A wind turbine blade inter-fiber failure prediction method and apparatus

Abstract

The application provides a wind turbine blade inter-fiber failure prediction method and device, which calculates transverse stress and shear stress generated by each section of a blade under the action of a limit load by using a pre-constructed blade finite element model; calculates a blade inter-fiber failure coefficient based on the transverse stress and shear stress generated by each section of the blade under the action of the limit load; and predicts the blade inter-fiber failure based on the blade inter-fiber failure coefficient. The blade inter-fiber failure coefficient is finally obtained through the blade finite element model, and the blade inter-fiber failure is predicted through the blade inter-fiber failure coefficient. The blade inter-fiber failure is predictable, the calculation time of the blade finite element model is saved, and the prediction efficiency and accuracy are improved.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, specifically to a method and device for predicting inter-fiber failure in wind turbine blades. Background Technology

[0002] Wind turbines are large-scale devices that efficiently convert wind energy into electrical energy, and the blades are the main load-bearing components of a wind turbine. Due to the harsh working environment and complex random alternating loads, the blades are prone to inter-fiber failure, which can lead to rotor and even the entire wind turbine failure and shutdown. Therefore, inter-fiber failure analysis of wind turbines is crucial. To ensure the reliable and stable operation of wind turbines, it is necessary to accurately predict inter-fiber failures in the blades.

[0003] Interfiber failure refers to cracks that penetrate the entire thickness of a single layer, parallel to the fiber direction. Interfiber failure includes matrix cracks and fiber / matrix interface cracks. Most existing technologies use the global finite element method for modeling and directly output prediction results from the model. However, the model has a huge mesh size, resulting in slow computation. Furthermore, blade design is a process of repeated modifications and iterations, and the finite element model consumes a lot of computation time and cannot respond quickly, leading to low prediction efficiency. Summary of the Invention

[0004] To overcome the shortcomings of low prediction efficiency in the prior art, the present invention provides a method for predicting inter-fiber failure in wind turbine blades, comprising:

[0005] The transverse stress and shear stress generated in each section of the blade under ultimate load were calculated using a pre-built finite element model of the blade.

[0006] The inter-fiber failure coefficient of the blade is calculated based on the transverse stress and shear stress generated in each section of the blade under ultimate load.

[0007] Inter-fiber failure of the blade is predicted based on the inter-fiber failure coefficient of the blade.

[0008] The construction of the blade finite element model includes:

[0009] A 3D model of the blade is created using 3D software, and the layup information of the blade is mapped onto the 3D model of the blade using layup software. Then, the layup file is output using layup software.

[0010] The trailing edge and tip of the blade 3D model are processed. Then, shell elements are used to mesh the processed blade 3D model. The resulting mesh is then combined and free edges are merged using finite element software to form the blade mesh model.

[0011] Import the layup file into the blade mesh model to form the blade finite element model.

[0012] The interfiber failure coefficient of the blade is calculated using the following formula:

[0013]

[0014] In the formula, f is the interfiber failure coefficient of the blade. The lateral compressive strength of the blade. R represents the transverse tensile strength of the blade. ⊥|| τ represents the longitudinal shear strength of the blade. 21 σ1 represents the shear stress generated in each section of the blade under the ultimate load, and σ2 represents the transverse stress generated in each section of the blade under the ultimate load. This refers to the tensile inclination angle parameter under longitudinal shearing. This is the compression angle parameter under longitudinal shearing. τ is the compression angle parameter under transverse shear. 21, This represents the shear stress of the blade at the inflection point. The strength of the blade at the inflection point.

[0015] The τ 21, and Calculate using the following formula:

[0016]

[0017]

[0018] The prediction of inter-fiber failure of the blade based on the inter-fiber failure coefficient includes:

[0019] Determine whether the interfiber failure coefficient of the blade is greater than or equal to 1. If it is, determine that the blade has interfiber failure; otherwise, determine that the blade has not experienced interfiber failure.

[0020] In another aspect, the present invention also provides a wind turbine blade inter-fiber failure prediction device, comprising:

[0021] The first calculation module is used to calculate the transverse stress and shear stress generated in each section of the blade under ultimate load using a pre-built finite element model of the blade.

[0022] The second calculation module is used to calculate the inter-fiber failure coefficient of the blade based on the transverse stress and shear stress generated in each cross section of the blade under ultimate load.

[0023] The prediction module is used to predict the inter-fiber failure of the blade based on the inter-fiber failure coefficient of the blade.

[0024] It also includes a modeling module, which is used for:

[0025] A 3D model of the blade is created using 3D software, and the layup information of the blade is mapped onto the 3D model of the blade using layup software. Then, the layup file is output using layup software.

[0026] The trailing edge and tip of the blade 3D model are processed. Then, shell elements are used to mesh the processed blade 3D model. The resulting mesh is then combined and free edges are merged using finite element software to form the blade mesh model.

[0027] Import the layup file into the blade mesh model to form the blade finite element model.

[0028] The second calculation module calculates the inter-fiber failure coefficient of the blade using the following formula:

[0029]

[0030] In the formula, f is the interfiber failure coefficient of the blade. The lateral compressive strength of the blade. R represents the transverse tensile strength of the blade. ⊥|| τ represents the longitudinal shear strength of the blade. 21 σ1 represents the shear stress generated in each section of the blade under the ultimate load, and σ2 represents the transverse stress generated in each section of the blade under the ultimate load. This refers to the tensile inclination angle parameter under longitudinal shearing. This is the compression angle parameter under longitudinal shearing. τ is the compression angle parameter under transverse shear. 21, This represents the shear stress of the blade at the inflection point. The strength of the blade at the inflection point.

[0031] The second calculation module calculates τ using the following formula. 21, and

[0032]

[0033]

[0034] The prediction module is specifically used for:

[0035] Determine whether the interfiber failure coefficient of the blade is greater than or equal to 1. If it is, determine that the blade has interfiber failure; otherwise, determine that the blade has not experienced interfiber failure.

[0036] The technical solution provided by this invention has the following beneficial effects:

[0037] The method for predicting inter-fiber failure of wind turbine blades provided by this invention uses a pre-constructed finite element model of the blade to calculate the transverse stress and shear stress generated in each section of the blade under ultimate load; the inter-fiber failure coefficient of the blade is calculated based on the transverse stress and shear stress generated in each section of the blade under ultimate load; the inter-fiber failure of the blade is predicted based on the inter-fiber failure coefficient of the blade; the inter-fiber failure coefficient is finally obtained through the finite element model of the blade, and the prediction of inter-fiber failure of the blade is realized through the inter-fiber failure coefficient, which saves the calculation time of the finite element model of the blade and improves the prediction efficiency.

[0038] This invention calculates the transverse and shear stresses generated in each section of the blade under ultimate load using a finite element model of the blade, and calculates the interfiber failure coefficient of the blade based on the transverse and shear stresses according to the formula. By combining the finite element model of the blade with the formula, the interfiber failure of the blade becomes predictable and the accuracy of the prediction is improved.

[0039] The calculation process for the inter-fiber failure coefficient of the blade is generalized and can be applied to the calculation of materials in different parts of the blade, such as the skin and web.

[0040] In this invention, if only the load on the blade is changed, only the ultimate load needs to be modified, and there is no need to repeat the calculation process, making the process simple. Attached Figure Description

[0041] Figure 1 This is a flowchart of the method for predicting inter-fiber failure in wind turbine blades in an embodiment of the present invention. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings.

[0043] Example 1

[0044] Embodiment 1 of the present invention provides a method for predicting inter-fiber failure in wind turbine blades, the specific flowchart of which is shown below. Figure 1 As shown, the specific process is as follows:

[0045] S101: Calculate the transverse stress and shear stress generated in each section of the blade under ultimate load using a pre-built finite element model of the blade.

[0046] S102: Calculate the interfiber failure coefficient of the blade based on the transverse stress and shear stress generated in each section of the blade under ultimate load;

[0047] S103: Predict inter-fiber failure of blades based on inter-fiber failure coefficient.

[0048] The construction of the blade finite element model in S101 above includes:

[0049] A 3D model of the blade is created using 3D software, and the layup information of the blade is mapped onto the 3D model of the blade using layup software. Then, the layup file is output using layup software.

[0050] The trailing edge and tip of the blade 3D model are processed. Then, shell elements are used to mesh the processed blade 3D model. The resulting mesh is then combined and free edges are merged using finite element software to form the blade mesh model.

[0051] Import the layup file into the blade mesh model to form the blade finite element model.

[0052] In S101 above, the ultimate load of the blade is calculated using load calculation software.

[0053] In S102 above, considering the combined effects of stress perpendicular to the fiber direction and shear stress on the inter-fiber failure coefficient, the inter-fiber failure coefficient of the blade is calculated using the following formula:

[0054]

[0055] In the formula, f is the interfiber failure coefficient of the blade. The lateral compressive strength of the blade. R represents the transverse tensile strength of the blade. ⊥|| τ represents the longitudinal shear strength of the blade. 21 σ1 represents the shear stress generated in each section of the blade under the ultimate load, and σ2 represents the transverse stress generated in each section of the blade under the ultimate load. This refers to the tensile inclination angle parameter under longitudinal shearing. This is the compression angle parameter under longitudinal shearing. τ is the compression angle parameter under transverse shear. 21, This represents the shear stress of the blade at the inflection point. Let τ be the blade strength at the inflection point. 21, and Calculate using the following formula:

[0056]

[0057]

[0058] Embodiment 1 of this invention classifies the failure modes between fibers into the following three modes: 1) Mode A: mainly transverse tension accompanied by shear; 2) Mode B: mainly shear accompanied by transverse compression; 3) Mode C: mainly transverse compression accompanied by shear. When the failure mode between the fibers of the blade is Mode A, σ2≥0, and the following is adopted. Calculate the inter-fiber failure factor of the blade. When the inter-fiber failure mode of the blade is mode B, σ² < 0 and Using f = σ² < 0 and Calculate the inter-fiber failure factor of the blade. When the inter-fiber failure mode of the blade is mode C, σ² < 0 and use Calculate the interfiber failure coefficient of the blade.

[0059] In S103 above, inter-fiber failure of the blade is predicted based on the inter-fiber failure coefficient. Specifically, it is determined whether the inter-fiber failure coefficient is greater than or equal to 1. If so, inter-fiber failure is determined to have occurred; otherwise, it is determined that no inter-fiber failure has occurred. The inter-fiber failure coefficient, also known as the safety factor, is the ratio of the actual stress to the allowable stress of the blade. When the actual stress is greater than the allowable stress, i.e., the ratio of the actual stress to the allowable stress is greater than 1, the blade structure will change, i.e., inter-fiber failure has occurred. When the actual stress is less than or equal to the allowable stress, i.e., the ratio of the actual stress to the allowable stress is less than or equal to 1, the blade structure will not change, i.e., no inter-fiber failure has occurred.

[0060] Example 2

[0061] Based on the same inventive concept, Embodiment 2 of the present invention also provides a wind turbine blade fiber failure prediction device, including a first calculation module, a second calculation module, and a prediction module. The functions of each component are described in detail below:

[0062] The first calculation module is used to calculate the transverse stress and shear stress generated in each section of the blade under ultimate load using a pre-built finite element model of the blade.

[0063] The second calculation module is used to calculate the inter-fiber failure coefficient of the blade based on the transverse stress and shear stress generated in each section of the blade under ultimate load.

[0064] The prediction module is used to predict inter-fiber failure of blades based on the inter-fiber failure coefficient.

[0065] The wind turbine blade fiber failure prediction device provided in Embodiment 2 of the present invention further includes a modeling module, which is used for:

[0066] A 3D model of the blade is created using 3D software, and the layup information of the blade is mapped onto the 3D model of the blade using layup software. Then, the layup file is output using layup software.

[0067] The trailing edge and tip of the blade 3D model are processed. Then, shell elements are used to mesh the processed blade 3D model. The resulting mesh is then combined and free edges are merged using finite element software to form the blade mesh model.

[0068] Import the layup file into the blade mesh model to form the blade finite element model.

[0069] The second calculation module calculates the inter-fiber failure coefficient of the blade using the following formula:

[0070]

[0071] In the formula, f is the interfiber failure coefficient of the blade. The lateral compressive strength of the blade. R represents the transverse tensile strength of the blade. ⊥|| τ represents the longitudinal shear strength of the blade. 21 σ1 represents the shear stress generated in each section of the blade under the ultimate load, and σ2 represents the transverse stress generated in each section of the blade under the ultimate load. This refers to the tensile inclination angle parameter under longitudinal shearing. This is the compression angle parameter under longitudinal shearing. τ is the compression angle parameter under transverse shear. 21, This represents the shear stress of the blade at the inflection point. The strength of the blade at the inflection point.

[0072] The second calculation module calculates τ using the following formula. 21, and

[0073]

[0074]

[0075] The prediction module is specifically used for:

[0076] The system determines whether the inter-fiber failure factor of the blade is greater than or equal to 1. If it is, inter-fiber failure is determined; otherwise, it is determined that no inter-fiber failure has occurred. The inter-fiber failure factor, also known as the safety factor, is the ratio of the actual stress to the allowable stress of the blade. When the actual stress is greater than the allowable stress (i.e., the ratio is greater than 1), the blade structure will change, indicating inter-fiber failure. When the actual stress is less than or equal to the allowable stress (i.e., the ratio is less than or equal to 1), the blade structure will not change, indicating no inter-fiber failure has occurred. For ease of description, the various parts of the above device are described separately as functional modules or units. Of course, in implementing this application, the functions of each module or unit can be implemented in one or more software or hardware components.

[0077] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0078] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0079] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0080] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Those skilled in the art can still make modifications or equivalent substitutions to the specific implementation of the present invention by referring to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the present invention pending approval.

Claims

1. A method for predicting inter-fiber failure in wind turbine blades, characterized in that, include: The transverse stress and shear stress generated in each section of the blade under ultimate load were calculated using a pre-built finite element model of the blade. The inter-fiber failure coefficient of the blade is calculated based on the transverse stress and shear stress generated in each section of the blade under ultimate load. Inter-fiber failure of the blade is predicted based on the inter-fiber failure coefficient of the blade. The interfiber failure coefficient of the blade is calculated using the following formula: （1） In the formula, The interfiber failure factor of the blade is denoted as . The lateral compressive strength of the blade. This represents the transverse tensile strength of the blade. The longitudinal shear strength of the blade. This refers to the shear stress generated in each section of the blade under ultimate load. This refers to the transverse stress generated in each section of the blade under ultimate load. This refers to the tensile inclination angle parameter under longitudinal shearing. This is the compression angle parameter under longitudinal shearing. This is the compression tilt angle parameter under transverse shear action. This represents the shear stress of the blade at the inflection point. The strength of the blade at the inflection point; The and Calculate using the following formula: （2） （3）。 2. The method for predicting inter-fiber failure in wind turbine blades according to claim 1, characterized in that, The construction of the blade finite element model includes: A 3D model of the blade is created using 3D software, and the layup information of the blade is mapped onto the 3D model of the blade using layup software. Then, the layup file is output using layup software. The trailing edge and tip of the blade 3D model are processed. Then, shell elements are used to mesh the processed blade 3D model. The resulting mesh is then combined and free edges are merged using finite element software to form the blade mesh model. Import the layup file into the blade mesh model to form the blade finite element model.

3. The method for predicting inter-fiber failure in wind turbine blades according to claim 1, characterized in that, The prediction of inter-fiber failure of the blade based on the inter-fiber failure coefficient includes: Determine whether the interfiber failure coefficient of the blade is greater than or equal to 1. If it is, determine that the blade has interfiber failure; otherwise, determine that the blade has not experienced interfiber failure.

4. A device for predicting inter-fiber failure in wind turbine blades, characterized in that, include: The first calculation module is used to calculate the transverse stress and shear stress generated in each section of the blade under ultimate load using a pre-built finite element model of the blade. The second calculation module is used to calculate the inter-fiber failure coefficient of the blade based on the transverse stress and shear stress generated in each cross section of the blade under ultimate load. The prediction module is used to predict the inter-fiber failure of the blade based on the inter-fiber failure coefficient of the blade. The second calculation module calculates the inter-fiber failure coefficient of the blade using the following formula: （1） In the formula, The interfiber failure factor of the blade is denoted as . The lateral compressive strength of the blade. This represents the transverse tensile strength of the blade. The longitudinal shear strength of the blade. This refers to the shear stress generated in each section of the blade under ultimate load. This refers to the transverse stress generated in each section of the blade under ultimate load. This refers to the tensile inclination angle parameter under longitudinal shearing. This is the compression angle parameter under longitudinal shearing. This is the compression tilt angle parameter under transverse shear action. This represents the shear stress of the blade at the inflection point. The strength of the blade at the inflection point; The second calculation module calculates according to the following formula. and : （2） （3）。 5. The wind turbine blade inter-fiber failure prediction device according to claim 4, characterized in that, It also includes a modeling module, which is used for: A 3D model of the blade is created using 3D software, and the layup information of the blade is mapped onto the 3D model of the blade using layup software. Then, the layup file is output using layup software. The trailing edge and tip of the blade 3D model are processed. Then, shell elements are used to mesh the processed blade 3D model. The resulting mesh is then combined and free edges are merged using finite element software to form the blade mesh model. Import the layup file into the blade mesh model to form the blade finite element model.

6. The wind turbine blade inter-fiber failure prediction device according to claim 4, characterized in that, The prediction module is specifically used for: Determine whether the interfiber failure coefficient of the blade is greater than or equal to 1. If it is, determine that the blade has interfiber failure; otherwise, determine that the blade has not experienced interfiber failure.

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