Method and system for determining blade extension bonding shear stress based on finite element model

Abstract

The invention discloses a method and system for determining blade extension bonding shear stress based on a finite element model, and belongs to the technical field of new energy. The method comprises the following steps: acquiring three-dimensional layering structure characteristic data of a blade to be analyzed, and constructing a blade finite element shell model containing a blade tip extension bonding section; a corresponding design load is applied to the finite element shell model, and mechanical response data of the blade structure are obtained through structural mechanical analysis and solution; obtaining an in-plane positive axis elastic constant of a single-layer plate of the to-be-analyzed blade, and calculating an elastic constant of the single-layer plate based on the in-plane elastic parameter; the normal stress of the target laying layer in each shell unit in the blade spanwise direction is obtained through calculation; the thickness of the target laying layers is obtained, the product of the normal stress and the thickness of each target laying layer in the blade spanwise direction is calculated, and the products of all the target laying layers in the same shell unit are accumulated to obtain the unit total force; and calculating the shear stress of the bonding layer based on the unit total force and the spanwise length of the blade tip extension bonding section.

Description

Technical Field

[0001] This invention belongs to the field of new energy technology and relates to a method and system for determining the shear stress of blade extension bonding based on a finite element model. Background Technology

[0002] Against the backdrop of the rapid development of the wind power industry, improving the power generation efficiency of wind turbine generators and expanding their applicable wind conditions have become core demands for technological upgrades in the industry. As the core component for capturing wind energy, the aerodynamic performance of wind turbine blades directly determines the power generation efficiency of the unit. Blade tip extension technology, by increasing blade span, can effectively increase the wind energy capture area, thereby improving the unit's power output. It has become an important technical means for upgrading and retrofitting old wind farms and optimizing the performance of new units. The reliability of the connection between the blade tip extension structure and the original blade is the key to the application of this technology. Currently, the mainstream method in the industry is to use adhesive bonding to achieve the connection. The shear stress distribution on the bonding surface directly determines the connection strength and service life of the blade tip extension structure. If the shear stress distribution on the bonding surface is uneven or the local stress concentration exceeds the allowable strength of the adhesive material, it can easily lead to bonding failure and serious safety accidents such as blade tip structure detachment. Therefore, accurately obtaining the shear stress distribution on the bonding surface of the blade tip extension is a prerequisite for assessing the bonding strength and ensuring the safe and reliable operation of the blade tip extension structure.

[0003] In existing technologies, the calculation of shear stress at the tip extension bonding surface mainly relies on solid modeling. Specifically, a complete three-dimensional solid model of the original blade, the tip extension, and the bonding layer must first be established. Then, meshing, boundary conditions are applied, and loads are applied. Finally, the shear stress distribution is obtained through finite element software. However, this method has significant technical drawbacks: firstly, wind turbine blades have complex structures, including intricate aerodynamic shapes, sandwich structures, and reinforcement areas. Establishing a complete solid model requires a significant amount of time and effort, resulting in extremely low modeling efficiency. Secondly, meshing a complete solid model is difficult, requiring fine meshes to ensure computational accuracy. This leads to a very high degree of model freedom, consumes substantial computational resources, and has a long computation cycle. This makes it difficult to meet the needs of rapid assessment of tip extension bonding strength in engineering practice, and is particularly unsuitable for rapid scheme verification and multi-scheme comparison during wind farm on-site modification. In addition, existing solid modeling and analysis methods place extremely high demands on the professional skills of operators. Operators need to have both proficient 3D modeling skills and extensive experience in finite element analysis. Otherwise, the calculation results may be distorted due to deviations in modeling details or improper setting of boundary conditions, which may further affect the accuracy of the bond strength assessment. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of low calculation efficiency and low accuracy of shear stress on the blade tip extension bonding surface in the prior art, and to provide a method and system for determining the blade extension bonding shear stress based on the finite element model.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention discloses a method for determining the extended bonding shear stress of a blade based on a finite element model, comprising: The three-dimensional ply structure feature data of the blade to be analyzed is obtained, and a finite element shell model of the blade including the tip extension bonding segment is constructed; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding segment; The corresponding design load is applied to the finite element shell model, and the mechanical response data of the blade structure is obtained by structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; Obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters; Based on the elastic constant of the single-layer plate and the spanwise and axial strain of each shell unit, the normal stress of the target layup along the blade spanwise in each shell unit is calculated. The thickness of the target ply is obtained, the product of the normal stress of each target ply along the blade span and the thickness is calculated, and the total force of the unit is obtained by summing the products of all target plies in the same shell unit. Based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip, the shear stress of the adhesive layer is calculated.

[0006] Further improvements are made in the following aspects: Also includes: Obtain the shear strength parameters and preset safety factor of the bonding material used for tip extension; Based on the shear stress, the shear strength parameters of the bonding material, and the preset safety factor, determine whether the tip extension bonding strength meets the design requirements.

[0007] The specific steps for constructing the finite element shell model of the blade, including the extended adhesive section at the blade tip, are as follows: Shell elements are used to discretize the three-dimensional layup structure of the blade to be analyzed. The mesh density of the shell elements in the blade tip extension bonding region is greater than that in other regions of the blade. The shell elements are quadrilateral shell elements or triangular shell elements, and the element thickness is determined according to the total layup thickness at the corresponding position of the blade.

[0008] The design loads include aerodynamic loads, gravity loads, centrifugal loads, and temperature loads; the structural mechanics analysis is a nonlinear structural analysis, and the interface contact nonlinearity of the adhesive layer is considered during the analysis; when applying the design loads, the finite element shell model is bounded by a constraint method consistent with the actual installation posture of the blade.

[0009] Obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed. The elastic constant of the single-layer plate is calculated based on the in-plane elastic parameters as follows: Q11 = E1 / (1 - v12 × v12 × E2 / E1) Q12=v12×E2 / (1-v12×v12×E2 / E1) Among them, E1, E2 and v12 represent the in-plane positive axis elastic constants of the single-layer plate, which are obtained through experimental testing or material handbook. After obtaining them, the validity of the parameters is verified and abnormal data is removed; Q11 and Q12 represent the elastic constants of the single-layer plate.

[0010] The specific normal stress along the blade spanwise of the target layup in each shell unit is calculated by combining the elastic constant of the single-layer plate, the spanwise strain and the axial strain of each shell unit: The target layup is a layup within the shell unit that is in direct contact with the adhesive layer; the normal stress along the blade spanwise is calculated using the following formula: sigx = e_strx × Q11 + e_stry × Q12 Where e_strx represents the spanwise strain of the shell element in the tip bonding region; e_stry represents the axial strain of the shell element in the tip bonding region. The thickness of the target ply is obtained, and the product of the normal stress along the blade span and the thickness of each target ply is calculated. The total force of the unit is obtained by summing the products of all target plies within the same shell unit. F=sigx×t Fb=ΣF Where t represents the thickness of this layer in the extraction unit; F represents the product of stress and thickness of a single layer; The calculated shear stress of the adhesive layer is Fb / L, where L represents the spanwise length of the blade tip adhesive segment.

[0011] The preset safety factor is sf=(Fb / L) / (τ / rm). When sf≥1, the bonding strength meets the requirements, and when sf<1, the bonding strength does not meet the requirements.

[0012] Secondly, this invention discloses a system for determining the shear stress of blade extension bonding based on a finite element model, comprising: The blade finite element shell model construction module is used to acquire the three-dimensional ply structure feature data of the blade to be analyzed and construct a blade finite element shell model including the tip extension bonding segment; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding segment; The mechanical analysis module is used to apply the corresponding design load to the finite element shell model and obtain the mechanical response data of the blade structure through structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; The single-layer plate mechanical analysis module is used to obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and to calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters. The target layup mechanical analysis module is used to calculate the normal stress along the blade spanwise of the target layup in each shell unit by combining the elastic constant of the single plate and the spanwise and axial strain of each shell unit. The unit total force calculation module is used to obtain the thickness of the target ply, calculate the product of the normal stress of each target ply along the blade span and the thickness, and accumulate the products of all target plies in the same shell unit to obtain the unit total force. The shear stress calculation module is used to calculate the shear stress of the adhesive layer based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip.

[0013] Thirdly, the present invention discloses an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method for determining the blade extension bonding shear stress based on a finite element model.

[0014] Fourthly, the present invention discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for determining the blade extension bonding shear stress based on a finite element model.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for determining the shear stress of the blade tip extension bonding section based on a finite element model. Through precise optimization of the technical process and parameter correlation design, it significantly improves the efficiency and reliability of blade tip extension bonding shear stress calculation compared to existing technologies, while also enhancing its adaptability to engineering applications. First, it greatly simplifies the modeling and calculation process, significantly improving computational efficiency. This invention constructs a finite element shell model by acquiring the three-dimensional layup structure feature data of the blade to be analyzed, instead of using the complex solid modeling method of existing technologies. Combined with the adaptability of shell elements to the thin-walled structure of blades, it significantly reduces the difficulty and time consumption of model construction. Simultaneously, the three-dimensional layup structure feature data already includes the spanwise length of the blade tip extension bonding section, eliminating the need for subsequent separate measurement or supplementary input of this core parameter. This achieves parameter correlation and reuse between modeling and subsequent shear stress calculation, effectively avoiding the cumbersome process caused by scattered parameter acquisition and multiple inputs in existing technologies. It significantly shortens the overall cycle from modeling to stress calculation, enabling rapid response to the timeliness requirements for blade tip extension bonding strength assessment in engineering practice. Second, it ensures the accuracy of shear stress calculation and improves the reliability of bonding strength assessment. This invention directly obtains the spanwise and axial strain of each shell element within the extended bonding region of the blade tip through structural mechanics analysis. Subsequent stress calculations are then performed based on these shell elements, accurately capturing the local mechanical response of the bonding region. Simultaneously, the elastic constants are calculated based on the in-plane positive axis elastic constant of the single-layer plate. The total force of the element is then obtained by multiplying and summing the normal stress and thickness of the target layup, ultimately deriving the shear stress of the bonding layer. This calculation logic completely reconstructs the force transmission path of the blade layup structure, avoiding the stress calculation distortion caused by simplified equivalent treatments in existing technologies. Furthermore, the discretized design of the shell elements can specifically optimize the mesh density of the bonding region, further improving the accuracy of strain extraction and stress calculation. This provides a reliable data analysis basis for bond strength assessment and effectively reduces the risk of bond failure due to stress calculation errors. Thirdly, it enhances engineering application adaptability and lowers the technical implementation threshold. The technical process of this invention closely aligns with the engineering realities of blade design and modification. The acquisition of three-dimensional ply structure characteristic data can be directly integrated with blade design drawings or measured data of existing blades. The application of design loads can match the stress requirements of blades under different operating conditions, without relying on complex dedicated experimental equipment or extreme operating condition simulation environments. At the same time, the entire calculation process revolves around a finite element shell model, which requires less computational resources and has more reasonable requirements for the professional skills of operators compared to solid model analysis. This facilitates its application in various engineering scenarios such as wind farm modification and new blade design verification. It is particularly suitable for multi-scheme comparison and screening and rapid on-site evaluation, providing efficient and feasible technical support for the safe application of blade tip extension technology. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a method for determining the blade extension bonding shear stress based on a finite element model, as described in an embodiment of the present invention. Figure 2 This is a block diagram of a system for determining the shear stress of blade extension bonding based on a finite element model, according to an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 This invention discloses a method for determining the extended bonding shear stress of a blade based on a finite element model, comprising: S1, acquire the three-dimensional ply structure feature data of the blade to be analyzed, and construct a finite element shell model of the blade including the tip extension bonding section; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding section; S2, apply the corresponding design load to the finite element shell model, and obtain the mechanical response data of the blade structure through structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding area; S3, obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters; S4. Combining the elastic constant of the single-layer plate with the spanwise and axial strain of each shell unit, the normal stress of the target layup along the blade spanwise in each shell unit is calculated. S5, obtain the thickness of the target ply, calculate the product of the normal stress of each target ply along the blade span and the thickness, and sum the products of all target plies in the same shell unit to obtain the total unit force; S6. Based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip, the shear stress of the adhesive layer is calculated.

[0022] This invention discloses a method for determining the shear stress of the blade tip extension bonding section based on a finite element model. Through precise optimization of the technical process and parameter correlation design, it significantly improves the efficiency and reliability of blade tip extension bonding shear stress calculation compared to existing technologies, while also enhancing its adaptability to engineering applications. First, it greatly simplifies the modeling and calculation process, significantly improving computational efficiency. This invention constructs a finite element shell model by acquiring the three-dimensional layup structure feature data of the blade to be analyzed, instead of using the complex solid modeling method of existing technologies. Combined with the adaptability of shell elements to the thin-walled structure of blades, it significantly reduces the difficulty and time consumption of model construction. Simultaneously, the three-dimensional layup structure feature data already includes the spanwise length of the blade tip extension bonding section, eliminating the need for subsequent separate measurement or supplementary input of this core parameter. This achieves parameter correlation and reuse between modeling and subsequent shear stress calculation, effectively avoiding the cumbersome process caused by scattered parameter acquisition and multiple inputs in existing technologies. It significantly shortens the overall cycle from modeling to stress calculation, enabling rapid response to the timeliness requirements for blade tip extension bonding strength assessment in engineering practice. Second, it ensures the accuracy of shear stress calculation and improves the reliability of bonding strength assessment. This invention directly obtains the spanwise and axial strain of each shell element within the extended bonding region of the blade tip through structural mechanics analysis. Subsequent stress calculations are then performed based on these shell elements, accurately capturing the local mechanical response of the bonding region. Simultaneously, the elastic constants are calculated based on the in-plane positive axis elastic constant of the single-layer plate. The total force of the element is then obtained by multiplying and summing the normal stress and thickness of the target layup, ultimately deriving the shear stress of the bonding layer. This calculation logic completely reconstructs the force transmission path of the blade layup structure, avoiding the stress calculation distortion caused by simplified equivalent treatments in existing technologies. Furthermore, the discretized design of the shell elements can specifically optimize the mesh density of the bonding region, further improving the accuracy of strain extraction and stress calculation. This provides a reliable data analysis basis for bond strength assessment and effectively reduces the risk of bond failure due to stress calculation errors. Thirdly, it enhances engineering application adaptability and lowers the technical implementation threshold. The technical process of this invention closely aligns with the engineering realities of blade design and modification. The acquisition of three-dimensional ply structure characteristic data can be directly integrated with blade design drawings or measured data of existing blades. The application of design loads can match the stress requirements of blades under different operating conditions, without relying on complex dedicated experimental equipment or extreme operating condition simulation environments. At the same time, the entire calculation process revolves around a finite element shell model, which requires less computational resources and has more reasonable requirements for the professional skills of operators compared to solid model analysis. This facilitates its application in various engineering scenarios such as wind farm modification and new blade design verification. It is particularly suitable for multi-scheme comparison and screening and rapid on-site evaluation, providing efficient and feasible technical support for the safe application of blade tip extension technology.

[0023] The present invention will be further described below with reference to specific embodiments: Example 1 Step 1: Obtain the three-dimensional layup structure feature data of the blade to be analyzed, and construct a finite element shell model of the blade including the tip extension bonding section; the three-dimensional layup structure feature data includes the spanwise length of the tip extension bonding section. The specific steps for constructing the finite element shell model of the blade, including the extended adhesive section at the blade tip, are as follows: Shell elements are used to discretize the three-dimensional layup structure of the blade to be analyzed. The mesh density of the shell elements in the blade tip extension bonding region is greater than that in other regions of the blade. The shell elements are quadrilateral shell elements or triangular shell elements, and the element thickness is determined according to the total layup thickness at the corresponding position of the blade.

[0024] Step 2: Apply the corresponding design load to the finite element shell model, and obtain the mechanical response data of the blade structure through structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; The design loads include aerodynamic loads, gravity loads, centrifugal loads, and temperature loads; the structural mechanics analysis is a nonlinear structural analysis, and the interface contact nonlinearity of the adhesive layer is considered during the analysis; when applying the design loads, the finite element shell model is bounded by a constraint method consistent with the actual installation posture of the blade.

[0025] Step 3: Obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters. Q11 = E1 / (1 - v12 × v12 × E2 / E1) Q12=v12×E2 / (1-v12×v12×E2 / E1) Among them, E1, E2 and v12 represent the in-plane positive axis elastic constants of the single-layer plate, which are obtained through experimental testing or material handbook consultation. After obtaining them, the validity of the parameters is verified and abnormal data is removed; Q11 and Q12 represent the elastic constants of the single-layer plate.

[0026] Step 5: Based on the elastic constant of the single-layer plate and the spanwise and axial strain of each shell unit, calculate the normal stress of the target layup along the blade spanwise in each shell unit. The target layup is a layup within the shell unit that is in direct contact with the adhesive layer; the normal stress along the blade spanwise is calculated using the following formula: sigx = e_strx × Q11 + e_stry × Q12 Where e_strx represents the spanwise strain of the shell element in the tip bonding region; e_stry represents the axial strain of the shell element in the tip bonding region. Step 6: Obtain the thickness of the target ply, calculate the product of the normal stress of each target ply along the blade span and the thickness, and sum the products of all target plies in the same shell unit to obtain the total unit force. F=sigx×t Fb=ΣF Where t represents the thickness of this layer in the extraction unit; F represents the product of stress and thickness of a single layer; Step 7: Based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip, calculate the shear stress of the adhesive layer. The calculated shear stress of the adhesive layer is Fb / L, where L represents the spanwise length of the adhesive section at the blade tip.

[0027] Step 8: Obtain the shear strength parameters and preset safety factor of the adhesive material used for tip extension; Based on the shear stress, the shear strength parameters of the bonding material, and the preset safety factor, determine whether the tip extension bonding strength meets the design requirements.

[0028] The preset safety factor is sf=(Fb / L) / (τ / rm). When sf≥1, the bonding strength meets the requirements, and when sf<1, the bonding strength does not meet the requirements.

[0029] Example 2 This embodiment discloses a method for determining the extended bonding shear stress of a blade based on a finite element model, including: 1) Based on the three-dimensional layup and structure of wind turbine blades, a finite element shell model of the wind turbine blade including the tip bonding section was established using finite element software.

[0030] 2) Apply the corresponding design load to the finite element model, use nonlinear structural calculation, and solve to obtain the result of the blade finite element model; 3) Read in the in-plane positive axis elastic constants E1, v12 and E2 of the single-layer plate material, and calculate the elastic constants Q11 and Q12 of the single-layer plate.

[0031] 4) Read in the shear strength τ of the adhesive and the corresponding safety factor rm Q11 = E1 / (1 - v12 * v12 * E2 / E1) Q12 = v12 * E2 / (1 - V12 * v12 * E2 / E1) 5) Extract the spanwise strain e_strx and axial strain e_stry of the shell element in the tip bonding region. 6) Calculate the stress along the blade span of a certain layer in the calculation unit.

[0032] sigx = e_strx * Q11 + e_stry * Q12 7) Extract the thickness t of this layer in the unit. 8) By iterating through all layers of the element and multiplying the stress and thickness product F, and summing them.

[0033] F=sigx*t Fb=ΣF 9) Calculate the shear stress of the adhesive layer. The spanwise length of the blade tip bonding section is L, and the shear stress is Fb / L.

[0034] 10) Determine whether the shear stress meets the requirements. The bonding safety factor is sf=(Fb / L) / (τ / rm). When sf≥1, the bonding strength meets the requirements, and when sf<1, the bonding strength does not meet the requirements.

[0035] See Figure 2 This invention discloses a system for determining the adhesion shear stress of a blade extension based on a finite element model, comprising: The blade finite element shell model construction module is used to acquire the three-dimensional ply structure feature data of the blade to be analyzed and construct a blade finite element shell model including the tip extension bonding segment; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding segment; The mechanical analysis module is used to apply the corresponding design load to the finite element shell model and obtain the mechanical response data of the blade structure through structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; The single-layer plate mechanical analysis module is used to obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and to calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters. The target layup mechanical analysis module is used to calculate the normal stress along the blade spanwise of the target layup in each shell unit by combining the elastic constant of the single plate and the spanwise and axial strain of each shell unit. The unit total force calculation module is used to obtain the thickness of the target ply, calculate the product of the normal stress of each target ply along the blade span and the thickness, and accumulate the products of all target plies in the same shell unit to obtain the unit total force. The shear stress calculation module is used to calculate the shear stress of the adhesive layer based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip.

[0036] A third objective of this invention is to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method for determining the blade extension bonding shear stress based on a finite element model.

[0037] The method for determining the blade extension bonding shear stress based on the finite element model includes the following steps: The three-dimensional ply structure feature data of the blade to be analyzed is obtained, and a finite element shell model of the blade including the tip extension bonding segment is constructed; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding segment; The corresponding design load is applied to the finite element shell model, and the mechanical response data of the blade structure is obtained by structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; Obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters; Based on the elastic constant of the single-layer plate and the spanwise and axial strain of each shell unit, the normal stress of the target layup along the blade spanwise in each shell unit is calculated. The thickness of the target ply is obtained, the product of the normal stress of each target ply along the blade span and the thickness is calculated, and the total force of the unit is obtained by summing the products of all target plies in the same shell unit. Based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip, the shear stress of the adhesive layer is calculated.

[0038] A fourth objective of this invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for determining the blade extension bonding shear stress based on a finite element model.

[0039] The method for determining the blade extension bonding shear stress based on the finite element model includes the following steps: The three-dimensional ply structure feature data of the blade to be analyzed is obtained, and a finite element shell model of the blade including the tip extension bonding segment is constructed; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding segment; The corresponding design load is applied to the finite element shell model, and the mechanical response data of the blade structure is obtained by structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; Obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters; Based on the elastic constant of the single-layer plate and the spanwise and axial strain of each shell unit, the normal stress of the target layup along the blade spanwise in each shell unit is calculated. The thickness of the target ply is obtained, the product of the normal stress of each target ply along the blade span and the thickness is calculated, and the total force of the unit is obtained by summing the products of all target plies in the same shell unit. Based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip, the shear stress of the adhesive layer is calculated.

[0040] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention 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.

[0041] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0042] 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.

[0043] 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.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the shear stress of blade extension bonding based on a finite element model, characterized in that, include: The three-dimensional ply structure feature data of the blade to be analyzed is obtained, and a finite element shell model of the blade including the tip extension bonding segment is constructed; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding segment; The corresponding design load is applied to the finite element shell model, and the mechanical response data of the blade structure is obtained by structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; Obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters; Based on the elastic constant of the single-layer plate and the spanwise and axial strain of each shell unit, the normal stress of the target layup along the blade spanwise in each shell unit is calculated. The thickness of the target ply is obtained, the product of the normal stress of each target ply along the blade span and the thickness is calculated, and the total force of the unit is obtained by summing the products of all target plies in the same shell unit. Based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip, the shear stress of the adhesive layer is calculated.

2. The method for determining the blade extension bonding shear stress based on the finite element model according to claim 1, characterized in that, Also includes: Obtain the shear strength parameters and preset safety factor of the bonding material used for tip extension; Based on the shear stress, the shear strength parameters of the bonding material, and the preset safety factor, determine whether the tip extension bonding strength meets the design requirements.

3. The method for determining the blade extension bonding shear stress based on the finite element model according to claim 2, characterized in that, The specific steps for constructing the finite element shell model of the blade, including the extended adhesive section at the blade tip, are as follows: Shell elements are used to discretize the three-dimensional layup structure of the blade to be analyzed. The mesh density of the shell elements in the blade tip extension bonding region is greater than that in other regions of the blade. The shell elements are quadrilateral shell elements or triangular shell elements, and the element thickness is determined according to the total layup thickness at the corresponding position of the blade.

4. The method for determining the blade extension bonding shear stress based on the finite element model according to claim 2, characterized in that, The design loads include aerodynamic loads, gravity loads, centrifugal loads, and temperature loads; the structural mechanics analysis is a nonlinear structural analysis, and the nonlinear characteristics of the interface contact of the adhesive layer are considered during the analysis. When applying the design load, the finite element shell model is bounded using a constraint method consistent with the actual installation posture of the blade.

5. The method for determining the blade extension bonding shear stress based on the finite element model according to claim 2, characterized in that, Obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed. The elastic constant of the single-layer plate is calculated based on the in-plane elastic parameters as follows: Q11 = E1 / (1 - v12 × v12 × E2 / E1) Q12=v12×E2 / (1-v12×v12×E2 / E1) Among them, E1, E2 and v12 represent the in-plane positive axis elastic constants of the single-layer plate, which are obtained through experimental testing or material handbook. After obtaining them, the validity of the parameters is verified and abnormal data is removed; Q11 and Q12 represent the elastic constants of the single-layer plate.

6. The method for determining the blade elongation bonding shear stress based on the finite element model according to claim 5, characterized in that, The specific normal stress along the blade spanwise of the target layup in each shell unit is calculated by combining the elastic constant of the single-layer plate, the spanwise strain and the axial strain of each shell unit: The target layup is a layup within the shell unit that is in direct contact with the adhesive layer; the normal stress along the blade spanwise is calculated using the following formula: sigx = e_strx × Q11 + e_stry × Q12 Where e_strx represents the spanwise strain of the shell element in the tip bonding region; e_stry represents the axial strain of the shell element in the tip bonding region. The thickness of the target ply is obtained, and the product of the normal stress along the blade span and the thickness of each target ply is calculated. The total force of the unit is obtained by summing the products of all target plies within the same shell unit. F=sigx×t Fb=ΣF Where t represents the thickness of this layer in the extraction unit; F represents the product of stress and thickness of a single layer; The calculated shear stress of the adhesive layer is Fb / L, where L represents the spanwise length of the blade tip adhesive segment.

7. The method for determining the blade extension bonding shear stress based on the finite element model according to claim 2, characterized in that, The preset safety factor is sf=(Fb / L) / (τ / rm). When sf≥1, the bonding strength meets the requirements, and when sf<1, the bonding strength does not meet the requirements.

8. A system for determining the shear stress of blade extension bonding based on a finite element model, characterized in that, include: The blade finite element shell model construction module is used to acquire the three-dimensional ply structure feature data of the blade to be analyzed and construct a blade finite element shell model including the tip extension bonding segment; the three-dimensional ply structure feature data includes the spanwise length of the tip extension bonding segment; The mechanical analysis module is used to apply the corresponding design load to the finite element shell model and obtain the mechanical response data of the blade structure through structural mechanics analysis; the mechanical response data includes the spanwise strain and axial strain of each shell element in the blade tip extension bonding region; The single-layer plate mechanical analysis module is used to obtain the in-plane positive axis elastic constant of the single-layer plate of the blade to be analyzed, and to calculate the elastic constant of the single-layer plate based on the in-plane elastic parameters. The target layup mechanical analysis module is used to calculate the normal stress along the blade spanwise of the target layup in each shell unit by combining the elastic constant of the single plate and the spanwise and axial strain of each shell unit. The unit total force calculation module is used to obtain the thickness of the target ply, calculate the product of the normal stress of each target ply along the blade span and the thickness, and accumulate the products of all target plies in the same shell unit to obtain the unit total force. The shear stress calculation module is used to calculate the shear stress of the adhesive layer based on the total force of the unit and the spanwise length of the extended adhesive section at the blade tip.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method for determining blade extension bonding shear stress based on a finite element model as described in any one of claims 1-7.

10. A computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for determining the blade extension bonding shear stress based on a finite element model according to any one of claims 1-7.

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