Method and device for designing fiber path of variable stiffness composite laminate
By establishing linear and nonlinear variable angle fiber paths and optimizing training using finite element models and surrogate models, fiber paths based on principal stress directions are generated. This solves the problems of complexity and low mechanical properties in the design of composite laminates in existing technologies, and achieves efficient fiber path design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TSINGHUA UNIVERSITY
- Filing Date
- 2024-04-12
- Publication Date
- 2026-06-23
Smart Images
Figure CN118230871B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of automated fiber placement technology for composite materials, and in particular to a fiber path design method and apparatus for variable stiffness composite laminates based on principal stress direction. Background Technology
[0002] Composite materials possess advantages such as high specific strength, high specific modulus, fatigue resistance, and high temperature resistance, leading to their widespread application in aerospace, rail transportation, shipbuilding, and energy fields. Traditional composite flat sheets typically have fixed fiber angles such as 0°, 90°, +45°, and -45°. However, with the continuous development of automated fiber placement technology, fibers can now be arranged not only in straight lines but also along pre-designed curved paths to form variable stiffness composite laminates. Curved fiber paths not only increase the design space for composite laminates but also, by altering the stiffness of local areas, yield optimal fiber paths that facilitate load-bearing, thereby improving the mechanical properties of the composite laminates.
[0003] There are three main methods for designing curved fiber paths: the function method, the principal stress method, and the stiffness method. The function method requires pre-assuming a curve function and then determining the optimal function parameters through an optimization algorithm. While simple to implement and able to ensure fiber continuity, the function method is widely used; however, the mechanical properties of variable stiffness composite laminates prepared using this method are difficult to optimize. The principal stress method requires calculating the principal stress of each element using finite element software and then designing the curved fiber path based on the discontinuous principal stress directions. Variable stiffness composite laminates obtained using the principal stress method exhibit excellent mechanical properties, but the significant differences in principal stress directions due to load conditions make the fabrication of composite laminates difficult. The stiffness method calculates the stiffness of the variable stiffness laminate using ply parameters and then obtains the fiber path corresponding to the ply parameters through an algorithm. The stiffness method has fewer design variables, but the fiber path corresponding to each set of ply parameters is not unique, the conversion to a fiber path is complex, and manufacturability is difficult to guarantee.
[0004] Currently, the function method is an important approach for designing curved fiber paths. Existing technologies have described curved fiber paths using linear variation functions of fiber angles, B-spline curves, and Lagrange polynomials. However, the lack of a connection between the parameters of the curved function and the principal stress direction makes it difficult to design fiber paths that are beneficial to load-bearing capacity based on the load state, resulting in the inability to achieve optimal mechanical properties in variable stiffness composite laminates. In addition, the numerous parameters required for flexible nonlinear fiber path design significantly increase the computational workload of the mechanical properties of the laminate, leading to complex optimization algorithms for variable stiffness composite laminates and making it difficult to guarantee the continuity and manufacturability of the fiber path. Summary of the Invention
[0005] This invention provides a fiber path design method and apparatus for variable stiffness composite laminates, which solves the problems of complex manufacturing process and low mechanical properties of the obtained variable stiffness composite laminates by existing fiber path design methods.
[0006] A first aspect of the present invention provides a fiber path design method for a variable stiffness composite laminate, comprising the following steps:
[0007] Linear and nonlinear variable-angle fiber paths are established separately. The fiber orientation of the variable-stiffness composite laminate is calculated using the pre-established finite element model of the linear variable-angle composite laminate and the linear variable-angle fiber paths. The initial mechanical properties of the variable-stiffness composite laminate are calculated based on its fiber orientation. A surrogate model of the linear variable-angle composite laminate is constructed based on the linear variable-angle fiber paths and the initial mechanical properties of the variable-stiffness composite laminate. This surrogate model is then optimized and trained to obtain the optimal mechanical properties of the variable-stiffness composite laminate. The optimal parameters of the linear variable-angle fiber paths are calculated based on the optimal mechanical properties of the variable-stiffness composite laminate, and these optimal parameters are input into the finite element model of the linear variable-angle composite laminate to obtain the stress distribution state of the variable-stiffness composite laminate. Finally, a fiber path for the variable-stiffness composite laminate based on the principal stress direction is generated using the stress distribution state of the variable-stiffness composite laminate and the nonlinear variable-angle fiber paths.
[0008] Optionally, the step of calculating the fiber orientation of the variable stiffness composite laminate using a pre-established finite element model of the linear variable angle composite laminate and the linear variable angle fiber path includes:
[0009] The finite element model of the linear variable angle composite laminate is divided into multiple mesh elements to obtain the node coordinates of each mesh element; the fiber direction of the variable stiffness composite laminate is calculated based on the node coordinates of each mesh element and the linear variable angle fiber path.
[0010] Optionally, calculating the initial mechanical properties of the variable stiffness composite laminate based on the fiber orientation of the variable stiffness composite laminate includes:
[0011] The layup pattern is determined based on the fiber orientation of the variable stiffness composite laminate; the material properties, boundary conditions, and external loads of each grid cell are set according to the layup pattern to calculate the initial mechanical properties of the variable stiffness composite laminate.
[0012] Optionally, the step of constructing a surrogate model of the linear variable-angle composite laminate based on the linear variable-angle fiber path and the initial mechanical properties of the variable-stiffness composite laminate, and optimizing and training the surrogate model of the linear variable-angle composite laminate to obtain the optimal mechanical properties of the variable-stiffness composite laminate, includes:
[0013] Input variables are determined based on the linear variable-angle fiber path, and output variables are determined based on the initial mechanical properties of the variable stiffness composite laminate. A surrogate model of the linear variable-angle composite laminate is constructed based on the input and output variables. A training set for the surrogate model is obtained using optimal Latin hypercube sampling, and a test set is obtained using genetic Latin hypercube sampling. The surrogate model is trained using the training set and validated using the test set to obtain the optimal surrogate model. The optimal mechanical properties of the variable stiffness composite laminate are then calculated based on the optimal surrogate model.
[0014] Optionally, generating a fiber path for the variable stiffness composite laminate based on the principal stress direction using the stress distribution state of the variable stiffness composite laminate and the nonlinear variable angle fiber path includes:
[0015] The abscissa of the maximum stress element and the principal stress direction of the maximum stress element are determined based on the stress distribution state of the variable stiffness composite laminate. The abscissa of the maximum stress element and the principal stress direction of the maximum stress element are input into the nonlinear variable angle fiber path to generate the fiber path of the variable stiffness composite laminate based on the principal stress direction.
[0016] Optionally, the step of solving for the abscissa of the maximum stress element and the principal stress direction of the maximum stress element based on the stress distribution state of the variable stiffness composite laminate includes:
[0017] The stress distribution of the variable stiffness composite laminate is processed using an image method to calculate the abscissa of the maximum stress element and the principal stress direction of the maximum stress element.
[0018] A second aspect of the present invention provides a fiber path design device for a variable stiffness composite laminate, comprising:
[0019] The system includes a setup module for establishing linear and nonlinear variable-angle fiber paths, a first calculation module for calculating the fiber orientation of a variable-stiffness composite laminate using a pre-established finite element model of the linear variable-angle composite laminate and the linear variable-angle fiber paths, a second calculation module for calculating the initial mechanical properties of the variable-stiffness composite laminate based on its fiber orientation, and a training module for constructing a proxy model of the linear variable-angle composite laminate based on the linear variable-angle fiber paths and the initial mechanical properties of the variable-stiffness composite laminate, and for training the linear variable-angle composite laminate... The proxy model of the composite laminate is optimized and trained to obtain the optimal mechanical properties of the variable stiffness composite laminate; the input module is used to calculate the optimal parameters of the linear variable angle fiber path based on the optimal mechanical properties of the variable stiffness composite laminate, and input the optimal parameters of the linear variable angle fiber path into the finite element model of the linear variable angle composite laminate to obtain the stress distribution state of the variable stiffness composite laminate; the generation module is used to generate the fiber path of the variable stiffness composite laminate based on the principal stress direction using the stress distribution state of the variable stiffness composite laminate and the nonlinear variable angle fiber path.
[0020] A third aspect of the present invention provides 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 program to implement the fiber path design method for variable stiffness composite laminates as described in the above embodiments.
[0021] A fourth aspect of the present invention provides a computer program product, which, when executed by a processor, implements the fiber path design method for variable stiffness composite laminates as described above.
[0022] A fifth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the fiber path design method for the variable stiffness composite laminate described above.
[0023] The fiber path design method and apparatus for variable stiffness composite laminates proposed in this invention improves the design space of variable stiffness composite materials by introducing the abscissa of the maximum stress element and the principal stress direction, while ensuring fiber continuity and component manufacturability. This solves the problem of lack of connection between curve function parameters and principal stress directions, and ultimately improves the mechanical properties of variable stiffness composite laminates.
[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:
[0026] Figure 1 A flowchart illustrating a fiber path design method for a variable stiffness composite laminate provided in an embodiment of the present invention;
[0027] Figure 2 This is a schematic diagram of nonlinear and linear variable angle fiber paths provided in an embodiment of the present invention, wherein (a) is a nonlinear variable angle fiber path, (b) is a linear variable angle fiber path, and (c) is a fiber angle;
[0028] Figure 3 This is a schematic diagram of the finite element model of a linear variable angle composite laminate provided in an embodiment of the present invention;
[0029] Figure 4 This is a schematic diagram of the boundary conditions and loads of the variable stiffness composite laminate provided in the embodiments of the present invention;
[0030] Figure 5 This is a detailed implementation diagram of a fiber path design method for a variable stiffness composite laminate provided in an embodiment of the present invention;
[0031] Figure 6 This is a schematic diagram of the stress distribution state of the variable stiffness composite laminate provided in the embodiment of the present invention, wherein (a) is a mesh element, (b) is the principal stress direction of the maximum stress element, and (c) is the abscissa of the maximum stress element.
[0032] Figure 7 This is a schematic diagram of the fiber path design device for variable stiffness composite laminate provided in an embodiment of the present invention.
[0033] Figure 8 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation
[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0035] The fiber path design method and apparatus for variable stiffness composite laminates according to embodiments of the present invention are described below with reference to the accompanying drawings.
[0036] Figure 1This is a schematic flowchart of a fiber path design method for a variable stiffness composite laminate provided in an embodiment of the present invention.
[0037] like Figure 1 As shown, the fiber path design method for this variable stiffness composite laminate includes the following steps:
[0038] In step S101, linear variable angle fiber paths and nonlinear variable angle fiber paths are established respectively.
[0039] In actual implementation, such as Figure 2 As shown, expressions for nonlinear fiber paths and linear variable-angle fiber paths are defined, respectively. The nonlinear and linear fiber paths share two identical parameters, for example:
[0040] The nonlinear variable angle fiber path is defined as:
[0041]
[0042] The linear variable angle fiber path is defined as:
[0043]
[0044] Where A is an intermediate variable, a is the width of the variable stiffness composite laminate, x is the fiber path coordinate system, T0 represents the fiber angle θ(0) at x=0, and T1 represents... fiber angle of position X2 represents the abscissa of the maximum stress element, and T represents the principal stress direction of the maximum stress element. Introducing intermediate variables X2 and T improves the flexibility of the curved fiber path.
[0045] In step S102, the fiber orientation of the variable stiffness composite laminate is calculated using a pre-established finite element model of the linear variable angle composite laminate and the linear variable angle fiber path.
[0046] In some embodiments, the fiber orientation of the variable stiffness composite laminate is calculated using a pre-established finite element model of a linear variable angle composite laminate and a linear variable angle fiber path, including:
[0047] The finite element model of the linear variable angle composite laminate is divided into multiple mesh elements, and the node coordinates of each mesh element are obtained.
[0048] The fiber orientation of the variable stiffness composite laminate is calculated based on the node coordinates of each grid cell and the linear variable angle fiber path.
[0049] In actual implementation, such as Figure 3As shown, a script file for the finite element software ABAQUS was written in Python beforehand to establish a finite element model of a linear variable angle composite laminate. The finite element model of the linear variable angle composite laminate was divided into multiple mesh elements, and the node coordinates of each mesh element were obtained. The selected T0, T1 and linear variable angle fiber paths were used to calculate the fiber direction of the variable stiffness composite laminate.
[0050] In step S103, the initial mechanical properties of the variable stiffness composite laminate are calculated based on the fiber orientation of the variable stiffness composite laminate.
[0051] In some embodiments, the initial mechanical properties of the variable stiffness composite laminate are calculated based on the fiber orientation of the variable stiffness composite laminate, including:
[0052] The layup method is determined based on the fiber orientation of the variable stiffness composite laminate.
[0053] The material properties, boundary conditions, and external loads of each grid cell are set according to the layup method to calculate the initial mechanical properties of the variable stiffness composite laminate.
[0054] In actual implementation, such as Figure 4 As shown, the layup method is determined according to the fiber direction of the variable stiffness composite laminate. The material properties of each mesh element are defined, boundary conditions and external loads are set according to the fixed layup method, and the initial mechanical properties of the variable stiffness composite laminate are calculated by the finite element software ABAQUS.
[0055] In step S104, a surrogate model of the linear variable angle composite laminate is constructed based on the initial mechanical properties of the linear variable angle fiber path and the variable stiffness composite laminate. The surrogate model of the linear variable angle composite laminate is then optimized and trained to obtain the optimal mechanical properties of the variable stiffness composite laminate.
[0056] In some embodiments, the initial mechanical properties of the variable stiffness composite laminate are input into a pre-established surrogate model of a linear variable angle composite laminate to obtain the optimal mechanical properties of the variable stiffness composite laminate, including:
[0057] A surrogate model of the linear variable-angle composite laminate is constructed based on the initial mechanical properties of the linear variable-angle fiber path and the variable stiffness composite laminate. This surrogate model is then optimized and trained to obtain the optimal mechanical properties of the variable stiffness composite laminate, including:
[0058] The input variables are determined based on the linear variable angle fiber path, the output variables are determined based on the initial mechanical properties of the variable stiffness composite laminate, and a surrogate model of the linear variable angle composite laminate is constructed based on the input and output variables.
[0059] The training set of the surrogate model of the linear variable angle composite laminate was obtained by using optimal Latin hypercube sampling, and the test set of the surrogate model of the linear variable angle composite laminate was obtained by using genetic Latin hypercube sampling.
[0060] The surrogate model of the linear variable angle composite laminate was trained using the training set and validated using the test set to obtain the optimal surrogate model of the linear variable angle composite laminate.
[0061] The optimal mechanical properties of variable stiffness composite laminates are solved using the optimal surrogate model for linear variable angle composite laminates.
[0062] In some embodiments, the surrogate model for the linear variable angle composite laminate can be selected from one of the following: polynomial response surface, radial basis function, Kriging function, or neural network.
[0063] In actual implementation, such as Figure 5 As shown, T0 and T1 of the linear variable angle fiber path are defined as input variables of the surrogate model, and the initial mechanical properties of the variable stiffness composite laminate are defined as output variables. A surrogate model of the linear variable angle composite laminate is constructed based on the input and output variables. The input and output variables are processed by experimental design method to obtain multiple sets of sample points. The optimal Latin hypercube sampling is used to process multiple sets of sample points to obtain the training set. The genetic Latin hypercube sampling is used to process multiple sets of sample points to obtain the test set. Among them, the genetic Latin hypercube sampling can identify the insufficient representativeness interval of the initial training points. This interval is regarded as the design space of the genetic points. The genetic points will fill the insufficient representativeness interval of each design variable and combine it with the initial training points. The updated training points also have spatial and directional uniformity. Therefore, the use of optimal Latin hypercube sampling and genetic Latin hypercube sampling can ensure the spatial uniformity of the sample points and reduce the number of sample points required for high-precision models.
[0064] Based on the training and testing sets, a surrogate model for linear variable angle composite laminates is trained and validated to obtain the optimal surrogate model for linear variable angle composite laminates that has passed accuracy validation. The optimal mechanical properties of variable stiffness composite laminates can be obtained by using the optimal surrogate model for linear variable angle composite laminates.
[0065] If the accuracy after verification is insufficient to meet the design requirements, the previous test set and training set are combined to form a new training set. Based on this, the surrogate model is iteratively updated, and the accuracy of the model is evaluated using the newly generated test points until the accuracy of the surrogate model meets the design requirements, thus obtaining the optimal surrogate model for the linear variable angle composite laminate.
[0066] In step S105, the optimal parameters of the linear variable angle fiber path are calculated based on the best mechanical properties of the variable stiffness composite laminate, and the optimal parameters of the linear variable angle fiber path are input into the finite element model of the linear variable angle composite laminate to obtain the stress distribution state of the variable stiffness composite laminate.
[0067] In actual implementation, such as Figure 6 As shown, the optimal mechanical properties of the variable stiffness composite laminate are solved using an optimization algorithm, and the optimal parameters T0 and T1 of the linear variable angle fiber path are obtained. The optimal path parameters are then substituted into the finite element model of the linear variable angle composite laminate to obtain the stress distribution state of the variable stiffness composite laminate.
[0068] In step S106, the fiber path of the variable stiffness composite laminate based on the principal stress direction is generated by utilizing the stress distribution state of the variable stiffness composite laminate and the nonlinear variable angle fiber path.
[0069] In some embodiments, the fiber path of the variable stiffness composite laminate based on the principal stress direction is generated using the stress distribution state of the variable stiffness composite laminate and the nonlinear variable angle fiber path, including:
[0070] The abscissa of the maximum stress element and the principal stress direction of the maximum stress element are determined based on the stress distribution state of the variable stiffness composite laminate.
[0071] Input the x-coordinate of the maximum stress element and the principal stress direction of the maximum stress element into the nonlinear variable angle fiber path to generate a variable stiffness composite laminate fiber path based on the principal stress direction.
[0072] In actual implementation, the stress distribution state of the variable stiffness composite laminate is processed using an image method to obtain the abscissa of the maximum stress element, which is set as X2. The principal stress direction of the maximum stress element is obtained by processing the stress distribution state of the variable stiffness composite laminate using an image method, which is set as T2. Since the fiber direction and the maximum principal stress direction are consistent, the mechanical properties of the laminate can be effectively improved. Therefore, after inputting the abscissa of the maximum stress element and the principal stress direction of the maximum stress element into the nonlinear variable angle fiber path, the fiber path of the variable stiffness composite laminate based on the principal stress direction is obtained.
[0073] The fiber path design method for variable stiffness composite laminates proposed in this invention has the following advantages:
[0074] (1) The stress cloud diagram of the linear variable angle composite laminate was calculated by finite element software. The abscissa and principal stress direction of the maximum stress element were obtained by image method and set as the parameters X2 and T2 of the nonlinear function. Since the fiber direction and the maximum principal stress direction are consistent, the mechanical properties of the composite laminate are further improved.
[0075] (2) By introducing intermediate variables X2 and T2, the design space of composite laminates is improved while ensuring fiber path continuity and manufacturability.
[0076] (3) The training set and test set are obtained by optimal and genetic Latin hypercube sampling respectively, and applied to the iterative update of the surrogate model, which reduces the number of sample points required by the high-precision model. The two identical parameters T0 and T1 of the nonlinear and linear fiber paths are obtained by the optimization algorithm, which significantly improves the optimization efficiency of variable stiffness composite laminate.
[0077] Next, with reference to the accompanying drawings, a fiber path design device for a variable stiffness composite laminate according to an embodiment of the present invention is described.
[0078] Figure 7 This is a block diagram of a fiber path design device for a variable stiffness composite laminate according to an embodiment of the present invention.
[0079] like Figure 7 As shown, the fiber path design device 70 for the variable stiffness composite laminate includes: a creation module 701, a first calculation module 702, a second calculation module 703, a training module 704, an input module 705, and a generation module 706.
[0080] The system comprises the following modules: Module 701 establishes linear and nonlinear variable-angle fiber paths, respectively. Module 702 calculates the fiber orientation of the variable-stiffness composite laminate using the pre-established finite element model and fiber paths. Module 703 calculates the initial mechanical properties of the variable-stiffness composite laminate based on its fiber orientation. Module 704 constructs a proxy model of the linear variable-angle composite laminate based on the fiber paths and initial mechanical properties, and optimizes this proxy model to obtain the optimal mechanical properties. Module 705 calculates the optimal parameters of the linear variable-angle fiber paths based on the optimal mechanical properties and inputs these parameters into the finite element model of the linear variable-angle composite laminate to obtain the stress distribution state of the variable-stiffness composite laminate. The generation module 706 is used to generate fiber paths for variable stiffness composite laminates based on the principal stress direction by utilizing the stress distribution state and nonlinear variable angle fiber paths of the variable stiffness composite laminate.
[0081] It should be noted that the explanation of the fiber path design method embodiment for variable stiffness composite laminates described above also applies to the fiber path design device for variable stiffness composite laminates in this embodiment, and will not be repeated here.
[0082] The fiber path design device for variable stiffness composite laminates proposed according to embodiments of the present invention has the following beneficial effects:
[0083] (1) The stress cloud diagram of the linear variable angle composite laminate was calculated by finite element software. The abscissa and principal stress direction of the maximum stress element were obtained by image method and set as the parameters X2 and T2 of the nonlinear function. Since the fiber direction and the maximum principal stress direction are consistent, the mechanical properties of the composite laminate are further improved.
[0084] (2) By introducing intermediate variables X2 and T2, the design space of composite laminates is improved while ensuring fiber path continuity and manufacturability.
[0085] (3) The training set and test set are obtained by optimal and genetic Latin hypercube sampling respectively, and applied to the iterative update of the surrogate model, which reduces the number of sample points required by the high-precision model. The two identical parameters T0 and T1 of the nonlinear and linear fiber paths are obtained by the optimization algorithm, which significantly improves the optimization efficiency of variable stiffness composite laminate.
[0086] Figure 8This is a schematic diagram of an electronic device provided in an embodiment of the present invention. The electronic device may include:
[0087] The memory 801, the processor 802, and the computer program stored on the memory 801 and capable of running on the processor 802.
[0088] When the processor 802 executes the program, it implements the fiber path design method for the variable stiffness composite laminate provided in the above embodiments.
[0089] Furthermore, electronic devices also include:
[0090] Communication interface 803 is used for communication between memory 801 and processor 802.
[0091] The memory 801 is used to store computer programs that can run on the processor 802.
[0092] The memory 801 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.
[0093] If the memory 801, processor 802, and communication interface 803 are implemented independently, then the communication interface 803, memory 801, and processor 802 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be divided into address buses, data buses, control buses, etc. For ease of representation, Figure 8 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.
[0094] Optionally, in a specific implementation, if the memory 801, processor 802, and communication interface 803 are integrated on a single chip, then the memory 801, processor 802, and communication interface 803 can communicate with each other through an internal interface.
[0095] The processor 802 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.
[0096] This invention also provides a computer program product, which, when executed by a processor, implements the fiber path design method for variable stiffness composite laminates as described above.
[0097] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the fiber path design method for the variable stiffness composite laminate described above.
[0098] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0099] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0100] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.
[0101] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.
[0102] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.
[0103] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.
[0104] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.
[0105] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.
Claims
1. A fiber path design method for a variable stiffness composite laminate, characterized in that, Includes the following steps: Linear variable angle fiber paths and nonlinear variable angle fiber paths are established respectively, wherein... The nonlinear variable angle fiber path is as follows: in, The fiber angle along the fiber path. As an intermediate variable, For the fiber path coordinate system, The width of the variable stiffness composite laminate. express fiber angle of position , express fiber angle of position , The x-coordinate represents the element with the maximum stress. To indicate the direction of the principal stress in the element with the maximum stress; The fiber orientation of the variable stiffness composite laminate is calculated using a pre-established finite element model of the linear variable angle composite laminate and the linear variable angle fiber path. The initial mechanical properties of the variable stiffness composite laminate are calculated based on the fiber orientation of the variable stiffness composite laminate. Based on the linear variable angle fiber path and the initial mechanical properties of the variable stiffness composite laminate, a surrogate model of the linear variable angle composite laminate is constructed, and the surrogate model of the linear variable angle composite laminate is optimized and trained to obtain the optimal mechanical properties of the variable stiffness composite laminate. The optimal parameters of the linear variable angle fiber path are calculated based on the best mechanical properties of the variable stiffness composite laminate, and the optimal parameters of the linear variable angle fiber path are input into the finite element model of the linear variable angle composite laminate to obtain the stress distribution state of the variable stiffness composite laminate. The fiber path of the variable stiffness composite laminate is generated based on the principal stress direction by utilizing the stress distribution state of the variable stiffness composite laminate and the nonlinear variable angle fiber path.
2. The fiber path design method for variable stiffness composite laminates according to claim 1, characterized in that, The calculation of the fiber orientation of the variable stiffness composite laminate using a pre-established finite element model of the linear variable angle composite laminate and the linear variable angle fiber path includes: The finite element model of the linear variable angle composite laminate is divided into multiple mesh elements, and the node coordinates of each mesh element are obtained. The fiber orientation of the variable stiffness composite laminate is calculated based on the node coordinates of each grid cell and the linear variable angle fiber path.
3. The fiber path design method for variable stiffness composite laminates according to claim 1, characterized in that, The calculation of the initial mechanical properties of the variable stiffness composite laminate based on the fiber orientation of the variable stiffness composite laminate includes: The layup method is determined based on the fiber orientation of the variable stiffness composite laminate. The material properties, boundary conditions, and external loads of each grid cell are set according to the layup method to calculate the initial mechanical properties of the variable stiffness composite laminate.
4. The fiber path design method for variable stiffness composite laminates according to claim 1, characterized in that, The process of constructing a surrogate model of the linear variable-angle composite laminate based on the initial mechanical properties of the linear variable-angle fiber path and the variable-stiffness composite laminate, and optimizing and training the surrogate model of the linear variable-angle composite laminate to obtain the optimal mechanical properties of the variable-stiffness composite laminate includes: Input variables are determined based on the linear variable angle fiber path, output variables are determined based on the initial mechanical properties of the variable stiffness composite laminate, and a proxy model of the linear variable angle composite laminate is constructed based on the input variables and the output variables. The training set of the surrogate model of the linear variable angle composite laminate is obtained by using optimal Latin hypercube sampling, and the test set of the surrogate model of the linear variable angle composite laminate is obtained by using genetic Latin hypercube sampling. The training set is used to train the surrogate model of the linear variable angle composite laminate, and the test set is used to verify the trained surrogate model of the linear variable angle composite laminate, so as to obtain the optimal surrogate model of the linear variable angle composite laminate. The optimal mechanical properties of the variable stiffness composite laminate are determined using the optimal surrogate model of the linear variable angle composite laminate.
5. The fiber path design method for variable stiffness composite laminates according to claim 1, characterized in that, The step of generating a fiber path for the variable stiffness composite laminate based on the principal stress direction using the stress distribution state of the variable stiffness composite laminate and the nonlinear variable angle fiber path includes: The abscissa of the maximum stress element and the principal stress direction of the maximum stress element are determined based on the stress distribution state of the variable stiffness composite laminate. The abscissa of the maximum stress element and the principal stress direction of the maximum stress element are input into the nonlinear variable angle fiber path to generate a variable stiffness composite laminate fiber path based on the principal stress direction.
6. The fiber path design method for variable stiffness composite laminates according to claim 5, characterized in that, The step of determining the abscissa of the maximum stress element and the principal stress direction of the maximum stress element based on the stress distribution state of the variable stiffness composite laminate includes: The stress distribution of the variable stiffness composite laminate is processed using an image method to calculate the abscissa of the maximum stress element and the principal stress direction of the maximum stress element.
7. A fiber path design device for variable stiffness composite laminates, characterized in that, include: The module is used to create linear variable angle fiber paths and nonlinear variable angle fiber paths, respectively. The nonlinear variable angle fiber path is as follows: in, The fiber angle along the fiber path. As an intermediate variable, For the fiber path coordinate system, The width of the variable stiffness composite laminate. express fiber angle of position , express fiber angle of position , The x-coordinate represents the element with the maximum stress. To indicate the direction of the principal stress in the element with the maximum stress; The first calculation module is used to calculate the fiber direction of the variable stiffness composite laminate using a pre-established finite element model of the linear variable angle composite laminate and the linear variable angle fiber path. The second calculation module is used to calculate the initial mechanical properties of the variable stiffness composite laminate based on the fiber direction of the variable stiffness composite laminate. The training module is used to construct a surrogate model of the linear variable angle composite laminate based on the linear variable angle fiber path and the initial mechanical properties of the variable stiffness composite laminate, and to optimize and train the surrogate model of the linear variable angle composite laminate to obtain the optimal mechanical properties of the variable stiffness composite laminate. The input module is used to calculate the optimal parameters of the linear variable angle fiber path based on the best mechanical properties of the variable stiffness composite laminate, and input the optimal parameters of the linear variable angle fiber path into the finite element model of the linear variable angle composite laminate to obtain the stress distribution state of the variable stiffness composite laminate. The generation module is used to generate fiber paths for the variable stiffness composite laminate based on the principal stress direction by utilizing the stress distribution state of the variable stiffness composite laminate and the nonlinear variable angle fiber path.
8. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, the processor executing the program to implement the fiber path design method for variable stiffness composite laminates as described in any one of claims 1-6.
9. A computer program product, characterized in that, When the computer program / instruction is executed by the processor, it implements the fiber path design method for the variable stiffness composite laminate as described in any one of claims 1-6.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the fiber path design method for variable stiffness composite laminates as described in any one of claims 1-6.