Curvature-controllable reinforcement design method, device and equipment for curved surface shell and storage medium

Abstract

The invention discloses a curvature-controllable reinforcement design method, device and equipment for a curved-surface shell and a storage medium, and the method comprises the steps: S1, setting continuous change of parameters through an implicit function control part, controlling the thickness, curvature and periodic layout characteristics of a plane rod, designing a reverse chiral plane rod system grating, and setting the thickness, curvature and periodic layout characteristics of the reverse chiral plane rod system grating; the space gradient change of the rods in the plane rod system grating is realized; and S2, the plane bar system grating is mapped to the curved surface shell through coordinate mapping to generate programmable gradient transition reinforcement, and reinforcement design of the rotary body structure of the cylindrical shell is completed. According to the method, reinforcement is described based on the analytic function and the coordinate function, reinforcement of different thicknesses and curvatures can be achieved through control over a small number of parameters of the function, local mechanical property strengthening is controlled, meanwhile, continuous changes of the reinforcement curvature are controlled through parameter distribution changes, the continuity of reinforcement grilles with different curvatures is guaranteed through parameter filtering, and the reinforcement effect is improved. The degree of freedom and reliability of gradient reinforcement design are guaranteed, and complex reinforcement description and gradient reinforcement design are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft structure design, in particular, to a controllable curvature stiffening design method, device, equipment and storage medium for a curved shell. BACKGROUND

[0002] As a kind of efficient bearing structure, stiffened plate has been widely used in aerospace equipment, ship engineering and automobile industry due to its lightweight design, high rigidity and superior mechanical properties. By reasonably configuring the material properties, cross-sectional shape, arrangement density and geometric parameters of the rib, the bending resistance of the structure can be significantly optimized under the premise of limited mass increment, thereby effectively improving the mechanical response characteristics and stability threshold of thin-walled components. Existing stiffened plate design methods include topology optimization method and explicit stiffening design method. Topology optimization optimizes the structure by defining the relative density distribution of space points, while the explicit method designs the stiffened structure with fixed geometric form.

[0003] The existing topology optimization method defines the relative density at each space point, which is difficult to efficiently describe the structure form of stiffening and other structures much smaller than the macro structure size. In addition, the traditional explicit description-based stiffening design method is limited to fixed forms such as orthogonal grid, triangular frame and hexagonal grid, making it difficult to achieve complex stiffening description and gradient stiffening design. SUMMARY

[0004] The present application provides a controllable curvature stiffening design method for a curved shell, which solves the technical problems that the existing technology is difficult to efficiently describe the structure form of stiffening and other structures much smaller than the macro structure size, and difficult to achieve complex stiffening description and gradient stiffening design.

[0005] The present application is realized by the following scheme: The controllable curvature stiffening design method for a curved shell includes the following steps: S1, set the continuous variation of parameters by implicit function control part, control the thickness, curvature and periodic layout characteristics of the plane rod, design the chiral plane rod system grid, and realize the spatial gradient variation of the rods in the plane rod system grid; S2, map the plane rod system grid to the curved shell through coordinate mapping to generate programmable gradient transition stiffening, and complete the stiffening design of the rotation body structure of the cylindrical shell.

[0006] Further, the step S1 specifically includes the following steps: S11, for the chiral metamaterial cell structure composed of two groups of symmetric curved rods, one group of symmetric curved rods is set as: The mathematical expression form of the curved rod in the entire vertical design direction is: ; ; where, ; ; The mathematical expression of the curved bar in the transverse design direction is defined by the rotational symmetry of the coordinates as: ; ; where, ; where, c represents the curvature parameter, which is used to control the curvature of the curved bar; l x and l y the extreme value of the influence function, which is used to control the thickness of the curved bar in the x and y directions, respectively; r x and r y the phase of the influence function, which is used to control the spatial position of the curved bar in the x and y directions; p x and p y control the number of curved bars in the x and y directions within a unit area; q x and q y control the spatial position of the curved bars in the x and y directions, but their value size has the opposite effect on the specific position compared to r x and r y ; x and y are the independent variables of the bar generation function, , , and represent the phase control function, represents the curved bar generation function with a curvature of c in the y direction, represents the curved bar generation function with a curvature of c in the y direction, represents the curved bar generation function with a curvature of c in the x direction, represents the curved bar generation function with a curvature of c in the x direction, t x and t y affects the period of the phase control function, which is used to control the repetition frequency of the curved bar bending characteristics,s x and s y for controlling the relative position of the curved rods in a single cell; S12, after obtaining two sets of vertically symmetrical curved rod descriptions, the chiral curved rod lattice structure is obtained by Boolean operation: ; wherein H(•) is the Heaviside function, and • represents the independent variable mapped by the Heaviside function.

[0007] Further, the step S1 further comprises the step of: S13, by changing the values of the curvature parameters c and thickness parameters l of the chiral curved rod lattice structure, chiral curved rod lattice structures of different shapes are obtained.

[0008] Further, the step S1 further comprises the step of: S14, for the periodically distributed chiral curved rod lattice structure, the continuously distributed control curvature parameters c continuous transition are defined by density filtering, to obtain the chiral curved rod lattice structure with continuous transition at the connection of different curvature lattices.

[0009] Further, the step S2 specifically comprises the steps of: S21, first complete the geometric modeling of the curved surface shell in the modeling software, to obtain the parameterized model of the cylindrical shell; S22, then extract the three-dimensional spatial position data of the cylindrical shell surface nodes through the format conversion interface, to establish a spatial coordinate database meeting the requirements of parameterized modeling; S23, extract the three-dimensional spatial position data, map the chiral curved rod lattice structure to the cylindrical shell based on the coordinate mapping principle and the chiral curved rod lattice structure, to generate the chiral lattice reinforced structure of the curved surface shell; S24, take the curvature parameter c value of the control rod curvature as a continuously changing value to generate the curved surface gradient reinforced structure continuously changing along the set direction.

[0010] Further, the step S23 specifically comprises the steps of: S231, reconstruct the curvature parameter c as a continuous function along the axial coordinate z of the cylindrical shell, assuming that the given minimum and maximum values of the axial coordinate of the cylindrical shell are z min and z max , the axial coordinate z∈[z min , z max ] is mapped to the dimensionless parameter c∈[-1,1] by linear transformation, and the mathematical expression is: ; Thus, a curved surface gradient rib structure with a continuous change along the axis of the cylinder is generated.

[0011] Further, the step S23 further includes the steps of: S232, mapping the curvature parameter c to a bilinear coupling function in the local coordinate system of the cylindrical shell, which is mathematically expressed as: ; In the formula, and are the normalized coordinate components of the shell surface point, R is the maximum radius of the cylindrical shell, and the denominator R 2 for eliminating the size effect, ensuring that the curvature parameter Thus, a curved surface gradient rib structure with a continuous change along the circumference of the cylinder is generated.

[0012] Another aspect of the present application also provides a controllable curvature rib design device for a curved surface shell, comprising: The chiral plane bar lattice design module is used for controlling the thickness, curvature and periodic layout characteristics of the plane bar by setting the continuous change of the implicit function control part, designing the chiral plane bar lattice, and realizing the spatial gradient change of the bar in the plane bar lattice. The curved surface shell controllable curvature rib design module is used for mapping the plane bar lattice to the curved surface shell through coordinate mapping to generate a programmable gradient transition rib, and completing the controllable curvature rib design of the revolution body structure of the cylindrical shell.

[0013] Another aspect of the present application also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to realize the steps of the controllable curvature rib design method for a curved surface shell.

[0014] Another aspect of the present application also provides a storage medium, comprising a stored program, wherein the program controls the device where the storage medium is located to execute the steps of the controllable curvature rib design method for a curved surface shell when the program is executed.

[0015] Compared with the prior art, the present application has the following beneficial effects: The application describes the stiffening based on an analytic function and a coordinate function, can control the stiffening of different thickness and curvature through a few parameters of the function, control the local mechanical performance strengthening, and avoid the problem that the design parameters are huge and it is difficult to directly control the geometric characteristics (such as curvature and thickness) of the stiffening based on the traditional topology optimization density field. In addition, unlike the traditional explicit stiffening based on the spline curve, the application can control the continuous change of the stiffening curvature through the parameter distribution change based on the implicit description of the function, ensure the continuity of the stiffening grid of different curvatures through the parameter filtering, ensure the freedom and reliability of the gradient stiffening design, and realize the complex stiffening description and gradient stiffening design.

[0016] In addition to the purposes, features and advantages described above, the application has other purposes, features and advantages. The application will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings incorporated into the specification and forming a part of the specification, show embodiments consistent with the application, and together with the specification, serve to explain the principles of the application.

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without creative labor. Figure 1 is a controllable curvature stiffening design method flowchart of a curved shell of a preferred embodiment of the application; Figure 2 is a straight rod grid structure generation principle flowchart; Figure 3 is a schematic diagram of a straight rod and a curved rod under the control of different parameters c ; Figure 4 is a chiral curved rod grid structure design flowchart; Figure 5 is a left-handed curved rod grid structure design flowchart; Figure 6 is a schematic diagram of a straight rod and a curved rod under the control of different parameters c and l ; Figure 7 (a) is a schematic diagram of a continuously distributed curvature parameter c ; Figure 7 (b) is a schematic diagram of a planar grid structure with gradient change; Figure 8 is a schematic diagram of a planar curved rod grid structure mapping to a three-dimensional curved surface stiffening structure; Figure 9 (a) is a schematic view of a main view of a curved shell stiffened structure; Figure 9 (b) is a schematic view of a top view of a curved shell stiffened structure; Figure 10 is a schematic view of the effect of parameters c and l on the anti-chiral lattice of the curved shell; Figure 11 is a schematic view of a curved shell gradient stiffener structure continuously changing along the axis of the cylinder; Figure 12 is a schematic view of a curved shell gradient stiffener structure continuously changing along the circumference of the cylinder; Figure 13 is a schematic view of a curved shell controllable curvature stiffener design device module of the preferred embodiment of the present application; Figure 14 is a schematic block diagram of an electronic device of the preferred embodiment of the present application; Figure 15 is an internal structure diagram of a computer device of the preferred embodiment of the present application. DETAILED DESCRIPTION

[0019] It should be understood that the specific embodiments described herein are merely intended to explain the technical solutions of the present application, and are not intended to limit the present application.

[0020] In order to better understand the technical solutions of the present application, the following will be described in detail in combination with the drawings and specific embodiments.

[0021] It should be noted that the execution subject of the present embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or a curved shell controllable curvature stiffener design device capable of realizing the above functions. The following will take the curved shell controllable curvature stiffener design device as an example to describe the present embodiment and the following embodiments.

[0022] As shown in Figure 1 , the preferred embodiment of the present application provides a curved shell controllable curvature stiffener design method, comprising the steps of: S1, setting parameters to control the continuous change of the implicit function part, controlling the thickness, curvature and periodic layout characteristics of the plane rod, designing the anti-chiral plane rod lattice, and realizing the spatial gradient change of the rod in the plane rod lattice; S2, mapping the plane rod lattice to the curved shell through coordinate mapping to generate a programmable gradient transition stiffener, and completing the stiffener design of the cylinder shell of the revolution body structure.

[0023] The embodiment based on the analysis function and the coordinate function describes the stiffening, can control the stiffening of different thickness and curvature through a small number of parameters of the function, controls the local mechanical performance strengthening, and avoids the problem that the design parameters are huge and it is difficult to directly control the geometric characteristics (such as curvature and thickness) of the stiffening based on the traditional topology optimization density field. In addition, unlike the traditional explicit stiffening based on the spline curve, the embodiment based on the implicit description of the function can control the continuous change of the stiffening curvature through the parameter distribution change, ensures the continuity of the stiffening grid of different curvatures through the parameter filtering, ensures the freedom and reliability of the gradient stiffening design, and realizes the complex stiffening description and gradient stiffening design.

[0024] Preferably, the step S1 specifically comprises the steps of: S11, for the chiral metamaterial cell structure composed of two groups of symmetric curved rods, the symmetry degree of the symmetric curved rods is controlled by increasing the symmetry degree parameter on the basis of the phase function , in addition, a group of symmetric curved rods is obtained by controlling the positive and negative of the phase function , and further, the vertical curved rods are obtained by utilizing the rotational symmetry of the coordinates, for one group of symmetric curved rods, the setting is: The mathematical expression of the curved rods in the whole vertical design direction is: ; ; Wherein, ; ; The mathematical expression of the curved rods in the horizontal design direction is defined by utilizing the rotational symmetry of the coordinates: ; ; Wherein, ; Wherein, c represents the curvature parameter, which is used for controlling the curvature of the curved rod; l x and l y affect the extreme value of the function, and are respectively used for controlling the thickness of the curved rod in the x direction and the y direction; r x and r y affect the phase of the function, which is used for controlling the spatial position of the curved rod in the x direction and the y direction; p x and p yThe number of curved rods in the x and y directions in the control unit area is controlled; q x And q y The spatial position of the x and y direction curved rods is controlled, but the value size has the opposite effect on the specific position to r x And r y , x And y is the independent variable of the rod generation function, , , And represents the phase control function, represents the curved rod generation function with a curvature of c in the y direction, represents the curved rod generation function with a curvature of c in the y direction, represents the curved rod generation function with a curvature of c in the x direction, represents the curved rod generation function with a curvature of c in the x direction, t x And t y The period of the phase control function is affected, which is used to control the repetition frequency of the curved rod bending characteristics, s x And s y is used to control the relative position of the curved rod in a single cell; S12, after obtaining two sets of vertical symmetric curved rod descriptions, the chiral curved rod lattice structure is obtained by Boolean operation: ; Where H(•) is the Heaviside function, • represents the independent variable mapped by the Heaviside function.

[0025] Specifically, the step S1 further comprises the steps of: S13, by changing the values of the curvature parameters c and thickness parameters l of the chiral curved rod lattice structure, different shapes of chiral curved rod lattice structures are obtained.

[0026] Specifically, the step S1 further comprises the steps of: S14, for the periodically distributed chiral curved rod lattice structure, the continuously distributed control curvature parameters cThe continuous transition is obtained at the connection of the different curvature grids.

[0027] Specifically, the step S2 specifically comprises the steps of: S21, first complete the geometric modeling of the curved surface shell in the modeling software to obtain a parameterized model of the cylindrical shell; S22, then extract the three-dimensional spatial position data of the cylindrical shell surface nodes through the format conversion interface to establish a spatial coordinate database meeting the requirements of parameterized modeling; S23, extract the three-dimensional spatial position data, map the chiral curved rod grid structure to the cylindrical shell based on the coordinate mapping principle and the chiral curved rod grid structure, and generate the chiral grid stiffened structure of the curved surface shell; S24, take the curvature parameter c value of the control rod piece curvature as a continuously changing value to generate a curved surface gradient stiffened structure continuously changing along the set direction.

[0028] Specifically, the step S23 specifically comprises the steps of: S231, reconstruct the curvature parameter c as a continuous function along the axial coordinate z of the cylindrical shell, assuming that the minimum and maximum values of the given cylindrical shell axial coordinate are z min and z max , map the axial coordinate z∈[z min , z max ] to the dimensionless parameter c∈[-1,1] through linear transformation, and the mathematical expression is: ; Thus, a curved surface gradient stiffened structure with continuously changing axial direction of the cylindrical body is generated.

[0029] Specifically, the step S23 further comprises the steps of: S232, reconstruct the curvature parameter c as a bilinear coupling function under the local coordinate system of the cylindrical shell, and the mathematical expression is: ; In the formula, and are the normalized coordinate components of the shell surface points, is the maximum radius of the cylindrical shell, and the denominator R 2 is used to eliminate the size effect and ensure that the curvature parameter , thus generating a curved surface gradient stiffened structure with continuously changing circumferential direction of the cylindrical body.

[0030] The basic principles of the present application are further described below.

[0031] The present application is based on the open source finite element analysis software FEniCS under Linux (Ubuntu system) to design different forms of metamaterial unit cells, and then export the metamaterial unit cell design model to a pvd file. Then import the pvd file into Paraview software for visualization. Finally, the metamaterial unit cell design model can be exported to an stl file in Paraview for post-processing and additive manufacturing processing. The technical optimization scheme of the present application is as follows: the design method is mainly based on Python programming language to analyze the metamaterial design model in FEniCS, and the macroscopic properties of the metamaterial unit cell are calculated by finite element analysis through homogenization theory, and finally the filling numerical example of the metamaterial unit cell is given to prove the reliability of the results.

[0032] Design of straight rod lattice based on trigonometric periodic function: In implicit function modeling, the membership of a point is determined by the function value of the point. In the field of structural mechanics, it is generally believed that points with positive and zero function values are included in the structure, and the zero level set represents the boundary of the microstructure. The function value of the trigonometric function is projected to 0 and 1 by the Heaviside function, where 0 represents a hole material and 1 represents a solid material. The Heaviside function is represented as: ; wherein, ξ x represents the independent variable mapped by the Heaviside function, controls the degree of step of the Heaviside function, which is a fixed value in the whole technical scheme process , if >0, return 1; if <0, return 0.

[0033] First, the process of generating a planar straight rod lattice structure using trigonometric periodic functions and functions is given, as shown in Figure 2 . The design space is selected as a Cartesian coordinate system, and are the coordinates of the space point X and Y directions, respectively, and the following trigonometric functions and Boolean operations are defined: ; ; ; wherein, and control the adjacent spacing of vertical and horizontal rods in the two-dimensional planar straight rod lattice structure; and are used to control the relative position of the rods in a single unit cell; and For solid materials, a threshold is set for function values ​​greater than [a certain threshold]. and The function is mapped to 1 or solid material, thereby controlling the thickness of the straight bars in the grid.

[0034] Figure 2 middle, and This visualizes the trigonometric function values ​​in two mutually perpendicular directions (X and Y directions) in a two-dimensional plane, through... Function mapping maps negative values ​​to 0, ensuring a 0 / 1 distribution of function values, represented as holes and solids respectively. Boolean operations allow us to take the union of points in the function space. This yields an orthogonal straight bar grid structure.

[0035] After a simple parameterization of the periodic function, the structural characterization can be controlled by a small number of parameters, and these parameters are associated with the stiffened geometric features.

[0036] Curved bar grille design based on parametric periodic functions: Adding a periodically varying phase along the vertical direction to the trigonometric functions describing a vertical bar grid can implicitly describe a curved bar. Figure 3 , Figure 3 The description function of the curved bar is as follows: ; ; in: ; in, and The meaning remains unchanged. This represents the added phase. middle c Control the curvature of the crank (when parameter) hour, and (Equivalent effect) This represents the inherent period of the curved rod, that is, the period of the curved rod's shape. Used to control the relative position of the lever within a single cell.

[0037] Chiral crank bar grille design: By adjusting the parameters, we can obtain... A single curved rod can be used to obtain a curved rod in the vertical direction by utilizing the cyclic symmetry of the X and Y coordinates. Boolean operations are then performed on the two rods. This leads to a chiral curved bar lattice structure. The term "chiral" refers to an object or structure whose mirror image cannot be perfectly superimposed through rotation or translation. The following is a schematic diagram illustrating the generation process of the chiral curved bar lattice structure. Figure 4 Its mathematical expression is as follows: Horizontal design direction has ; in ; Vertical design direction has ; in ; ; In the above formula ， and The physical meaning of the variable corresponding to the subscript x is the same, but it is used for control. y Geometric features of the steering column. Boolean operations can be used to take the union of points in the function space. U .

[0038] Reverse-hand curved bar grille design: Antichirality can be composed of two sets of chiral lattices with a period of two times. For an antichiral metamaterial cell structure composed of two sets of symmetrical curved rods, through the function Add parameters based on This controls the degree of symmetry of the symmetrical curved rod. Additionally, it uses a control function... The positive and negative signs yield a set of symmetrical curved rods, and further, by utilizing the cyclic symmetry of the coordinates, a curved rod in the vertical direction can be obtained. Control function For a set of symmetrical curved rods, refer to step S11 above. After obtaining two sets of perpendicular symmetrical curved rod descriptions, merge them using Boolean operations, referring to step S12 above.

[0039] Boolean operations yield a reciprocal curved bar grid structure. A flowchart illustrating the process of generating reciprocal cells can be found here. Figure 5 By changing the curvature parameter in the parametric composite trigonometric function c and thickness parameters l The value of can be used to obtain reciprocal curved bar grid structures of different shapes, see Figure 6 .

[0040] A gradient grid can be implemented by controlling the parameters of a periodic function to describe the grid. For example... Figure 7 As shown, this paper defines density filtering. Figure 7 The curvature parameters in (a) are continuously distributed. c Then you can get the followingFigure 7 Gradient variation of planar grid structure in (b). Due to the curvature parameter c Continuous transition, different curvature grids can also be continuously transitioned at the connection.

[0041] Design of chiral grid stiffener structure of curved shell: A parametric model of cylindrical shell with inner diameter 0.8m, outer diameter 1.0m and height 3m was established based on Gmsh finite element analysis platform. By executing mesh data conversion from msh format to xml format, the three-dimensional spatial position information of the shell surface nodes was accurately extracted. This data preprocessing procedure provides a key geometric basis for the parametric reconstruction of curved stiffened structure, and the specific implementation process includes: first, complete the shell geometric modeling in Gmsh, then extract the structured node data through the format conversion interface, and finally establish a spatial coordinate database that meets the requirements of parametric modeling, and the specific mapping process is shown in Figure 8 .

[0042] Analysis of data characteristics shows that the original coordinates output by the software are discrete point sets M(x, y,z) in the rectangular coordinate system. In order to adapt to the geometric characteristics of curved structures, coordinate system transformation operation is performed to convert it to cylindrical coordinate system M'(r, ,z'), and its mathematical relationship can be expressed as:

[0043] The layout area of the stiffener is limited to the annular interval of the cylindrical shell, specifically located in the radial range of R=0.9 to R=1.0. To realize the structure optimization on the complex curved surface, this application proposes a mapping method based on surface unfolding: the three-dimensional curved surface is unfolded into a two-dimensional plane along the cylindrical generatrix direction, and the original cylindrical coordinate points M'(r, φ, z') are projected to the plane coordinate system M''(x', y') through the coordinate mapping relationship, and the conversion criterion is:

[0044] Based on the coordinate mapping principle and the design method of chiral curved rod grid structure, the chiral grid stiffener structure of curved shell is generated, which is shown in Figure 9 (a) and Figure 9 (b).

[0045] In the parametric process of curved surface, in order to obtain a more reasonable layout structure of stiffener, the key parameters of stiffener layout and need to be dynamically adjusted according to the curvature characteristics. For the rotating shell structure, the mathematical relationship between the stiffener distribution density parameter ω and the circumference of the curved surface can be expressed as: let the circumference of the shell be L=2πR (R is the radius), when the design requires arranging n complete cycles of stiffener along the circumferential direction, the angular frequency parameter needs to meet Recombine Calculated When the period parameter T is approximately equal to , to achieve the n-period continuous distribution of the curved surface composite trigonometric function structure, the axial development length needs to meet the geometric constraint L = nT, and thus it is derived that (n is an even number).

[0046] The rib distribution of the space-continuous stiffened configuration generated by the algorithm can meet the mechanical performance requirements through geometric shape control, while maintaining the geometric harmony of the curved surface. The innovation of the method is to transform the three-dimensional curved surface stiffening problem into a two-dimensional plane problem through differential geometric transformation, which significantly reduces the computational complexity.

[0047] In the parametric design of the curved shell stiffened structure, based on the parametric modeling method, the geometric characteristics of the stiffener can be controlled with high precision. By changing the size of the curvature parameter c , the bending degree of the curved rod can be controlled, and the chiral stiffened structure of the curved shell can present different shapes. Through reasonable configuration of the thickness parameter l , the thickness of the rib rod can be controlled in a certain direction, and the curved shell stiffened structure generated thereby is shown in Figure 10 .

[0048] In order to generate a curved surface gradient stiffened structure with continuous change along the axial direction of the cylindrical shell, the curvature parameter c value of the control rod curvature is taken as a continuously changing value to generate a curved surface gradient stiffened structure. First, the curvature parameter c is reconstructed as a continuous function along the axial coordinate z of the cylindrical shell. Assuming that the minimum and maximum values of the given cylindrical shell axial coordinate are z min and z max , the axial coordinate z∈[z min , z max ] is mapped to the dimensionless parameter c∈[-1,1] through linear transformation, and the mathematical expression is as shown in the foregoing step S231, and the generated result is shown in Figure 11 .

[0049] In order to realize the curved surface gradient stiffened structure with continuous change along the circumferential direction of the cylindrical shell, the curvature parameter c is reconstructed as a bilinear coupling function in the local coordinate system of the cylindrical shell, and the mathematical expression is shown in the foregoing step S232, thereby generating a curved surface gradient stiffened structure with continuous change along the circumferential direction of the cylindrical shell (see Figure 12 ).

[0050] The mapping method based on coordinate standardization in the application establishes an explicit association between spatial position and geometric characteristics while ensuring the parameter value specification, and provides a universal mathematical model for the construction of complex gradient structures. The design of the curved surface gradient reinforcement rib provides a new idea for the development of the reinforced layout.

[0051] As Figure 13 shown, another preferred embodiment of the application further provides a curved surface shell controllable curvature reinforced design device, comprising: The left-handed planar bar system grid design module is configured to control the thickness, curvature and periodic layout characteristics of the planar bar by setting the continuous variation of the implicit function control parameters, design the left-handed planar bar system grid, and realize the spatial gradient variation of the bars in the planar bar system grid. The curved surface shell controllable curvature reinforced design module is configured to map the planar bar system grid to the curved surface shell through coordinate mapping to generate a programmable gradient transition reinforcement, and complete the controllable curvature reinforced design of the rotation body structure of the cylindrical shell.

[0052] The curved surface shell controllable curvature reinforced design device provided by the application adopts the curved surface shell controllable curvature reinforced design method in the above embodiments, and can solve the technical problems that the prior art is difficult to efficiently describe the structure form of the reinforcement and other structures much smaller than the macro structure size, and is difficult to realize complex reinforcement description and gradient reinforced design. Compared with the prior art, the curved surface shell controllable curvature reinforced design device provided by the application has the same beneficial effects as the curved surface shell controllable curvature reinforced design method provided by the above embodiments, and other technical features in the curved surface shell controllable curvature reinforced design device are the same as the features disclosed in the above embodiments, which will not be repeated here.

[0053] As Figure 14 shown, the preferred embodiment of the application further provides an electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the curved surface shell controllable curvature reinforced design method in the above embodiments when executing the computer program.

[0054] The electronic device provided by the application adopts the curved surface shell controllable curvature reinforced design method in the above embodiments, and can solve the technical problems that the prior art is difficult to efficiently describe the structure form of the reinforcement and other structures much smaller than the macro structure size, and is difficult to realize complex reinforcement description and gradient reinforced design. Compared with the prior art, the electronic device provided by the application has the same beneficial effects as the curved surface shell controllable curvature reinforced design method provided by the above embodiments, and other technical features in the electronic device are the same as the features disclosed in the above embodiments, which will not be repeated here.

[0055] As Figure 15As shown, a preferred embodiment of this application also provides a computer device, which may be a terminal or a liveness detection server, and its internal structure diagram may be as follows. Figure 15 As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface is used to communicate with other external computer devices via a network connection. When the computer program is executed by the processor, it implements the steps of the aforementioned controlled curvature stiffening design method for curved shells.

[0056] Those skilled in the art will understand that Figure 15 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0057] The computer device provided in this application employs the controllable curvature stiffening design method for curved shells described in the above embodiments, which solves the technical problems of existing technologies, such as the difficulty in efficiently describing stiffened structures much smaller than macroscopic structural dimensions and the difficulty in achieving complex stiffening descriptions and gradient stiffening designs. Compared with the prior art, the beneficial effects of the computer device provided in this application are the same as those of the controllable curvature stiffening design method for curved shells provided in the above embodiments, and other technical features in the electronic device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0058] A preferred embodiment of this application also provides a storage medium, the storage medium including a stored program, which, when the program is executed, controls the device where the storage medium is located to perform the steps of the curved shell controllable curvature stiffening design method in the above embodiments.

[0059] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0060] If the functions of the method in the embodiments are implemented in the form of software function units and sold or used as independent products, the software function units can be stored in one or more computer readable storage media. Based on such an understanding, the part of the prior art or the part of the technical solutions of the embodiments of the present application that make contributions to the prior art can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for causing a computer (which can be a personal computer, a server, a mobile computing device, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0061] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present application can be implemented in various computer languages, such as the object-oriented programming language C++ and the embedded programming language C.

[0062] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams 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 produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one flow or multiple flows and / or blocks Figure 1 an apparatus that implements the functions specified in one block or multiple blocks.

[0063] These computer program instructions can also be stored in a computer readable storage medium that can direct the computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable storage medium produce a manufactured product that includes instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one flow or multiple flows and / or blocks Figure 1 an apparatus that implements the functions specified in one block or multiple blocks.

[0064] These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operation steps are performed on the computer or other programmable devices to generate a computer implemented process, so that the instructions executed on the computer or other programmable devices provide a process for implementing the function specified in the flowchart Figure 1 one flow or multiple flows and / or the function specified in one block or multiple blocks. Figure 1 one flow or multiple flows and / or the function specified in one block or multiple blocks.

[0065] The application also provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of the method for designing a controllable curvature stiffening of a curved shell as described above.

[0066] The computer program product provided by the application can solve the technical problems that the prior art is difficult to efficiently describe a structure form of stiffening and the like which is much smaller than the size of a macrostructure, and is difficult to implement complex stiffening description and gradient stiffening design. Compared with the prior art, the beneficial effects of the computer program product provided by the application are the same as those of the method for designing a controllable curvature stiffening of a curved shell provided by the above-described embodiments, and are not described here.

[0067] Although the preferred embodiments of the application have been described, those skilled in the art who are familiar with the basic inventive concept can make additional changes and modifications to the embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the application.

[0068] Obviously, those skilled in the art can make various modifications and variations to the application without departing from the spirit and scope of the application. Thus, if these modifications and variations of the application fall within the scope of the claims of the application and their equivalent technologies, the application also intends to include these modifications and variations.

Claims

1. A method for controllable curvature stiffening design of a curved shell, characterized in that, The method comprises the steps of: S1, setting parameter continuous variation through an implicit function control part to control the thickness, curvature and periodic layout characteristics of the planar rod, designing a chiral planar rod lattice, and realizing spatial gradient variation of the rods in the planar rod lattice; S2, mapping the planar rod lattice to a curved shell through coordinate mapping to generate a programmable gradient transition stiffener, and completing the stiffener design of the rotation body structure of the cylindrical shell.

2. The method of claim 1, wherein, The step S1 specifically comprises the steps of: S11, for a chiral metamaterial unit cell structure composed of two groups of symmetrical curved rods, one group of symmetrical curved rods is set as: For the mathematical expression form of the curved rod in the entire vertical design direction: ； ； Wherein, ； ； The mathematical expression of the curved rod in the horizontal design direction is defined by using the rotational symmetry of the coordinates: ； ； Wherein, ； ； wherein, c represents a curvature parameter for controlling the curvature of the curved bar; l x and l y affect the extreme value of the function, respectively for controlling the thickness of the curved bar in the x direction and the y direction; r x and r y affect the phase of the function, for controlling the spatial position of the curved bar in the x direction and the y direction; p x and p y control the number of curved bars in the x direction and the y direction within a unit area; q x and q y control the spatial position of the curved bars in the x direction and the y direction, but the magnitude of their values has an effect on the specific position opposite to r x and r y have opposite effects to x and y are independent variables of the bar generation function, , , and represent phase control functions, represents a curved bar generation function with a curvature of c in the y direction, represents a curved bar generation function with a curvature of c in the y direction, represents a curved bar generation function with a curvature of c in the x direction, represents a curved bar generation function with a curvature of c in the x direction, t x and t y affect the period of the phase control function, for controlling the repetition frequency of the curved bar bending characteristics, s x and s y for controlling the relative position of the curved bar in a single cell. S12, after obtaining the description of the two groups of vertical symmetrical curved rods, the chiral curved rod lattice structure is obtained through Boolean operation: ； Wherein, H(•) is a Heaviside function, and • represents an independent variable mapped through the Heaviside function.

3. The method of claim 2, wherein the step S1 further comprises the steps of: S13. Obtain different shaped achiral curved rod lattice structures by changing the value of the curvature parameter c and thickness parameter l of the achiral curved rod lattice structure.

4. The method of claim 3, wherein the step S1 further comprises the steps of: S14. For a periodic distribution of the chiral curved rod lattice structure, the continuously distributed control curvature parameter is defined by density filtering c Continuous transition, resulting in a chiral curved rod lattice structure with continuous transition at the connection of different curvature lattices.

5. The method of claim 4, wherein, The step S2 specifically comprises the steps of: S21, first completing geometric modeling of the curved shell in the modeling software to obtain a parameterized model of the cylindrical shell; S22, then extracting three-dimensional spatial position data of the cylindrical shell surface nodes through a format conversion interface to establish a spatial coordinate database meeting the requirements of parameterized modeling; S23, extracting the three-dimensional spatial position data, mapping the chiral curved rod lattice structure to the cylindrical shell based on the coordinate mapping principle and the chiral curved rod lattice structure, and generating a chiral lattice stiffener structure of the curved shell; S24, taking the curvature parameter c value of the control rod curvature as a continuously changing value to generate a curved surface gradient stiffener structure continuously changing along the set direction.

6. The method of controllable curvature stiffening design of curved shell according to claim 5, characterized in that, The step S23 specifically comprises the steps of: S231, reconstruct the curvature parameter c as a continuous function of the axial coordinate z of the cylindrical shell, assuming that the given minimum and maximum values of the axial coordinate of the cylindrical shell are z min and z max , the axial coordinate z∈[z min , z max ] is mapped to the dimensionless parameter c∈[-1,1] by a linear transformation, whose mathematical expression is: ； Thus, a curved surface gradient stiffener structure continuously changing along the axial direction of the cylindrical body is generated.

7. The method of claim 6, wherein, The step S23 further comprises the steps of: S232, Curvature parameters c Reconstructed as a bilinear coupled function in the local coordinate system of the cylindrical shell, its mathematical expression is: ； wherein and are the normalized coordinate components of the shell surface point, is the maximum radius of the cylindrical shell, and the denominator R 2 for eliminating the size effect, ensuring the curvature parameter so as to generate a curved surface gradient rib structure with continuous variation along the circumference of the cylinder.

8. A controllable curvature stiffened design apparatus for a curved shell, characterized by, Comprise: A chiral planar rod lattice design module for setting parameter continuous variation through an implicit function control part to control the thickness, curvature and periodic layout characteristics of the planar rod, designing a chiral planar rod lattice, and realizing spatial gradient variation of the rods in the planar rod lattice; A curved shell controllable curvature stiffener design module for mapping the planar rod lattice to a curved shell through coordinate mapping to generate a programmable gradient transition stiffener, and completing the controllable curvature stiffener design of the rotation body structure of the cylindrical shell.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the steps of the curved shell controllable curvature stiffener design method according to any one of claims 1 to 7.

10. A storage medium comprising a stored program, which, when executed, controls a device in which the storage medium is located to perform the steps of the curved shell controllable curvature stiffener design method according to any one of claims 1 to 7.

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