Lattice structure design method and system based on shape and load

Abstract

The invention belongs to the field of aero-engines, relates to a lattice structure design technology, and provides a lattice structure design method and system based on shapes and loads, and the method comprises the steps: generating a single cell initial model of each lattice design area on a part; according to a load result of the part, performing topological optimization on the single cell initial model by adopting the established multi-objective optimization function to obtain an optimized single cell model; and reconstructing each optimized unit cell model by adopting a curved surface fitting method to obtain a lattice unit cell geometric model, and performing size parameter optimization on each lattice unit cell geometric model according to the part design strength to obtain a final unit cell geometric model. According to the method, the optimization result of the target part can be quickly and accurately given, guidance is provided for design and application of the lattice structure, and the lattice structure which meets constraint conditions and can be manufactured can be quickly obtained.

Description

Technical Field

[0001] The present invention belongs to the field of aero-engines, relates to lattice structure design technology, and particularly relates to a lattice structure design method and system based on shape and load. Background Art

[0002] Lattice materials are a type of porous materials. Porous media are a widely existing structural form in nature. Inspired by natural structures, artificial porous materials have made great progress. Moreover, with the development of additive manufacturing (AM) and material preparation technology, the manufacturing of lattice structures has been able to be easily realized and has been widely applied in fields such as aerospace and tissue engineering.

[0003] Porous materials can be divided into two categories, foam materials and lattice materials, according to the geometric form of the microstructure. Since lattice materials and structures have a large adjustable design space, various excellent multifunctional characteristics can be achieved through design with variable microstructures and porosity. Currently, many morphologies of lattice materials have been designed, such as three-dimensional truss lattices, triply periodic minimal surface lattices, phase change structure lattices, negative Poisson's ratio lattices, etc. Through the design of lattice topological structures, many performances that cannot be achieved by solid materials have been realized, and even multifunctional integrations such as "heat insulation - load bearing" integration and "load bearing - stealth" integration have been realized, greatly improving the material utilization rate.

[0004] In addition, traditional lattice design methods usually only design for a simple cubic unit cell model. However, with the increasing requirements for structural integration and lightweight, for structures such as rotationally periodic symmetric structures, if traditional lattice design methods are directly used for filling, a large number of "broken lattices" will be generated, thus affecting the overall performance of the structure.

[0005] Therefore, designing a lattice structure design method with stronger adaptability and simpler calculation is of great significance for the design and research and development of lattice structures. Summary of the Invention

[0006] In order to solve the technical problem that the traditional lattice design method affects the overall performance of the structure, the present invention discloses a lattice structure design method based on shape and load, and the method includes the following steps: S1. According to the structural characteristics and load results of the part, obtain the single-cell initial model of the lattice design region on the part, and there is at least one lattice design region; S2. According to the load results, perform topology optimization on each single-cell initial model under multiple working conditions by using the established multi-objective optimization function to obtain the optimized single-cell model; S3. Use the surface fitting method to reconstruct each optimized single-cell model to obtain a lattice single-cell geometric model, and optimize the size parameters of each lattice single-cell geometric model according to the design strength of the part to obtain the final single-cell geometric model.

[0007] Further, in the above step S1, according to the structural characteristics and load results of the part, obtain the initial single-cell model of the lattice design area on the part, including: S11. Conduct a load analysis on the part to obtain the load results, obtain the lattice design area of the part according to the mechanical load and temperature load in the load results, and extract the load type and load value borne by each lattice design area; S12. Conduct a structural analysis on the part to obtain the structural characteristics, and simplify each lattice design area according to the structural characteristics to obtain a simple geometric structure with regular shape; S13. Cut each simple geometric structure according to the load type to obtain the initial single-cell model of each lattice design area.

[0008] Further, in the above step S2, according to the load results, use the established multi-objective optimization function to perform topology optimization on each initial single-cell model under multiple working conditions to obtain an optimized single-cell model, including: S21. Take the artificial pseudo-density of the material in the initial single-cell model as the design variable, use deformation, stress, and design domain volume fraction as constraint conditions, and use compliance and thermal compliance as design objectives to construct a multi-objective optimization function of the part under multiple working conditions; S22. Obtain the number of initial single-cell models in each lattice design area, and extract the load type and corresponding load value of the lattice design area; S23. Allocate the load values corresponding to the load type to the initial single-cell models according to the number of models, and use the multi-objective optimization function to perform topology optimization on the initial single-cell models to obtain optimized single-cell models.

[0009] Even further, in the above step S21, the expression of the multi-objective optimization function is: ; ; Among them, q is the number of design working conditions, k is the number of design objectives under a certain working condition, represents the weight of the i-th design objective under the m-th working condition, C mi represents the i-th design objective under the m-th working condition, is the design domain volume fraction, is the upper limit of the volume fraction, p is the artificial pseudo-density, R represents the unbalanced force generated during the structural geometric nonlinear finite element iterative analysis process, u is the structural displacement, u0 is the initial displacement, σ is the structural stress, and σ0 is the initial structural stress; Minimize is to find the minimum value of the function, s.t. is the constraint condition.

[0010] Furthermore, in the above step S23, allocating the load value corresponding to the load type to the single-cell initial model according to the number of models includes: S231. Judge the load type. When the load type includes mechanical loads, evenly allocate the load value corresponding to the mechanical loads to the single-cell initial model; S231. When the load type includes temperature loads, allocate the load value corresponding to the temperature loads to the single-cell initial model.

[0011] In an improved embodiment of the above method for designing a lattice structure based on shape and load, the method further includes: S4. Evaluate each of the single-cell models.

[0012] Furthermore, in the above step S4, evaluating each of the single-cell models includes: S41. Under each working condition, evaluate the performance of the single-cell model by the finite element method; S42. Evaluate the additive manufacturing feasibility of the single-cell model; S43. When the performance evaluation result and the feasibility evaluation both meet the design requirements, complete the lattice structure design; when any one of the performance evaluation result and the feasibility evaluation does not meet the design requirements, re-perform topology optimization on the single-cell initial model according to the multi-objective optimization function.

[0013] The embodiment of the present invention also provides a system for designing a lattice structure based on shape and load, including a single-cell initial model design module, a topology optimization module, and a model parameter optimization module.

[0014] Among them, the single-cell initial model design module is used to obtain the single-cell initial model of the lattice design area on the part according to the structural characteristics and load results of the part, and there is at least one lattice design area; The topology optimization module is used to perform topology optimization on each of the single-cell initial models under multiple working conditions according to the load results by using the established multi-objective optimization function to obtain the optimized single-cell model; The model parameter optimization module is used to reconstruct the lattice unit cell geometric model for each optimized single unit cell model by using the surface fitting method, and optimize the size parameters of each lattice unit cell geometric model according to the designed strength of the part to obtain the final unit cell geometric model.

[0015] Furthermore, the system further includes a performance evaluation module, a feasibility evaluation module, and a judgment module.

[0016] Among them, the performance evaluation module is used to evaluate the performance of the single cell model by using the finite element method under various working conditions; The feasibility evaluation module is used to evaluate the additive manufacturing feasibility of the single cell model; The judgment module is used to complete the lattice structure design when both the performance evaluation result and the feasibility evaluation meet the design requirements; when any one of the performance evaluation result and the feasibility evaluation does not meet the design requirements, re-perform topology optimization on the initial single cell model according to the multi-objective optimization function.

[0017] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of the present specification at least include: 1. The lattice structure design method of the present invention can simplify and split complex configuration parts into parts composed of simple geometric configurations, greatly simplifying the complexity of the model during calculation.

[0018] 2. The lattice structure design method of the present invention can optimize the target component under multiple load conditions (such as mechanical load and temperature load), divide the load according to the load area and apply it to the initial single cell model after segmentation, optimize the structure of the initial single cell model, and perform periodic arrangement after reconstruction to obtain the lattice configuration, shortening the design cycle of the lattice configuration.

[0019] 3. Through the lattice structure designed by the present invention, on the basis of ensuring strength and stiffness, the weight of the part can be significantly reduced, and the goal of reducing the weight by more than 40% compared with general solid components can be achieved.

[0020] 4. The lattice structure design method of the present invention greatly reduces the difficulty of lattice filling design for complex configuration parts under multiple loads, and plays a certain reference and promotion role in the lattice filling design of complex configurations. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 The flowchart of the lattice structure design method based on shape and load disclosed in the embodiments of the present invention; Figure 2 The operation process of the lattice structure design method based on shape and load disclosed in the embodiments of the present invention; Figure 3 The flowchart of the lattice structure design for the cylindrical rotating body structure disclosed in the embodiments of the present invention; Figure 4 The schematic diagram of applying boundary conditions (loads) to the lattice initial models in Region I and Region II respectively disclosed in the embodiments of the present invention; Figure 5 The single-cell models after topology optimization in Region I and Region II of the cylindrical rotating body structure disclosed in the embodiments of the present invention; Figure 6 The reconstruction results of the single-cell models after topology optimization in Region I and Region II of the cylindrical rotating body structure disclosed in the embodiments of the present invention; Figure 7 The architecture diagram of the lattice structure design system based on shape and load disclosed in the embodiments of the present invention; Among them, 701 is the single-cell initial model design module; 702 is the topology optimization module; 703 is the model parameter optimization module; 704 is the performance evaluation module; 705 is the feasibility evaluation module; 706 is the judgment module. Detailed implementation manners

[0023] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0024] The following uses specific specific examples to illustrate the implementation manners of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features of the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0025] The embodiments of the present invention disclose a lattice structure design method based on shape and load. Refer to Figure 1 and Figure 2 As shown, the method includes the following steps: S1. Obtain the single - cell initial model of the lattice design region on the part according to the structural characteristics and load results of the part, where there is at least one lattice design region; S2. According to the load results, perform topology optimization on each of the single - cell initial models under multiple working conditions using the established multi - objective optimization function to obtain the optimized single - cell models; S3. Reconstruct each optimized single - cell model using the surface fitting method to obtain the lattice single - cell geometric model, and optimize the size parameters of each lattice single - cell geometric model according to the design strength of the part to obtain the final single - cell geometric model.

[0026] Further, in the above step S1, obtaining the single - cell initial model of the lattice design region on the part according to the structural characteristics and load results of the part includes: S11. Conduct a load analysis on the part to obtain the load results, and based on the mechanical load and temperature load in the load results, obtain the lattice design regions of the part, and extract the load types and load values borne by each lattice design region. Specifically, when determining the lattice design regions on the part, if a certain region on the part does not bear a load or bears a load lower than the set value, it is ignored and no lattice design is carried out.

[0027] S12. Conduct a structural analysis on the part to obtain the structural characteristics, and simplify each lattice design region according to the structural characteristics to obtain a simple geometric structure with regular shape. When simplifying the lattice design regions, features that are not obvious on the lattice design regions, such as surface strengthening ribs, flanges, holes, etc., can be simplified and removed.

[0028] S13. Cut each simple geometric structure according to the load type to obtain the single - cell initial model of each lattice design region, and this single - cell initial model is a three - dimensional solid model with a solid structure.

[0029] Further, in the above step S2, performing topology optimization on each of the single - cell initial models under multiple working conditions using the established multi - objective optimization function to obtain the optimized single - cell models includes: S21. Take the artificial pseudo - density of the material in the single - cell initial model as the design variable, use deformation, stress, and design domain volume fraction as constraint conditions, and use compliance and thermal compliance as design objectives to construct the multi - objective optimization function of the part under multiple working conditions; S22. Obtain the number of single - cell initial models in each lattice design region, and extract the load types and corresponding load values of the lattice design regions; S23. Assign the load values corresponding to the load type to the single-cell initial model according to the number of models, and perform topology optimization on the single-cell initial model using the multi-objective optimization function to obtain an optimized single-cell model.

[0030] Furthermore, in the above step S21, the expression of the multi-objective optimization function is: ; ; Among them, q is the number of design conditions, k is the number of design objectives under a certain condition, represents the weight of the i-th design objective under the m-th condition, C mi represents the i-th design objective under the m-th condition, is the volume fraction of the design domain, is the upper limit of the volume fraction, p is the artificial pseudo-density, R represents the unbalanced force generated during the structural geometric nonlinear finite element iterative analysis process, u is the structural displacement, u0 is the initial displacement, σ is the structural stress, σ0 is the initial structural stress; Minimize is to find the minimum value of the function, s.t. is the constraint condition.

[0031] Furthermore, in the above step S23, assigning the load values corresponding to the load type to the single-cell initial model according to the number of models includes: S231. Judge the load type. When the load type includes mechanical load, evenly distribute the load value corresponding to the mechanical load (i.e., the total mechanical load magnitude in the lattice design area) to the single-cell initial model; S231. When the load type includes thermal load, assign the load value corresponding to the thermal load to the single-cell initial model.

[0032] Further, in the above step S3, use the surface fitting method to reconstruct each optimized single-cell model to obtain a lattice single-cell geometric model, and optimize the size parameters of each lattice single-cell geometric model according to the part design strength. The specific method is: Use the surface fitting method to reconstruct each optimized single-cell model to make the force-transmitting and load-bearing skeleton in the single-cell uniform, smooth, and continuous, and obtain a lattice single-cell geometric model. Use the following formula to optimize the size of the lattice single-cell geometric model according to the part design strength: ; ; ; Among them, x is a design variable, that is, the key dimension of the unit cell model, is the optimization objective function, k is the number of design objectives under a certain working condition, represents the weight of the i-th design objective, C i represents the i-th design objective, x min and x max are the maximum and minimum thresholds of the design variable, R represents the unbalanced force generated during the iterative analysis of the structural geometric nonlinear finite element, is the volume fraction of the design domain, is the upper limit of the volume fraction, u is the structural displacement, u0 is the initial displacement, σ is the structural stress, σ0 is the initial structural stress, and the final unit cell geometric model can be obtained by solving the above formula.

[0033] In an improved embodiment of the above lattice structure design method based on shape and load, the method further includes: S4. Evaluate each of the single-cell models.

[0034] Furthermore, in the above step S4, as shown in Figure 2 evaluating each of the single-cell models includes: S41. Under each working condition, perform performance evaluation on the single-cell model by the finite element method. The performance evaluation method can be: perform performance evaluation on the strength, stiffness, and heat conduction ability of the lattice filling area formed by the single-cell model through finite element analysis. If any one of the strength reserve, deformation amount, heat insulation / heat transfer, etc. under each working condition does not meet the design requirements, then re-conduct topology optimization design and model reconstruction.

[0035] S42. Perform additive manufacturing feasibility evaluation on the single-cell model. The feasibility evaluation method can be: prepare the reconstructed model by additive manufacturing process. If it cannot be realized, then it is necessary to re-conduct topology optimization design and model reconstruction.

[0036] S43. When the performance evaluation result and the feasibility evaluation both meet the design requirements, complete the lattice structure design; when any one of the performance evaluation result and the feasibility evaluation does not meet the design requirements, re-perform topology optimization on the initial single-cell model according to the multi-objective optimization function.

[0037] Taking the overall aeroengine casing assembly with a cylindrical rotating body structure as an example, the above-mentioned lattice structure design method is described. The cylindrical rotating body structure has a radius of 590 mm, a thickness of 7 mm, and a length of 540 mm. It is divided into two halves along the axial direction and is designed with multiple mounting seats. Under the stamping working condition, the working temperature of the stamping duct is about 650 °C. The main loads borne by the casing assembly during operation are the pressure difference stress caused by the pressure difference between the inner and outer cavities, the axial tensile stress, and the bending stress. The inner surface is uniformly compressed with a magnitude of 3 MPa, the average axial tensile stress is 2000 N, and the average bending stress is 500 N·M. The specific process of lattice design is as follows: First, before designing the lattice unit cell, refer to Figure 3 As shown, according to the main geometric features of the cylindrical rotating body structure, extra features with less influence on the function of the surface, such as mounting edges, limit screw holes, etc., are ignored, and only the morphology of the lattice material filling area is considered to obtain a simplified geometric structure, which is a rotating cylinder with a radius of 589.5 mm, a thickness of 6 mm, and a length of 540 mm.

[0038] Second, according to the simplified geometric structure and the load-bearing area, the simplified geometric model is regularly divided. For example, Figure 3 As shown, according to the load analysis results, the rotating cylinder is decomposed into Region I and Region II. The length of Region I is 260 mm, and the length of Region II is 280 mm. According to the geometric features of the rotating cylinder, the initial unit cell model is set as a sector model with a sweep angle of 3°, a height of 2 mm, and a distance of 2 mm between the front and back surfaces.

[0039] Third, according to the geometric division of Region I and Region II, the loads in each region are distributed and applied to the initial model, and at the same time, boundary conditions are applied to the lattice initial model. For example, as Figure 4 shown, a uniform tensile force of 2000 N and a bending moment of 500 N·M are applied to the upper surface of the initial unit cell geometric model divided in Region I. At the same time, a temperature load of 400 °C is applied to the inner surface, a temperature load of 650 °C is applied to the outer surface, and a periodic constraint is applied to the contact surface of the unit cell geometric model. A uniform tensile force of 1000 N is applied to the upper surface of the initial unit cell geometric model divided in Region II. At the same time, a temperature load of 400 °C is applied to the inner surface, a temperature load of 650 °C is applied to the outer surface, a pressure load of 3 MPa is uniformly applied to the inner surface, and a periodic boundary is applied to the surface of the unit cell geometric model.

[0040] Then, endow the material properties of GH4169 superalloy to the initial unit cell model. The material properties mainly include elastic modulus, density, Poisson's ratio, etc. at different temperatures. Set the objective function of topology optimization. Take the artificial pseudo-density ρ of the material in the design unit as the design variable. When performing the optimization design, set compliance and thermal compliance as the optimization objectives. Among them, minimize the compliance, that is, minC(ρ); minimize the thermal compliance (heat conduction ability), that is, minK(ρ). Weights (W i ) should be assigned to both optimization objectives and considered using the analytic hierarchy process. The given weights of compliance and thermal compliance are 0.74 and 0.26 respectively.

[0041] Next, impose the constraint conditions for the topology optimization design, mainly including: (1) Consider the influence of different volume fraction constraint conditions on the optimization results. Take the volume fraction as the constraint condition and require that the volume fraction ≤ 30%; (2) Consider that the maximum combined stress of stress concentration does not exceed the yield strength σ 0.2 of the material, and σ max ≤ 650 MPa. (3) Set geometric symmetry constraints to ensure the symmetry and uniformity of the structure, that is, the structure is axisymmetric about its geometric center point along the X, Y, and Z planes.

[0042] Use the finite element software Hypermesh to complete the optimization calculation of the above initial unit cell geometric model, and obtain the force transmission path of the topology optimization region. Use the UG·NX software to reconstruct the model of the optimized lattice, including: summarize the discrete force transmission paths in the unit cell model and extend their directions to the model boundary to obtain a regular and manufacturable unit cell model. Arrange the unit cell model periodically, and cover the outer surface of the arranged unit cell model with a 0.5 mm skin to obtain the topologically optimized unit cell models of Region I and Region II as shown in Figure 5 . Reconstruct the unit cell model shown in Figure 4 to obtain the reconstruction result shown in Figure 6 . After completing the lattice filling design of the two regions, assemble and combine the two regions in the software, and restore the part features of the outer surface skin to obtain the digital model of the complete engine casing assembly.

[0043] Finally, the lattice unit cells designed according to the shape are filled back into the split casing model, and mechanical simulation tests such as tensile and torsional tests are carried out on the obtained lattice-filled model for strength verification. Through calculation and analysis, the strength reserve of the casing component filled with the lattice is 1.86 under the design point condition, and the strength initially meets the requirements of engineering design, and is significantly improved compared with the strength reserve of the traditional casing component. The maximum displacement of the casing under the stamping condition is 0.26 mm, which is smaller than the maximum displacement of the traditional structure, that is, the stiffness of the lattice-filled casing is relatively higher. At the same time, the manufacturability of the lattice-filled casing component after model reconstruction is analyzed by using the additive manufacturing auxiliary design software Materialise Magics, powder removal holes with a diameter of 1 mm are set, and the forming direction of additive manufacturing is determined to be printing along the axis.

[0044] It is verified that the weight of the lattice-filled GH4169 superalloy casing component obtained by the present invention is reduced by 40% after additive printing, and the porosity of the lattice-filled area reaches 60%.

[0045] The lattice structure design based on shape and load of the present invention has the following advantages: 1. The lattice structure design method of the present invention can simplify and split complex configuration parts into parts composed of simple geometric configurations, greatly simplifying the complexity of the model during calculation.

[0046] 2. The lattice structure design method of the present invention can optimize the target component under multiple load conditions (such as mechanical load and temperature load), partition the load and apply it to the initial model of the divided unit cell, optimize the structure of the initial model of the unit cell, and obtain the lattice configuration after periodic arrangement, shortening the design cycle of the lattice configuration.

[0047] 3. Through the lattice structure designed by the present invention, on the basis of ensuring strength and stiffness, the weight of the part can be significantly reduced, and the goal of reducing the weight by more than 40% compared with general solid components can be achieved.

[0048] 4. The lattice structure design method of the present invention greatly reduces the difficulty of lattice filling design for parts with complex configurations under multiple loads, and plays a certain reference and promotion role in the lattice filling design of complex configurations.

[0049] Based on the same inventive concept, embodiments of the present invention also provide a lattice structure design system based on shape and load, as described in the following embodiments. Since the principle of the lattice structure design system based on shape and load to solve problems is similar to the lattice structure design method based on shape and load disclosed in the above embodiments, the implementation of the lattice structure design system based on shape and load can refer to the implementation of the lattice structure design method based on shape and load, and the repeated parts will not be elaborated. As used hereinafter, the term "unit" or "module" may be a combination of software and / or hardware that can implement a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0050] Figure 7 is a structural block diagram of a lattice structure design system based on shape and load disclosed in an embodiment of the present invention, as Figure 7 shown. The system includes a single-cell initial model design module 701, a topology optimization module 702, and a model parameter optimization module 703. The structure will be described below.

[0051] Among them, the single-cell initial model design module 701 is used to obtain a single-cell initial model of the lattice design area on the part according to the structural characteristics and load results of the part, and there is at least one lattice design area; The topology optimization module 702 is used to perform topology optimization on each single-cell initial model under multiple working conditions by using the established multi-objective optimization function according to the load results to obtain an optimized single-cell model; The model parameter optimization module 703 is used to reconstruct each optimized single-cell model by using the surface fitting method to obtain a lattice single-cell geometric model, and optimize the size parameters of each lattice single-cell geometric model according to the design strength of the part to obtain the final single-cell geometric model.

[0052] Further, referring to Figure 7 shown, the system further includes a performance evaluation module 704, a manufacturability evaluation module 705, and a judgment module 706.

[0053] Among them, the performance evaluation module 704 is used to evaluate the performance of the single-cell model by using the finite element method under each working condition; The manufacturability evaluation module 705 is used to evaluate the additive manufacturing manufacturability of the single-cell model; The judgment module 706 is used to complete the lattice structure design when both the performance evaluation result and the manufacturability evaluation meet the design requirements; when any one of the performance evaluation result and the manufacturability evaluation does not meet the design requirements, re-perform topology optimization on the single-cell initial model according to the multi-objective optimization function.

[0054] In this embodiment, a computer device is provided, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the above-mentioned arbitrary dot matrix structure design method based on shape and load is implemented to solve the technical problem that the traditional dot matrix design method affects the overall performance of the structure.

[0055] Specifically, the computer device can be a computer terminal, a server, or a similar computing device.

[0056] In this embodiment, a computer-readable storage medium is provided, and the computer-readable storage medium stores a computer program for executing the above-mentioned arbitrary dot matrix structure design method based on shape and load.

[0057] Specifically, the computer-readable storage medium includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassette tapes, magnetic disk storage, or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device. As defined herein, computer-readable storage media do not include transitory media such as modulated data signals and carrier waves.

[0058] Obviously, those skilled in the art should understand that the above-mentioned modules or steps of the embodiments of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. Optionally, they can be implemented by program codes executable by the computing device, so that they can be stored in a storage device and executed by the computing device. And in some cases, the steps shown or described can be executed in a different order than here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to implement. Thus, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0059] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method for lattice structures based on shape and load, characterized in that, Comprising: Obtain the single-cell initial model of the lattice design region on the part according to the structural characteristics and load results of the part, where there is at least one lattice design region; According to the load results, perform topology optimization on each single-cell initial model under multiple working conditions using the established multi-objective optimization function to obtain the optimized single-cell model; Reconstruct each optimized single-cell model using the surface fitting method to obtain the lattice single-cell geometric model, and optimize the size parameters of each lattice single-cell geometric model according to the design strength of the part to obtain the final single-cell geometric model.

2. The method for designing a lattice structure based on shape and load according to claim 1, wherein Obtain the single-cell initial model of the lattice design region on the part according to the structural characteristics and load results of the part, including: Perform load analysis on the part to obtain load results, obtain the lattice design region of the part according to the mechanical load and temperature load in the load results, and extract the load type and load value borne by each lattice design region; Perform structural analysis on the part to obtain structural characteristics, and simplify each lattice design region according to the structural characteristics to obtain a simple geometric structure with regular shape; Cut each simple geometric structure according to the load type to obtain the single-cell initial model of each lattice design region.

3. The method for designing a lattice structure based on shape and load according to claim 1, wherein According to the load results, perform topology optimization on each single-cell initial model under multiple working conditions using the established multi-objective optimization function to obtain the optimized single-cell model, including: Take the artificial pseudo-density of the material in the single-cell initial model as the design variable, use deformation, stress and design domain volume fraction as the constraint conditions, and use compliance and thermal compliance as the design objectives to construct the multi-objective optimization function of the part under multiple working conditions; Obtain the number of single-cell initial models in each lattice design region, and extract the load type and corresponding load value of the lattice design region; Allocate the load value corresponding to the load type to the single-cell initial model according to the number of models, and perform topology optimization on the single-cell initial model using the multi-objective optimization function to obtain the optimized single-cell model.

4. The method for designing a lattice structure based on shape and load according to claim 3, characterized in that The expression of the multi-objective optimization function is: ； ； Among them, q is the number of design conditions, k is the number of design objectives under a certain condition, represents the weight of the i-th design objective under the m-th condition, C mi represents the i-th design objective under the m-th condition, is the volume fraction of the design domain, is the upper limit of the volume fraction, p is the artificial pseudo-density, R represents the unbalanced force generated during the structural geometric nonlinear finite element iterative analysis process. u is the structural displacement, u0 is the initial displacement, σ is the structural stress, σ0 is the initial structural stress, Minimize is to find the minimum value of the function, s.t. is the constraint condition.

5. The method for designing a lattice structure based on shape and load according to claim 1, characterized in that Allocate the load value corresponding to the load type to the single-cell initial model according to the number of models, including: Judge the load type. When the load type includes mechanical load, evenly allocate the load value corresponding to the mechanical load to the single-cell initial model; When the load type includes temperature load, allocate the load value corresponding to the temperature load to the single-cell initial model.

6. The method for designing a lattice structure based on shape and load according to claim 1, wherein Also comprising: Evaluate each single-cell model.

7. The method for designing a lattice structure based on shape and load according to claim 6, wherein Evaluate each single-cell model, including: Under each working condition, perform performance evaluation on the single-cell model by the finite element method; Evaluate the manufacturability of the single-cell model by additive manufacturing; When the performance evaluation result and the manufacturability evaluation both meet the design requirements, complete the lattice structure design; when any one of the performance evaluation result and the manufacturability evaluation does not meet the design requirements, re-perform topology optimization on the single-cell initial model according to the multi-objective optimization function.

8. A lattice structure design system based on shape and load, characterized in that, Comprising: Single-cell initial model design module, which is used to obtain the single-cell initial model of the lattice design area on the part according to the structural characteristics and load results of the part, and there is at least one lattice design area; Topology optimization module, which is used to perform topology optimization on each single-cell initial model under multiple working conditions by using the established multi-objective optimization function according to the load results to obtain the optimized single-cell model; Model parameter optimization module, which is used to reconstruct the lattice unit geometric model for each optimized unit cell model by using the surface fitting method, and optimize the size parameters of each lattice unit geometric model according to the design strength of the part to obtain the final unit cell geometric model.

9. The dot matrix structure design system based on shape and load according to claim 8, characterized in that It also includes: Performance evaluation module, which is used to evaluate the performance of the single-cell model by the finite element method under each working condition; Realizability evaluation module, which is used to evaluate the additive manufacturing realizability of the single-cell model; Judgment module, which is used to complete the lattice structure design when both the performance evaluation result and the realizability evaluation meet the design requirements; when any one of the performance evaluation result and the realizability evaluation does not meet the design requirements, re-perform topology optimization on the single-cell initial model according to the multi-objective optimization function.

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