A wind turbine blade composite material failure analysis method and related device

Abstract

This invention relates to the field of wind power generation technology, specifically to a method and related equipment for failure analysis of composite materials in wind turbine blades. The method involves establishing a three-dimensional ply finite element model of the wind turbine blade; determining the load distribution across each cross-section along the blade's span based on aeroelastic analysis, and calculating the force load at each cross-section. The force load is then applied to the finite element model for nonlinear solution to obtain the blade strain field. Combined with the fiber orientation angles of the composite material ply, the strain components of each ply in the fiber coordinate system are calculated. The stress components along the fiber direction and perpendicular to the fiber direction are further calculated using elastic constants. Finally, the fiber failure state and inter-fiber failure state are assessed based on the stress components. This method achieves failure risk prediction for composite material structures in wind turbine blades through multiphysics coupling analysis.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, specifically to a method and related equipment for failure analysis of composite materials for wind turbine blades. Background Technology

[0002] As the core component of wind turbine units for capturing wind energy, the structural strength of wind turbine blades directly determines the operational safety, stability, and power generation efficiency of the unit. Wind turbine blades are mostly made of composite materials such as glass fiber and carbon fiber. The failure of fibers and between fibers in composite materials is one of the main causes of blade structural damage and breakage. Therefore, accurate analysis and prediction of the fiber failure characteristics of composite materials is currently a key research direction.

[0003] Currently, the industry primarily employs finite element analysis combined with failure criteria to assess the strength of composite materials in wind turbine blades. The PUCK criterion, due to its excellent failure prediction performance, has become a commonly used criterion for calculating inter-fiber strength. Related technologies can calculate the damage coefficient between blade fibers and correct the results by incorporating environmental and temperature factors to determine whether the inter-fiber strength meets design standards. However, existing technologies still have many shortcomings in the comprehensive analysis of fiber layup failures in wind turbine blade composite materials, failing to meet the requirements for accuracy, comprehensiveness, and standardized data management in the blade design phase. Furthermore, existing technologies often directly apply design loads to the finite element model for simulation calculations, without considering the aeroelastic characteristics of wind turbine blades during actual operation to derive the loads. This results in a low degree of correlation between the load input and the actual stress state of the blade. Simultaneously, the model solution often uses conventional linear calculation methods, neglecting the influence of the nonlinear characteristics of materials and structures on the calculation results. This leads to discrepancies between the calculated blade mechanical response and the actual situation, failing to provide accurate mechanical data support for fiber failure analysis. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and related equipment for analyzing the failure of composite materials in wind turbine blades, in order to solve the technical problem that the current analysis methods for the failure of blade plywood fibers are relatively inaccurate.

[0005] The objective of this invention is achieved through the following technical solutions: In a first aspect, the present invention provides a method for failure analysis of composite materials for wind turbine blades, comprising: Establish a three-dimensional layup finite element model of wind turbine blades; The load distribution along the spanwise cross section of the wind turbine blade was determined using aeroelastic analysis methods. The force load of each section is calculated based on the load distribution, and the force load is applied to the three-dimensional plywood finite element model for nonlinear solution to obtain the strain field of the wind turbine blade structure. Based on the strain field and the fiber orientation angle of the composite material layup of the wind turbine blade, the strain components of each layup in the fiber coordinate system are calculated. Based on the strain components in the fiber coordinate system and the stiffness coefficient of the composite material, calculate the stress components of each layup along the fiber direction and the stress components perpendicular to the fiber direction. The fiber failure state and inter-fiber failure state of the wind turbine blade are evaluated based on the stress components along the fiber direction and the stress components perpendicular to the fiber direction.

[0006] As a further improvement of the present invention, determining the load distribution of the wind turbine blade along its spanwise cross-sections includes: Obtain the flapping moment and swaying moment of the wind turbine blade; Based on the relationship between force and moment, the force load of each section is determined using the swinging moment and the oscillation moment.

[0007] As a further improvement of the present invention, the step of obtaining the strain field of the wind turbine blade structure includes: Information about all ply units in the three-dimensional ply finite element model is extracted to establish an information set about the ply units. This information set is then used as the strain field of the wind turbine blade structure. The information includes at least two of the following: unit number, ply layer number, material properties, and strain components of the material properties in the coordinate system of the three-dimensional ply finite element model.

[0008] As a further improvement of the present invention, the strain components of each layup in the fiber coordinate system are calculated, including: Calculate the coordinate transformation matrix based on the fiber orientation angle of the composite material layup of the wind turbine blade; Using the coordinate transformation matrix, the strain components in the coordinate system of the three-dimensional plywood finite element model are transformed to the fiber coordinate system to obtain the strain components along the fiber direction, the strain components perpendicular to the fiber direction, and the in-plane shear strain components.

[0009] As a further improvement of the present invention, before calculating the strain components of each layup in the fiber coordinate system, the method further includes: Obtain the positive axis elastic constant of a single-layer plate in a composite material; The stiffness coefficient of the corresponding single-layer plate is calculated based on the positive axis elastic constant; a coordinate transformation matrix is ​​constructed according to the stiffness coefficient of the single-layer plate and the ply angle of the composite material; the strain field is transformed based on the coordinate transformation matrix to obtain the strain components of each ply in the fiber coordinate system. The positive axis elastic constant includes the elastic modulus along the fiber direction, the elastic modulus perpendicular to the fiber direction, the principal Poisson's ratio, the secondary Poisson's ratio, and the in-plane shear modulus.

[0010] As a further improvement of the present invention, the calculation of the stress components of each layup along the fiber direction and the stress components perpendicular to the fiber direction includes: Using the strain components in the fiber coordinate system and the stiffness coefficient, the normal stress in the fiber direction, the normal stress perpendicular to the fiber direction, and the in-plane shear stress are calculated through constitutive relations.

[0011] As a further improvement of the present invention, the evaluation of the fiber failure state and inter-fiber failure state of the wind turbine blade includes: using the PUCK criterion to evaluate the stress components along the fiber direction and the stress components perpendicular to the fiber direction to obtain the fiber failure state and inter-fiber failure state of the wind turbine blade.

[0012] Secondly, the present invention provides a failure analysis system for composite materials of wind turbine blades, comprising: The model building module is used to create a three-dimensional layup finite element model of wind turbine blades; The load processing module is used to determine the load distribution of the wind turbine blade along each cross section along the span direction based on the aeroelastic analysis method. The strain extraction module is used to calculate the force load of each section according to the load distribution, apply the force load to the three-dimensional ply finite element model for nonlinear solution, and obtain the strain field of the wind turbine blade structure. The strain conversion module is used to calculate the strain components of each ply in the fiber coordinate system based on the strain field and the fiber orientation angle of the composite material ply of the wind turbine blade. The calculation module is used to calculate the stress components along the fiber direction and perpendicular to the fiber direction of each ply based on the strain components in the fiber coordinate system and the stiffness coefficient of the composite material. The failure assessment module is used to assess the fiber failure state and inter-fiber failure state of the wind turbine blade based on the stress components along the fiber direction and the stress components perpendicular to the fiber direction.

[0013] Thirdly, the present invention provides a computer-readable storage medium for storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform the above-described method for analyzing the failure of composite materials for wind turbine blades.

[0014] Fourthly, the present invention provides a computing device, comprising: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include steps for performing the above-described method for analyzing the failure of composite materials for wind turbine blades.

[0015] The beneficial effects of this invention are as follows: This invention provides a method for failure analysis of composite materials for wind turbine blades. By establishing a three-dimensional ply finite element model of the wind turbine blade, a structural simulation basis is achieved. Based on aeroelastic analysis, the load distribution of each cross section in the spanwise direction is determined to accurately reflect the coupling effect between aerodynamics and structure. According to the load distribution, the force load of each cross section is calculated and applied to the model for nonlinear solution to obtain the strain field under real working conditions. Combined with the fiber direction angle of the composite material ply, the strain components in the fiber coordinate system can be calculated to accurately capture the deformation characteristics of each ply. By using elastic constants to calculate the stress components along the fiber and perpendicular to the fiber direction, the stress state of each ply can be quantified. Finally, the fiber failure and inter-fiber failure state are evaluated by stress components. This invention achieves accurate analysis of the entire process from load distribution to failure assessment, which significantly improves the accuracy and reliability of failure prediction of composite material structures for wind turbine blades compared with the prior art. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the failure analysis method for wind turbine blade composite materials in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the wind turbine blade composite material failure analysis system in an embodiment of the present invention; Figure 3 This is an internal structural diagram of a computer device in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives and technical solutions of this invention clearer and easier to understand, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. The described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Example 1 Current failure analyses of composite structures in wind turbine blades mostly focus on the overall structural level, concentrating only on macroscopic stress and strain distribution, without addressing the anisotropy of composite materials and the structural characteristics of multi-layer layups. Traditional methods typically employ simplified loads and a single coordinate system for calculations, failing to achieve accurate conversion from a global coordinate system to a fiber-local coordinate system, and struggling to distinguish between mechanical responses along fiber directions and those perpendicular to fiber directions. Furthermore, existing technologies often use macroscopic methods for failure assessment, failing to effectively differentiate between fiber fracture scenarios, leading to biases in wind turbine blade failure analyses, and consequently, failing to provide accurate data support for blade structural reinforcement and layup optimization.

[0021] Therefore, this embodiment provides a method for failure analysis of composite materials in wind turbine blades. For example... Figure 1 As shown, this method establishes a three-dimensional ply finite element model of the wind turbine blade and determines the load distribution of each section based on aeroelastic analysis. After obtaining the strain field through nonlinear solution, the stress components along the fiber and perpendicular to the fiber direction of each ply are calculated by combining the fiber orientation angle and stiffness coefficient. Finally, the failure state between fibers is evaluated based on the stress components, realizing accurate analysis of the entire process from load distribution to failure assessment, significantly improving the accuracy and reliability of failure prediction for composite material structures of wind turbine blades. The specific implementation method is as follows.

[0022] First, a three-dimensional layup finite element model of the wind turbine blade is established.

[0023] This embodiment utilizes finite element analysis software to construct a three-dimensional finite element model that accurately reflects the multi-layered laminated structure, based on the wind turbine blade's external profile, dimensions, cross-sectional characteristics, and composite material layup design. Specifically, based on the wind turbine blade's two-dimensional cross-sectional drawings, three-dimensional shape data, and composite material layup design documents, a three-dimensional layup finite element model containing shell / solid elements is established using finite element software. During the modeling process, the number of layups, layup angles, layup thicknesses, and material distribution in different structural regions such as the blade, skin, main beam, and web are fully considered. Element types compatible with the composite laminated structure are used for mesh generation. By defining the material properties of each layup, element attributes, and interlayer relationships, the actual layup structure and mechanical properties of the blade are fully reproduced. This refined modeling accurately reflects the mechanical behavior of the composite laminated structure, providing a high-precision geometric and mechanical basis for subsequent load application and strain calculations, ensuring that the subsequent analysis results are consistent with the actual stress state.

[0024] As one example, finite element software such as Abaqus / Ansys is used to import the blade geometric model, define the layup groups of each region according to the design layup information, assign properties to the glass fiber / carbon fiber reinforced epoxy resin composite material, and complete the model assembly, boundary conditions (blade root fixed support) and contact definition.

[0025] Secondly, based on the aeroelastic analysis method, the load distribution of each section along the span of the wind turbine blade is determined.

[0026] The aeroelastic coupling analysis method is adopted to comprehensively consider the coupling effect of aerodynamic load inertial force and structural elastic deformation. The mechanical response of wind turbine blades under actual operating conditions is simulated and calculated to obtain the load distribution law of each section along the span of the blade.

[0027] Specifically, aeroelastic simulation software is used to obtain the dynamic response of the blade under different wind conditions. The flapping and swaying moments of each section are extracted, and the bending moment loads are converted into load parameters such as shear force and torque at the corresponding sections based on mechanical equilibrium relationships, forming a continuously distributed section load sequence along the blade span. This step obtains load inputs based on real operating conditions, avoiding calculation errors caused by simplified loads and improving the realism and accuracy of load boundary conditions.

[0028] In some embodiments of this application, aeroelastic simulation is first performed using software such as Bladed and FAST to output the flapping moment and oscillation moment of each section of the blade. Then, based on the balance relationship between force and moment, the force load of each section is obtained by inversion.

[0029] Then, the force load of each section is calculated according to the load distribution, and the force load is applied to the three-dimensional ply finite element model for nonlinear solution to obtain the strain field of the wind turbine blade structure.

[0030] The spanwise cross-sectional loads obtained from aeroelastic analysis are matched and mapped to the nodes of the finite element model according to the cross-sectional location. The cross-sectional loads are applied to the corresponding positions of the finite element model in the form of force and bending moment. Considering the large geometric deformation and nonlinear material behavior of the wind turbine blade during the stress process, this embodiment uses the nonlinear finite element method for solution calculation. By setting appropriate convergence criteria and loading strategies, the calculation results are ensured to converge stably. After the solution is completed, the relevant information of all ply elements in the three-dimensional ply finite element model is extracted. The relevant information of the ply elements mainly includes the element number, ply layer number, material properties, and strain components in the coordinate system of the three-dimensional ply finite element model. Based on the relevant information of the ply elements, a strain field that can completely reflect the deformation state of the structure is constituted. The nonlinear solution can more closely approximate the actual stress and deformation characteristics of the blade. The obtained strain field contains detailed data of the entire ply domain, providing a reliable foundation for subsequent ply-level mechanical calculations.

[0031] Then, based on the strain field and the fiber orientation angle of the composite material layup of the wind turbine blade, the strain components of each layup in the fiber coordinate system are calculated.

[0032] Based on the fiber orientation angle given in the composite material layup design, a coordinate transformation relationship is constructed from the global finite element coordinate system to the fiber coordinate system of the layup itself. Through coordinate transformation, the strain components of the global coordinate system output by the finite element model are transformed to the fiber coordinate system.

[0033] Before coordinate transformation, the positive elastic constants of the composite single-layer plate are obtained. These constants include the elastic modulus along the fiber direction, the elastic modulus perpendicular to the fiber direction, the principal Poisson's ratio, the secondary Poisson's ratio, and the in-plane shear modulus. Based on these positive elastic constants, the stiffness coefficient of the single-layer plate is calculated. The coordinate transformation matrix is ​​then determined by combining the ply angles. This coordinate transformation matrix is ​​used to perform a tensor transformation on the global strain components, obtaining the fiber-direction strain components, perpendicular-fiber-direction strain components, and in-plane shear strain components of each ply in the fiber coordinate system. This embodiment fully considers the anisotropic characteristics of composite materials, transforming the global structural response into the mechanical response of the ply itself, which conforms to the stress mechanism of composite single-layer plates and improves the accuracy of stress calculation.

[0034] In some embodiments of this application, the positive axis elastic constants (elastic modulus in the fiber direction, elastic modulus perpendicular to the fiber direction, principal Poisson's ratio, secondary Poisson's ratio, and in-plane shear modulus) of the composite single-layer plate are first obtained. The stiffness coefficient of the single-layer plate is calculated based on the positive axis elastic constants. Then, a coordinate transformation matrix is ​​constructed by combining the ply angle to complete the coordinate transformation of the strain field.

[0035] Then, based on the strain components in the fiber coordinate system and the stiffness coefficient of the composite material, the stress components along the fiber direction and the stress components perpendicular to the fiber direction of each layup are calculated.

[0036] Based on the linear elastic constitutive relationship of composite materials, the strain components in the fiber coordinate system are combined with the stiffness coefficients of the corresponding ply. The normal stress components along the fiber direction, the normal stress components perpendicular to the fiber direction, and the in-plane shear stress components of the ply are calculated using constitutive equations. The calculation process uses the single-layer plate stiffness matrix as the core, fully considering the influence of ply angles and material elastic constants on stress transmission, and performs stress calculations layer by layer and element by element. This step allows for the acquisition of the true stress of each ply in its main load-bearing direction, achieving a precise conversion from macroscopic strain of the structure to microscopic stress of the ply, providing direct and reliable stress data for failure assessment.

[0037] Finally, the fiber failure state and inter-fiber failure state of the wind turbine blade are evaluated based on the stress components along the fiber direction and the stress components perpendicular to the fiber direction.

[0038] Specifically, the PUCK failure criterion is used to determine the failure of stress components in each ply. This criterion can effectively distinguish between fiber-dominated failure modes and inter-fiber matrix-dominated failure modes, identifying failure modes such as fiber tensile failure, fiber compressive failure, and inter-fiber matrix cracking and debonding. By calculating the failure factors of each ply, the location, degree, and evolution trend of failure are determined, clarifying the weak areas and main failure mechanisms of the blade structure. This criterion enables accurate identification of composite material failure modes, closely matching the actual failure modes of wind turbine blades, and provides clear theoretical basis and data support for blade structure optimization, ply adjustment, and strength verification.

[0039] Example 2 As some embodiments of the failure analysis method for wind turbine blade composite materials in Example 1, this embodiment extracts all elements of the blade ply structure and establishes an element set E(i,j,k,o,p,q……), where i represents the element number, j represents the ply number, k represents the material property of the element, and o represents the corresponding value.

[0040] Store the element number, all layers, element type number, material number, strain in the x-direction, strain in the y-direction, and other information of all elements into the element set E(i,j,k,o,p,q…). Read in the positive axis elastic constants of the single-layer plate: fiber-direction elastic modulus E1, principal Poisson's ratio v12, secondary Poisson's ratio v21, elastic modulus perpendicular to the fiber direction E2, and in-plane shear modulus G12, and calculate the stiffness coefficients Q11, Q12, Q21, Q22, and Q66 of the single-layer plate.

[0041] The stiffness coefficients Q11, Q12, Q21, Q22, and Q66 of the single-layer plate are as follows:

[0042]

[0043]

[0044]

[0045]

[0046] In the formula, This is the elastic modulus in the fiber direction. This is the elastic modulus perpendicular to the fiber direction. The main Poisson ratio, The second Poisson ratio, This is the in-plane shear modulus.

[0047] The coordinate transformation matrix is:

[0048] in,

[0049]

[0050]

[0051]

[0052] Let the fiber layup angle be theta, then the variables are: , .

[0053] Therefore, the strain of each layer along the fiber direction and the strain perpendicular to the fiber direction are:

[0054]

[0055]

[0056] The stress along the fiber direction and the stress perpendicular to the fiber direction are respectively:

[0057]

[0058]

[0059] In the formula, The normal strain in the x-direction is given in the finite element coordinate system. Let be the normal strain in the y-direction under the finite element coordinate system. For plane shear strain in the finite element coordinate system, Let x be the normal strain along the fiber direction. This represents the normal strain perpendicular to the fiber direction. The shear strain is the fiber-perpendicular to the fiber direction.

[0060] Example 3 This embodiment provides a failure analysis system for composite materials in wind turbine blades, including: The model building module is used to create a three-dimensional layup finite element model of wind turbine blades; The load processing module is used to determine the load distribution of each section along the span of the wind turbine blade based on aeroelastic analysis methods. The strain extraction module is used to calculate the force load on each section according to the load distribution, apply the force load to the three-dimensional ply finite element model for nonlinear solution, and obtain the strain field of the wind turbine blade structure. The strain conversion module is used to calculate the strain components of each ply in the fiber coordinate system based on the strain field and the fiber orientation angle of the composite material ply of the wind turbine blade. The calculation module is used to calculate the stress components along the fiber direction and perpendicular to the fiber direction of each ply based on the strain components in the fiber coordinate system and the stiffness coefficient of the composite material. The failure assessment module is used to assess the fiber failure state and inter-fiber failure state of wind turbine blades based on the stress components along the fiber direction and the stress components perpendicular to the fiber direction.

[0061] Specific limitations regarding the failure analysis system for wind turbine blade composite materials can be found in the limitations of the failure analysis method for wind turbine blade composite materials mentioned above; the corresponding technical effects are equivalent and will not be repeated here. Each module in the aforementioned failure analysis system for wind turbine blade composite materials can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored as software in the memory of a computer device, so that the processor can call and execute the corresponding operations of each module.

[0062] Example 4 In another embodiment of the present invention, a computer-readable storage medium is provided as a storage component within a terminal device, the function of which is to store programs and data. It should be noted that the computer-readable storage medium here encompasses not only the built-in storage components of the terminal device but also extended storage components supported by the device. Essentially, it is a tangible medium capable of containing or storing programs that can be invoked by or in conjunction with an instruction execution system, device, or apparatus. This storage medium provides storage areas for the terminal's operating system and stores one or more instructions suitable for processor loading and execution, which can constitute one or more computer programs containing program code.

[0063] Specifically, examples of computer-readable storage media (a non-exclusive list) include: portable disks, hard disks, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, portable optical disc read-only memory, optical storage devices, magnetic storage devices, or any reasonable combination of the above types.

[0064] This storage medium carries readable program code. Such transmitted data signals can take many forms, including but not limited to electromagnetic signals, optical signals, or any reasonable combination of both. Furthermore, computer-readable storage medium can also refer to other readable media besides conventional readable storage media, capable of sending, propagating, or transmitting programs for use or operation by an instruction execution system, apparatus, or device. The program code on the storage medium can be transmitted via any suitable medium, including but not limited to wireless, wired, optical fiber, or any reasonable combination thereof.

[0065] The program code used to implement the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C. The execution modes of the program code include: running entirely on the user's computing device, running partially on the user's device as a standalone software package, running partially in a distributed manner on both the user's device and a remote computing device, or running entirely on a remote computing device or server. When a remote computing device is involved, the device can be connected to the user's computing device via any type of network such as a local area network (LAN) or a wide area network (WAN), or connected to an external computing device via the Internet through an Internet service provider.

[0066] The processor is capable of loading and executing one or more instructions stored in a computer-readable storage medium to implement the corresponding steps of the wind turbine blade composite material failure analysis method described in Example 1.

[0067] Example 5 Figure 3 This is a schematic diagram of a computer device provided according to an embodiment of the present invention.

[0068] Please see Figure 3 The terminal device is a computer device. In this embodiment, the computer device 60 includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the processor 61 executes the computer program 63, it implements the wind turbine blade composite material failure analysis method of this embodiment. To avoid repetition, these details are not elaborated here. Alternatively, when the processor 61 executes the computer program 63, it implements the functions of each model / unit in the computational system constituting the wind turbine blade composite material failure analysis method of this embodiment. To avoid repetition, these details are not elaborated here.

[0069] Computer device 60 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. Computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will understand that... Figure 3 This is merely an example of computer device 60 and does not constitute a limitation on computer device 60. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0070] The processor 61 may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, quantum computing-based data processing logic units, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0071] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, a Secure Digital (SD) card, a flash card, etc.

[0072] Furthermore, the memory 62 may include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0073] Any references to memory, databases, or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (Read-Only Memory). Memory includes ROM, magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0074] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

Claims

1. A method for failure analysis of composite materials for wind turbine blades, characterized in that, include: Establish a three-dimensional layup finite element model of wind turbine blades; The load distribution along the spanwise cross section of the wind turbine blade was determined using aeroelastic analysis methods. The force load of each section is calculated based on the load distribution, and the force load is applied to the three-dimensional plywood finite element model for nonlinear solution to obtain the strain field of the wind turbine blade structure. Based on the strain field and the fiber orientation angle of the composite material layup of the wind turbine blade, the strain components of each layup in the fiber coordinate system are calculated. Based on the strain components in the fiber coordinate system and the stiffness coefficient of the composite material, calculate the stress components of each layup along the fiber direction and the stress components perpendicular to the fiber direction. The fiber failure state and inter-fiber failure state of the wind turbine blade are evaluated based on the stress components along the fiber direction and the stress components perpendicular to the fiber direction.

2. The method for failure analysis of wind turbine blade composite materials according to claim 1, characterized in that, Determining the load distribution along the spanwise cross-sections of the wind turbine blade includes: Obtain the flapping moment and swaying moment of the wind turbine blade; Based on the relationship between force and moment, the force load of each section is determined using the swinging moment and the oscillation moment.

3. The method for failure analysis of wind turbine blade composite materials according to claim 1, characterized in that, The steps for obtaining the strain field of the wind turbine blade structure include: Information about all ply units in the three-dimensional ply finite element model is extracted to establish an information set about the ply units. This information set is then used as the strain field of the wind turbine blade structure. The information includes at least two of the following: unit number, ply layer number, material properties, and strain components of the material properties in the coordinate system of the three-dimensional ply finite element model.

4. The method for failure analysis of wind turbine blade composite materials according to claim 3, characterized in that, Calculate the strain components of each layer in the fiber coordinate system, including: Calculate the coordinate transformation matrix based on the fiber orientation angle of the composite material layup of the wind turbine blade; Using the coordinate transformation matrix, the strain components in the coordinate system of the three-dimensional plywood finite element model are transformed to the fiber coordinate system to obtain the strain components along the fiber direction, the strain components perpendicular to the fiber direction, and the in-plane shear strain components.

5. The method for failure analysis of composite materials for wind turbine blades according to claim 4, characterized in that, Before calculating the strain components of each layer in the fiber coordinate system, the following steps are also included: Obtain the positive axis elastic constant of a single-layer plate in a composite material; The stiffness coefficient of the corresponding single-layer plate is calculated based on the positive axis elastic constant; a coordinate transformation matrix is ​​constructed according to the stiffness coefficient of the single-layer plate and the ply angle of the composite material; the strain field is transformed based on the coordinate transformation matrix to obtain the strain components of each ply in the fiber coordinate system. The positive axis elastic constant includes the elastic modulus along the fiber direction, the elastic modulus perpendicular to the fiber direction, the principal Poisson's ratio, the secondary Poisson's ratio, and the in-plane shear modulus.

6. The method for failure analysis of composite materials for wind turbine blades according to claim 5, characterized in that, Calculate the stress components of each layup along the fiber direction and perpendicular to the fiber direction, including: Using the strain components in the fiber coordinate system and the stiffness coefficient, the normal stress in the fiber direction, the normal stress perpendicular to the fiber direction, and the in-plane shear stress are calculated through constitutive relations.

7. The method for failure analysis of composite materials for wind turbine blades according to any one of claims 1 to 6, characterized in that, The evaluation of the fiber failure state and inter-fiber failure state of the wind turbine blade includes: evaluating the stress components along the fiber direction and the stress components perpendicular to the fiber direction using the PUCK criterion to obtain the fiber failure state and inter-fiber failure state of the wind turbine blade.

8. A failure analysis system for composite materials in wind turbine blades, characterized in that, include: The model building module is used to create a three-dimensional layup finite element model of wind turbine blades; The load processing module is used to determine the load distribution of the wind turbine blade along each cross section along the span direction based on the aeroelastic analysis method. The strain extraction module is used to calculate the force load of each section according to the load distribution, apply the force load to the three-dimensional ply finite element model for nonlinear solution, and obtain the strain field of the wind turbine blade structure. The strain conversion module is used to calculate the strain components of each ply in the fiber coordinate system based on the strain field and the fiber orientation angle of the composite material ply of the wind turbine blade. The calculation module is used to calculate the stress components along the fiber direction and perpendicular to the fiber direction of each ply based on the strain components in the fiber coordinate system and the stiffness coefficient of the composite material. The failure assessment module is used to assess the fiber failure state and inter-fiber failure state of the wind turbine blade based on the stress components along the fiber direction and the stress components perpendicular to the fiber direction.

9. A computer-readable storage medium for storing one or more programs, characterized in that, The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform the wind turbine blade composite material failure analysis method according to any one of claims 1 to 7.

10. A computing device, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including steps for performing the steps in the wind turbine blade composite material failure analysis method of any one of claims 1 to 7.

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