A method and system for topological optimization of free-form double-layer lattice shell structure

Abstract

The present disclosure provides a free-form double-layer lattice shell structure topology optimization method and system, which relates to the technical field of lattice shell topology optimization, obtains various basic parameters of the double-layer lattice shell for parametric modeling; establishes an optimization unit suitable for topology optimization, and constructs an optimization unit mapping matrix based on the optimization unit; applies loads and constraints, establishes a double-layer lattice shell finite element model and performs finite element analysis and calculation; traverses all rods in the double-layer lattice shell for strength verification and stability verification, obtains the stress ratio of all rods, and generates a stress ratio matrix based on the optimization unit mapping matrix; optimizes the optimized unit rods in the double-layer lattice shell parametric model based on the stress ratio matrix; performs an iterative optimization process until the double-layer lattice shell cannot be optimized again or the optimization unit that meets the conditions cannot be found, and obtains a evacuated double-layer lattice shell structure after topology optimization. The present disclosure solves the problems of low intelligence and low efficiency in the existing lattice shell optimization process.

Description

Technical Field

[0001] The present disclosure relates to the technical field of lattice shell topology optimization, and in particular to a method and system for topology optimization of a free-form double-layer lattice shell structure. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] The space grid structure is a common structural form for large public buildings. It has a wide range of applications and is suitable for industrial buildings, sports buildings, and public buildings of various spans, meeting various requirements for flexible and complex building functions or processes. In the double-layer grid shell structure, the space between the upper and lower chords can be used to arrange various equipment and pipelines, which can effectively utilize space, is economical and convenient to use.

[0004] Although the surface of the lattice shell structure is diverse, the components are mainly subjected to pressure from the overall point of view. Through careful design, the stress of the lattice shell can be reasonably and evenly applied, which also achieves the purpose of saving steel. The traditional double-layer lattice shell structure is characterized by relatively simple and stereotyped components and nodes. Through the connection of rods, a regular, continuous and uniform grid can be formed. This arrangement has a simple structure, good mechanical properties and high bearing capacity. However, under the action of load, there are large differences in the stress of the rods in the structure, and some rods have very low stress levels, resulting in a large self-weight of the overall structure and waste of steel. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a topology optimization method and system for a free-form double-layer lattice shell structure. Based on the progressive structural optimization method, a topology optimization method suitable for a free-form double-layer lattice shell structure is proposed. The method can optimize the grid topology of double-layer lattice shell structures of various forms and change the topology of the double-layer lattice shell. Under the premise of ensuring the overall stability, symmetry, and stability of the rods, the method can effectively reduce the number of rods, significantly reduce the dead weight of the structure, shorten the construction period, and save costs.

[0006] According to some embodiments, the present disclosure adopts the following technical solutions:

[0007] A free-form double-layer lattice shell structure topology optimization method, comprising:

[0008] Obtaining basic parameters of a double-layer lattice shell and performing parameterized modeling on the double-layer lattice shell;

[0009] According to the parametric model of the double-layer lattice shell, an optimization unit suitable for topology optimization is established, and an optimization unit mapping matrix is ​​constructed based on the optimization unit;

[0010] Applying loads and constraints, establishing a double-layer lattice shell finite element model, and performing finite element analysis and calculation on the finite element model;

[0011] According to the analysis and calculation results, all the bars in the double-layer lattice shell are traversed to perform strength and stability checks, the stress ratios of all bars are obtained, and the stress ratio matrix is ​​generated based on the optimized unit mapping matrix;

[0012] Optimizing the optimized unit bars in the double-layer lattice shell parameterized model based on the stress ratio matrix;

[0013] A new double-layer lattice shell parametric model is established based on the optimized optimization unit, and the mapping relationship matrix between the optimization unit and the rod is re-established. The iterative optimization process is performed until the double-layer lattice shell cannot be optimized again or the optimization unit that meets the conditions cannot be found, and the evacuated double-layer lattice shell structure after topology optimization is obtained.

[0014] According to some embodiments, the present disclosure adopts the following technical solutions:

[0015] A free-form double-layer lattice shell structure topology optimization system, comprising:

[0016] An initialization module is used to obtain various basic parameters of the double-layer lattice shell and perform parameterized modeling on the double-layer lattice shell;

[0017] The analysis and calculation module is used to establish an optimization unit suitable for topology optimization based on the parametric model of the double-layer lattice shell, and to construct an optimization unit mapping matrix based on the optimization unit; to apply loads and constraints, to establish a double-layer lattice shell finite element model, and to perform finite element analysis and calculation on the finite element model; according to the analysis and calculation results, to traverse all the rods in the double-layer lattice shell to perform strength verification and stability verification, to obtain the stress ratios of all the rods, and to generate a stress ratio matrix based on the optimization unit mapping matrix;

[0018] The optimization iteration module is used to optimize the optimized unit rods in the double-layer lattice shell parametric model based on the stress ratio matrix; establish a new double-layer lattice shell parametric model based on the optimized optimized unit, and re-establish the mapping relationship matrix between the optimized unit and the rods, and perform an iterative optimization process until the double-layer lattice shell cannot be optimized again or the optimized unit that meets the conditions cannot be found, thereby obtaining a evacuated double-layer lattice shell structure after topology optimization.

[0019] According to some embodiments, the present disclosure adopts the following technical solutions:

[0020] A non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, a free-form double-layer lattice shell structure topology optimization method is implemented.

[0021] According to some embodiments, the present disclosure adopts the following technical solutions:

[0022] An electronic device comprises: a processor, a memory and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory so that the electronic device executes the free-form double-layer lattice shell structure topology optimization method.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention discloses a topology optimization method for a free-form double-layer lattice shell structure. Based on the idea of ​​the progressive structural optimization method, a topology optimization method suitable for a free-form double-layer lattice shell structure is proposed. The method can optimize the grid topology of double-layer lattice shell structures of various forms, change the topology of the double-layer lattice shell, and achieve the purpose of effectively reducing the number of rods, significantly reducing the deadweight of the structure, shortening the construction period, and saving costs while ensuring the overall stability, symmetry, and stability of the rods. At the same time, it also solves the problems of low intelligence and low efficiency in the existing lattice shell optimization process.

[0025] The present invention discloses a topology optimization method for a free-form double-layer lattice shell structure, which establishes an optimization unit suitable for topology optimization, and establishes an optimization unit mapping matrix of the mapping relationship between the optimization unit and the rod. The mapping relationship between the optimization unit and the rod is to establish a mapping relationship between the topological model of the structure and the structural rod model. The topology optimization is directly for the topology optimization unit, and the rod deletion operation is for the structural rod model. Therefore, it is necessary to determine the relationship between the two to facilitate subsequent programming.

[0026] The present invention discloses a method for topological optimization of a free-form double-layer lattice shell structure. The method applies loads and constraints to the model, establishes a double-layer lattice shell finite element model, performs finite element analysis on the double-layer lattice shell finite element model, sorts the stress ratios of optimized unit rods in ascending order, obtains an ascending array of optimized unit stress ratios, sorts the sums of the stress ratios in ascending order, and the optimized unit with the smallest stress sum is ranked first. The operation of deleting rods can be directly performed based on the sorting results, which can simplify the programming process of the optimization method. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure.

[0028] Figure 1 A schematic diagram of a topology optimization method for a free-form double-layer lattice shell structure according to an embodiment of the present disclosure;

[0029] Figure 2 It is a front view schematic diagram of the first row of nodes of the upper lattice shell according to an embodiment of the present disclosure;

[0030] Figure 3 This is a top view schematic diagram of the node numbering of the upper layer lattice shell of the embodiment of the present disclosure;

[0031] Figure 4 It is a front view schematic diagram of the first row of nodes of the double-layer lattice shell according to an embodiment of the present disclosure;

[0032] Figure 5 It is a top view schematic diagram of the node numbering of a double-layer lattice shell according to an embodiment of the present disclosure;

[0033] Figure 6 is a schematic diagram of an optimization unit according to an embodiment of the present disclosure;

[0034] Figure 7 is a schematic diagram of an optimization unit according to an embodiment of the present disclosure;

[0035] Figure 8 A schematic diagram of the numbering of the double-layer lattice shell optimization units according to an embodiment of the present disclosure;

[0036] Fig. 9 A schematic diagram of optimizing unit numbering for a part of a double-layer lattice shell according to an embodiment of the present disclosure;

[0037] Fig.10 This is a schematic diagram of a double-layer lattice shell before optimization according to an embodiment of the present disclosure;

[0038] Fig.11 This is a schematic diagram of the double-layer lattice shell after optimization of the embodiment of the present disclosure is completed. DETAILED DESCRIPTION

[0039] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] Example 1

[0043] In one embodiment of the present disclosure, a method for topology optimization of a free-form double-layer lattice shell structure is provided, the steps comprising:

[0044] Step 1: Obtain various basic parameters of the double-layer lattice shell and perform parameterized modeling on the double-layer lattice shell;

[0045] Step 2: According to the parametric model of the double-layer lattice shell, an optimization unit suitable for topology optimization is established, and an optimization unit mapping matrix is ​​constructed based on the optimization unit;

[0046] Step 3: Apply loads and constraints, establish a double-layer lattice shell finite element model, and perform finite element analysis and calculation on the finite element model;

[0047] Step 4: According to the analysis and calculation results, all the bars in the double-layer lattice shell are traversed to perform strength and stability calculations, the stress ratios of all bars are obtained, and the stress ratio matrix is ​​generated based on the optimized unit mapping matrix;

[0048] Step 5: Optimizing the optimized unit bars in the double-layer lattice shell parameterized model based on the stress ratio matrix;

[0049] Step 6: Establish a new double-layer lattice shell parametric model based on the optimized optimization unit, and re-establish the mapping relationship matrix between the optimization unit and the rod, and perform an iterative optimization process until the double-layer lattice shell cannot be optimized again or the optimization unit that meets the conditions cannot be found, and obtain the evacuated double-layer lattice shell structure after topology optimization.

[0050] As an embodiment, the specific implementation process of a free-form double-layer lattice shell structure topology optimization method disclosed in the present invention is as follows:

[0051] Step 1: Input the basic parameters of the lattice shell to perform parametric modeling of the double-layer lattice shell, mainly including the spatial morphological parameters of the double-layer lattice shell, the mechanical parameters of the structural members, and the connection relationship between the members and the nodes;

[0052] Specifically, the spatial morphological parameters of the double-layer lattice shell, the mechanical parameters of the structural members, and the connection relationship between the members and the nodes are expressed in the form of a matrix, as follows:

[0053] The nodes of the constructed double-layer lattice shell model are numbered, and the coordinates of each node number are summarized into a node coordinate matrix ,in The node number is Nodes, , , are the horizontal, vertical and vertical coordinates of the node;

[0054] The members of the double-layer lattice shell model are numbered and the data of each member number are summarized into a member unit matrix. ,in Indicates the number of the bar element, Indicates the starting point node number of the bar element, Indicates the node number of the end point of the bar element. The element type representing the bar element, represents the cross-section type of the bar element, Represents the material properties of the bar element, Indicates the number of segments of the bar element.

[0055] Step 2: According to the connection relationship between bars and nodes and the lattice shell form, establish the optimization unit suitable for topology optimization, and establish the optimization unit mapping matrix of the mapping relationship between the optimization unit and bars;

[0056] Specifically, according to the connection relationship between rods and nodes and the lattice shell form, an optimization unit suitable for topology optimization is established, and the mapping relationship between the optimization unit and the rods is established in the form of a matrix, specifically:

[0057] The double-layer lattice shell model is divided into several optimization units. The four bars of each grid in the upper lattice shell, the middle web connected to its node, and the lower lattice shell bars connected to the web node are called an optimization unit. Each optimization unit is numbered in the form of coding, and the optimization unit mapping matrix is ​​established based on the mapping relationship between the optimization unit and the bar:

[0058] , the number of optimization units starts from 0, and the matrix Representative number is The optimization unit, , … It represents the rods in the optimization unit. Due to the different positions of the optimization unit, the number of rods inside the optimization unit will be different.

[0059] Step 3: Apply loads and constraints, establish a double-layer lattice shell finite element model, conduct finite element analysis on the model, calculate the displacement of the structural nodes, and calculate the axial force, bending moment and shear force of the rods;

[0060] Specifically, the material properties, loads and constraints of the lattice shell are expressed in the form of a matrix, as follows:

[0061] The material properties matrix is ​​used to define the model material properties. Indicates that Representative Different materials, represents the elastic modulus of the material, represents the shear modulus of the material, , represents the moment of inertia of the material, Represents the cross-sectional area of ​​the material

[0062] The load matrix used to apply the loads to the model Indicates that Indicates the node number to which the load is applied. Indicates that at the node The degrees of freedom to which the load is applied, It indicates the magnitude of the load value.

[0063] The constraints imposed on the model are expressed using the boundary constraint matrix It is similar to the load matrix, where Indicates the constrained node number, Indicates that at the node The degrees of freedom constrained on Indicates the value of the constraint.

[0064] Step 4: According to the calculation results of step 3, all the bars in the lattice shell are traversed to perform strength and stability checks, the stress ratios of all bars are obtained, and the stress ratio matrix is ​​generated based on the optimized unit mapping matrix;

[0065] Specifically, all the bars of the lattice shell are judged, the strength of the tension bars is checked, the stability of the compression bars is checked, and the stress ratios of all bars and the optimized unit stress ratios are generated in ascending order, specifically:

[0066] Generate a stress ratio matrix based on the optimized unit mapping matrix and the required stress ratio of the lattice shell member ,in The value of is the value of the optimized unit mapping matrix The stress ratio of the rod in the stress ratio matrix is , … and the optimized unit mapping matrix , … Each row in the stress ratio matrix represents the stress ratio of a member in an optimized unit.

[0067] The strength check of the tension rods is based on the "Structural Design Standard" GB50017-2017, and the formula σ=N / A≤f is used for calculation, where N is the design value of the tension at the calculated section, f is the design value of the tensile strength of the steel, and A is the gross cross-sectional area of ​​the component.

[0068] The stability calculation of the compression rod is based on the "Structural Design Standard" GB50017-2017, formula Calculate, where is the stability factor of the compressive member, is the pressure on the compression member, is the cross-sectional area of ​​the compression member, is the strength design value.

[0069] Step 5: Calculate the sum of the stress ratios of all optimized unit members according to the stress ratio matrix generated in step 4, and sort them in ascending order based on the sum of the stress ratios of the optimized unit members to obtain an ascending array of optimized unit stress ratios. Then, combine various constraints and the optimized unit activation matrix to update the ascending array of optimized unit stress ratios, extract the first optimized unit number in the array, and delete the corresponding member in the first optimized unit number in the double-layer lattice shell structure model based on the optimized unit mapping matrix.

[0070] Specifically, the sum of the stress ratios of all optimized unit members is calculated according to the stress ratio matrix generated in step 4, and the optimized unit members are sorted in ascending order based on the sum of the stress ratios of the optimized unit members to obtain an ascending array of the optimized unit stress ratios, and the following steps are performed in sequence according to the sorting:

[0071] Step 5.1: Remove the optimized element numbers that have been optimized from the ascending array of optimized element stress ratios, and update the ascending array of optimized stress ratios;

[0072] Step 5.2: According to the optimization restriction condition (the optimization units adjacent to the optimized optimization units do not participate in the optimization), the optimization units adjacent to the optimized optimization units are removed from the optimization unit stress ratio ascending array, and the optimization stress ratio ascending array is updated again;

[0073] Step 5.3: Based on the ascending array of optimized unit stress ratios obtained in step 5.2, extract the first optimized unit number in the array, and based on the optimized unit mapping matrix, delete the corresponding member in the first optimized unit number in the double-layer lattice shell structure model.

[0074] As an embodiment, the double-layer lattice shell can be optimized in a symmetrical manner. The symmetrical manner can adopt single-axis symmetry or double-axis symmetry as required. This method can greatly reduce the optimization steps, improve the optimization efficiency, and ensure the coordination and aesthetics of the entire lattice shell.

[0075] Step 6: After deleting the optimized unit in step 5, a new lattice shell model is established, and the mapping relationship matrix between the optimized unit and the rod is re-established; the optimization process from step 3 to step 5 is repeated for the model until the double-layer lattice shell cannot be optimized again or the optimized unit that meets the conditions cannot be found. The optimized unit number optimized in each step is exported, and the rods in the lattice shell corresponding to the optimized unit are deleted from the structure to obtain the evacuated double-layer lattice shell structure after topology optimization.

[0076] Specifically, the lattice shell is divided into several optimization units and these optimization units are represented in the form of coding, and the optimization unit activation matrix is ​​introduced As an auxiliary matrix to complete the optimization operation, the optimization unit activation matrix has three columns. The first column indicates the number of the optimization unit. , … ; The second column indicates the position of the optimization unit. When the value is 1, it means that the optimization unit is in the middle position, and the optimization units on both the left and right sides need to be restricted. When the value is 2, it means that the optimization unit is in the leftmost position, and only the optimization unit on the right needs to be restricted. When the value is 3, it means that the optimization unit is in the rightmost position, and only the optimization unit on the left needs to be restricted. The third column indicates whether the optimization unit with this number can be optimized. When the value is 0, it means that the optimization unit is restricted and cannot be optimized. When the value is 1, it means that the optimization unit is not restricted and can be optimized.

[0077] The optimized unit number optimized in each step is exported, and the rods in the lattice shell corresponding to the optimized unit are deleted in the structure (the process of deleting structural rods is the process of deleting the rod unit matrix data), and finally the evacuated double-layer lattice shell structure after topology optimization is obtained.

[0078] Example 2

[0079] In one embodiment of the present disclosure, a free-form double-layer lattice shell structure topology optimization method is provided. Figure 1 As shown, it mainly includes the following steps:

[0080] Step 1: First, input the basic parameters of the lattice shell according to the requirements to perform parametric modeling on the double-layer lattice shell, generate the node coordinate matrix, the member unit matrix and the optimized unit matrix in the optimization process. The specific modeling method is:

[0081] Step 1.1: Generate the node coordinate matrix by generating the node coordinates of the upper lattice shell and the lower lattice shell separately ,in The node number is Nodes, , , are the horizontal coordinate, vertical coordinate and vertical coordinate of the node. Taking the cylindrical lattice shell as an example, the specific modeling method is:

[0082] (1) Calculate the coordinates of the upper lattice shell nodes, such as Figure 2 As shown, according to the geometric relationship, the coordinates of the lattice node numbered 1 are ( , , ), this coordinate is the first row of the node coordinate matrix; according to the geometric relationship, the coordinate of the node numbered 2 can be calculated as ( , , ); The coordinates of the node numbered 3 are ( , , ); By analogy, the coordinates of all upper lattice shell nodes on y=0 can be obtained, such as Figure 3 Nodes 1-11 in the lattice shell. Since the length of the rod in the y-axis direction is a constant value d, the x and z coordinates of the subsequent nodes remain unchanged with the x and z coordinates of the previous nodes, and only the y coordinate changes. This can generate all the node coordinates of the upper lattice shell in the double-layer lattice shell, such as Figure 3 Nodes 1-121 in .

[0083] (2) Calculate the coordinates of the nodes of the lower lattice shell: The position of the nodes of the lower lattice shell is the geometric center of each grid of the upper lattice shell offset downward by a certain distance along the z-axis direction, such as Figure 4 , Figure 5 As shown, according to the geometric relationship, the coordinates of the first node of the lower lattice shell, that is, the node numbered 122, can be calculated as ( , , ); The coordinates of the node numbered 123 are ( , , ); The coordinates of the node numbered 124 are ( , , ); By analogy, the coordinates of all nodes of the lower lattice shell on y=0 can be obtained, and then the coordinates of all nodes of the lower lattice shell can be obtained.

[0084] Step 1.2: Generate member element matrix ,in Indicates the number of the bar element, Indicates the starting point node number of the bar element, Indicates the node number of the end point of the bar element. The element type representing the bar element, represents the cross-section type of the bar element, Represents the material properties of the bar element, Indicates the number of segments of the bar element. Figure 6 As shown in the figure, ① represents the first unit, and the unit coding order is the upper grid shell cross bar, the upper grid shell vertical bar, the grid shell middle web bar, the lower grid shell cross bar and vertical bar. The unit coding order of the upper and lower grid shells is from left to right and from bottom to top. The middle web bar is coded from left to right and from bottom to top in grid units.

[0085] Step 2: The four members of each grid in the upper lattice shell, the intermediate web members connected to their nodes, and the lower lattice shell members connected to the web member nodes are combined into an optimization unit, such as Figure 6 As shown. The optimization unit mapping matrix is ​​established based on the mapping relationship between the optimization unit and the member:

[0086] , the number of optimization units starts from 0, and the matrix Representative number is The optimization unit, , … It represents the rods in the optimization unit. Due to the different positions of the optimization unit, the number of rods inside the optimization unit will be different, such as Figure 7 There are only 10 rods in the optimization unit, and the positions without rods in the optimization unit are replaced by 0 in the matrix.

[0087] Step 3: Define the double-layer lattice shell material properties, loads and constraints in the form of a matrix: (1) Material property matrix ,in Representative Different materials, represents the elastic modulus of the material, represents the shear modulus of the material, , represents the moment of inertia of the material, Represents the cross-sectional area of ​​the material (2) Load matrix ,in Indicates the node number to which the load is applied. Indicates that at the node The degrees of freedom to which the load is applied, It indicates the magnitude of the load value. (3) Boundary constraint matrix , similar to the load matrix, where Indicates the constrained node number, Indicates that at the node The degrees of freedom constrained on Represents the constrained value. (4) By adding the material properties, loads and boundary constraints of the model to the model for calculation, the displacement of each member of the model and the axial force, shear force, bending moment and other information of each member of the lattice shell can be obtained.

[0088] Step 4: In step 3, the force information of all the rods of the double-layer lattice shell has been generated. All the rods are traversed in order from small to large according to the rod number, and the strength and stability of the rods are checked in combination with the force conditions at the rod ends. If the lattice shell rod is a tension rod, its strength is checked. Based on the "Structural Design Standard" GB50017-2017, the formula is used. Calculate, where is the design value of the tensile force at the calculated section, is the design value of tensile strength of steel, is the gross cross-sectional area of ​​the component; if the lattice shell member is a compression member, the stability is verified based on the "Structural Design Standard" GB50017-2017, using the formula Calculate, where is the stability factor of the compressive member, is the pressure on the compression member, is the cross-sectional area of ​​the compression member, The calculated stress ratio values ​​are summarized and the stress ratio matrix is ​​generated by imitating the structural form of the optimization unit mapping matrix. ,in The value of is the value of the optimized unit mapping matrix The stress ratio of the rod in the stress ratio matrix is , … and the optimized unit mapping matrix , … Each row in the stress ratio matrix represents the stress ratio of a member in an optimized unit.

[0089] Step 5: Observe the lattice shell from the top view, such as Figure 8 , each of the four-deformation grids is part of an optimized unit. The coding of the optimized unit starts from 0, and is successively optimized unit 0, optimized unit 1... According to the stress ratio matrix generated in step 4, the sum of the stress ratios of all optimized unit members is calculated, and the optimized unit member stress ratios are sorted in ascending order to obtain the optimized unit stress ratio ascending array. In this way, the optimization order of all optimized units of the double-layer lattice shell is obtained. Add the following conditions: (1) The web with the largest stress ratio among the four webs of each optimized unit should not be greater than the root of the sum of the squares of the stress ratios of the other three webs (2) The optimized units around the optimized optimized unit can be restricted according to the structural and morphological characteristics of the lattice shell (3) The edge of the lattice shell does not participate in the optimization, etc. The optimized units that do not meet the requirements are eliminated from the optimized unit stress ratio ascending array and do not participate in the subsequent optimization process. The specific steps are as follows:

[0090] Step 5.1: After the first optimization is completed, during the second optimization process, the optimized optimization unit will still appear in the next optimization unit stress ratio ascending array, and its stress ratio sum must be smaller than that of other optimization units, so the optimized optimization unit should be eliminated from the optimization unit stress ratio ascending array and the optimization unit stress ratio ascending array should be updated.

[0091] Step 5.2: According to the structural and morphological characteristics of the lattice shell, restrict the optimized units around the optimized units, such as Fig. 9 , if e5 participates in the optimization, then its adjacent e2, e4, e6, and e8 will not participate in the subsequent optimization process. Taking the cylindrical lattice shell as an example, its force is mainly transmitted in the horizontal direction, so the two adjacent optimization units on the left and right cannot be optimized at the same time, while the upper and lower adjacent optimization units are not restricted, which is reflected in Fig. 9 , after e5 participates in the optimization, only e4 and e6 are restricted. In this process, the optimization unit activation matrix is ​​introduced As an auxiliary matrix to complete the above operations, the optimization unit activation matrix has three columns. The first column indicates the number of the optimization unit. , … ; The second column indicates the position of the optimization unit. When the value is 1, it means that the optimization unit is in the middle position, and the optimization units on the left and right sides need to be restricted. When the value is 2, it means that the optimization unit is in the leftmost position, and only the optimization unit on the right needs to be restricted. When the value is 3, it means that the optimization unit is in the rightmost position, and only the optimization unit on the left needs to be restricted. The third column indicates whether the optimization unit with this number can be optimized. When the value is 0, it means that the optimization unit is restricted and cannot be optimized. When the value is 1, it means that the optimization unit is not restricted and can be optimized. Combined with the optimization unit activation matrix, the restricted optimization unit is removed from the optimization unit stress ratio ascending array to update the optimization unit stress ratio ascending array.

[0092] Step 5.3: Extract the first optimized unit number in the ascending array of the optimized unit stress ratio, and find all the bar numbers in the optimized unit by combining it with the optimized unit mapping matrix. During the optimization process, the bars of the upper lattice shell of the optimized unit are retained, and the material properties of the remaining bars are modified to be infinitely close to 0, which is equivalent to deleting the bars in algebra. In this way, a complete optimization process ends and the second optimization process begins.

[0093] In particular, the double-layer lattice shell can be optimized in a symmetrical way, and the symmetrical way can be single-axis symmetry or double-axis symmetry according to the needs. Taking the cylindrical lattice shell as an example, the double-axis symmetry method can be used to simplify the optimization of the entire lattice shell to the optimization of 1 / 4 lattice shell, so that the stress ratio of the optimized unit of the lattice shell in the ascending array becomes 1 / 4 of the original. This method can greatly reduce the steps of optimization, improve the efficiency of optimization, and ensure the coordination and aesthetics of the entire lattice shell.

[0094] Step 6: After deleting the optimized unit in step 5, a new lattice shell model is established, and the mapping relationship matrix between the optimized unit and the rod is re-established; the optimization process from step 3 to step 5 is repeated for the model until the double-layer lattice shell cannot be optimized again or the optimized unit that meets the conditions cannot be found. The optimized unit number optimized in each step is exported, and the rods in the lattice shell corresponding to the optimized unit are deleted from the structure to obtain the evacuated double-layer lattice shell structure after topology optimization. Fig.10 , Fig.11 This is a comparison chart of the final optimization effect.

[0095] Example 3

[0096] In one embodiment of the present disclosure, a free-form double-layer lattice shell structure topology optimization system is provided, comprising:

[0097] An initialization module is used to obtain various basic parameters of the double-layer lattice shell and perform parameterized modeling on the double-layer lattice shell;

[0098] The analysis and calculation module is used to establish an optimization unit suitable for topology optimization based on the parametric model of the double-layer lattice shell, and to construct an optimization unit mapping matrix based on the optimization unit; to apply loads and constraints, to establish a double-layer lattice shell finite element model, and to perform finite element analysis and calculation on the finite element model; according to the analysis and calculation results, to traverse all the rods in the double-layer lattice shell to perform strength verification and stability verification, to obtain the stress ratios of all the rods, and to generate a stress ratio matrix based on the optimization unit mapping matrix;

[0099] The optimization iteration module is used to optimize the optimized unit rods in the double-layer lattice shell parametric model based on the stress ratio matrix; establish a new double-layer lattice shell parametric model based on the optimized optimized unit, and re-establish the mapping relationship matrix between the optimized unit and the rods, and perform an iterative optimization process until the double-layer lattice shell cannot be optimized again or the optimized unit that meets the conditions cannot be found, thereby obtaining a evacuated double-layer lattice shell structure after topology optimization.

[0100] Example 4

[0101] In one embodiment of the present disclosure, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, the method for topology optimization of a free-form double-layer lattice shell structure is implemented.

[0102] Example 5

[0103] In one embodiment of the present disclosure, an electronic device is provided, comprising: a processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the method for topological optimization of a free-form double-layer lattice shell structure.

[0104] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0105] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0106] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A free-form double-layer lattice shell structure topology optimization method, characterized in that: include: Obtaining basic parameters of a double-layer lattice shell and performing parameterized modeling on the double-layer lattice shell; The basic parameters of the double-layer lattice shell include the spatial morphological parameters of the double-layer lattice shell, the mechanical parameters of the structural members, and the connection relationship between the members and the nodes. The spatial morphological parameters of the double-layer lattice shell, the mechanical parameters of the structural members, and the connection relationship between the members and the nodes are expressed in the form of a matrix for parametric modeling. According to the parametric model of the double-layer lattice shell, an optimization unit suitable for topology optimization is established, and an optimization unit mapping matrix is ​​constructed based on the optimization unit; According to the connection relationship between the rods and nodes and the spatial morphological parameters of the double-layer lattice shell, an optimization unit suitable for topology optimization is established, and a mapping relationship between the optimization unit and the rods is established in the form of a matrix. Specifically, the double-layer lattice shell parameterized model is divided into several optimization units, and the four rods of each grid in the upper lattice shell, the middle web connected to its node and the lower lattice shell rod connected to the web node are called an optimization unit, and each optimization unit is numbered in the form of coding, and an optimization unit mapping matrix is ​​established based on the mapping relationship between the optimization unit and the rods; Applying loads and constraints, establishing a double-layer lattice shell finite element model, and performing finite element analysis and calculation on the finite element model; According to the analysis and calculation results, all the bars in the double-layer lattice shell are traversed to perform strength and stability checks, the stress ratios of all bars are obtained, and the stress ratio matrix is ​​generated based on the optimized unit mapping matrix; The optimized unit rods in the double-layer lattice shell parametric model are optimized based on the stress ratio matrix, including: calculating the sum of the stress ratios of all optimized unit rods according to the generated stress ratio matrix, and sorting them in ascending order based on the sum of the stress ratios of the optimized unit rods to obtain an ascending array of optimized unit stress ratios, removing the optimized unit numbers that have been optimized from the ascending array of optimized unit stress ratios, updating the ascending array of optimized stress ratios, removing the adjacent optimized units of the optimized units that have been optimized from the ascending array of optimized unit stress ratios according to optimization constraints, updating the ascending array of optimized stress ratios again, and extracting the first optimized unit number in the array, and deleting the corresponding rod in the first optimized unit number in the double-layer lattice shell structure model based on the optimized unit mapping matrix; The double-layer lattice shell is optimized in a symmetrical manner, and the symmetrical manner adopts single-axis symmetry or double-axis symmetry according to needs; A new double-layer lattice shell parametric model is established based on the optimized optimization unit, and the mapping relationship matrix between the optimization unit and the rod is re-established. The iterative optimization process is performed until the double-layer lattice shell cannot be optimized again or the optimization unit that meets the conditions cannot be found, and the evacuated double-layer lattice shell structure after topology optimization is obtained.

2. A free-form double-layer lattice shell structure topology optimization method according to claim 1, characterized in that: The definition of the model material properties is expressed by the material property matrix, the load applied to the model is expressed by the load matrix, the imposed constraints are expressed by the boundary constraint condition matrix, and a double-layer lattice shell finite element model is established.

3. A free-form double-layer lattice shell structure topology optimization method according to claim 1, characterized in that: After deleting the optimized unit, a new lattice shell model is established, and the mapping relationship matrix between the optimized unit and the rod is re-established; The optimization process is repeated until the double-layer lattice shell cannot be optimized again or the optimization unit that meets the conditions cannot be found. The optimized unit number optimized in each step is exported, and the rods in the lattice shell corresponding to the optimization unit are deleted from the structure to obtain the evacuated double-layer lattice shell structure after topology optimization.

4. A free-form double-layer lattice shell structure topology optimization system, characterized in that: include: An initialization module is used to obtain various basic parameters of the double-layer lattice shell and perform parameterized modeling on the double-layer lattice shell; The basic parameters of the double-layer lattice shell include the spatial morphological parameters of the double-layer lattice shell, the mechanical parameters of the structural members, and the connection relationship between the members and the nodes. The spatial morphological parameters of the double-layer lattice shell, the mechanical parameters of the structural members, and the connection relationship between the members and the nodes are expressed in the form of a matrix for parametric modeling. The analysis and calculation module is used to establish an optimization unit suitable for topology optimization based on the parametric model of the double-layer lattice shell, and to construct an optimization unit mapping matrix based on the optimization unit; to apply loads and constraints, to establish a double-layer lattice shell finite element model, and to perform finite element analysis and calculation on the finite element model; according to the analysis and calculation results, to traverse all the rods in the double-layer lattice shell to perform strength verification and stability verification, to obtain the stress ratios of all the rods, and to generate a stress ratio matrix based on the optimization unit mapping matrix; According to the connection relationship between the rods and nodes and the spatial morphological parameters of the double-layer lattice shell, an optimization unit suitable for topology optimization is established, and a mapping relationship between the optimization unit and the rods is established in the form of a matrix. Specifically, the double-layer lattice shell parameterized model is divided into several optimization units, and the four rods of each grid in the upper lattice shell, the middle web connected to its node and the lower lattice shell rod connected to the web node are called an optimization unit, and each optimization unit is numbered in the form of coding, and an optimization unit mapping matrix is ​​established based on the mapping relationship between the optimization unit and the rods; An optimization iteration module is used to optimize the optimized unit rods in the double-layer lattice shell parametric model based on the stress ratio matrix; establish a new double-layer lattice shell parametric model based on the optimized optimized unit, and re-establish the mapping relationship matrix between the optimized unit and the rods, and perform an iterative optimization process until the double-layer lattice shell cannot be optimized again or the optimized unit that meets the conditions cannot be found, thereby obtaining a evacuated double-layer lattice shell structure after topological optimization; The optimized unit rods in the double-layer lattice shell parametric model are optimized based on the stress ratio matrix, including: calculating the sum of the stress ratios of all optimized unit rods according to the generated stress ratio matrix, and sorting them in ascending order based on the sum of the stress ratios of the optimized unit rods to obtain an ascending array of optimized unit stress ratios, removing the optimized unit numbers that have been optimized from the ascending array of optimized unit stress ratios, updating the ascending array of optimized stress ratios, removing the adjacent optimized units of the optimized units that have been optimized from the ascending array of optimized unit stress ratios according to optimization constraints, updating the ascending array of optimized stress ratios again, and extracting the first optimized unit number in the array, and deleting the corresponding rod in the first optimized unit number in the double-layer lattice shell structure model based on the optimized unit mapping matrix; The double-layer lattice shell is optimized in a symmetrical manner, and the symmetrical manner adopts single-axis symmetry or double-axis symmetry according to needs.

5. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by the processor, a free-form double-layer lattice shell structure topology optimization method as described in any one of claims 1 to 3 is implemented.

6. An electronic device, characterized in that: include: A processor, a memory and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory so that the electronic device executes a free-form double-layer lattice shell structure topology optimization method as described in any one of claims 1 to 3.

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