A method of simulating failure of a modular blade subcomponent bonding interface

Abstract

The present application relates to the technical field of wind power blade, and more particularly to a kind of modular blade subcomponent bonding interface failure simulation method, comprising the following steps: making connecting sample of different thickness structural glue;The connecting sample of different thickness structural glue is subjected to force loading test, and corresponding displacement-load data is obtained;Cohesion model is constructed, and the displacement-load data obtained by test is converted into model attribute;Establish the entity simulation model of modular blade subcomponent, and set the structural glue attribute according to the set cohesion model attribute;Boundary conditions and loading conditions are set, simulation is carried out, and the failure mode and failure load of blade subcomponent are obtained.The present application carries out failure simulation analysis on bonding interface by the cohesion model of fracture mechanics, compared with the strain analysis mode in the prior art, the interface failure model and the limit load can be obtained, which provides more reliable design support for the design of blade.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade technology, and in particular to a method for simulating the failure of the bonding interface of modular blade sub-components. Background Technology

[0002] With the development of wind turbine blades towards larger and lighter sizes, modular blade manufacturing methods have begun to be adopted. This involves dividing the wind turbine blade into several modules along its length or width, and then connecting these modules to form a complete wind turbine blade structure after each module is manufactured. This structural form is beneficial for the manufacturing, transportation, and on-site installation of wind turbine blades, but it places higher demands on the connection strength between modules. In the prior art, such as the Chinese utility model patent with authorization announcement number CN216767624U, which disclosed a large modular wind turbine blade connection structure on June 17, 2022, the blade includes a blade root module, a blade middle module and a blade tip module connected in sequence in the blade length direction, and each module includes a leading edge part, a front main beam part, a middle part, a rear main beam part and a trailing edge part in the blade thickness direction, and the modules are connected by adhesive bonding. To simulate failure at blade bonding joints, traditional simulation methods mainly involve modeling the blade shell and analyzing the blade's strain level. However, this approach is insufficient for analyzing the failure modes and ultimate loads at segmented blade connections. Summary of the Invention

[0003] In view of at least one of the above technical problems, the present invention provides a method for simulating the failure of the bonding interface of a modular blade sub-component, which adopts an improvement in the simulation method to obtain the failure mode and ultimate load of the blade bonding interface.

[0004] A method for simulating the failure of the bonding interface of a modular blade sub-component includes the following steps: Fabricate connection samples with structural adhesive of different thicknesses. The connection sample is a fiberglass plate with two coplanar surfaces joined by inclined planes, and the structural adhesive is bonded between the two inclined planes. Force loading tests were conducted on the joint samples of structural adhesives with different thicknesses. The force loading tests included normal peel tests and shear tests, and the corresponding displacement-load data were obtained. A cohesive model is constructed, and the displacement-load data obtained from the experiment is converted into model attributes. The attribute parameters of the cohesive model are determined by the following formulas: normal ultimate strength σnn=Fmax / A, stiffness Knn=σ / δint=Fmax / A·δint; critical energy release rate GIC=δfall·Fmax / 2A; the tangential direction is determined similarly. Establish a solid simulation model of the modular blade sub-component, and set the structural adhesive properties according to the set cohesive force model properties; By setting boundary conditions and loading conditions, and performing simulations, the failure modes and failure loads of the blade sub-components are obtained. In the simulation model, the structural adhesive part is set as a cohesive element, and the structural adhesive bonding interface is set as a cohesive contact.

[0005] In some embodiments of the present invention, the force loading test adopts the ASTM standard.

[0006] In some embodiments of the present invention, the cohesive model includes cohesive units and cohesive contacts.

[0007] In some embodiments of the present invention, the cohesion model adopts a bilinear constitutive model.

[0008] In some embodiments of the present invention, the modular blade sub-component entity includes a trailing edge connecting component, a web connecting component, and a housing connecting component.

[0009] The beneficial effects of this invention are as follows: This invention uses the cohesive force model of fracture mechanics to perform failure simulation analysis on the bonding interface. Compared with the strain analysis method in the prior art, it can derive the interface failure model and ultimate load, providing more reliable design support for blade design. Attached Figure Description

[0010] 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 only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a structural schematic diagram of the type I failure mode of the adhesive interface in an embodiment of the present invention; Figure 2 This is a structural schematic diagram of the type II failure mode of the adhesive interface in an embodiment of the present invention; Figure 3 This is a structural schematic diagram of the type III failure mode of the adhesive interface in an embodiment of the present invention; Figure 4 This is a flowchart illustrating the steps of the modular blade sub-component bonding interface failure simulation method in an embodiment of the present invention. Figure 5 This is a schematic diagram of the connecting sample in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the bilinear constitutive model in an embodiment of the present invention; Figure 7 This is a schematic diagram of the solid simulation model of the blade sub-component in an embodiment of the present invention; Figure 8 This is a schematic diagram of the simulated failure modes and failure loads of the 6mm sample in an embodiment of the present invention; Figure 9 This is a schematic diagram of the simulated failure modes and failure loads of the 8mm sample in an embodiment of the present invention. Detailed Implementation

[0012] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0013] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0015] To facilitate understanding of this solution, the following section introduces cohesion and the types of adhesive interface failure. Cohesion refers to the intermolecular forces within the adhesive layer. Cohesion models are often used to simulate the adhesion between two objects. Under certain external conditions, the phenomenon of interface separation caused by minute fractures or progressive failure at the contact interface between the two objects is called adhesive interface failure. Figures 1 to 3 The diagram illustrates three interface failure modes. A critical fracture energy is applied to the material interface; if the energy generated by the external environment exceeds this critical fracture energy, the adhesive layer at the bonding surface will detach, resulting in adhesive failure. Figure 1 The image shows a peeling failure (Type I). Figure 2 The failure type is the sliding type (Type II). Figure 3 This is a tear-type failure (Type III). like Figure 4 The method for simulating the failure of the bonding interface of the modular blade sub-component shown includes the following steps: S10: Fabricate connection samples with structural adhesive of different thicknesses; in this embodiment of the invention, the structure of the connection sample is as follows: Figure 5As shown, there are two coplanar fiberglass plates joined by inclined planes, with structural adhesive bonding between the two inclined planes. In this embodiment of the invention, different thicknesses refer to different thicknesses of the structural adhesive. S20: Force loading tests were conducted on the joint samples of structural adhesives with different thicknesses, and the corresponding displacement-load data were obtained; in this embodiment of the invention, the force loading test adopted the ASTM standard. Specifically, the force loading test employed normal peel and shear tests.

[0016] S30: Construct a cohesive force model and convert the displacement-load data obtained from the experiment into model properties; In this embodiment of the invention, the cohesive force model includes cohesive force elements and cohesive force contacts. Regarding the properties of the cohesive force model, the constitutive model used in this embodiment of the invention is as follows: Figure 6 The bilinear constitutive model shown describes the linear elastic stage before the material reaches its ultimate strength and the linear stiffness reduction to softening stage after reaching the ultimate strength. The horizontal axis represents displacement, the vertical axis represents stress, the slope K of the elastic stage represents stiffness, and the area under the triangle represents the energy release rate at fracture. In this embodiment of the invention, when using the cohesive model, it is necessary to provide the normal and tangential stiffness, ultimate strength, and critical energy release rate. Figure 6 In the diagram, Fmax is the maximum traction force; K is the stiffness; δint is the damage initiation displacement; and δfall is the damage failure displacement. Figure 6 The curves in the model can be simplified from the load-displacement curves. Specifically, when conducting tests in different directions, the corresponding cohesive model property parameters are as follows: Normal: Ultimate strength σnn = Fmax / A, where A is the bond area; Stiffness Knn = σ / δint = Fmax / A·δint; Critical energy release rate GIC = δfall·Fmax / 2A. Tangential 1: Ultimate strength τss = Fmax / A, where A is the bond area; Stiffness Kss = σ / δint = Fmax / A·δint; Critical energy release rate GIC = δfall·Fmax / 2A. Tangential 2: Ultimate strength τtt = Fmax / A, where A is the bond area; Stiffness Ktt = σ / δint = Fmax / A·δint; Critical energy release rate GIC = δfall·Fmax / 2A.

[0017] S40: Establish a solid simulation model of the modular blade sub-component, and set the structural adhesive properties according to the set cohesive model properties; in specific settings, such as... Figure 7 As shown, the structural adhesive portion is set as a cohesive unit, and the structural adhesive bonding interface is set as a cohesive contact. When specifically setting the component entities of the modular blade, these can be trailing edge connecting components, web connecting components, and box connecting components, etc.

[0018] S50: Set boundary conditions and loading conditions, perform simulation, and obtain the failure modes and failure loads of the blade sub-component. For example... Figure 8 and Figure 9 As shown, simulations can reveal the failure modes and loads of samples with different thicknesses, as well as the failure locations. Through these settings, the failure modes and loads of blade sub-components can be obtained, along with their specific failure locations and ultimate strain levels, providing effective support for full-scale blade design.

[0019] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for simulating the failure of the bonding interface of a modular blade sub-component, characterized in that, Includes the following steps: Fabricate connection samples with structural adhesive of different thicknesses. The connection sample is a fiberglass plate with two coplanar surfaces joined by inclined planes, and the structural adhesive is bonded between the two inclined planes. Force loading tests were conducted on the joint samples of structural adhesives with different thicknesses. The force loading tests included normal peel tests and shear tests, and the corresponding displacement-load data were obtained. A cohesive model was constructed, and the displacement-load data obtained from the experiment was converted into model attributes. When using the cohesive model, the stiffness, ultimate strength, and critical energy release rate in the normal and tangential directions were given; Fmax is the maximum traction force; K is the stiffness; δint is the damage initiation displacement; δfall is the damage failure displacement. The corresponding cohesive model attribute parameters for experiments in different directions are as follows: Normal: Ultimate strength σnn=Fmax / A, A is the bond area; Stiffness Knn=σ / δint=Fmax / A·δint; Critical energy release rate GIC=δfall·Fmax / 2A; Tangential 1: Ultimate strength τss=Fmax / A, A is the bond area; Stiffness Kss=σ / δint=Fmax / A·δint; Critical energy release rate GIC=δfall·Fmax / 2A; Tangential 2: Ultimate strength τtt=Fmax / A, A For the bonding area; stiffness Ktt=σ / δint=Fmax / A·δint; critical energy release rate GIC=δfall·Fmax / 2A; Establish a solid simulation model of the modular blade sub-component, and set the structural adhesive properties according to the set cohesive force model properties; By setting boundary conditions and loading conditions, and performing simulations, the failure modes and failure loads of the blade sub-components are obtained. In the simulation model, the structural adhesive part is set as a cohesive element, and the structural adhesive bonding interface is set as a cohesive contact.

2. The method for simulating the failure of the bonding interface of modular blade sub-components according to claim 1, characterized in that, The force loading test was conducted according to ASTM standards.

3. The method for simulating the failure of the bonding interface of modular blade sub-components according to claim 1, characterized in that, The cohesive model includes cohesive units and cohesive contacts.

4. The method for simulating the failure of the bonding interface of modular blade sub-components according to claim 1, characterized in that, The cohesive model adopts a bilinear constitutive model.

5. The method for simulating the failure of the bonding interface of modular blade sub-components according to claim 1, characterized in that, The modular blade sub-component includes a trailing edge connecting component, a web connecting component, and a housing connecting component.

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