Generalized parametric geometric modeling method for cylindrical skin stringer structures with openings

Abstract

In order to overcome the deficiency that the existing parameterized modeling method cannot meet the general parameterized modeling demand of the complex skin stringer structure with openings, the present application provides a general parameterized geometric modeling method for the cylindrical skin stringer structure with openings. First, the reference coordinate axis of the model is established, and the parameters of the model are determined, including the diameter and height of the skin, the layout and cross-section attribute of each stringer and frame, the number and position of the openings. Then, the cross-section attribute of each stringer and frame is created according to the known parameters. Next, the cylindrical shell is established to simulate the skin, and the longitudinal and circumferential lines are established on the shell to simulate the stringer and frame. Then, the opening position is determined, and the surface and line elements contained in the opening area are removed. Finally, the cross-section attribute is assigned to the corresponding element, and the three-dimensional geometric model of the skin stringer with openings is obtained. Since the geometric modeling has the parameterized characteristics, the present application can reduce the repetitive modeling and improve the efficiency of subsequent finite element calculation.

Description

Technical Field

[0001] This invention belongs to the field of three-dimensional geometric modeling of rocket skin stringer structures, specifically relating to a parametric three-dimensional geometric modeling method for cylindrical skin stringer structures with openings. Background Technology

[0002] Cylindrical skin stringer structures are load-bearing structures composed of stringers, a circular frame, and attached skin. They are characterized by their simple structure, ease of manufacture, low production cost, and good load-bearing performance, and have been widely used in spacecraft structures. As thin-walled, stiffened cylindrical structures primarily bearing axial loads, the overall instability of cylindrical skin stringer structures often precedes structural strength failure, making axial compressive stability a key design consideration. Therefore, accurate and efficient three-dimensional modeling methods are essential for conducting finite element analysis of this type of structure.

[0003] Parametric modeling is a rapid design method that uses dimensional parameters in a geometric model as the driving force and programming languages ​​as the tool to generate multiple similar geometric models based on given parameters. When establishing the geometric model of a skinned stringer structure, parametric modeling can avoid repetitive modeling, save time, and improve work efficiency. The literature "Xu Kaituo. Dynamic Optimization Design of Skinned Stringer Structures Based on Equivalent Static Loads [D]. Dalian University of Technology, 2020" establishes a 3D model of a skinned stringer structure based on the APDL language. However, this literature fails to provide a modeling method for skinned stringer structures with openings, which is an important feature of skinned stringer structures; at the same time, the literature assumes that the layout of stringers and frames in a skinned stringer structure is fixed, which is not conducive to subsequent optimization of the skinned stringer structure. Therefore, a general parametric modeling method for skinned stringer structures with openings that can comprehensively consider the detailed geometry of stringers and frames and their spatial localities is needed. Summary of the Invention

[0004] To overcome the shortcomings of existing methods for creating 3D models of skinned stringer structures based on APDL language, which cannot meet the general parametric modeling requirements of complex skinned stringer structures with openings, this invention proposes a general parametric geometric modeling method for cylindrical skinned stringer structures with openings.

[0005] The concept of this invention is:

[0006] First, establish the reference coordinate axis of the model and determine the parameters of the model, including the diameter and height of the skin, the layout and cross-sectional properties of each stringer and frame, and the number and location of openings.

[0007] Secondly, create the section properties of each stringer and frame based on the known parameters.

[0008] Next, a cylindrical shell is built to simulate the skin, and longitudinal and circumferential lines are created on the shell to simulate the stringers and frame; then the location of the opening is determined, and the surface and line elements contained in the opening area are removed.

[0009] Finally, the section properties are assigned to the corresponding elements to obtain a three-dimensional geometric model of a skin stringer with openings.

[0010] The technical solution adopted by this invention to solve its technical problem is as follows:

[0011] A general parametric geometric modeling method for cylindrical skin stringer structures with openings, characterized by the following steps:

[0012] Step 1: Establish a reference coordinate system to describe the relative positions of the components in the skin stringer structure;

[0013] Step 2: Define the model parameters of the skin stringer structure, including the geometric dimensions of the cylindrical skin, the geometric dimensions and layout of the stringer and frame sections, the material properties of the cylindrical skin, stringers and frames, and the number and location of openings;

[0014] Step 3: Based on the model parameters defined in Step 2, create the cross-sectional geometry and material properties of the stringers and frames;

[0015] Step 4: Create the skin section geometry and material properties. Create a cylindrical skin model in the reference coordinate system. The skin section geometry properties include section type and thickness.

[0016] Step 5: In the reference coordinate system, determine the distribution position of each stringer and frame relative to the skin model, and create lines on the skin model to simulate the stringers and frames based on the distribution position;

[0017] Step 6: Determine the opening location on the skin model, remove the curved surfaces and lines contained within that location, and thicken the stringers at the boundary of the opening to create the skin opening;

[0018] Step 7: Assign the cross-sectional geometric properties of the skin set in Step 4 to the corresponding curved surface, and assign the cross-sectional geometric properties of the stringers and frames created in Step 3 to the corresponding lines to obtain a three-dimensional geometric model of a cylindrical skin stringer structure with openings.

[0019] Furthermore, the material properties described in step 2 include density, elastic modulus, and Poisson's ratio.

[0020] Furthermore, the cross-sectional geometric properties of the stringers in step 3 include at least one of the following: “T” type cross-sectional geometric properties, “L” type cross-sectional geometric properties, and “I” type cross-sectional geometric properties.

[0021] The geometric properties of the “T” profile are defined by the following parameters: stringer width, stringer height, stringer width thickness, and stringer height thickness;

[0022] The geometric properties of the “L” shaped section are defined by the following parameters: stringer width, stringer height, stringer width thickness, and stringer height thickness;

[0023] The geometric properties of the “I” profile are defined by the following parameters: stringer bottom width, stringer top width, stringer height, stringer bottom thickness, stringer top thickness, and stringer height thickness.

[0024] Furthermore, the cross-sectional geometric properties of the frame in step 3 include "L"-shaped section geometric properties and "n"-shaped section geometric properties;

[0025] The geometric properties of the “L” shaped section are defined by the following parameters: stringer width, stringer height, stringer width thickness, and stringer height thickness;

[0026] The geometric properties of the “n”-shaped section are defined by the following parameters: bottom edge width, top edge width, height, bottom edge thickness, top edge thickness, and height thickness.

[0027] Furthermore, step 4 specifically includes:

[0028] Step 4.1 Create a projection sketch of the cylindrical skin model in the xOy plane of the reference coordinate system;

[0029] Step 4.2 Extrude the projection sketch along the positive z-axis of the reference coordinate system. The extrusion height H is the height of the cylindrical skin stringer structure. Set the skin section type, thickness and material properties to obtain the skin three-dimensional model.

[0030] Furthermore, in step 5, each stringer is composed of line P. i P i ' indicates that P i The coordinates are (R·sinθ) i ,R·cosθ i ,0), P i The coordinates are (R·sinθ) i ,R·cosθ i ,H),θ i The phase angle of each stringer; within the frame: the topmost and bottommost frames are the topmost and bottommost edges of the skin model, respectively; the remaining frames are represented by ring lines generated at the intersection of the reference plane and the skin model, where the reference plane is a distance h from the xOy plane. i The plane, i = 1, 2, ..., n, where n is the number of the remaining frames.

[0031] Furthermore, the opening position in step 6 is determined by the following parameters: the height of the lower frame of the opening, the height of the upper frame of the high opening, the phase angle of the stringer at the starting position of the opening, and the phase angle of the stringer at the ending position of the opening.

[0032] Furthermore, in step 7, after assigning the cross-sectional geometric properties of the stringers and frames to the corresponding lines, the direction of the stringers and frames is assigned, thus completing the assignment of the cross-sectional properties of the stringers and frames.

[0033] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when run, is used to execute the above-described general parametric geometric modeling method for cylindrical skin stringer structures with openings.

[0034] The present invention also provides an electronic device, including a processor and a storage medium, wherein the storage medium stores a computer program, wherein the computer program, when run by the processor, is used to execute the above-described general parametric geometric modeling method for cylindrical skin stringer structures with openings.

[0035] The beneficial effects of this invention are:

[0036] 1. This invention first establishes a reference coordinate system and determines the relevant parameters required for model construction; secondly, it creates the cross-sectional properties of the stringers and frame based on the given parameters; thirdly, it creates a skin model and draws lines on the skin model to simulate the stringers and frame; then, it creates skin openings at specified locations; finally, it assigns cross-sectional properties to each element of the model, thus obtaining a parametric modeling method for a three-dimensional geometric model of a skin stringer with openings. Because geometric modeling is parametric, the method of this invention can reduce repetitive modeling, improve the efficiency of subsequent finite element calculations, provide an accurate geometric model with openings, and fill the gap in existing methods that do not provide general parametric modeling for skin stringer structures with openings.

[0037] 2. This invention solves the problems of fixed stringer layout and difficulty in defining skin openings in the parametric 3D modeling of complex skin stringer structures with openings, and provides a fast and accurate 3D geometric model construction method for the mechanical analysis of various skin stringer structures. Attached Figure Description

[0038] Figure 1 This is the model reference coordinate system established in this invention.

[0039] Figure 2 This is a cross-sectional view of a commonly used typical stringer.

[0040] Figure 3 It is a cross-sectional view of a commonly used typical frame.

[0041] Figure 4It is a projection of the skinned model.

[0042] Figure 5 It is a 3D model of the skin (including stringers and frame).

[0043] Figure 6 This is a side view of the skinned stringer model.

[0044] Figure 7 This is a diagram illustrating the direction of the stringers and frame.

[0045] Figure 8 This is a sketch of the bottom edge of the skin stringer structure.

[0046] Figure 9 This is a three-dimensional geometric model of the skin of the girder structure.

[0047] Figure 10 This is the xOy plane projection of the skin stringer structure.

[0048] Figure 11 This is a schematic diagram of the opening in the skin stringer structure.

[0049] Figure 12 It is a three-dimensional geometric model of the skin stringer with openings. Detailed Implementation

[0050] This invention proposes a parametric modeling method for cylindrical skin stringer structures with openings. It mainly defines the relevant parameters of the skin stringer structure with openings and establishes an accurate three-dimensional geometric model that includes material properties through parametric modeling.

[0051] The present invention will be further described below with reference to the accompanying drawings.

[0052] The present invention provides a general parametric geometric modeling method for cylindrical skin stringer structures with openings, comprising the following steps:

[0053] Step 1: Establish the model reference coordinate system

[0054] To describe the relative positions of the components in the skinned truss structure in three-dimensional space, a reference coordinate system CSO is established at an arbitrary point O. The z-axis points vertically upwards, the y-axis points horizontally to the right, and the x-axis is determined using the right-hand rule. Subsequently, when describing the model, the center of the lower end face of the model is aligned with the origin O of the reference coordinate system, and the model's axis is aligned with the z-axis of the reference coordinate system. The established reference coordinate system CSO is shown below. Figure 1 As shown.

[0055] Step 2: Define the model parameters describing the skin stringer structure

[0056] To build the model, the model parameters required for its creation need to be defined. The model parameters required to create a cylindrical skin stringer model with openings include:

[0057] (1) Model geometry: Model geometry refers to the parameters required to construct the geometric shape of the model. For a cylindrical shell, the model geometry includes the radius R of the bottom surface of the cylinder and the height H of the cylinder.

[0058] (2) Geometric dimensions of the cross section: The geometric dimensions of the cross section refer to the parameters required to draw the cross-sectional shape of the stringers and frames. The types and numbers of parameters required vary for different cross sections.

[0059] (3) Model layout parameters: Model layout parameters refer to the parameters required to describe the layout of skin, stringers and frames on a cylindrical shell, including the cross-sectional type and spacing of frames, the cross-sectional type and relative position of stringers, and the position of all components at openings.

[0060] (4) Material properties of the model: The material properties of the model refer to the parameters required to describe the material properties (density, elastic modulus and Poisson's ratio) of each element of the model.

[0061] Step 3: Create the cross-sectional geometry and material properties of the stringers and frames that make up the skin stringer structure.

[0062] Step 3.1 To create the cross-sectional geometry of the stringers, it is necessary to create the sections of each stringer to define its precise geometry. There are three types of section geometries commonly used in skinned stringer structures: "T" section (e.g., ... Figure 2 As shown in (a), the "L"-shaped section (as shown in the middle) Figure 2 (as shown in (b)) and the "I" type section (as shown in...) Figure 2 (As shown in (c)). Among them, the n1 axis and the n2 axis are a set of coordinate axes used to describe the position of the cross section. They are perpendicular to the tangent of the stringer, and the intersection of the coordinate axes is the centroid of the cross section.

[0063] For stringers with a "T" shaped cross section, the following parameters define them:

[0064] b – Width of the “T”-shaped cross-section truss;

[0065] h—Height of the T-shaped cross-section truss;

[0066] t f —Thickness of the T-shaped cross-section stringers;

[0067] t w —Thickness of the T-shaped cross-section stringers;

[0068] For stringers with an "L" shaped cross section, the following parameters define them:

[0069] a – Width of the “L” shaped cross-section truss;

[0070] b – Height of the “L” shaped cross-section truss;

[0071] t1 — Thickness of the "L"-shaped cross-section stringer width;

[0072] t2 – Thickness of the L-shaped cross-section stringer height;

[0073] For stringers with an "I" shaped section, the following parameters define them:

[0074] b1 – Width of the bottom edge of the “I”-shaped cross-section truss;

[0075] b2 – Width of the top edge of the “I”-shaped cross-section truss;

[0076] h – Height of the “I”-shaped cross-section truss;

[0077] t1 — Thickness of the bottom edge of the "I"-shaped cross-section stringer;

[0078] t2 — Thickness of the top edge of the "I"-shaped cross-section stringer;

[0079] t3 – Thickness of the stringer height in the “I”-shaped section;

[0080] Step 3.2 To create the cross-sectional geometry of the frames, it is necessary to create the sections of each frame to define the precise geometry of the frame. Typical frames in skinned stringer structures have two types of section geometry: "L" shaped sections (such as...) Figure 3 (as shown in (a)) and the “n” type profile (as shown in (a)). Figure 3 (As shown in (b)). Among them, the n1 axis and the n2 axis are a set of coordinate axes used to describe the position of the cross section. They are perpendicular to the tangent of the frame, and the intersection of the coordinate axes is the centroid of the cross section.

[0081] For an "L" shaped section frame, the following parameters define it:

[0082] a – Width of the “L”-shaped section frame

[0083] b – Height of the “L”-shaped profile frame

[0084] t1 — Thickness of the “L” shaped cross-section frame width

[0085] t2 — Thickness of the “L”-shaped profile frame height

[0086] For a frame with an "n"-shaped profile, the following parameters define it:

[0087] b1 – Width of the bottom edge of the “n”-shaped section frame

[0088] b2 – Width of the top edge of the “n”-shaped section frame

[0089] h – Height of the “n”-shaped section frame

[0090] t1 — Thickness of the bottom edge of the “n”-shaped profile frame

[0091] t2 — Thickness of the top edge of the “n”-shaped cross-section frame

[0092] t3 – Thickness of the “n”-shaped profile frame height

[0093] Based on steps 3.1 and 3.2 above, the precise cross-sectional geometry of the stringers and frames that constitute the skin stringer structure can be obtained; the order of steps 3.1 and 3.2 above can be interchanged.

[0094] Step 3.3 Define the material properties of the stringers and frames, including density ρ, elastic modulus E, and Poisson's ratio ν, in order to complete the material property definition of the stringers and frames, which will facilitate subsequent finite element calculations.

[0095] Step 4: Create the skin model that constitutes the skin stringer structure

[0096] like Figure 4 As shown, first, a projection sketch of the cylindrical skin model is created on the xOy plane of the reference coordinate system CSO. A circle is drawn with the origin O of the reference coordinate system CSO as the center and R as the radius, where R is the bottom radius of the cylindrical skin model.

[0097] Next, the projection sketch created in the previous step is extruded. The extrude direction is the positive z-axis of the reference coordinate system CSO, and the extrude height is the height H of the cylindrical skin stringer structure. The section type is set to mean shell, the skin thickness is t, and material properties are set for the skin, including density ρ, elastic modulus E, and Poisson's ratio ν. The created 3D skin model is as follows: Figure 5 As shown ( Figure 5 The cylindrical part after removing the stringers and frame is the skinned 3D model.

[0098] Step 5: Determine the distribution position of each stringer and frame relative to the skin.

[0099] Step 5.1 In order to describe the position of the main load-bearing members in the skin stringer structure, the specific position of each stringer relative to the skin is required.

[0100] First, based on steps 2 and 4, the projection of each stringer onto the xOy plane of the reference coordinate system CSO can be represented by a point P. i Let θ represent its phase angle relative to the x-axis of the reference coordinate system CSO. i (i = 1, 2, ..., n), the distribution of each stringer is as follows: Figure 4 As shown.

[0101] Subsequently, based on the phase angle θ of the stringeri Determine the coordinates of the upper and lower endpoints of each stringer in the reference coordinate system CSO, where the lower endpoint P... i The coordinates are (R·sinθ) i ,R·cosθ i ,0), upper endpoint P i The coordinates are (R·sinθ) i ,R·cosθ i H).

[0102] Finally, the corresponding point P mentioned above i and P i By connecting the lines in pairs, the position of each stringer is defined, and the stringer will be located at P. i P i 'On top, and distributed on the outer side of the skin, such as Figure 5 As shown.

[0103] Step 5.2 In order to describe the position of the radial main load-bearing members—the frames—in the skin stringer structure, it is necessary to know the specific position of each frame relative to the skin.

[0104] Since the top and bottom frames are located at the top and bottom edges of the skin, respectively, they are built at the same time as the skin is constructed.

[0105] Assuming there are n intermediate frames, the distance of each intermediate frame relative to the xOy plane in the reference coordinate system CSO can be obtained by defining the model layout parameters in step 2, denoted as h. i (i = 1, 2, ..., n).

[0106] Then, with the xOy plane facing the positive z-axis, h... i (i = 1, 2, ..., n) are offset to obtain n planes, and these planes are used as reference planes to split the skin model. The ring-shaped line generated at the intersection of the reference plane and the cylindrical surface of the skin model is the middle frame, such as... Figure 5 As shown.

[0107] Step 6: Create skin openings

[0108] The skin has openings on its sidewalls, and these openings exist between two frames and two stringers. Based on the definition of the model layout parameters in step 2, the parameters used to record the positions of the skin openings are h. c1 h c2 θ c1 θ c2 , where h c1 h is the height of the bottom frame of the opening. c2 θ is the height of the upper frame of the opening. c1 θ is the phase angle of the stringer at the starting position of the opening. c2The phase angle of the stringer at the end of the opening. Figure 6 This is a schematic diagram of the skin stringer structure unfolding along θ = 0°. It is clear that the positional relationship between the skin opening and the relevant stringers and frame can be defined based on the above parameters.

[0109] Because of the opening, the bending and torsional resistance of the skin stringer structure is severely weakened. Reinforcing stringers need to be placed on both sides of the opening to ensure complete force transmission and continuous stiffness. This can be achieved by thickening the stringers at the opening boundary. Finally, removing the skin at the opening location and the stringers on that skin yields the skin stringer model with the opening.

[0110] Step 7: Assign section properties to the skin, stringers, and frame.

[0111] Step 7.1 Assign the skin section created in Step 4 to all surface elements in the skin stringer model with openings established in Step 6 to complete the assignment of skin section properties.

[0112] Step 7.2 Assign the geometric section properties of the stringers and frames created in Step 3 to the corresponding line segments and circles representing the positions of the stringers and frames, and assign the directions of the stringers and frames to complete the assignment of the stringer and frame section properties.

[0113] Assigning stringer or frame direction refers to the direction of the stringer or frame. Figure 2 or Figure 3 The n1 direction is defined in the shown cross-section. After assigning stringer or frame section properties to a line, a direction must be assigned to it. For example... Figure 6 As shown, for the stringer, the direction of section n1 points from the origin O at the lower end face to the lower end point P of the stringer. i For the frame, the direction of the cross section n1 points from the origin O of the lower end face to the origin O' of the upper end face.

[0114] Thus, by following the steps described above, a three-dimensional geometric model of a complex cylindrical skin stringer structure with openings can be established.

[0115] Example:

[0116] Step 1: Establish a reference coordinate system CSO to describe the positions of each component in the skin stringer structure;

[0117] Step 2: Define the model parameters describing the skin stringer structure;

[0118] The model parameters for the skin stringer structure established in this embodiment include:

[0119] Geometric dimensions: Model height H = 3500mm, model radius R = 1500mm;

[0120] Layout parameters: There are 30 stringers and 8 frames in total, and skin openings exist between the stringers at 48° and 72° in the second and third intermediate frames.

[0121] Material properties: Density of stringer material ρ = 2800 kg / m³ 3 The elastic modulus of the stringer material is E = 68000 MPa, and the Poisson's ratio of the stringer material is ν = 0.3; the density of the frame material is ρ = 2800 kg / m³. 3 The elastic modulus of the frame material is E = 68000 MPa, and the Poisson's ratio of the frame material is ν = 0.3; the density of the skin material is ρ = 2800 kg / m³. 3 The elastic modulus of the skin material is E = 6800 MPa, and the Poisson's ratio of the skin material is ν = 0.3.

[0122] Step 3: Create the cross-sectional geometry and material properties of the stringers and frames that make up the skin stringer structure.

[0123] Step 3.1 To create the cross-sectional properties of the stringers, it is necessary to create the cross-sections of each stringer. The model in this embodiment includes "T" shaped stringers, which are named stringer T-1, stringer T-2, and stringer T-3, respectively.

[0124] The cross-section of the T-1 stringer is as follows: Figure 2 As shown in (a), the stringer width b = 40 mm, the stringer height h = 35 mm, and the stringer thickness t f =2.5mm, stringer height thickness t w =4mm.

[0125] The cross-section of the T-2 truss is as follows: Figure 2 As shown in (a), the stringer width b = 40 mm, the stringer height h = 40 mm, and the stringer thickness t f =2.5mm, stringer height thickness t w =4mm.

[0126] The cross-section of the T-3 stringer is as follows: Figure 2 As shown in (a), the stringer width b = 50 mm, the stringer height h = 50 mm, and the stringer thickness t f =2.5mm, stringer height thickness t w =4mm.

[0127] Step 3.2 To create the cross-sectional properties of the frames, it is necessary to create the cross-sections of each frame. The model in this embodiment includes "L"-shaped and "n"-shaped frames, named kL-1 frame and kn-1 frame respectively.

[0128] The cross-section of frame kL-1 is as follows Figure 3As shown in (a), the width of the frame is a = 80 mm, the height of the frame is b = 70 mm, the thickness of the frame width is t1 = 6 mm, and the thickness of the frame height is t2 = 8 mm.

[0129] The cross-section of frame kn-1 is as follows Figure 3 As shown in (b), the width of the bottom edge of the frame is b1 = 54 mm, the width of the top edge of the frame is b2 = 25 mm, the height of the frame is h = 80 mm, the thickness of the bottom edge of the frame is t1 = 2 mm, the thickness of the top edge of the frame is t2 = 2 mm, and the thickness of the height of the frame is t3 = 2 mm.

[0130] Step 3.3, based on Step 3.2, obtains the precise cross-sectional geometry of the stringers and frames that constitute the skin stringer structure. Then, the material properties of the stringers and frames are defined (as given in Step 2) to complete the material property definition for subsequent finite element calculations.

[0131] Step 4: Create the skin geometry and material properties that constitute the skin stringer structure.

[0132] First, create a projection sketch of the cylindrical skin model in the xOy plane of the reference coordinate system CSO. Draw a circle with the origin O as the center and R = 1500 mm as the radius. Figure 8 As shown, R is the radius of the bottom surface of the cylindrical skin model.

[0133] Then, the projected sketch of the cylindrical skin model is extruded in the positive z-axis direction, with an extrusion height of H = 3500 mm, the section type is set to mean shell, the skin thickness is t, and the material properties are set for the skin: density ρ = 2800 kg / m³. 3 The elastic modulus E = 6800 MPa and the Poisson's ratio ν = 0.3 (as shown in Figure 8).

[0134] Step 5: Define the distribution position of each stringer and frame relative to the skin.

[0135] 5.1 In order to create lines on the skin model to simulate stringers, it is necessary to know the specific position of each stringer relative to the skin. In this embodiment, the skin stringer structure model has a total of 30 stringers with phase angles θ. i =0°,12°,24°,36°,48°,60°,72°,84°,96°,108°,120°,132°,144°,156°,168°,180°,192°, 204°, 216°, 228°, 240°, 252°, 264°, 276°, 288°, 300°, 312°, 324°, 336°, 348° (i=1,2,…,30). like Figure 10 As shown, the projection of the model onto the xOy plane of the reference coordinate system CSO clearly shows the position of each stringer on the skin model.

[0136] Then, the coordinates of the upper and lower endpoints of the stringer in the reference coordinate system CSO are determined based on the phase angle of the stringer, where the lower endpoint P... i The coordinates are (R·sinθ) i ,R·cosθ i ,0), upper endpoint P i The coordinates are (R·sinθ) i ,R·cosθ i The model radius R = 1500 mm and height H = 3500 mm have been given above. Finally, the upper and lower endpoints are connected to draw a line, thus completing the definition of the line representing the centroid position of the stringer.

[0137] 5.2 In order to create lines on the skin model to simulate frames, it is necessary to know the specific position of each frame relative to the skin. In this embodiment, the skin stringer structure model has a total of 8 frames, and their distances relative to the xOy plane in the reference coordinate system CSO are h, ... i =0mm, 420mm, 980mm, 1560mm, 2065mm, 2590mm, 3115mm, 3500mm (i=1,2,…,8).

[0138] Then, with the xOy plane facing the positive z-axis, h... i The offset process yielded eight planes, each with a distance h from the xOy plane. i (i = 1, 2, ..., 8). The skin model is split using these 8 planes as reference planes. The annular lines generated at the intersection of the reference planes and the cylindrical surfaces of the skin model define the lines representing the position of the frame's centroid. The established skin stringer model is as follows: Figure 9 As shown.

[0139] Step 6: Create skin openings

[0140] The skin stringer structure model in this embodiment has one opening, and for this opening, there is a parameter h describing its opening position. c1 =980mm, h c2 =1540mm, θ c1 =48°, θ c2 =72°, where h c1 h is the height of the bottom frame of the opening. c2 θ is the height of the upper frame of the opening. c1 θ is the phase angle of the stringer at the starting position of the opening. c2 The phase angle of the stringer at the opening termination position.

[0141] By removing the skin at the opening location and the stringers on that skin, you can obtain a skin stringer model with the opening. The model opening is as follows: Figure 11As shown.

[0142] Step 7: Assign section properties to the skin, stringers, and frame.

[0143] 7.1 Assign the skin section created in step 3 to all surface elements in the model to complete the assignment of skin section properties.

[0144] 7.2 Assign the cross-sections of the stringers and frames created in step 3 to their corresponding line elements, and assign the stringer and frame directions to complete the assignment of the stringer and frame cross-section properties.

[0145] Assigning stringer or frame direction refers to the direction of the stringer or frame. Figure 2 or Figure 3 The n1 direction is defined in the shown cross-section. After assigning stringer or frame section properties to a line, a direction must be assigned to it. For example... Figure 7 As shown, for the stringer, the direction of section n1 points from the origin O at the lower end face to the lower end point P of the stringer. i For the frame, the direction of section n1 points from the origin O of the lower end face to the origin O' of the upper end face. The above steps can then be used to establish a three-dimensional geometric model of a cylindrical skin stringer with openings.

[0146] In the model of this embodiment, the phase angle θ i The stringers with angles of 0°, 24°, 60°, 96°, 120°, 144°, 168°, 192°, 216°, 240°, 264°, 288°, 312°, and 336° are T-1 stringers, with a phase angle θ. i The stringers with angles of 12°, 36°, 84°, 108°, 132°, 156°, 180°, 204°, 228°, 252°, 276°, 300°, 324°, and 348° are T-2 stringers, with a phase angle θ. i =48°, 72° stringers are T-3 stringers (reinforcing stringers on both sides of the opening); height h i =0mm, the 3500mm frame is a kL-1 frame, height h i The frames with dimensions of 420mm, 980mm, 1560mm, 2065mm, 2590mm, and 3115mm are kn-1 frames. The completed model is as follows: Figure 12 As shown.

[0147] In addition to the modeling method described above, the present invention also provides a computer-readable storage medium storing a computer program thereon, which, when run, is used to execute the general parametric geometric modeling method for cylindrical skin stringer structures with openings provided by the present invention.

[0148] Meanwhile, the present invention also provides an electronic device comprising a processor and a storage medium, wherein the storage medium stores a computer program, which, when executed by the processor, is used to perform the general parametric geometric modeling method for cylindrical skin stringer structures with openings provided by the present invention.

Claims

1. A general parametric geometric modeling method for cylindrical skin stringer structures with openings, characterized in that, Includes the following steps: Step 1: Establish a reference coordinate system to describe the relative positions of the components in the skin stringer structure; Step 2: Define the model parameters of the skin stringer structure, including the geometric dimensions of the cylindrical skin, the geometric dimensions and layout of the stringer and frame sections, the material properties of the cylindrical skin, stringers and frames, and the number and location of openings; Step 3: Based on the model parameters defined in Step 2, create the cross-sectional geometry and material properties of the stringers and frames; Step 4: Create the skin section geometry and material properties. Create a cylindrical skin model in the reference coordinate system. The skin section geometry properties include section type and thickness. Step 5: In the reference coordinate system, determine the distribution position of each stringer and frame relative to the skin model, and create lines on the skin model to simulate the stringers and frames based on the distribution position; Step 6: Determine the opening location on the skin model, remove the curved surfaces and lines contained within that location, and thicken the stringers at the boundary of the opening to create the skin opening; Step 7: Assign the cross-sectional geometric properties of the skin set in Step 4 to the corresponding curved surface, and assign the cross-sectional geometric properties of the stringers and frames created in Step 3 to the corresponding lines to obtain a three-dimensional geometric model of a cylindrical skin stringer structure with openings.

2. The general parametric geometric modeling method for cylindrical skin stringer structures with openings according to claim 1, characterized in that: The material properties mentioned in step 2 include density, elastic modulus, and Poisson's ratio.

3. The general parametric geometric modeling method for cylindrical skin stringer structures with openings according to claim 1, characterized in that: In step 3, the cross-sectional geometric properties of the stringers include at least one of the following: "T" type cross-sectional geometric properties, "L" type cross-sectional geometric properties, and "I" type cross-sectional geometric properties. The geometric properties of the "T"-shaped section are defined by the following parameters: stringer width, stringer height, stringer width thickness, and stringer height thickness; The geometric properties of the "L"-shaped section are defined by the following parameters: stringer width, stringer height, stringer width thickness, and stringer height thickness; The geometric properties of the "I"-shaped section are defined by the following parameters: stringer bottom width, stringer top width, stringer height, stringer bottom thickness, stringer top thickness, and stringer height thickness.

4. The general parametric geometric modeling method for cylindrical skin stringer structures with openings according to claim 1, characterized in that: The cross-sectional geometric properties of the frame in step 3 include "L" shaped section geometric properties and "n" shaped section geometric properties; The geometric properties of the "L"-shaped section are defined by the following parameters: stringer width, stringer height, stringer width thickness, and stringer height thickness; The geometric properties of the "n"-shaped section are defined by the following parameters: bottom edge width, top edge width, height, bottom edge thickness, top edge thickness, and height thickness.

5. The general parametric geometric modeling method for cylindrical skin stringer structures with openings according to any one of claims 1-4, characterized in that: Step 4 specifically involves: Step 4.1 Create a projection sketch of the cylindrical skin model in the xOy plane of the reference coordinate system; Step 4.2 Extrude the projection sketch along the positive z-axis of the reference coordinate system. The extrusion height H is the height of the cylindrical skin stringer structure. Set the skin section type, thickness and material properties to obtain the skin three-dimensional model.

6. The general parametric geometric modeling method for cylindrical skin stringer structures with openings according to claim 5, characterized in that: In step 5, each stringer is composed of line P. i P i ' indicates that P i The coordinates are (R·sinθ) i ,R·cosθ i ,0), P i The coordinates are (R·sinθ) i ,R·cosθ i ,H),θ i The phase angle of each stringer; within the frame: the topmost and bottommost frames are the topmost and bottommost edges of the skin model, respectively; the remaining frames are represented by ring lines generated at the intersection of the reference plane and the skin model, where the reference plane is a distance h from the xOy plane. i The plane, i = 1, 2, ..., n, where n is the number of the remaining frames.

7. The general parametric geometric modeling method for cylindrical skin stringer structures with openings according to claim 6, characterized in that: The opening position in step 6 is determined by the following parameters: the height of the lower frame of the opening, the height of the upper frame of the high opening, the phase angle of the stringer at the starting position of the opening, and the phase angle of the stringer at the ending position of the opening.

8. The general parametric geometric modeling method for cylindrical skin stringer structures with openings according to claim 7, characterized in that: In step 7, after assigning the cross-sectional geometric properties of the stringers and frames to the corresponding lines, and then assigning the directions of the stringers and frames, the assignment of the cross-sectional properties of the stringers and frames is completed.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is run, it is used to execute the general parametric geometric modeling method for cylindrical skin stringer structures with openings as described in any one of claims 1-8.

10. An electronic device, comprising a processor and a storage medium, wherein a computer program is stored on the storage medium, characterized in that: When the computer program is run by the processor, it is used to execute the general parametric geometric modeling method for cylindrical skin stringer structures with openings as described in any one of claims 1-8.

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