buckling mode of the main beam is distinguished by the center nodes of the upper and lower sub-plate surfaces where the layers are located. L and U represent the center nodes of the upper and lower sub-plate surfaces, respectively. The node set is defined at the center point L on the upper surface of the sub-plate and the center point U on the lower surface of the sub-plate. The output request is set in abaqus to extract the out-of-plane displacements of these key points (such as Figure 8 as shown in Figure 3), and the failure history of delamination expansion with load action time.

[0082] Step 5: According to the distribution trend of the out-of-plane displacement of the upper and lower sub-plates, determine whether the failure mode of the delamination damage is local buckling, global buckling or mixed buckling; the specific judgment process is as follows:

[0083] When the displacement paths of the two nodes are the same and the upper and lower sub-plates move in the same direction, the delamination gap is closed, which is global buckling. When the node of the lower sub-plate where the delamination is located remains horizontally displaced and the center node of the upper sub-plate moves upward, the delamination gap opens. The buckling mode in this state is local buckling. The mixed buckling mode is that the center nodes of the upper and lower sub-plates are both away from the starting position to varying degrees, and the delamination gap is open (such as Fig. 9 shown).

[0084] Step 6: According to the damage factor cloud diagram at different load action times, determine the extension path of delamination failure with continuous loading, thereby realizing the delamination failure study of full-size blade delamination damage based on body-shell coupling; the specific analysis process is:

[0085] Extract the damage factor of the layered interface, ensure that the output step is consistent with the loading step, and use abaqus post-processing to draw the damage factor cloud map (such as Fig.10 At different load action time points, observe and record the changes in the damage factor cloud map, analyze the distribution and change trend of the damage factor in the damage factor cloud map, especially the damage degree of the delamination interface, and judge the expansion path of the delamination failure according to the accumulation and expansion of the damage factor in the cloud map.

[0086] The present invention solves the existing research deficiency of the lack of effective analysis method for the main beam delamination failure mode and expansion path of wind turbine blades, clarifies the evolution mechanism of delamination failure of wind turbine blades, and is of great significance for reducing the operation and maintenance cost of wind turbine blades and ensuring the healthy and stable operation of wind turbine blades.

[0087] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0088] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0089] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0090] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0091] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0092] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling, characterized in that: The method comprises the following steps: Step 1: Geometrically model the shape of the blade body-shell coupling structure to be analyzed. The aerodynamic centers of all airfoil sections of the established full-size blade geometric model are located on the same straight line, and all aerodynamic centers are located at 1 / 3 of the blade chord length. The blade airfoil data is transformed into three-dimensional coordinates according to the aerodynamic shape; Step 2: Create a full-size blade shell finite element analysis model based on the full-size blade geometry model; Step 3: Based on the full-size blade shell finite element analysis model, the full-size blade from the blade root pitch circle to 1 / 3 of the blade length is selected as the shell analysis model, and the main beam ply thickness increases from 0 to the maximum thickness; a prefabricated layered body model is created based on the laminate theory and cohesive force model, and the prefabricated layering defects are embedded in the full-size blade main beam area using the body-shell coupling method to obtain a body-shell coupling model for blade main beam damage failure analysis; Step 4: Based on the body-shell coupling model, the blade root is fixedly constrained, and the equivalent fatigue load is applied at the end of the shell analysis model using the multi-point constraint method. The out-of-plane displacements of the center points of the upper and lower surfaces of the sub-plates and the failure history of the layered expansion with the load action time are extracted. The distribution trend of the out-of-plane displacements of the upper and lower sub-plates and the damage factor cloud diagrams at different load action times are obtained respectively; Step 5: According to the distribution trend of the out-of-plane displacements of the upper and lower sub-plates, determine whether the failure mode of the delamination damage is local buckling, global buckling or mixed buckling; Step 6: Based on the damage factor cloud diagram at different load action times, the expansion path of delamination failure under continuous loading is analyzed.

2. The wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling according to claim 1 is characterized in that: In step 1, the process of performing three-dimensional coordinate transformation on the blade airfoil data according to the aerodynamic shape includes the following steps: Retrieve the original two-dimensional plane coordinates (X, Y) of the blade element airfoil, and solve the two-dimensional coordinates (X 1, Y1): (X1,Y1)=(X,Y-X0,Y0) Where, (X0, Y0) is the aerodynamic center coordinate; Calculate the coordinates of each blade element based on the chord length: (X2,Y2)=C(X1,Y1) Where C is the cross-sectional chord length; Rotate the blade element to get the actual space coordinates: Where θ is the twist angle, and r is the position of the airfoil section; Combining the above two formulas we get:

3. The wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling according to claim 1 is characterized in that: Step 2 further includes: The full-size blade geometry model is imported into the commercial finite element software ABAQUS in the form of a STEP file. According to the structural layout, layup design, and material selection, the chord-wise and span-wise structural partitions and layup planning are performed to create a full-size blade shell finite element analysis model.

4. The wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling according to claim 1 is characterized in that: In step 3, a full-size blade from the blade root pitch circle to 1 / 3 of the blade length is selected as the shell analysis model, and delamination defects are preset at different main beam thickness positions of the blade segment; Among them, the main beam partition in the blade segment geometry model adopts a design of equal width and unequal thickness, and the inner width of the double web edge strip is used as the width of the main beam delamination failure model; the layered size blade segment grid of the embedded layer is divided into three areas: the first area is the blade shell part, which adopts the four-node S4R unit; the second area is the main beam area, which adopts the eight-node continuous unit SC8R; the third area is the embedded layer area and the layered peripheral extension area, which adopts the three-dimensional cohesive unit COH3D8; the SC4R unit in the first area is connected with the SC8R unit in the second area by body-shell coupling, and contact constraints are set to avoid mutual penetration between units.

5. The wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling according to claim 4 is characterized in that: In step 3, the process of connecting the SC4R unit in the first region and the SC8R unit in the second region using body-shell coupling includes the following steps: An internal distributed coupling constraint set is created using reference nodes at the shell edges and coupling nodes on the solid surface to make the SC4R and SC8R elements compatible with displacement and stress equilibrium at the connection; specifically, the nodal displacements of the shell elements at the connection are equal to the displacements of the corresponding nodes in the thickness direction of the solid element: In the formula, w i Based on the multi-point constraint type and the location of the nodes, is the displacement of the i-th multi-point constraint node, n is the total number of multi-point constraint nodes, u x is the displacement of the entity node; the rotational freedom of the shell element node at the connection is consistent with the node in the thickness direction of the entity element. Assuming that the nodes on the entity remain on a line, the normalized direction N of the undeformed configuration and the normalized direction m of the deformed configuration represent the line. The rotation of the node is represented by the finite rotation vector Φ. The rotation constraint formula is: A·N=m in, is the skew-symmetric matrix form of Φ.

6. The wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling according to claim 1 is characterized in that: Step 4 further includes: Based on the body-shell coupling model, a fixed constraint is set at the root of the blade to limit all degrees of freedom (U1, U2, U3, UR1, UR2, UR3), where U1, U2, U3 are the translational degrees of freedom along the three directions of the coordinate axis x, y, and z, respectively, and UR1, UR2, UR3 are the rotational degrees of freedom along the three directions of the coordinate axis x, y, and z, respectively, so that the degrees of freedom of each node in the root section in each direction are 0; MPC multi-point constraints are set at the ends of the analysis model to constrain the motion coupling of the main beam nodes to a reference node, which is used to load equivalent fatigue loads and select different multiples of load coefficients for loading; The buckling modes of the main beams are distinguished by the central nodes of the upper and lower sub-plate surfaces where the layers are located. The node sets are defined at the central point L on the upper surface of the sub-plate and the central point U on the lower surface of the sub-plate, and the out-of-plane displacements of each key point in the node set are extracted.

7. The wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling according to claim 1 is characterized in that: Step 5 further includes: When the displacement paths of the two nodes are the same and the upper and lower sub-plates move in the same direction, the delamination gap is closed, and the failure mode of the delamination damage is judged to be global buckling; when the node of the lower sub-plate where the delamination is located remains horizontally displaced and the center node of the upper sub-plate moves upward, causing the delamination gap to open, the failure mode of the delamination damage is judged to be local buckling; when the center nodes of the upper and lower sub-plates are both away from the starting position to varying degrees and the delamination gap is in an open state, the failure mode of the delamination damage is judged to be a mixed buckling mode.

8. The wind turbine blade main beam delamination damage failure analysis method based on body-shell coupling according to claim 1 is characterized in that: Step 6 further comprises: Extract the damage factor of the layered interface, make the output step consistent with the loading step, and draw a damage factor cloud map; At different load action time points, observe and record the changes in the damage factor cloud map, analyze the distribution and change trend of the damage factor, and determine the expansion path of delamination failure based on the accumulation and expansion of the damage factor in the damage factor cloud map.

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