Lightweight design method for shape maintaining tool of large-opening structure

Abstract

The invention belongs to the technical field of aviation digital assembly, and particularly relates to a lightweight design method of a large-opening structure shape-preserving tool, which comprises the following steps of: 1, acquiring a load and a boundary condition of a large-opening structure in a hoisting and racking process, and according to the load and the boundary condition of the shape-preserving tool in practical application, determining a shape-preserving model of the large-opening structure; designing a topological optimization grid model of the required shape-preserving tool; 2, determining a design area, a response constraint and a target function according to the lightweight requirement of the shape-preserving tool, and then carrying out iterative calculation to obtain a topological optimization grid model after preliminary optimization; 3, performing model reconstruction on the topological optimization grid model after the preliminary optimization, replacing a continuous solid structure in the preliminary optimization model with a space truss structure, and splitting the optimized structure into basic parts to realize shape-preserving tool assembly modularization; and 4, carrying out finite element statics analysis and modal analysis verification on the assembled shape-preserving tool, judging whether an optimized structure meets design requirements or not, if not, modifying part design and reassembling, and if yes, outputting a result.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation digital assembly, and in particular relates to a lightweight design method for a large-opening structure-preserving tooling. Background Art

[0002] The large opening structure in the aircraft cabin is a typical structure that is easy to become unstable and deform under the action of uneven stress, and the deformation state is also difficult to control. At the same time, the docking surface inside the cabin is prone to structural deformation that is inconsistent with the design during the assembly process due to its low stiffness, and the complexity of the structure makes it difficult to predict the distribution of assembly stress and deformation. However, for the docking surface of the large opening structure, the existing shape-keeping device is a rigid tooling. Since only the guarantee of its own stiffness is considered, the designed structure is often complex and inconvenient to disassemble, which brings a series of other impacts to the actual assembly operation. In addition, the design of the shape-keeping tooling is usually based on design experience and subjective judgment to select and design the form of the shape-keeping frame and the shape-keeping tooling and product support points. There is a lack of effective theoretical analysis of the shape-keeping tooling material, strength, and deformation during use, and it is impossible to solve the problem of product opening deformation during actual use. Therefore, in order to fundamentally solve this problem, a lightweight design method for shape-keeping tooling suitable for large opening structures is needed.

[0003] From the current research status at home and abroad, it can be seen that the existing research on lightweight large-opening structure-preserving tooling mainly relies on the experience of designers to make rough stiffness estimates, which results in bulky tooling structures, high costs, and great difficulties in manufacturing and use. Summary of the invention

[0004] Purpose of the invention: In view of the characteristics of large-opening structures that are prone to instability and deformation, and in order to avoid relying on rough stiffness estimation based on experience, which leads to bulky tooling structures and high costs, the present invention provides a lightweight design method for large-opening structure-preserving tooling. The method effectively analyzes the stress distribution of the tooling under load in actual applications, and performs topological optimization to seek lightweighting, and finally completes assembly, thereby reducing the weight of the large-opening structure-preserving tooling, which is used to optimize the assembly process of large aircraft large-opening structures and promote the development of large aircraft assembly technology. Summary of the invention:

[0006] A lightweight design method for a large-opening structure-preserving tooling, the steps are as follows:

[0007] Step 1: Obtain the loads and boundary conditions of the large opening structure during the hoisting process, and design the topological optimization mesh model of the required conformal tooling according to the loads and boundary conditions of the conformal tooling in actual application;

[0008] Step 2: Determine the design area, response constraints and objective function according to the requirements of lightweight conformal tooling, and then perform iterative calculations to obtain the topology optimization mesh model after preliminary optimization;

[0009] Step 3: Reconstruct the topology optimization mesh model after preliminary optimization, replace the continuous solid structure in the preliminary optimization model with a spatial truss structure, split the optimized structure into basic parts, and realize the assembly of conformal tooling;

[0010] Step 4: Perform finite element static analysis and modal analysis verification on the assembled conformal tooling to determine whether the optimized structure meets the design requirements. If not, modify the part design and reassemble it. If it does, output the results.

[0011] Further, in step one, the specific process is as follows:

[0012] 1.1, measure the size information of the large opening structure, determine the design domain and non-design domain according to the reference structure, take the positioning support end of the conformal tooling as the non-design domain, and the main structure as the design domain. The design domain is determined as a solid cuboid, and use the modeling software to preliminarily build a geometric model of the conformal tooling topology optimization;

[0013] 1.2. According to the hoisting position and rising displacement of the large opening structure during the hoisting process, the load and boundary condition information of the large opening structure is obtained, and the pre-processing process of the optimization model of the conformal tooling is further completed. The design domain and non-design domain entity models of the topological optimization structure of the conformal tooling are meshed using topological optimization software to obtain the topological optimization mesh model of the conformal tooling.

[0014] Further, in step 2, the specific process is as follows:

[0015] 2.1. According to the requirement of lightweight conformal tooling structure, the middle main mass distribution area is set as the design optimization area, and the design variables that can reflect the stiffness and mass of the design domain are selected as constraints and objective functions;

[0016] 2.2, taking the strain energy of the structure as the optimization target, applying the volume constraint upper limit of the conformal area, and performing structural topology optimization, so that the optimized conformal tooling can control the material usage and the warping deformation of the conformal area within a certain range, seek the optimal distribution of the material, and achieve the minimization of the structural flexibility under given boundary conditions and external forces;

[0017] 2.3, the maximum flexibility minimization topology optimization is performed for the single load condition, and the linear weighted flexibility minimization topology optimization is performed for the multi-load condition, using the maximum flexibility minimization objective function and the linear weighted flexibility minimization objective function respectively;

[0018] 2.4. By analyzing the convergence of the strain energy response under volume constraints, it is judged whether the optimized structure meets the optimization goal. The convergence conditions and number of iterations are set. If the strain energy meets the conditions, the preliminary optimization result of the conformal tooling is obtained. If the conditions are not met, the iteration is continued until convergence is completed. If convergence cannot be completed within the specified number of iterations, the parameters are modified and the topology optimization is performed again until the preliminary optimization of the structure is completed.

[0019] Further, in step three, the process is as follows:

[0020] 3.1. Export the preliminary result file of topology optimization, and reconstruct the model after export; reconstruct the design domain, slice the topology optimization result to obtain the cross-sectional curve, and use a straight line to fit it to obtain the optimized fitting result;

[0021] 3.2. According to the optimization fitting results, the conformal tooling model is split into basic parts, and connected and assembled to realize the assembly of lightweight conformal tooling.

[0022] Further, in step 4, the process is as follows:

[0023] 4.1. Import the optimized external model of the conformal tooling, divide the mesh, define the material, section, specify the section material properties, set the boundary conditions and loads, and use the finite element software to perform static analysis on the reconstructed model to obtain the stress and displacement analysis results;

[0024] 4.2. According to the stress-strain analysis results, analyze the insufficient rigidity and stress concentration areas of the optimized structure of the conformal tooling, and strengthen the structural rigidity and alleviate the structural stress concentration based on the shape optimization principle;

[0025] 4.3. Use finite element software to perform modal analysis on the reconstructed model of the conformal tooling. Use the fourth-order natural frequency results to analyze the structural natural vibration characteristics to determine whether it meets the design requirements. If the structural natural vibration characteristics are smaller than the unoptimized conformal tooling structure, the design requirements are met. If not, modify the part design and reassemble.

[0026] Furthermore, the linear weighted compliance minimization objective function is as follows:

[0027]

[0028] 0<ρ min ≤ρ e ≤1

[0029] w is the weight factor, c j is the compliance, the subscript j indicates the jth load condition, is the design domain volume, f is the volume ratio, ρ min is the minimum cell density, ρ eis the relative density of unit e.

[0030] Furthermore, the maximum compliance minimization objective function is as follows:

[0031] min:max(c j )

[0032]

[0033] 0<ρ min ≤ρ e ≤1

[0034] V is the optimized volume.

[0035] Furthermore, basic parts include: rods, beams, and frames.

[0036] The present invention provides a lightweight design method for a large-opening structure conformal tooling, which effectively analyzes the stress distribution of the tooling under load in actual applications, performs topological optimization to seek lightweighting, and finally completes assembly, thereby reducing the weight of the large-opening structure conformal tooling, and is used to optimize the large-opening structure assembly process of large aircraft and promote the development of large aircraft assembly technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flow chart of a lightweight design method for a large-opening structure-preserving tooling;

[0038] Figure 2 Schematic diagram of the initial integrated model of the large opening structure retaining tooling;

[0039] Figure 3 Schematic diagram of the topologically optimized large opening structure conformal tooling model;

[0040] Figure 4 Schematic diagram of the assembly model of the large opening structure retaining tooling;

[0041] Figure 5 Schematic diagram of stress and strain in static analysis of the large opening structure conformal tooling frame structure;

[0042] Figure 6 Schematic diagram of strain energy for static analysis of the large opening structure conformal tooling frame structure. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0044] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0045] Based on the topological optimization method, this invention proposes a lightweight design method for large opening structure conformal tooling. The steps are as follows:

[0046] 1. Obtain the loads and boundary conditions of the large opening structure during the hoisting process, and design the integrated model of the required shape-keeping tooling according to the loads and boundary conditions of the shape-keeping tooling in actual application.

[0047] 1.1 Measure the dimensional information of the large opening structure, determine the design domain and non-design domain based on the reference structure, take the positioning support end of the conformal tooling as the non-design domain, and the main structure as the design domain. The design domain is determined as a solid cuboid, and use the modeling software to preliminarily construct a geometric model of the topological optimization of the conformal tooling.

[0048] 1.2 According to the hoisting position and rising displacement of the large opening structure during the hoisting process, the load, boundary conditions and other working condition information of the large opening structure are obtained, and the pre-processing process of the optimization model of the conformal tooling is further completed. The design domain and non-design domain solid models of the topological optimization structure of the conformal tooling are meshed using topology optimization software to obtain the topological optimization mesh model of the conformal tooling.

[0049] 2. After establishing the topology optimization model based on load, boundary conditions and other working condition information, determine the design area, response constraints and objective function according to the requirements of lightweight conformal tooling, and then perform iterative calculations to obtain the optimal solution target structure.

[0050] 2.1 According to the demand for lightweight conformal tooling structure, the conformal tooling needs to achieve lightweight design of the conformal tooling structure while ensuring the conformal effect. Therefore, the middle main mass distribution area is set as the design optimization area, and the design variables that can reflect the stiffness and mass of the design domain are selected as constraints and objective functions.

[0051] 2.2 Taking the strain energy of the structure as the optimization target, considering the deformation and quality requirements, the volume constraint upper limit of the conformal area is imposed, and the structural topology optimization is performed. The optimized conformal tooling seeks the optimal distribution of materials while controlling the material usage and the warping deformation of the conformal area within a certain range, so as to minimize the structural flexibility under given boundary conditions and external forces.

[0052] The minimum mesh size is set to eliminate the common numerical instability problem of mesh dependence, avoid the computational difficulties caused by too many meshes, and set plane symmetry to ensure the symmetry of the optimized structure.

[0053] 2.3 Since the conformal tooling with large opening structure is subjected to different complex external loads during the conformal process, the maximum flexibility minimization topology optimization is performed for the single load condition, and the linear weighted flexibility minimization topology optimization is performed for the multi-load condition. The maximum flexibility minimization objective function and the linear weighted flexibility minimization objective function are used respectively, and the linear weighted flexibility minimization objective function is as follows:

[0054]

[0055] 0<ρ min ≤ρ e ≤1

[0056] The maximum compliance minimization objective function is as follows:

[0057] min:max(c j )

[0058]

[0059] 0<ρ min ≤ρ e ≤1

[0060] w is the weight factor, c j is the compliance, subscript j indicates the jth load condition, V is the optimized volume, is the design domain volume, f is the volume ratio, ρ min is the minimum cell density, ρ e is the relative density of unit e.

[0061] 2.4 By analyzing the convergence of the strain energy response under volume constraints, it is judged whether the optimized structure meets the optimization objectives. The convergence conditions and number of iterations are set. If the strain energy meets the conditions, the preliminary optimization results of the conformal tooling are obtained. If the conditions are not met, the iteration is continued until convergence is achieved. If convergence cannot be achieved within the specified number of iterations, the parameters are modified and the topology optimization is performed again until the preliminary optimization of the structure is completed.

[0062] 3. Reconstruct the model of the preliminary optimization results, replace the continuous solid structure in the preliminary optimization model with a spatial truss structure, split the optimized structure into basic parts such as rods and beams, and realize the assembly of shape-preserving tooling.

[0063] 3.1 Export the preliminary result file of topology optimization and reconstruct the model after export. First, reconstruct the design domain, slice the topology optimization result to obtain the cross-sectional curve, and use a straight line to fit it to obtain the optimized fitting result.

[0064] 3.2 According to the optimization fitting results, the conformal tooling model is split into basic parts such as rods, beams, and frames, and connected and assembled to realize the assembly of lightweight conformal tooling.

[0065] 4. Perform finite element statics analysis and modal analysis verification on the assembled conformal tooling to determine whether the optimized structure meets the design requirements. If not, modify the part design and reassemble it. If it does, output the results.

[0066] 4.1 Import the optimized external model of the conformal tooling, divide the mesh, define the material, section, specify the section material properties, set the boundary conditions and loads, and use finite element software to perform static analysis on the reconstructed model to obtain stress and displacement analysis results.

[0067] 4.2 According to the stress-strain analysis results, analyze the insufficient rigidity and stress concentration areas of the optimized structure of the conformal tooling, and strengthen the structural rigidity and alleviate the structural stress concentration based on the shape optimization principle, such as setting chamfers, reinforcing ribs, and thickening.

[0068] 4.3 Use finite element software to perform modal analysis on the reconstructed model of the conformal tooling. Use the fourth-order natural frequency results to analyze the structural natural vibration characteristics to determine whether it meets the design requirements. If the structural natural vibration characteristics are smaller than the unoptimized conformal tooling structure, the design requirements are met. If not, modify the part design and reassemble.

[0069] Example

[0070] like Figure 1 As shown, this example takes a large opening structure and Q235 steel material as an example to provide a lightweight design method for a large opening structure conformal tooling, including the following steps:

[0071] 1. Obtain the required load and boundary conditions of the large opening structure, and design the integrated model of the required conformal tooling based on the applied load and boundary conditions.

[0072] 1.1 Measure the size information of the large opening structure, and preliminarily construct a geometric model of a conformal tooling with a length of l = 4000 mm, a width of d = 1500 mm, and a height of h = 1500 mm. This area is used as the design domain, and the non-design domain is the corresponding conformal positioning structure.

[0073] 1.2 Use force sensors to measure and obtain the load information and boundary conditions of the large opening structure. The loads are located at the four corners of the top, and each load is set with three components. Fixed constraints are applied to the four corners of the bottom of the tooling to limit the degrees of freedom in the three translation directions and the degrees of freedom in the three rotation directions, such as Figure 2 The load information is shown in Table 1:

[0074] Table 1 Load information of large opening structure

[0075] Load Component <![CDATA[F1]]> <![CDATA[F2]]> <![CDATA[F3]]> <![CDATA[F4]]> x 2550 1895 -3805 -3340 y -1750 -2865 -1790 -2350 z 2760 -1990 -2360 2700

[0076] 2. Based on the load, boundary conditions and working condition information, a topology optimization model is established to determine the design area, response constraints, objective function, etc., and iterative calculations are performed to obtain the optimal solution target structure.

[0077] 2.1 Based on the obtained load, boundary conditions and working condition information, a topological optimization model of the conformal tooling is established. Since the tooling bears the load as a whole, the entire model is set as the design area, and the conformal positioning structure is selected as the non-design domain.

[0078] 2.2 According to the requirements of grid division, the conformal positioning structure of the conformal tooling model is appropriately simplified, non-main components such as bolts are removed, and the main load-bearing components are retained. The simplified structure is imported into the finite element software. Q235 steel is selected as the material, and the material parameters are shown in Table 2.

[0079] Table 2 Q235 steel material parameters

[0080]

[0081] 2.3 The conformal tooling design structure adopts the tetrahedral element C3D6 to obtain the conformal tooling design domain mesh model. In the contact module, the design domain and the non-design domain are bound and constrained to simulate the fixed relationship between the components.

[0082] 2.4 In the load and boundary module, the load conditions in Table 1 are applied in the LOAD module according to the actual working conditions.

[0083] 2.5 Use programming language to write a numerical method for topological optimization with the minimum strain energy of the structure as the optimization target and the design domain volume as the constraint condition, where the optimization volume is set to 10% of the initial volume, and the structural topology optimization is performed with the minimum strain energy of the structure as the optimization target. The optimization results are imported into the finite element software for dynamic and static mechanical simulation, and the volume and strain energy results are extracted. Iteration is performed until the final optimized structure is obtained. At the same time, the minimum size needs to be set to 0.1 in the program to eliminate the common numerical instability problem caused by mesh dependence, and the plane symmetry is set to ensure the symmetry of the optimized conformal tooling structure.

[0084] 2.6 In the topology optimization analysis of linear weighted compliance minimization and compliance maximum minimization under multiple working conditions, the topology optimization unit density retention threshold is set to 0.5, and the OC optimization criterion is selected for topology optimization iterative calculation. The tolerance of iterative convergence is defined as 0.01%. In this way, the optimized conformal tooling can seek the optimal distribution of materials while controlling the material usage within a certain range, so as to achieve the minimization of structural flexibility under given boundary conditions and external forces.

[0085] 2.7 According to the strain energy and volume of the optimized structure, iterative convergence is performed until the conditions are met. If it is unreasonable, the material distribution parameters are modified and the topology optimization is performed again. If it is reasonable, the results are output. The optimization results are as follows: Figure 3 shown.

[0086] 3. Re-optimize the preliminary reconstruction model, replace the continuous solid structure in the preliminary optimization model with a spatial truss structure, split the optimized structure into basic parts such as rods and beams, and realize the assembly of shape-preserving tooling.

[0087] 3.1 According to the topology optimization results, the material distribution in the topology optimization model is mapped to nodes (connection points) and rods (components), the force characteristics of the rods are analyzed, and hollow rods are selected as connectors for the shape-preserving tooling to form the preliminary structural selection and layout of the truss structure.

[0088] 3.2 According to the design of the spatial truss structure, it is further divided into basic parts, straight rods and diagonal rods are selected to ensure the bearing capacity in all directions, and beams are selected as bending and torsion components.

[0089] 3.3 Modularize the basic parts to ensure that they can be connected to each other during assembly and meet the requirements of the shape-preserving tooling. At the same time, design reasonable connectors (such as bolts, welding, riveting, etc.) to ensure the integrity and stability of the structure and realize the assembly of the shape-preserving tooling. The results are as follows: Figure 4 shown.

[0090] 4. Conduct finite element analysis and verification on the assembled conformal tooling space truss, analyze its stress, displacement, strain energy and natural frequency to determine whether it meets the design requirements. If not, modify the part design and reassemble it. If so, complete the lightweight design of the conformal tooling.

[0091] 4.1 Import the reconstructed space truss structure into the finite element software, use the finite element software to establish a three-dimensional geometric model of the conformal tooling structure, assign the material properties of Q235 steel to different components in the material module, and assemble them into a space truss assembly model in the assembly module.

[0092] 4.2 Use the Tie constraint function in the Constraint module to bind the contact surface sets of each component of the conformal tooling to make them conform to the actual contact state.

[0093] 4.3 Use the mesh module to divide the mesh for different parts, using the reduced integration hexahedral element C3D8R

[0094] , and set enhanced hourglass control to reduce mesh distortion. A total of 81006 units are divided. Then, in the load and boundary module, the motion coupling reference point of the conformal end surface is established, and the loads shown in Table 1 are applied to the reference point.

[0095] 4.4 Read the static simulation result file of the conformal tooling, and its stress-strain, strain energy, and natural frequency are as follows: Figure 5 , Figure 6 As shown in Table 3, it can be seen from the stress-strain cloud diagram and curve that the conformal tooling space truss structure has no obvious stress concentration and dangerous deformation position, and the structural stiffness and stability meet the requirements.

[0096] Table 3 Natural frequency of the conformal tooling truss structure

[0097]

[0098]

[0099] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the embodiment of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0100] Through the description of the above implementation modes, those skilled in the art can clearly understand that the above implementation modes can be implemented by means of software plus a necessary general hardware platform, and of course by means of hardware, but in many cases the former is a better implementation mode. The above describes the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above specific implementation modes, which are merely illustrative and not restrictive. Under the enlightenment of the present invention, those skilled in the art can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A lightweight design method for a large-opening structure-preserving tooling, characterized by: Here are the steps: Step 1: Obtain the loads and boundary conditions of the large opening structure during the hoisting process, and design the topological optimization mesh model of the required conformal tooling according to the loads and boundary conditions of the conformal tooling in actual application; Step 2: Determine the design area, response constraints and objective function according to the requirements of lightweight conformal tooling, and then perform iterative calculations to obtain the topology optimization mesh model after preliminary optimization; Step 3: Reconstruct the topology optimization mesh model after preliminary optimization, replace the continuous solid structure in the preliminary optimization model with a spatial truss structure, split the optimized structure into basic parts, and realize the assembly of conformal tooling; Step 4: Perform finite element static analysis and modal analysis verification on the assembled conformal tooling to determine whether the optimized structure meets the design requirements. If not, modify the part design and reassemble it. If it does, output the results.

2. The method according to claim 1, characterized in that: In step one, the specific process is as follows: 1.1, measure the size information of the large opening structure, determine the design domain and non-design domain according to the reference structure, take the positioning support end of the conformal tooling as the non-design domain, and the main structure as the design domain. The design domain is determined as a solid cuboid, and use the modeling software to preliminarily build a geometric model of the conformal tooling topology optimization; 1.

2. According to the hoisting position and rising displacement of the large opening structure during the hoisting process, the load and boundary condition information of the large opening structure is obtained, and the pre-processing process of the optimization model of the conformal tooling is further completed. The design domain and non-design domain entity models of the topological optimization structure of the conformal tooling are meshed using topological optimization software to obtain the topological optimization mesh model of the conformal tooling.

3. The method according to claim 1, characterized in that: In step 2, the specific process is as follows: 2.

1. According to the requirement of lightweight conformal tooling structure, the middle main mass distribution area is set as the design optimization area, and the design variables that can reflect the stiffness and mass of the design domain are selected as constraints and objective functions; 2.2, taking the strain energy of the structure as the optimization target, applying the volume constraint upper limit of the conformal area, and performing structural topology optimization, so that the optimized conformal tooling can control the material usage and the warping deformation of the conformal area within a certain range, seek the optimal distribution of the material, and achieve the minimization of the structural flexibility under given boundary conditions and external forces; 2.3, the maximum flexibility minimization topology optimization is performed for the single load condition, and the linear weighted flexibility minimization topology optimization is performed for the multi-load condition, using the maximum flexibility minimization objective function and the linear weighted flexibility minimization objective function respectively; 2.

4. By analyzing the convergence of the strain energy response under volume constraints, it is judged whether the optimized structure meets the optimization goal. The convergence conditions and number of iterations are set. If the strain energy meets the conditions, the preliminary optimization result of the conformal tooling is obtained. If the conditions are not met, the iteration is continued until convergence is completed. If convergence cannot be completed within the specified number of iterations, the parameters are modified and the topology optimization is performed again until the preliminary optimization of the structure is completed.

4. The method according to claim 3, characterized in that: In step three, the process is as follows: 3.

1. Export the preliminary result file of topology optimization, and reconstruct the model after export; reconstruct the design domain, slice the topology optimization result to obtain the cross-sectional curve, and use a straight line to fit it to obtain the optimized fitting result; 3.

2. According to the optimization fitting results, the conformal tooling model is split into basic parts, and connected and assembled to realize the assembly of lightweight conformal tooling.

5. The method according to claim 4, characterized in that: In step 4, the process is as follows: 4.

1. Import the optimized external model of the conformal tooling, divide the mesh, define the material, section, specify the section material properties, set the boundary conditions and loads, and use the finite element software to perform static analysis on the reconstructed model to obtain the stress and displacement analysis results; 4.

2. According to the stress-strain analysis results, analyze the insufficient rigidity and stress concentration areas of the optimized structure of the conformal tooling, and strengthen the structural rigidity and alleviate the structural stress concentration based on the shape optimization principle; 4.

3. Use finite element software to perform modal analysis on the reconstructed model of the conformal tooling. Use the fourth-order natural frequency results to analyze the structural natural vibration characteristics to determine whether it meets the design requirements. If the structural natural vibration characteristics are smaller than the unoptimized conformal tooling structure, the design requirements are met. If not, modify the part design and reassemble.

6. The method according to claim 5, characterized in that: The linear weighted compliance minimization objective function is as follows: 0<ρ min ≤ρ e ≤1 w is the weight factor, c j is the compliance, the subscript j indicates the jth load condition, is the design domain volume, f is the volume ratio, ρ min is the minimum cell density, ρ e is the relative density of unit e.

7. The method according to claim 6, characterized in that: The maximum compliance minimization objective function is as follows: min:max(c j ) 0<ρ min ≤ρ e ≤1 V is the optimized volume.

8. The method according to claim 7, characterized in that: Basic parts include: rods, beams, and frames.

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