Modeling method and system for simulating wrinkles of multilayer woven fabric

Abstract

The invention belongs to the technical field of mechanical simulation and prediction of woven fabrics, and particularly discloses a modeling method and system for simulating wrinkles of a multi-layer woven fabric, and the method comprises the steps: building a numerical model considering the characteristics of the multi-layer woven fabric, and enabling the multi-layer woven fabric to be formed by stacking single-layer woven fabrics according to a target layering sequence; determining a numerical value implementation method of the numerical value model in the finite element framework, wherein the numerical value implementation method is implemented through a subprogram interface; simulating the wrinkle defect generated in the deformation process of the two-dimensional woven fabric by adopting the finite element framework according to the numerical model through the numerical implementation method; wherein the numerical model is established by simulating tensile deformation, shear deformation and bending deformation of a single-layer fabric through shell units of the multi-layer woven fabric and indirectly simulating compression deformation and interlayer slippage behaviors through contact interaction among the shell units. According to the invention, the accuracy of wrinkle defect simulation of the multi-layer woven fabric can be improved.

Description

Technical Field

[0001] The present application belongs to the technical field of mechanical simulation and prediction of woven fabrics, and more specifically, relates to a modeling method and system for simulating wrinkles in multi-layer woven fabrics. Background Art

[0002] Two-dimensional woven fabrics are fabrics made of alternating warp and weft yarns. They do not require additional stitching and are suitable for fibers with greater bending stiffness. Due to their high specific strength and high specific stiffness, two-dimensional woven fabrics can meet the requirements of composite materials for directional mechanical properties in different service environments and have been widely used as reinforcements for fiber-reinforced composites. Liquid forming technology is currently one of the most widely used processes for manufacturing fiber-reinforced composites. During the pre-forming process of the liquid forming process, the woven fabric will undergo significant deformation and even defects. Therefore, it is necessary to develop a stable numerical simulation method to simulate the deformation and defects of woven fabrics. Wrinkles are the most important defect in the deformation process of woven fabrics.

[0003] Multilayer woven fabrics are constructed by stacking single layers of fabric in a specific layup sequence. Single layers of woven fabric are relatively thin (less than 1 mm), so the thickness change caused by compression is negligible. However, when using multilayer woven fabrics to produce thicker parts, the thickness changes of the single layers caused by compression accumulate, resulting in significant changes in the part thickness. Therefore, compression behavior is an important deformation mode in the multilayer woven fabric preforming process.

[0004] Composite components fabricated using liquid forming processes often have complex geometries. When multiple layers of woven fabric are preformed into components with complex curvature, the thickness variations caused by compaction will cause changes in the path length of each layer. Compression drives the outer fabric layer from the outer edge to the inner edge, shortening the path length of the outer fabric layer and thus generating redundant length.

[0005] The redundant length determines the overall size of wrinkles in a fabric. However, the size and shape of local wrinkles in a woven fabric depend on the fabric's tensile, shear, and bending behaviors. Therefore, accurately modeling wrinkle defects in multilayer woven fabrics requires comprehensive consideration of the fabric's tensile, shear, bending, compression, and interlayer slippage behaviors.

[0006] Currently, there are two main types of numerical methods used for woven fabric forming simulation: one uses two-dimensional elements (membrane elements, shell elements, etc.) to model each layer of woven fabric, and the other uses three-dimensional solid elements to model each layer of woven fabric. However, both methods face difficulties in fully characterizing the mechanical behavior of woven fabrics. Shell elements can account for the membrane behavior (tensile and shear behavior) and bending behavior of woven fabrics. However, shell elements are still two-dimensional elements and follow the plane stress assumption, so shell elements cannot account for compression behavior (stress-strain relationship in the thickness direction). Three-dimensional solid elements can easily account for the tensile, shear, and compression behavior of woven fabrics. However, three-dimensional solid elements are prone to numerical locking when subjected to bending loads, making it impossible to account for the bending behavior of woven fabrics. In addition, three-dimensional solid elements require more expensive computational resources than two-dimensional elements.

[0007] In general, existing numerical methods cannot fully characterize the tensile, shear, bending, compression and interlayer slip behaviors of multi-layer woven fabrics, and therefore cannot accurately simulate the wrinkle defects of multi-layer woven fabrics. Summary of the Invention

[0008] In view of the defects of the prior art, the purpose of this application is to provide a modeling method for simulating the wrinkles of multi-layer woven fabrics, aiming to solve the problem in the prior art that it is difficult to accurately simulate the wrinkle defects of multi-layer woven fabrics.

[0009] To achieve the above objectives, in a first aspect, the present application provides a modeling method for simulating wrinkles in a multi-layer woven fabric, comprising: Establishing a numerical model that considers the characteristics of a multi-layer woven fabric, wherein the multi-layer woven fabric is formed by stacking single layers of woven fabric according to a target layup sequence; Determining a numerical implementation method of the numerical model in a finite element framework, wherein the numerical implementation method is implemented through a subroutine interface; The numerical model is used to simulate wrinkle defects generated during the deformation of a two-dimensional woven fabric using the finite element framework through the numerical realization method; The numerical model is established by simulating the tensile deformation, shear deformation and bending deformation of a single layer of fabric through shell elements of multi-layer woven fabrics, and indirectly simulating the compression deformation and interlayer slip behavior through the contact interaction between the shell elements.

[0010] Optionally, the method for constructing the numerical model includes: Determining strain metrics for various deformation modes of a two-dimensional woven fabric; the deformation modes include tension, shear, bending, compression, and interlayer slip behaviors, and the strain metrics corresponding to each deformation mode are respectively a tensile strain invariant, a shear strain invariant, a bending strain invariant, a compressive strain, and an interlayer slip displacement; The membrane deformation and bending deformation are modeled using shell elements to obtain the first numerical submodel; The second numerical submodel is obtained by using shell element interlayer contact to model compression deformation and interlayer slip; The numerical model is established based on the strain metric, the first sub-model, and the second sub-model.

[0011] Optionally, the membrane deformation includes tensile deformation and shear deformation; The method for constructing the first numerical sub-model includes: A hyperelastic model is used to describe membrane deformation and bending deformation, and the total strain energy is decoupled into membrane strain energy and bending strain energy. Membrane stress is calculated based on the tensile strain invariant, shear strain invariant and membrane strain energy, and bending moment is calculated based on the bending strain invariant and bending strain energy; The first numerical sub-model is determined based on the membrane stress and bending moment.

[0012] Optionally, the method for constructing the second numerical sub-model includes: Shell element interlayer contact is used to model compression deformation and interlayer slip; The normal penetration distance of the shell element is used to represent the compressive strain, and the compressive stress is calculated based on the compressive stress-strain relationship; Compressive stress is used to characterize normal stress, and based on Coulomb's friction law, normal stress is used to calculate tangential stress and interlayer slip displacement; The second numerical sub-model is determined based on the compressive stress, the tangential stress, and the interlaminar slip displacement.

[0013] Optionally, the method for obtaining the strain measurement of each deformation mode includes: Determine a deformation gradient tensor based on the relationship between the current position of the material particle and the initial configuration position, and determine a right Cauchy Green strain tensor based on the deformation gradient tensor; obtain an initial warp unit vector in the warp direction and an initial weft unit vector in the weft direction in the initial configuration; Determine the tensile strain invariants corresponding to the tensile deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the right Cauchy Green strain tensor; Determining shear strain invariants corresponding to shear deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, the right Cauchy Green strain tensor and the tensile strain invariant; Determining a curvature tensor to describe the curvature and torsion of the material particles in the current configuration, and determining bending strain invariants corresponding to the bending deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the curvature tensor; The normal penetration distance of the shell element is obtained and the compressive strain is determined by combining the normal penetration distance with the initial thickness of the shell element.

[0014] Optionally, the numerical implementation process includes a shell element calculation process and a shell element interlayer contact calculation process; The calculation process of the shell element includes: Reading deformation gradient tensors and curvature tensors from a shell element subroutine interface of the finite element framework; defining initial unit vectors in the warp and weft directions in the initial configuration, and calculating the unit vectors in the warp and weft directions in the current configuration based on the initial unit vectors; defining and calculating a membrane strain invariant and a bending strain invariant, and calculating membrane strain energy and bending strain energy based on the membrane strain invariant and the bending strain invariant, respectively; the bending strain energy includes the strain energy of warp yarn bending deformation and the strain energy of weft yarn bending deformation; Calculating membrane stress based on the membrane strain energy combined with the determinant corresponding to the deformation gradient tensor, and calculating bending moment based on the bending strain energy combined with the determinant corresponding to the deformation gradient tensor; The membrane stresses and bending moments are returned to the main program of the finite element framework.

[0015] Optionally, the calculation process of the shell element interlayer contact includes: Reading compressive strains from a shell element subroutine interface of the finite element framework; defining a compressive stress-strain relationship, and calculating a compressive stress as a normal stress based on the compressive strain; Define the interlaminar friction behavior of the shell elements, calculate the tangential stress and interlaminar slip displacement based on the normal stress and return to the main program of the finite element framework.

[0016] In a second aspect, the present application further provides a modeling system for simulating wrinkles of a multi-layer woven fabric, comprising: a model building module for building a numerical model considering the characteristics of a multi-layer woven fabric, wherein the multi-layer woven fabric is formed by stacking single layers of woven fabric in a target ply order; A numerical implementation module, used for determining a numerical implementation method of the numerical model in a finite element framework, wherein the numerical implementation method is implemented through a subroutine interface; a wrinkle simulation module, configured to apply the numerical model to the numerical realization method and adopt the finite element framework to simulate wrinkle defects generated during the deformation of a two-dimensional woven fabric; The numerical model is established by simulating the tensile deformation, shear deformation and bending deformation of a single layer of fabric through shell elements of multi-layer woven fabrics, and indirectly simulating the compression deformation and interlayer slip behavior through the contact interaction between the shell elements.

[0017] In a third aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method described in the first aspect or any possible implementation of the first aspect.

[0018] In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method described in the first aspect or any possible implementation of the first aspect.

[0019] In a fifth aspect, the present application provides a computer program product, which, when executed on a processor, enables the processor to execute the method described in the first aspect or any possible implementation of the first aspect.

[0020] It can be understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0021] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies: (1) This application accurately models the tensile, shear and bending deformations of a single layer of fabric through the shell elements of a multi-layer woven fabric. Combined with the contact interaction between the shell elements, the compression deformation and interlayer slip behavior are indirectly reflected. The interlayer coupling effect of the multi-layer structure and the influence of the ply sequence on the overall mechanical properties are fully considered, which improves the model's simulation ability for wrinkle formation and development, making the prediction of wrinkle defects of two-dimensional woven fabrics in the finite element framework more accurate, thereby achieving improved accuracy in wrinkle defect simulation.

[0022] (2) This application uses shell elements to model membrane deformation (tensile, shear) and bending deformation; uses a hyperelastic model to describe membrane deformation and bending deformation, decoupling the total strain energy into membrane strain energy and bending strain energy; calculates membrane stress based on membrane strain energy, and calculates bending moment based on bending strain energy. Shell elements are used to model interlayer contact for compressive deformation and interlayer slip; uses the normal penetration distance of shell elements to characterize compressive strain, and calculates compressive stress based on the compressive stress-strain relationship; uses compressive stress to characterize normal stress, and uses normal stress to calculate tangential stress and interlayer slip displacement based on Coulomb's friction law. The numerical model of this application can fully consider the tensile, shear, bending, compression, and interlayer friction behaviors of two-dimensional woven fabrics, thereby accurately simulating wrinkle defects in multilayer woven fabrics.

[0023] (3) The system of this application can be numerically implemented in the shell element subroutine interface VUGENS and the interlayer contact subroutine interface VUINTER of the general finite element framework ABAQUS / Explicit. This overcomes both the shortcomings of the shell element modeling method, which cannot consider compression behavior, and the shortcomings of the solid element modeling method, which cannot consider bending behavior and has low computational efficiency. This application combines the advantages of high computational accuracy and efficiency and has the potential to be used for the simulation of wrinkles in preformed thick parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a flow chart of a modeling method for simulating wrinkles of multi-layer woven fabrics provided in an embodiment of the present application; Figure 2 This is a flow chart of the numerical implementation of the multi-layer woven fabric numerical model constructed in the embodiment of the present application through the shell element subroutine interface VUGENS and the interlayer contact subroutine interface VUINTER of the general finite element software ABAQUS / Explicit; Figure 3 is a schematic diagram of a C-shaped member simulating a multi-layer woven fabric forming structure constructed according to a preferred embodiment of the present application; Figure 4 is a deformation cloud diagram of a multi-layer woven fabric forming C-shaped component constructed according to a simulation prediction of a preferred embodiment of the present application; Figure 5 1 is a schematic structural diagram of a modeling system for simulating wrinkles of multi-layer woven fabrics provided in an embodiment of the present application; Figure 6 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0026] The term "and / or" as used herein describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. The symbol " / " as used herein indicates that the related objects are in an "or" relationship, for example, A / B means either A or B.

[0027] The terms "first" and "second" in this specification and claims are used to distinguish different objects rather than to describe a specific order of objects. For example, "first response message" and "second response message" are used to distinguish different response messages rather than to describe a specific order of response messages.

[0028] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0029] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, for example, multiple processing units means two or more processing units, etc.; multiple elements means two or more elements, etc.

[0030] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0031] Reference Figure 1 , the present application provides a modeling method for simulating wrinkles of multi-layer woven fabrics, comprising: S101. Establishing a numerical model considering the characteristics of a multi-layer woven fabric, wherein the multi-layer woven fabric is formed by stacking single layers of woven fabric in a target ply order; S102. Determine a numerical implementation method of the numerical model in a finite element framework, wherein the numerical implementation method is implemented through a subroutine interface; S103. The numerical model is implemented by the numerical method, and the finite element framework is used to simulate the wrinkle defects generated during the deformation of the two-dimensional woven fabric; The numerical model is established by simulating the tensile deformation, shear deformation and bending deformation of a single layer of fabric through shell elements of multi-layer woven fabrics, and indirectly simulating the compression deformation and interlayer slip behavior through the contact interaction between the shell elements.

[0032] Specifically, through the above step S101 , a numerical model is established that can fully consider the stretching, shearing, bending, compression and interlayer friction behaviors of the multi-layer woven fabric.

[0033] It should be noted that multi-layer woven fabrics are made of single-layer woven fabrics stacked in a certain laying order, and their mechanical mechanisms during the forming process are complex, including stretching, shearing, bending, compression and inter-layer friction behaviors.

[0034] Secondly, the established numerical model is implemented in the finite element framework through the above-mentioned S102. Finite element frame rotation: Utilize finite element analysis software such as ABAQUS / Explicit. Subroutine interface implementation: The numerical model is numerically implemented through user-defined shell element subroutines (such as VUGNES) and interlayer contact subroutines (such as VUINTER) to facilitate the connection of the membrane behavior, bending behavior, compression behavior, and interlayer friction behavior of the numerical model with the finite element solution process. A hyperelastic model is used to describe membrane deformation and bending deformation, and the total strain energy is decoupled into membrane strain energy and bending strain energy; membrane stress is calculated based on membrane strain energy, and bending moment is calculated based on bending strain energy. Shell element interlayer contact is used to model compression deformation and interlayer slip; the shell element normal penetration distance is used to represent compressive strain, and compressive stress is calculated based on the compressive stress-strain relationship; the compressive stress is used to represent normal stress, and the normal stress is used to calculate tangential stress and interlayer slip displacement based on Coulomb's friction law.

[0035] Finally, S103 was used to simulate the wrinkle defects that occurred during the forming process of the multi-layer woven fabric. Using the established numerical model and finite element software, forming simulations were performed to obtain the deformation behavior and wrinkle defects of the multi-layer fabric under different loading conditions.

[0036] Using established numerical implementation methods and placing the numerical model within a finite element framework, the team simulated and analyzed wrinkle defects generated during the deformation of two-dimensional woven fabrics. By simulating various deformation modes, including stretching, shearing, and bending, and incorporating interlayer contact and interaction mechanisms, the team effectively captured the formation and evolution of wrinkles, as well as the distribution characteristics of the defects.

[0037] The numerical model in this embodiment uses shell elements to describe the tensile, shear, and bending deformations of a single fabric layer in detail. It also indirectly simulates compression and interlayer slippage through the contact interactions between the shell elements. This modeling strategy takes into account the multi-physics properties of fabric flexibility, enhancing the model's realism and accuracy. It also addresses the difficulty of traditional models in simultaneously reflecting the complex deformations of multiple fabric layers, improving the ability to predict wrinkle defects.

[0038] Optionally, the method for constructing the numerical model includes: Determining strain metrics for various deformation modes of a two-dimensional woven fabric; the deformation modes include tension, shear, bending, compression, and interlayer slip behaviors, and the strain metrics corresponding to each deformation mode are respectively a tensile strain invariant, a shear strain invariant, a bending strain invariant, a compressive strain, and an interlayer slip displacement; The membrane deformation and bending deformation are modeled using shell elements to obtain the first numerical submodel; The second numerical submodel is obtained by using shell element interlayer contact to model compression deformation and interlayer slip; The numerical model is established based on the strain metric, the first sub-model, and the second sub-model.

[0039] Furthermore, the membrane deformation includes tensile deformation and shear deformation; The method for constructing the first numerical sub-model includes: A hyperelastic model is used to describe membrane deformation and bending deformation, and the total strain energy is decoupled into membrane strain energy and bending strain energy. Membrane stress is calculated based on the tensile strain invariant, shear strain invariant and membrane strain energy, and bending moment is calculated based on the bending strain invariant and bending strain energy; The first numerical sub-model is determined based on the membrane stress and bending moment.

[0040] Furthermore, the method for constructing the second numerical sub-model includes: Shell element interlayer contact is used to model compression deformation and interlayer slip; The normal penetration distance of the shell element is used to represent the compressive strain, and the compressive stress is calculated based on the compressive stress-strain relationship; Compressive stress is used to characterize normal stress, and based on Coulomb's friction law, normal stress is used to calculate tangential stress and interlayer slip displacement; The second numerical sub-model is determined based on the compressive stress, the tangential stress, and the interlaminar slip displacement.

[0041] Specifically, in this embodiment, five main deformation modes need to be identified and defined: tensile deformation, shear deformation, bending deformation, compression deformation, and interlayer slip deformation. The strain metric corresponding to each deformation mode is used to capture the deformation mechanism of the multi-layer woven fabric during the forming process.

[0042] The strain invariant of tensile deformation describes the tensile deformation of the woven fabric in the warp and weft directions; the shear deformation describes the relative shear deformation of the warp and weft yarns of the woven fabric; the strain invariant of bending deformation describes the bending curvature of the woven fabric in the warp and weft directions; the compressive strain describes the deformation characteristics in the thickness direction of the woven fabric, mainly reflecting the thickness change of the woven fabric under compressive load; the interlayer sliding displacement describes the relative sliding displacement between adjacent layers of a multi-layer woven fabric during the forming process, mainly describing the interlayer friction behavior of the multi-layer fabric.

[0043] The five deformation modes of the 2D woven fabric are then decoupled. Specifically, shell elements are used to model the tensile, shear, and bending deformations, while interlayer contact of shell elements is used to model the compressive deformation and interlayer slip.

[0044] Shell elements are used to model membrane deformation and bending deformation, which include tensile deformation and shear deformation. A hyperelastic model is used to describe membrane deformation and bending deformation, decoupling the total strain energy into membrane strain energy and bending strain energy. Membrane stress is calculated based on the tensile strain invariant, shear strain invariant, and membrane strain energy, while bending moment is calculated based on the bending strain invariant and bending strain energy. Shell element interlayer contact is used to model compression deformation and interlayer slip. Shell element normal penetration distance is used to represent compression strain, and compression stress is calculated based on the compression stress-strain relationship. Compression stress is used to represent normal stress, and based on Coulomb's friction law, normal stress is used to calculate tangential stress and interlayer slip displacement. Finally, the numerical model is established based on the strain measurement, shell element modeling of membrane deformation and bending deformation, and shell element interlayer contact modeling of compression deformation and interlayer slip by integrating the results of the above parts.

[0045] Optionally, the method for obtaining the strain measurement of each deformation mode includes: Determine a deformation gradient tensor based on the relationship between the current position of the material particle and the initial configuration position, and determine a right Cauchy Green strain tensor based on the deformation gradient tensor; obtain an initial warp unit vector in the warp direction and an initial weft unit vector in the weft direction in the initial configuration; Determine the tensile strain invariants corresponding to the tensile deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the right Cauchy Green strain tensor; Determining shear strain invariants corresponding to shear deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, the right Cauchy Green strain tensor and the tensile strain invariant; Determining a curvature tensor to describe the curvature and torsion of the material particles in the current configuration, and determining bending strain invariants corresponding to the bending deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the curvature tensor; The normal penetration distance of the shell element is obtained and the compressive strain is determined by combining the normal penetration distance with the initial thickness of the shell element.

[0046] Specifically, the following method for obtaining the strain invariant of the deformation mode includes: The strain measure for a deformation mode is given by the following formula:

[0047]

[0048]

[0049]

[0050]

[0051]

[0052] in, are the strain invariants related to the tensile deformation of the warp and weft yarns, is the strain invariant related to the shear deformation between the warp and weft yarns, are the strain invariants associated with the bending deformation of warp and weft yarns, respectively; is the curvature tensor in the current configuration, which is used to describe the curvature and torsion of material particles; is the compressive strain in the thickness direction of the woven fabric; is the thickness change of woven fabric under compression load; is the initial thickness of the woven fabric.

[0053] are the unit vectors in the warp and weft directions in the initial (undeformed) configuration, are the unit vectors in the warp and weft directions in the current (deformed) configuration, respectively.

[0054] is the right Cauchy Green strain tensor, which is defined as follows:

[0055] in, is the deformation gradient tensor, defined as follows:

[0056] in, are the positions of the material particles in the current and initial configurations, respectively.

[0057] Optionally, the numerical implementation process includes a shell element calculation process and a shell element interlayer contact calculation process; The calculation process of the shell element includes: Reading deformation gradient tensors and curvature tensors from a shell element subroutine interface of the finite element framework; defining initial unit vectors in the warp and weft directions in the initial configuration, and calculating the unit vectors in the warp and weft directions in the current configuration based on the initial unit vectors; defining and calculating a membrane strain invariant and a bending strain invariant, and calculating membrane strain energy and bending strain energy based on the membrane strain invariant and the bending strain invariant, respectively; the bending strain energy includes the strain energy of warp yarn bending deformation and the strain energy of weft yarn bending deformation; Calculating membrane stress based on the membrane strain energy combined with the determinant corresponding to the deformation gradient tensor, and calculating bending moment based on the bending strain energy combined with the determinant corresponding to the deformation gradient tensor; The membrane stresses and bending moments are returned to the main program of the finite element framework.

[0058] Specifically, the strain energy associated with deformation modes such as tension, shear, and bending is calculated as follows: The total strain energy is decoupled into membrane strain energy and bending strain energy as follows:

[0059] in, is the total strain energy, is the strain energy of membrane deformation, is the strain energy of bending deformation.

[0060] membrane strain energy It can be decomposed into two parts related to tensile and shear deformation as follows:

[0061] in, are the strain energies associated with the tensile deformation of the warp and weft yarns, respectively. It can be considered as the corresponding strain invariant function.

[0062] Bending strain energy It can be decomposed into the strain energy associated with the bending deformation of the warp and weft yarns as follows:

[0063] in, are the strain energies associated with the bending deformation of the warp and weft yarns, respectively. It can be considered as the corresponding strain invariant function.

[0064] Based on the strain energy function, the membrane stress and bending moment are calculated as follows: Based on the membrane strain energy, the membrane stress is calculated as follows:

[0065] in, is the determinant of the deformation gradient tensor, which is used to describe the volume change of the infinitesimal element before and after deformation; is the deformation gradient tensor The transpose of .

[0066] Based on the bending deformation strain energy, the bending moment is calculated as follows:

[0067] in, are the bending moments along the warp and weft directions, respectively. It is assumed that the bending behavior of the woven fabric depends mainly on the bending behavior of the warp and weft yarns. Therefore, the torque between the warp and weft yarns is Can be ignored.

[0068] Optionally, the calculation process of the shell element interlayer contact includes: Reading compressive strains from a shell element subroutine interface of the finite element framework; defining a compressive stress-strain relationship, and calculating a compressive stress as a normal stress based on the compressive strain; Define the interlaminar friction behavior of the shell elements, calculate the tangential stress and interlaminar slip displacement based on the normal stress and return to the main program of the finite element framework.

[0069] Specifically, the normal penetration distance of the shell element is used to represent the compressive strain, and the compressive stress is calculated based on the compressive stress-strain relationship as follows: Calculation of compressive stress based on the compressive stress-strain relationship as follows:

[0070] in, is the parameter of the compressive stress-strain relationship.

[0071] Using compressive stress Characterizing normal pressure as follows:

[0072] Based on Coulomb's friction law, the normal stress Calculation of tangential stress and interlayer slip displacement ;

[0073]

[0074] in, is the Coulomb friction coefficient; is the relative displacement of the two contact surfaces per unit time; is the interlaminar shear stiffness, which is used to describe the ability of the interface to resist slip.

[0075] Specifically, the numerical model is implemented in the shell element subroutine interface VUGENS and the interlayer contact subroutine interface VUINTER of the general finite element software ABAQUS / Explicit as follows: Reference Figure 2 , the numerical model implements shell element calculation and shell element interlayer contact calculation in the numerical implementation process as follows: Shell element calculation process: Read the deformation gradient tensor and curvature tensor from the Abaqus / Explicit shell element subroutine interface VUGENS. Define the unit vectors for the warp and weft directions in the initial configuration. Define and calculate the strain invariants associated with the membrane deformation and bending deformation. Then, calculate the membrane strain energy associated with the membrane deformation and the bending strain energy associated with the bending deformation. Finally, calculate the membrane stress and bending moment and return to the main Abaqus / Explicit program.

[0076] Shell element interlayer contact calculation process: Read the compressive strain from the ABAQUS / Explicit shell element subroutine interface VUINTER. Define the compressive stress-strain relationship for the woven fabric and calculate the compressive stress. Use the compressive stress to represent the normal stress. Define the interlayer friction behavior of the shell elements. Use the normal stress to calculate the tangential stress and interlayer slip displacement, and then return to the ABAQUS / Explicit main program.

[0077] The present application is described in detail below with reference to specific embodiments.

[0078] Example 1: The numerical method for simulating the wrinkles of multi-layer woven fabrics proposed in this application is used to simulate the C-shaped component formed by multi-layer carbon fiber two-dimensional woven fabrics.

[0079] like Figure 3 As shown in the figure, a finite element model of a multi-layer woven fabric forming C-shaped component is established in ABAQUS software. Considering the model symmetry and computing resources, a 1 / 2 symmetric model is established. Figure 3 As shown, the 1 / 2 model is symmetrical about the XOZ plane, and the displacement boundary condition is applied to the symmetry plane ( The model is composed of C-shaped mold (1 / 2), fabric, and vacuum bag from the inside to the outside. The C-shaped mold is modeled as a rigid body and a fixed displacement boundary condition is applied ( The fabric is modeled layer by layer, consisting of 24 layers, each modeled using shell elements. The fabric's tensile, shear, and bending behavior are numerically simulated using the ABAQUS / Explicit shell element subroutine interface VUGENS. The fabric's compression behavior and interlayer slip are numerically simulated using the ABAQUS / Explicit shell element subroutine interface VUINTER. The vacuum bag is modeled using shell elements, and an atmospheric pressure of 0.1 MPa is applied to the outer surface.

[0080] Reference Figure 4 , Figure 4 The deformation cloud diagram of the multi-layer fabric preformed C-shaped component predicted by simulation is shown. Figure 4 The three-dimensional and two-dimensional (cross-sectional) displacement contours of the C-shaped component are shown. Clearly, compression causes the multiple layers of fabric to move from the outer edge to the inner edge, creating redundant lengths. This redundant material creates wrinkles at the C-shaped corners. Figure 4 The local wrinkles generated at the C-shaped fillet are demonstrated, and the simulation results illustrate the effectiveness of the numerical method proposed in this application for simulating wrinkle defects in multi-layer fabrics.

[0081] Reference Figure 5 The present application also provides a modeling system for simulating wrinkles of multi-layer woven fabrics, comprising: a model building module 510 for building a numerical model that considers the characteristics of a multi-layer woven fabric, wherein the multi-layer woven fabric is formed by stacking single layers of woven fabric in a target ply order; A numerical implementation module 520 is used to determine a numerical implementation method of the numerical model in a finite element framework, wherein the numerical implementation method is implemented through a subroutine interface; a wrinkle simulation module 530 for applying the numerical model to the numerical realization method and using the finite element framework to simulate wrinkle defects generated during the deformation of a two-dimensional woven fabric; The numerical model is established by simulating the tensile deformation, shear deformation and bending deformation of a single layer of fabric through shell elements of multi-layer woven fabrics, and indirectly simulating the compression deformation and interlayer slip behavior through the contact interaction between the shell elements.

[0082] Optionally, the method for constructing the numerical model includes: Determining strain metrics for various deformation modes of a two-dimensional woven fabric; the deformation modes include tension, shear, bending, compression, and interlayer slip behaviors, and the strain metrics corresponding to each deformation mode are respectively a tensile strain invariant, a shear strain invariant, a bending strain invariant, a compressive strain, and an interlayer slip displacement; The membrane deformation and bending deformation are modeled using shell elements to obtain the first numerical submodel; The second numerical submodel is obtained by using shell element interlayer contact to model compression deformation and interlayer slip; The numerical model is established based on the strain metric, the first sub-model, and the second sub-model.

[0083] Optionally, the membrane deformation includes tensile deformation and shear deformation; The method for constructing the first numerical sub-model includes: A hyperelastic model is used to describe membrane deformation and bending deformation, and the total strain energy is decoupled into membrane strain energy and bending strain energy. Membrane stress is calculated based on the tensile strain invariant, shear strain invariant and membrane strain energy, and bending moment is calculated based on the bending strain invariant and bending strain energy; The first numerical sub-model is determined based on the membrane stress and bending moment.

[0084] Optionally, the method for constructing the second numerical sub-model includes: Shell element interlayer contact is used to model compression deformation and interlayer slip; The normal penetration distance of the shell element is used to represent the compressive strain, and the compressive stress is calculated based on the compressive stress-strain relationship; Compressive stress is used to characterize normal stress, and based on Coulomb's friction law, normal stress is used to calculate tangential stress and interlayer slip displacement; The second numerical sub-model is determined based on the compressive stress, the tangential stress, and the interlaminar slip displacement.

[0085] Optionally, the method for obtaining the strain measurement of each deformation mode includes: Determine a deformation gradient tensor based on the relationship between the current position of the material particle and the initial configuration position, and determine a right Cauchy Green strain tensor based on the deformation gradient tensor; obtain an initial warp unit vector in the warp direction and an initial weft unit vector in the weft direction in the initial configuration; Determine the tensile strain invariants corresponding to the tensile deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the right Cauchy Green strain tensor; Determining shear strain invariants corresponding to shear deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, the right Cauchy Green strain tensor and the tensile strain invariant; Determining a curvature tensor to describe the curvature and torsion of the material particles in the current configuration, and determining bending strain invariants corresponding to the bending deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the curvature tensor; The normal penetration distance of the shell element is obtained and the compressive strain is determined by combining the normal penetration distance with the initial thickness of the shell element.

[0086] Optionally, the numerical implementation process includes a shell element calculation process and a shell element interlayer contact calculation process; The calculation process of the shell element includes: Reading deformation gradient tensors and curvature tensors from a shell element subroutine interface of the finite element framework; defining initial unit vectors in the warp and weft directions in the initial configuration, and calculating the unit vectors in the warp and weft directions in the current configuration based on the initial unit vectors; defining and calculating a membrane strain invariant and a bending strain invariant, and calculating membrane strain energy and bending strain energy based on the membrane strain invariant and the bending strain invariant, respectively; the bending strain energy includes the strain energy of warp yarn bending deformation and the strain energy of weft yarn bending deformation; Calculating membrane stress based on the membrane strain energy combined with the determinant corresponding to the deformation gradient tensor, and calculating bending moment based on the bending strain energy combined with the determinant corresponding to the deformation gradient tensor; The membrane stresses and bending moments are returned to the main program of the finite element framework.

[0087] Optionally, the calculation process of the shell element interlayer contact includes: Reading compressive strains from a shell element subroutine interface of the finite element framework; defining a compressive stress-strain relationship, and calculating a compressive stress as a normal stress based on the compressive strain; Define the interlaminar friction behavior of the shell elements, calculate the tangential stress and interlaminar slip displacement based on the normal stress and return to the main program of the finite element framework.

[0088] It should be understood that the above-mentioned device is used to execute the method in the above-mentioned embodiment. The implementation principle and technical effect of the corresponding program module in the device are similar to those described in the above-mentioned method. The working process of the device can refer to the corresponding process in the above-mentioned method and will not be repeated here.

[0089] Reference Figure 6 Based on the method in the above embodiment, an embodiment of the present application provides an electronic device, which may include: a processor (Processor) 610, a communication interface (Communications Interface) 620, a memory (Memory) 630 and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other via the communication bus 640. The processor 610 can call the logic instructions in the memory 630 to execute the method in the above embodiment.

[0090] In addition, the logic instructions in the aforementioned memory 630 can be implemented in the form of a software functional unit and, when sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0091] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method in the above embodiment.

[0092] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the method in the above embodiment.

[0093] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0094] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC.

[0095] The above embodiments can be implemented in whole or in part using software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions. When loaded and executed on a computer, the computer program instructions fully or partially produce the processes or functions described in the embodiments of this application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disk, hard disk, tape), optical media (e.g., DVD), or semiconductor media (e.g., solid-state drive (SSD)).

[0096] It will be understood that the various numerical numbers involved in the embodiments of the present application are merely distinctions for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

[0097] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A modeling method for simulating wrinkles in multi-layer woven fabrics, characterized in that: include: Establishing a numerical model that considers the characteristics of a multi-layer woven fabric, wherein the multi-layer woven fabric is formed by stacking single layers of woven fabric according to a target layup sequence; Determining a numerical implementation method of the numerical model in a finite element framework, wherein the numerical implementation method is implemented through a subroutine interface; The numerical model is used to simulate wrinkle defects generated during the deformation of a two-dimensional woven fabric using the finite element framework through the numerical realization method; The numerical model is established by simulating the tensile deformation, shear deformation and bending deformation of a single layer of fabric through shell elements of multi-layer woven fabrics, and indirectly simulating the compression deformation and interlayer slip behavior through the contact interaction between the shell elements.

2. The modeling method for simulating wrinkles of multi-layer woven fabrics according to claim 1, characterized in that: The method for constructing the numerical model includes: Determining strain metrics for various deformation modes of a two-dimensional woven fabric; the deformation modes include tension, shear, bending, compression, and interlayer slip behaviors, and the strain metrics corresponding to each deformation mode are respectively a tensile strain invariant, a shear strain invariant, a bending strain invariant, a compressive strain, and an interlayer slip displacement; The membrane deformation and bending deformation are modeled using shell elements to obtain the first numerical submodel; The second numerical submodel is obtained by using shell element interlayer contact to model compression deformation and interlayer slip; The numerical model is established based on the strain metric, the first sub-model, and the second sub-model.

3. The modeling method for simulating wrinkles of multi-layer woven fabrics according to claim 2, characterized in that: The method for constructing the first numerical sub-model includes: A hyperelastic model is used to describe membrane deformation and bending deformation, and the total strain energy is decoupled into membrane strain energy and bending strain energy; the membrane deformation includes tensile deformation and shear deformation; Membrane stress is calculated based on the tensile strain invariant, shear strain invariant and membrane strain energy, and bending moment is calculated based on the bending strain invariant and bending strain energy; The first numerical sub-model is determined based on the membrane stress and bending moment.

4. The modeling method for simulating wrinkles of multi-layer woven fabrics according to claim 2, characterized in that: The method for constructing the second numerical sub-model includes: Shell element interlayer contact is used to model compression deformation and interlayer slip; The normal penetration distance of the shell element is used to represent the compressive strain, and the compressive stress is calculated based on the compressive stress-strain relationship; Compressive stress is used to characterize normal stress, and based on Coulomb's friction law, normal stress is used to calculate tangential stress and interlayer slip displacement; The second numerical sub-model is determined based on the compressive stress, the tangential stress, and the interlaminar slip displacement.

5. The modeling method for simulating wrinkles of multi-layer woven fabrics according to claim 2, characterized in that: The method for obtaining the strain measurement of each deformation mode includes: Determine a deformation gradient tensor according to the relationship between the current position of the material particles and the initial configuration position, and determine the right Cauchy Green strain tensor based on the deformation gradient tensor; Obtaining an initial warp unit vector in the warp direction and an initial weft unit vector in the weft direction in the initial configuration; Determine the tensile strain invariants corresponding to the tensile deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the right Cauchy Green strain tensor; Determining shear strain invariants corresponding to shear deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, the right Cauchy Green strain tensor and the tensile strain invariant; Determining a curvature tensor to describe the curvature and torsion of the material particles in the current configuration, and determining bending strain invariants corresponding to the bending deformation of the warp and weft yarns based on the initial warp unit vector, the initial weft unit vector, and the curvature tensor; The normal penetration distance of the shell element is obtained and the compressive strain is determined by combining the normal penetration distance with the initial thickness of the shell element.

6. The modeling method for simulating wrinkles of multi-layer woven fabrics according to claim 1, characterized in that: The numerical realization process includes a shell element calculation process and a shell element interlayer contact calculation process; The calculation process of the shell element includes: Reading deformation gradient tensors and curvature tensors from a shell element subroutine interface of the finite element framework; defining initial unit vectors in the warp and weft directions in the initial configuration, and calculating the unit vectors in the warp and weft directions in the current configuration based on the initial unit vectors; defining and calculating a membrane strain invariant and a bending strain invariant, and calculating membrane strain energy and bending strain energy based on the membrane strain invariant and the bending strain invariant, respectively; the bending strain energy includes the strain energy of warp yarn bending deformation and the strain energy of weft yarn bending deformation; Calculating membrane stress based on the membrane strain energy combined with the determinant corresponding to the deformation gradient tensor, and calculating bending moment based on the bending strain energy combined with the determinant corresponding to the deformation gradient tensor; The membrane stresses and bending moments are returned to the main program of the finite element framework.

7. The modeling method for simulating wrinkles of multi-layer woven fabrics according to claim 6, characterized in that: The calculation process of the shell element interlayer contact includes: Reading compressive strains from a shell element subroutine interface of the finite element framework; defining a compressive stress-strain relationship, and calculating a compressive stress as a normal stress based on the compressive strain; Define the interlaminar friction behavior of the shell elements, calculate the tangential stress and interlaminar slip displacement based on the normal stress and return to the main program of the finite element framework.

8. A modeling system for simulating wrinkles in multi-layer woven fabrics, characterized in that: include: a model building module for building a numerical model considering the characteristics of a multi-layer woven fabric, wherein the multi-layer woven fabric is formed by stacking single layers of woven fabric in a target ply order; A numerical implementation module, used for determining a numerical implementation method of the numerical model in a finite element framework, wherein the numerical implementation method is implemented through a subroutine interface; a wrinkle simulation module, configured to apply the numerical model to the numerical realization method and adopt the finite element framework to simulate wrinkle defects generated during the deformation of a two-dimensional woven fabric; The numerical model is established by simulating the tensile deformation, shear deformation and bending deformation of a single layer of fabric through shell elements of multi-layer woven fabrics, and indirectly simulating the compression deformation and interlayer slip behavior through the contact interaction between the shell elements.

9. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed on a processor, the processor is caused to execute the method according to any one of claims 1 to 7.

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