A method and system for converter tank design

Abstract

The application discloses a converter box design method and system, and belongs to the technical field of box structure design. The application solves the problem of lacking of systematic design method in preparation of large bearing parts by using light materials such as carbon fibers. The application comprises the following steps: S1, obtaining a basic structure model of the converter box; S2, splitting the basic structure model of the converter box into several substructure components; S3, material selection optimization; S4, performing layer structure optimization, and sequentially comprising layer block thickness optimization, layer sequence optimization and weight optimization; S5, performing connection structure optimization; S6, obtaining a converter box design scheme, and preparing the converter box according to the converter box design scheme. The converter box design scheme obtained finally not only can meet the actual preparation requirements of the converter box, but also takes into account good mechanical properties and lightweight design, and is more conducive to the actual application of the converter box.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of box structure design, and particularly relates to a converter box design method and system. BACKGROUND

[0002] As a core component of vehicle operation, the traction converter of rail transit mainly undertakes the functions of energy conversion and transmission, and its performance directly affects the operation of the vehicle and the in-vehicle riding environment. A large number of electrical components are installed inside the converter, and the converter has a complex structure and a large self-weight. The converter box as a carrier must first be able to be safely and stably installed at the bottom of the vehicle, and secondly must be able to ensure the normal operating environment of the internal components, thus involving various design requirements such as protection, lightweight, cooling, noise reduction, maintainability, etc.

[0003] The converter box of the existing rail transit at home and abroad is mainly made of aluminum alloy, and the surface is protected by anodic oxidation or adding a surface coating. With the continuous progress of science and technology, boxes made of non-metallic materials such as silicon carbide and carbon fiber have gradually entered our field of vision. Carbon fiber has excellent properties such as low density, high specific strength, high specific modulus, high temperature resistance, fatigue resistance, and friction resistance, so that the technical development and application of carbon fiber in rail vehicles are in a stage of breakthrough development, and are realizing the transformation from small structural parts to large structural parts and from non-load-bearing parts to large load-bearing parts. If carbon fiber can be used to prepare large load-bearing parts (such as converter boxes), it will have a significant impact on the lightweight of large load-bearing parts.

[0004] However, at present, when carbon fiber is used to prepare large load-bearing parts, it is mostly designed based on experience without a systematic design method, which limits the performance of the designed large load-bearing parts. When the large load-bearing parts are subjected to complex and variable stresses in long-term use, fatigue damage and structural damage may occur, affecting the safe operation of the rail transit and increasing the cost of later maintenance and replacement. With the continuous deepening of research, if a scientific and perfect design method for large load-bearing parts can be provided, the performance of the load-bearing parts will be greatly improved, providing a strong guarantee for the safe and efficient operation of rail transit. SUMMARY

[0005] In view of the problem in the prior art that there is a lack of systematic design method in the process of preparing large bearing parts, especially rail vehicle converter box, by using carbon fiber, and the performance of the non-metallic material converter box designed and manufactured according to traditional experience is limited, and the converter box cannot fully meet the use requirements in the whole life cycle, the present application provides a converter box design method and system in the field of rail transportation, the strength of the converter box prepared according to the design method in the present application meets the standard requirements of DINEN 12663-1:2024 'Structural requirements for railway vehicles-car body', IEC 61373:2024 'Railway vehicle equipment-Standard for shock and vibration tests', and TB / T 3548-2019 'General specification for strength design and test identification of rolling stock', and the vibration deformation of the converter box generated in the process of normal operation of the vehicle does not affect the overall dustproof and waterproof performance of the converter box.

[0006] The technical scheme adopted by the present application is as follows:

[0007] A converter box design method, comprising the following steps:

[0008] S1: obtaining basic parameter data of an existing converter box, the basic parameter data including structure parameter data, manufacturing material data, stiffness data, strength data and thickness data of the existing converter box, and obtaining a basic structure model of the converter box based on the structure parameter data;

[0009] S2: splitting the basic structure model of the converter box into a plurality of sub-structure components, the plurality of sub-structure components being a main frame structure, a main bearing structure, a secondary bearing structure and an accessory respectively;

[0010] S3: obtaining the strength and density of the manufacturing material of the existing converter box based on the manufacturing material data obtained in S1, and selecting a new manufacturing material for the converter box based on the strength and density of the original manufacturing material, the strength of the new manufacturing material being greater than or equal to the strength of the manufacturing material of the existing converter box, and the density of the new manufacturing material being less than the density of the manufacturing material of the existing converter box; selecting any one of the selected new manufacturing materials as the manufacturing material of the converter box, and performing material selection optimization based on the selected new manufacturing material to obtain a material selection result;

[0011] S4: obtaining performance parameters of the new manufacturing material based on the material selection result obtained in S3, the performance parameters including strength, stiffness, thickness and density, and performing layer structure optimization on the sub-structure components with composite laminate structure based on the performance parameters of the new manufacturing material to obtain layer structure design parameters, and the layer structure optimization including layer block thickness optimization, layer sequence optimization and weight optimization in sequence;

[0012] S5: based on the layup structure design parameters obtained in S4, the connection structure between each sub-structure component is optimized to obtain connection structure design parameters;

[0013] S6: the material selection results obtained in S3, the layup structure design parameters obtained in S4, and the connection structure design parameters obtained in S5 are integrated to obtain a converter box design scheme, and a converter box is prepared according to the converter box design scheme.

[0014] As preferred, the layup structure optimization in S4 is calculated by using a genetic algorithm, and the specific steps include:

[0015] S401, layup block thickness optimization: according to the load distribution of the converter box, each sub-structure component is partitioned, and based on the performance parameters of the new manufacturing material, the initial laminates with corresponding number and corresponding angle are selected from the four standard layup angles of ±45°, 0°, and 90° for each region, and the number of initial laminates in each region is overlapped in any order to form a number of layup blocks, the stiffness and strength of the layup blocks obtained in each region are greater than or equal to the stiffness and strength of the corresponding region in the existing converter box, and then the thickness of each layup block is optimized, the optimization variable is the number of initial laminates in each region of the layup block, the thickness optimization of the layup block is to seek the thickness of each region of the layup block under the constraints of strength, stiffness, and stability, and the initial thickness parameters of each layup block are obtained, and the weight of each region after the thickness optimization of the layup block is less than the weight of the region in the existing converter box;

[0016] S402, layup sequence optimization: first, the layup blocks after thickness optimization in each region are cut, then the adjacent layup blocks are integrated according to the layup angle, number of initial laminates, and corresponding relationship of adjacent initial laminates in the layup blocks of different regions, so that a shared layup structure is formed between the adjacent layup blocks, and finally the layup sequence is optimized based on the shared layup structure, the optimization variable is the layup sequence of each initial laminate in each layup block, the layup sequence optimization is to seek the layup sequence of each initial laminate in each layup block under the constraints of layup block stress and strain, and the maximum critical buckling load of the structure, and the layup sequence parameters of each layup block are obtained;

[0017] S403, weight optimization: the optimization variable is the thickness of each initial laminate in each region of the layup block, the weight optimization is to seek the optimal thickness of each initial laminate in each layup block under the constraints of strength, stiffness, and stability, and the weight of the layup block is the lightest, and the final thickness parameters of each layup block are obtained through the optimal thickness of each initial laminate in each layup block;

[0018] The layup sequence parameters of each layup block and the final thickness parameters of each layup block obtained above constitute the layup structure design parameters.

[0019] As preferred, the model formula for the ply block thickness optimization in S401 is:

[0020]

[0021] wherein, represents the optimal initial number of laminates in the i ply block of the x th region, xi represents the initial number of laminates in the ply block, i represents the initial number of laminates in the ply block of the Xi th region, i represents the thickness value of the ply block of the th region, and Z represents the initial thickness value of the initial laminates, Xi(min) represents the minimum thickness value of the ply block defined in the i th region, Xi(max) represents the maximum thickness value of the ply block defined in the i th region, Fi represents the structural stiffness value of the ply block of the i th region, F represents the design value of the structural stiffness constraint of the i th region, Ai represents the structural strength value of the ply block of the i th region, A represents the design value of the structural strength constraint of the i ply block under boundary constraints, Bi represents the structural deformation value of the ply block of the i th region, B represents the design value of the structural deformation constraint of the i ply block under boundary constraints ，V represents the volume fraction of the i th region.

[0022] As preferred, the model formula for the ply sequence optimization in S402 is:

[0023] ;

[0024] wherein, represents the optimal ply sequence of the initial laminates in the ply block, y represents the ply sequence of the initial laminates in the ply block, yi represents the ply sequence of the initial laminates in the ply block of the i th region, E represents the critical buckling load of the ply block of the i th region,Di represents the structural directional strain value of the first i region layup block, D represents the structural directional strain design value of the first i region layup block under boundary constraint, Ci represents the structural directional stress value of the first i region layup block, C is the structural stress value of the first i region layup block under boundary constraint.

[0025] As preferred, the model formula of weight optimization in S403 is:

[0026]

[0027] In the formula, represents the optimal thickness value of each initial laminate in the layup block, z represents the thickness value of the initial laminate in the layup block, zi represents the thickness value of the initial laminate in the first i region layup block, m represents the weight of the first i region layup block, Fi represents the structural stiffness value of the first i region layup block, F represents the structural stiffness design value of the first i region constraint, Ai represents the structural strength value of the first i region layup block, A is the structural strength design value of the first i region layup block under boundary constraint, Bi represents the structural deformation value of the first i region layup block, B represents the structural deformation design value of the first i region layup block under boundary constraint.

[0028] As preferred, the cutting in S402 specifically includes the following steps:

[0029] S4021: Determine the shape and size of the preliminary cutting window according to the position of the layup block in the converter tank;

[0030] S4022: Determine the magnification parameters of the preliminary cutting window based on the material selection results and the initial thickness parameters of each layup block, and magnify the preliminary cutting window through the magnification parameters to obtain the optimized cutting window;

[0031] S4023: Obtain factory size data of the new manufacturing material based on the material selection result, obtain window size and shape limiting parameters based on the factory size data, compare the size and shape parameters of the optimized cutting window with the window size and shape limiting parameters, optimize the optimized cutting window according to the comparison result, and obtain a final cutting window;

[0032] The optimization process includes: if the size and shape parameters of the optimized cutting window meet the limitation of the window size and shape limiting parameters, the optimized cutting window is not adjusted, and the optimized cutting window is the final cutting window; if the size and shape parameters of the optimized cutting window do not meet the limitation of the window size and shape limiting parameters, the preliminary cutting window is reduced based on the window size and shape limiting parameters, and the final cutting window is obtained;

[0033] S4024: Cutting the layup block using the final cutting window to obtain a cut layup block.

[0034] As preferred, the specific steps of S6 include:

[0035] S601, based on the layup structure design parameters, prepare a substructure component sample, detect whether the stiffness and strength of the substructure component sample corresponding to different parts of the converter box are greater than or equal to the stiffness and strength of the existing converter box at the part, if the requirement is met, proceed to S602, if the requirement is not met, return to S4 and re-optimize;

[0036] S602, manufacture substructure component parts with composite laminate structure according to the layup structure design parameters, manufacture the remaining substructure component parts according to the structure parameter data of the existing converter box, detect whether the process parameter values of the geometric assembly relationship of each substructure component part meet the set values limited by the connection structure design parameters, the process parameter values of the geometric assembly relationship include interface parameters, hole diameter position and size; if the requirement is met, proceed to S603, if the requirement is not met, return to S4 and S5 and re-optimize;

[0037] S603, assemble each substructure component part obtained in S602 into an assembly based on the connection structure design parameters, detect whether the stiffness and strength of the assembly meet the set values, if the requirement is not met, return to S4 and S5 and re-optimize, if the requirement is met, obtain a final design scheme of the converter box, and prepare the converter box according to the final design scheme of the converter box.

[0038] As preferred, the optimization of the connection structure in S5 takes the connection parameters as variables, the connection parameters include the number and size of the joint plates and the number and size of the connecting pieces; the minimum weight at the connection structure is taken as the target; the strength and stiffness at the connection structure are taken as the constraint conditions, and the model formula for the connection structure optimization is:

[0039]

[0040] In the formula, represents the number of joint plates to be found for optimization, a represents the number of joint plates, aj represents the number of joint plates at the j th connection, represents the number of connectors to be found for optimization, b represents the number of connectors, bj represents the number of connectors at the j th connection, represents the size of the joint plate to be found for optimization, c represents the size of the joint plate, cj represents the size of the joint plate at the j th connection, represents the size of the connector to be found for optimization, d represents the size of the connector, dj represents the size of the connector at the j th connection, m represents the weight of the connection structure, Gj represents the stiffness value of the connection structure at the j th connection structure, G represents the stiffness design value of the connection structure constraint at the j th connection structure, Hj represents the strength value of the connection structure at the j th connection structure, H represents the strength design value of the connection structure under boundary constraints at the j th connection structure.

[0041] As a preferred, in the material selection optimization in S3, the model of the selected new manufacturing material is used as the optimization variable, and the cost of the new manufacturing material is used as the constraint condition, and the optimal model of the new manufacturing material is sought.

[0042] A converter box design system for implementing the converter box design method, comprising the following modules:

[0043] An interactive module for human-computer interaction, inputting converter box design performance requirement data and existing converter box basic parameter data into the system, and outputting design result data externally;

[0044] A preprocessing module for splitting the converter box basic structure model into a plurality of sub-structure components;

[0045] A material selection module for screening new manufacturing materials of the converter box, and performing material selection optimization on the new manufacturing materials;

[0046] The laying structure design module is used for laying structure optimization of the sub-structure components with the composite layer plate structure in the converter box.

[0047] The connecting structure design module is used for optimization of the connecting structure between the sub-structure components of the converter box.

[0048] The integration module is used for integration of the design results obtained by the material selection module, the laying structure design module and the connecting structure design module, to obtain the converter box design scheme, and the converter box design scheme is output to the interactive module.

[0049] As described above, due to the adoption of the above technical solutions, the beneficial effects of the present application are:

[0050] In the present application, the converter box is divided into components according to the structural characteristics and stress conditions of each position in the converter box, and then the areas with composite layer plate structure are optimized. In the process of laying structure optimization, the stress conditions in the use process of the converter box are fully considered. The materials used in each part of the converter box are selected and optimized according to the actual situation, and then the components are divided into regions based on the material selection and optimization results and the structural characteristics and stress conditions of each position in the components. Then, the laying blocks suitable for each region are established, and then the thickness of the laying block, the laying sequence of the initial layer plate in the laying block, and the weight of the laying block are optimized in turn. Finally, the connecting structure of each part of the converter box is optimized. The final converter box design scheme not only meets the actual preparation requirements of the converter box, but also realizes lightweight design under the premise of good bearing capacity, which is more conducive to the actual application of the converter box. The present application effectively solves the problem that there is no systematic design method in the process of preparing large bearing parts from carbon fiber in the prior art, and most of them are designed and prepared by relying on traditional experience, resulting in limited performance of the designed large bearing parts and inability to meet the use requirements.

[0051] The strength of the converter box prepared according to the design method in the present application meets the requirements of DIN EN 12663-1:2024 "Structural requirements for railway vehicles - Car body", IEC 61373:2024 "Railway vehicle equipment - Standard for impact and vibration test", and TB / T 3548-2019 "General specification for strength design and test identification of rolling stock", and the vibration deformation of the converter box during normal operation of the vehicle does not affect its overall dustproof and waterproof performance. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 The flowchart of the converter box design method in the present application;

[0053] Figure 2Flow chart of genetic algorithm in the present application;

[0054] Figure 3 Layup thickness optimization result chart obtained in one of the embodiments of the present application;

[0055] Figure 4 Layup sequence optimization result chart obtained in one of the embodiments of the present application;

[0056] Figure 5 Weight optimization result chart obtained in one of the embodiments of the present application;

[0057] Figure 6 Model chart of converter box obtained in one of the embodiments of the present application. DETAILED DESCRIPTION

[0058] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0059] In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0060] As shown in Figure 1 A converter box design method, comprising the following steps:

[0061] S1: Obtain basic parameter data of the existing converter box, the basic parameter data including structure parameter data (size, shape, etc.), manufacturing material data, rigidity data, strength data, and thickness data (structure thickness at each part) of the existing converter box; and obtain a basic structure model (parameter model) of the converter box based on the structure parameter data; in this embodiment, the manufacturing material data of the existing converter box is that the main body is manufactured by using a metal material, the connection mode of the main frame is welding, the connection mode of the skin and the internal partition is riveting, the electrical device is fixed by using bolt connection, the manufacturing material of the main frame structure, the main bearing structure, and the secondary bearing structure of the box body is SUS304, and the manufacturing material of the door plate and the accessory such as the part of the electrical device mounting plate is 5083H111 aluminum plate;

[0062] S2: According to the bearing characteristics of the force forms of each part in the converter box, the basic structure model of the converter box is split into a plurality of sub-structure components, and according to the conventional decomposition mode in the field, the plurality of sub-structure components include the main frame structure, the main bearing structure, the secondary bearing structure, and the accessory;

[0063] S3: Obtain the strength and density of the existing converter box manufacturing material based on the manufacturing material data obtained in S1, and select a new manufacturing material for the converter box based on the strength and density of the original manufacturing material, the strength of the new manufacturing material being greater than or equal to the strength of the existing converter box manufacturing material, and the density of the new manufacturing material being less than the density of the existing converter box manufacturing material; select any one of the selected new manufacturing materials as the manufacturing material of the converter box, and perform material selection optimization on the selected new manufacturing material based on the selected new manufacturing material, with the lowest cost and the highest matching degree between the size of the new manufacturing material and the size of the corresponding substructure component as the constraint conditions, to obtain a material selection result; it should be noted that there are obviously more than one new manufacturing material with a strength greater than the original manufacturing material and a density less than the original manufacturing material, and any one of the selected new manufacturing materials can be selected as the manufacturing material of the converter box; in this embodiment, since the density of carbon fiber is less than the density of SUS304 and 5083H111 aluminum plate, and the strength of carbon fiber is greater than the strength of SUS304 and 5083H111 aluminum plate, carbon fiber meets the selection condition and is preliminarily considered as the manufacturing material of the converter box; since the converter box needs to have sufficient bearing strength, T300 carbon fiber, T600 carbon fiber, T800 carbon fiber and T1000 carbon fiber are further selected as the new manufacturing material of the converter box according to experience; then, the type of carbon fiber is optimized based on these selected carbon fibers, and specifically, the type of the selected new manufacturing material (carbon fiber) is taken as the design variable, and the lowest cost of the selected type of new manufacturing material is taken as the constraint condition to seek the optimal type of new manufacturing material; since the cheapest carbon fiber among the several carbon fibers is T300 carbon fiber, the final manufacturing material of the converter box obtained in this embodiment is T300 carbon fiber;

[0064] S4: Perform layer structure optimization on the substructure component with a composite laminate structure based on the material selection result obtained in S3 to obtain layer structure design parameters, and the layer structure optimization includes layer block thickness optimization, layer sequence optimization and weight optimization in sequence; specifically, the layer structure optimization in this embodiment is calculated by using a genetic algorithm (as shown in Figure 2 ), and the specific steps include:

[0065] S401, Ply Block Thickness Optimization: Based on the load distribution of the converter housing, each sub-structural component is divided into zones. Based on the performance parameters of the new manufacturing material, initial laminar flow plates of corresponding quantity and angle from four standard ply angles (±45°, 0°, 90°) are selected for each zone. Several initial laminar flow plates from each zone are then stacked vertically in any order to form several ply blocks. The specific method for determining which initial laminar flow plate angles and the quantity of initial laminar flow plates to select for each zone is as follows: Taking a flat plate structure as an example, first analyze that the external load is tensile force, thus determining the ply block parameters for this zone to be 90° / 0° cross ply blocks to maximize material utilization. The stress characteristics of the material and structure are analyzed. If the external load is shear force, the initial laminations in this region need to be added at ±45° angles and interlaced into the ply blocks to resist the shear load. The stiffness and strength of the ply blocks obtained in each region are greater than or equal to the stiffness and strength of the corresponding region in the existing converter housing. Then, the thickness of each ply block is optimized. The optimization variable is the number of initial laminations in each region's ply block. The ply block thickness optimization seeks the ply block thickness in each region under the constraints of strength, stiffness, and stability, where the stiffness is maximized and the weight is optimal, thus obtaining the initial thickness parameters of each ply block. Specifically, the model formula for ply block thickness optimization is as follows:

[0066]

[0067] In the formula, Indicates searching for the first i The optimal number of initial laminates in each region's ply block. x This indicates the number of initial laminates in the layup block. xi Indicates the first i The number of initial laminates in each area ply block Xi Indicates the first i The thickness value of each area's ply block, and , Z This represents the initial thickness value of the initial laminate (it should be noted that the initial thickness value of the initial laminate is the same for all ply angles, and its specific value is obtained empirically), and Xi(min) Indicates the first i The minimum thickness value of the ply block defined in each region. Xi(max) Indicates the first i The maximum thickness value of the ply block defined in each region. Fi Indicates the first i Structural stiffness values ​​of plywood blocks in each region F Indicates the first i Design values ​​for structural stiffness under regional constraints Ai Indicates the first i Structural strength values ​​of plywood blocks in each region A For the first under boundary constraintsi Structural strength design values ​​for each area of ​​plywood block, Bi Indicates the first i Structural deformation values ​​of each region's plywood block B Represents the first under boundary constraints i Structural deformation design value of each region's ply block ，V Indicates the first i The volume fraction of each region, its value Based on experience; the result obtained after optimizing the ply thickness is as follows: Figure 3 As shown, the white area represents one of the ply blocks with a thickness of 0.6 mm, and the green area represents another ply block with a thickness of 0.4 mm. In the ply block thickness optimization process of this invention, the maximum stiffness is taken as the optimization objective, while the weight is selected as the optimal value, without limiting the minimum weight. This is because the application scenarios of the converter housing are considered, which not only require light weight but also sufficient mechanical performance to meet the usage requirements. Therefore, in the ply block thickness optimization stage, the weight should be framed within a certain range based on the maximum stiffness as the optimization objective in order to seek an effective coordination between weight and other performance. Giving a wider "optimization space" at the beginning can provide more precise lightweighting in the later stages.

[0068] S402, Ply Sequence Optimization: First, the ply blocks with optimized thickness in each region are trimmed. After trimming, adjacent ply blocks are integrated according to the initial lamination angle, number of initial laminations, and correspondence of adjacent initial laminations in different regions, so that adjacent ply blocks form a shared ply structure. Finally, the ply sequence is optimized based on the shared ply structure. The optimization variable is the ply sequence of each initial lamination in each ply block. The ply sequence optimization seeks the ply sequence of the initial laminations in each ply block under the stress and strain constraints of the ply block to maximize the critical buckling load of the structure, and obtains the ply sequence parameters of each ply block.

[0069] Specifically, the cutting in S402 of this embodiment includes the following steps:

[0070] S4021: Determine the shape and size of the preliminary cutting window based on the position of the layup block in the converter housing;

[0071] S4022: Based on the material selection results and the initial thickness parameters of each ply block, determine the magnification parameters of the preliminary cutting window, and magnify the preliminary cutting window through the magnification parameters to obtain the optimized cutting window;

[0072] S4023: Obtain the factory size data of the new manufacturing material based on the material selection results, obtain the window size and shape limitation parameters based on the factory size data, compare the size and shape parameters of the optimized cutting window with the window size and shape limitation parameters, optimize the optimized cutting window according to the comparison results, and obtain the final cutting window;

[0073] The optimization process includes: if the size and shape parameters of the optimized clipping window meet the constraints of the window size and shape limit parameters, then the optimized clipping window is not adjusted, and the optimized clipping window is the final clipping window; if the size and shape parameters of the optimized clipping window do not meet the constraints of the window size and shape limit parameters, then the initial clipping window is reduced based on the window size and shape limit parameters, thus obtaining the final clipping window; it should be noted that the degree of reduction needs to be determined in conjunction with the magnification parameters, and it is necessary to ensure that the final clipping window is still slightly larger than the required actual ply block size;

[0074] S4024: The ply block is cut using the final cutting window to obtain the cut ply block; in this invention, the area and boundary are first determined by cutting, and only adjacent areas are spliced ​​to achieve the feasibility of ply manufacturing, which is more practical.

[0075] The model formula for optimizing the layup sequence in S402 is as follows:

[0076] ;

[0077] In the formula, This indicates the search for the optimal layup sequence of the initial laminates in the given ply block. y This indicates the layup sequence of the initial laminates in the ply block. yi Indicates the first i The layup sequence of each initial laminate in each region's ply block. E Indicates the first i The critical buckling load of the structure of each region ply block. Di Indicates the first i Structural strain values ​​of each region's ply block D Represents the first under boundary constraints i The structural directional strain design value (e.g., 3000 microstrain) for each region of the plywood. Ci Indicates the first i The structural stress values ​​of each region's ply block. C For the first under boundary constraints i The structural stress value of each region's ply block (e.g., 200 MPa); the results obtained after optimizing the ply sequence are as follows: Figure 4 As shown, Figure 4 The dark blue area represents the initial 90° lamination zone, with an area of ​​100 cm². 20.6mm, light blue and gray area and so on;

[0078] S403, weight optimization: the optimization variable is the thickness of each initial laminate in each area layup block, the weight optimization is to find the optimal thickness of each initial laminate in each layup block under the constraints of strength, stiffness and stability, and the final thickness parameter of each layup block is obtained by the optimal thickness of each initial laminate in each layup block;

[0079] Specifically, the model formula of weight optimization in S403 in the embodiment is:

[0080]

[0081] In the formula, represents the optimal thickness value of each initial laminate in the layup block, z represents the thickness value of the initial laminate in the layup block, zi represents the thickness value of the initial laminate in the i area layup block, m represents the weight of the i area layup block, Fi represents the structural stiffness value of the i area layup block, F represents the structural stiffness design value of the i area constraint, Ai represents the structural strength value of the i area layup block, A is the structural strength design value of the i area layup block under boundary constraints, Bi represents the structural deformation value of the i area layup block, B represents the structural deformation design value of the i area layup block under boundary constraints; the weight optimization result is shown in Figure 5 From Figure 5 it can be seen that there is a significant change in the thickness of the initial laminate compared with Figure 4 .

[0082] The layup sequence parameters and final thickness parameters of each ply block obtained above constitute the layup structure design parameters, such as [0 / 45 / -45 / 90 / 90 / 0 / 0 / 45 / -45 / 90]s. This invention, through layup structure optimization, obtains a reasonable and scientific layup scheme, resulting in greater stiffness and lower strain stress in the box structure, thus meeting its performance requirements. The ultimate optimization goal of this invention is to minimize weight, because weight reduction will, to some extent, weaken structural stiffness. However, the layup block thickness optimization has already maximized stiffness; even sacrificing some stiffness here achieves the best results, which is the advantage of the optimization logic of this invention.

[0083] S5: Based on the ply structure design parameters obtained in S4, the connection structure between each sub-structural component is optimized to obtain the connection structure design parameters; the optimization of the connection structure in S5 uses the connection parameters as variables, including the number and size of the joint plates and the number and size of the connectors (screws, etc.); the objective is to minimize the weight at the connection structure; the strength and stiffness at the connection structure are used as constraints, and the model formula for the connection structure optimization is:

[0084]

[0085] In the formula, This indicates the number of joint plates being searched for optimally. a Indicates the number of connector plates. aj Indicates the first j The number of connector plates at each connection point This indicates the number of connectors to find the optimal number. b Indicates the number of connectors. bj Indicates the first j The number of connectors at each connection point This indicates the search for the optimal size of the connector plate. c Indicates the dimensions of the connector plate. cj Indicates the first j The dimensions of the connector plate at each connection point. This indicates the search for the optimal dimensions of the connector. d Indicates the dimensions of the connector. dj Indicates the first j The dimensions of the connectors at each connection point m Indicates the weight of the connection structure. Gj Indicates the first j The stiffness value of the connection structure at each connection point. G Indicates the first j The design value of the stiffness of the connection structure constraint at each connection structure. Hj Indicates the first j The strength value of the connection structure at each connection point. H Represents the first under boundary constraintsj a strength design value of the connection structure at the connection structure;

[0086] S6: integrating the material selection result obtained in S3, the design parameters of the layer structure obtained in S4 and the design parameters of the connection structure obtained in S5 to obtain a design scheme of the converter box, and preparing the converter box according to the design scheme of the converter box.

[0087] In one embodiment, the specific steps of S6 include:

[0088] S601: preparing a sub-structure component sample based on the design parameters of the layer structure, and detecting whether the stiffness and strength of the sub-structure component sample corresponding to different parts of the converter box are greater than or equal to the stiffness and strength of the existing converter box at the parts, if the requirements are met, S602 is performed, if the requirements are not met, S4 is returned to re-optimize; it should be noted that for sub-structure components with the same structure, only one sample is prepared for performance detection;

[0089] S602: manufacturing sub-structure component parts with a composite layer structure according to the design parameters of the layer structure, and manufacturing the remaining sub-structure component parts according to the structure parameter data of the existing converter box, detecting whether the process parameter values of the geometric assembly relationship of each sub-structure component part meet the set values defined by the design parameters of the connection structure, the process parameter values of the geometric assembly relationship including interface parameters, hole diameter position and size; if the requirements are met, S603 is performed, if the requirements are not met, S4 and S5 are returned to re-optimize; the design parameters of the connection structure limit the size and number of the connection plate and the size and number of the connecting piece, the interface parameters need to meet the size and number limitation of the connection plate, and the hole diameter position and size need to meet the size and number limitation of the connecting piece; it should be noted that the sub-structure component parts refer to all the parts required for manufacturing the converter box, the sub-structure component parts with a composite layer structure are prepared according to the design parameters of the layer structure, and the remaining sub-structure components without a composite layer structure are prepared according to the structure parameters of the sub-structure components in the existing converter box, and the manufacturing material is simply replaced by T300 carbon fiber;

[0090] S603, assembling the parts of each sub-structure component obtained in S602 into an assembly based on the connection structure design parameters, detecting whether the rigidity and strength of the assembly meet the set values, if not meeting the requirements, returning to S4 and S5 to re-optimize, if meeting the requirements, obtaining the final design scheme of the converter box, and preparing the converter box according to the final design scheme of the converter box; the rigidity specifically refers to the overall rigidity and local rigidity of the structure, which is measured by vibration mode, the overall rigidity requires that the first-order vibration mode frequency of the structure is large enough, generally greater than the excitation frequency of the vibration impact, and the local rigidity requires that the vibration mode frequency avoids the excitation frequency of the nearby active accessory equipment; the strength specifically refers to the stress and strain of the structure, which requires that the overall and local stress and strain are less than the allowable value under the service load working condition, and the allowable value refers to the maximum value of the basic mechanical properties of the material divided by the safety factor;

[0091] A converter box design system for implementing the converter box design method, comprising the following modules:

[0092] An interactive module for human-computer interaction, inputting the converter box design performance requirement data and the basic parameter data of the existing converter box into the system, and outputting the design result data to the outside;

[0093] A preprocessing module for splitting the basic structure model of the converter box into a plurality of sub-structure components;

[0094] A material selection module for screening the new manufacturing materials of the converter box and performing material selection optimization on the new manufacturing materials;

[0095] A layer structure design module for optimizing the layer structure of the sub-structure component with a composite layer plate structure in the converter box;

[0096] A connection structure design module for optimizing the connection structure between each sub-structure component of the converter box;

[0097] An integration module for integrating the design results obtained by the material selection module, the layer structure design module and the connection structure design module, obtaining the converter box design scheme, and outputting the converter box design scheme to the interactive module.

[0098] The converter box structure obtained in the embodiment is as shown in Figure 6As shown in the figure, after testing, the weight of the original converter metal enclosure (the main frame structure, main load-bearing structure and secondary load-bearing structure of the enclosure are all made of SUS304, and the door panel and some electrical component mounting plates and other accessories are made of 5083H111 aluminum plate) is 304kg. The weight of the carbon fiber converter enclosure obtained after optimization is 147kg. It can be seen that the carbon fiber converter enclosure obtained by the present invention achieves lightweight design, and the weight of the enclosure is reduced by 157kg (51.6%).

[0099] Furthermore, the performance test results of the carbon fiber converter housing obtained by this invention are as follows:

[0100] During testing, a coordinate system is first selected. In this embodiment, the coordinate system is selected with the vehicle's forward direction as the positive X direction, vertical downward as the positive Z direction, and the Y-axis (which is consistent with the vehicle's horizontal axis) determined by the right-hand rule. The static strength calculation conditions for the converter housing are shown in Table 1.

[0101] Table 1

[0102]

[0103] The stress statistics for static strength calculations under conditions 1 to 5 are shown in Table 2:

[0104] Table 2

[0105]

[0106] As shown in Table 2, the maximum stress occurs in operating condition 5, with a maximum value of 126.3 MPa, which is significantly less than the strength that carbon fiber can withstand. This demonstrates that the carbon fiber converter housing provided by this invention is not only lightweight but also possesses excellent load-bearing capacity.

[0107] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A converter housing design method, characterized in that: Includes the following steps: S1: Obtain the basic parameter data of the existing converter housing, including the structural parameter data, manufacturing material data, stiffness data, strength data, and thickness data of the existing converter housing; and obtain the basic structural model of the converter housing based on the structural parameter data; S2: The basic structural model of the converter housing is divided into several sub-structural components, namely the main frame structure, the main load-bearing structure, the secondary load-bearing structure, and the accessories; S3: Based on the manufacturing material data obtained in S1, obtain the strength and density of the existing converter housing manufacturing materials, and screen out new manufacturing materials for the converter housing based on the strength and density of the original manufacturing materials. The strength of the new manufacturing materials is greater than or equal to the strength of the existing converter housing manufacturing materials, and the density of the new manufacturing materials is less than the density of the existing converter housing manufacturing materials. Select any one of the screened new manufacturing materials as the manufacturing material of the converter housing, and perform material selection optimization based on the selected new manufacturing materials to obtain the material selection results. S4: Based on the material selection results obtained in S3, obtain the performance parameters of the new manufacturing material, including strength, stiffness, thickness and density. Based on the performance parameters of the new manufacturing material, optimize the layup structure of the sub-structural component with composite laminate structure to obtain the layup structure design parameters. The layup structure optimization includes layup block thickness optimization, layup sequence optimization and weight optimization in sequence. S5: Based on the ply structure design parameters obtained in S4, the connection structure between each sub-structural component is optimized to obtain the connection structure design parameters; S6: Integrate the material selection results obtained in S3, the ply structure design parameters obtained in S4, and the connection structure design parameters obtained in S5 to obtain the converter housing design scheme, and fabricate the converter housing according to the converter housing design scheme.

2. The converter housing design method according to claim 1, characterized in that: The ply structure optimization in S4 is calculated using a genetic algorithm, and the specific steps include: S401, Ply Block Thickness Optimization: Based on the load distribution of the converter housing, each sub-structural component is divided into zones. Based on the performance parameters of the new manufacturing material, initial laminating plates of corresponding quantity and angle are selected for each zone from four standard ply angles: ±45°, 0°, and 90°. Several initial laminating plates in each zone are stacked vertically in any order to form several ply blocks. The stiffness and strength of the ply blocks obtained in each zone are greater than or equal to the stiffness and strength of the corresponding zone in the existing converter housing. Then, the thickness of each ply block is optimized. The optimization variable is the number of initial laminating plates in the ply blocks of each zone. The ply block thickness optimization seeks the ply block thickness of each zone under the conditions of maximum stiffness and optimal weight under the constraints of strength, stiffness, and stability, and obtains the initial thickness parameters of each ply block. S402, Ply Sequence Optimization: First, the ply blocks with optimized thickness in each region are trimmed. After trimming, adjacent ply blocks are integrated according to the initial lamination angle, number of initial laminations, and correspondence of adjacent initial laminations in different regions, so that adjacent ply blocks form a shared ply structure. Finally, the ply sequence is optimized based on the shared ply structure. The optimization variable is the ply sequence of each initial lamination in each ply block. The ply sequence optimization seeks the ply sequence of the initial laminations in each ply block under the stress and strain constraints of the ply block to maximize the critical buckling load of the structure, and obtains the ply sequence parameters of each ply block. S403. Weight optimization: The optimization variable is the thickness of each initial laminar flow in each region's ply block. The weight optimization seeks the optimal thickness of each initial laminar flow in each ply block under the constraints of strength, stiffness, and stability, so as to minimize the weight of the ply block. The final thickness parameter of each ply block is obtained through the optimal thickness of each initial laminar flow in each ply block. The ply sequence parameters and final thickness parameters of each ply block obtained above constitute the ply structure design parameters.

3. The converter housing design method according to claim 2, characterized in that: The model formula for optimizing the ply thickness in S401 is as follows: ； In the formula, Let represent the optimal number of initial laminae in the i-th region ply block, x represent the number of initial laminae in the ply block, xi represent the number of initial laminae in the i-th region ply block, and Xi represent the thickness of the i-th region ply block. Z represents the initial thickness of the initial laminate, and Xi(min) represents the minimum thickness of the ply block defined in the i-th region, Xi(max) represents the maximum thickness of the ply block defined in the i-th region, Fi represents the structural stiffness of the ply block in the i-th region, F represents the structural stiffness design value of the i-th region under constraint, Ai represents the structural strength of the ply block in the i-th region, A is the structural strength design value of the ply block in the i-th region under boundary constraint, Bi represents the structural deformation of the ply block in the i-th region, B represents the structural deformation design value of the ply block in the i-th region under boundary constraint, and V represents the volume fraction of the i-th region.

4. The converter housing design method according to claim 2, characterized in that: The model formula for optimizing the layup sequence in S402 is as follows: ； In the formula, This indicates the search for the optimal layup sequence of the initial laminates in the given ply block. y This indicates the layup sequence of the initial laminates in the ply block. yi Indicates the first i The layup sequence of each initial laminate in each region's ply block. E Indicates the first i The critical buckling load of the structure of each region ply block. Di Indicates the first i Structural strain values ​​of each region's ply block D Represents the first under boundary constraints i Design values ​​of structural directional strain for each region of the plywood block. Ci Indicates the first i The structural stress values ​​of each region's ply block. C For the first under boundary constraints i Structural stress values ​​of each region's ply block.

5. The converter housing design method according to claim 2, characterized in that: The formula for weight optimization in S403 is as follows: ; In the formula, This indicates the search for the optimal thickness value of each initial laminate in the ply block. This indicates the initial thickness of the laminate in the layup block. zi Indicates the first i The initial laminate thickness value in each area of ​​the ply block. m Indicates the first i The weight of each area's plywood block. Fi Indicates the first i Structural stiffness values ​​of plywood blocks in each region F Indicates the first i Design values ​​for structural stiffness under regional constraints Ai Indicates the first i Structural strength values ​​of plywood blocks in each region A For the first under boundary constraints i Structural strength design values ​​for each area of ​​plywood block, Bi Indicates the first i Structural deformation values ​​of each region's plywood block B Represents the first under boundary constraints i The structural deformation design value of each area's ply block.

6. The converter housing design method according to claim 2, characterized in that: The cutting process in S402 specifically includes the following steps: S4021: Determine the shape and size of the preliminary cutting window based on the position of the layup block in the converter housing; S4022: Based on the material selection results and the initial thickness parameters of each ply block, determine the magnification parameters of the preliminary cutting window, and magnify the preliminary cutting window through the magnification parameters to obtain the optimized cutting window; S4023: Obtain the factory size data of the new manufacturing material based on the material selection results, obtain the window size and shape limitation parameters based on the factory size data, compare the size and shape parameters of the optimized cutting window with the window size and shape limitation parameters, optimize the optimized cutting window according to the comparison results, and obtain the final cutting window; The optimization process includes: if the size and shape parameters of the optimized cropping window meet the constraints of the window size and shape parameters, then the optimized cropping window is not adjusted, and the optimized cropping window is the final cropping window; if the size and shape parameters of the optimized cropping window do not meet the constraints of the window size and shape parameters, then the initial cropping window is reduced based on the window size and shape parameters, and the final cropping window is obtained. S4024: Use the final trimming window to trim the ply block to obtain the trimmed ply block.

7. The converter housing design method according to any one of claims 1-6, characterized in that: The specific steps of S6 include: S601. Based on the ply structure design parameters, prepare sub-structural component samples and test whether the stiffness and strength of the sub-structural component samples at different parts of the converter housing are greater than or equal to the stiffness and strength of the existing part in the converter housing. If the requirements are met, proceed to S602; otherwise, return to S4 for re-optimization. S602. Manufacture sub-structural components with composite layered plate structures according to the ply structure design parameters. Manufacture the remaining sub-structural components according to the existing converter housing structural parameter data. Check whether the process parameter values ​​of the geometric assembly relationship of each sub-structural component meet the set values ​​limited by the connection structure design parameters. The process parameter values ​​of the geometric assembly relationship include interface parameters, hole diameter position and size. If the requirements are met, proceed to S603. If the requirements are not met, return to S4 and S5 to re-optimize. S603. Based on the connection structure design parameters, assemble the various sub-structural components obtained in S602 into a assembly. Check whether the stiffness and strength of the assembly meet the set values. If they do not meet the requirements, return to S4 and S5 for re-optimization. If they meet the requirements, the final design scheme of the converter housing is obtained. The converter housing is then manufactured according to the final design scheme of the converter housing.

8. The converter housing design method according to any one of claims 1-6, characterized in that: In S5, the optimization of the connection structure uses connection parameters as variables, including the number and size of joint plates and the number and size of connectors; the objective is to minimize the weight at the connection structure; and the constraints are the strength and stiffness at the connection structure. The model formula for the connection structure optimization is as follows: ; In the formula, This indicates the number of joint plates being searched for. a Indicates the number of connector plates. aj Indicates the first j The number of connector plates at each connection point This indicates the number of connectors to find the optimal number. b Indicates the number of connectors. bj Indicates the first j The number of connectors at each connection point This indicates the search for the optimal size of the connector plate. c Indicates the dimensions of the connector plate. cj Indicates the first j The dimensions of the connector plate at each connection point. This indicates the search for the optimal dimensions of the connector. d Indicates the dimensions of the connector. DJ Indicates the first j The dimensions of the connectors at each connection point m Indicates the weight of the connecting structure. Gj Indicates the first j The stiffness value of the connection structure at each connection point. G Indicates the first j The design value of the stiffness of the connection structure constraint at each connection structure. Hj Indicates the first j The strength value of the connection structure at each connection point. H Represents the first under boundary constraints j The strength design value of the connection structure at each connection point.

9. The converter enclosure design method according to any one of claims 1-6, characterized in that: In S3, when optimizing material selection, the model of the selected new manufacturing material is used as the optimization variable, and the cost of the new manufacturing material is used as the constraint to seek the optimal model of the new manufacturing material.

10. A converter enclosure design system, characterized in that: A converter housing design method for implementing any one of claims 1-9 includes the following modules: The interaction module is used for human-computer interaction, inputting the performance requirements data of the converter enclosure design and the basic parameter data of the existing converter enclosure into the system, and outputting the design result data to the outside. The preprocessing module is used to break down the basic structural model of the converter housing into several sub-structural components; The material selection module is used to screen new manufacturing materials for the converter housing and to optimize the selection of new manufacturing materials. The layup structure design module is used to optimize the layup structure of sub-structural components with composite laminate structures in the converter housing. The connection structure design module is used to optimize the connection structure between the various sub-structural components of the converter housing; The integration module is used to integrate the design results obtained from the material selection module, the layup structure design module, and the connection structure design module to obtain the converter housing design scheme, and output the converter housing design scheme to the interaction module.

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