Double-layer hollow aluminum alloy latticed shell structure and design method thereof

Abstract

The invention discloses a double-layer open-web aluminum alloy latticed shell which adopts a rib ring type grid with variable density, an open-web truss effect is formed between an upper layer of latticed shell and a lower layer of latticed shell through three-dimensional rigid-connection full-assembly aluminum alloy nodes and vertical web members, and strong enough flexural rigidity and reliable bending moment transmission are ensured. Oblique web members can be prevented from being arranged between the upper-layer latticed shell and the lower-layer latticed shell, the number of rod pieces of the latticed shell is remarkably reduced, and the assembly difficulty of aluminum alloy double-layer latticed shell construction is lowered. The corresponding design method comprises a grid forming method and a mechanical analysis method, the grid forming method can form a matched rib ring type grid according to requirements, the mechanical analysis method can accurately calculate the strength and rigidity of the latticed shell, and a reliable basis is provided for component design of the latticed shell. Compared with a common single-layer aluminum alloy latticed shell and a common aluminum alloy net frame, the double-layer hollow aluminum alloy latticed shell structure can provide larger spanning capacity, higher bearing capacity and higher adaptive capacity to building modeling.

Description

Technical Field

[0001] This invention relates to the field of structural design technology in building engineering, and in particular to a double-layer hollow aluminum alloy reticulated shell structure and its design method. Background Technology

[0002] Compared to traditional steel structures, aluminum alloy structures offer advantages such as light weight, good corrosion resistance, low remanence, and flexible processing and design. Their component extrusion and stamping processes allow for the formation of complex cross-sections. However, aluminum alloy structures also suffer from limitations such as low strength (only 67% of commonly used Q355 steel), low stiffness (only 1 / 3 of steel structures), and poor mechanical properties in the heat-affected zone after welding. Therefore, traditional aluminum alloy structures typically use plate joints to achieve assembly connections between components to avoid welding. However, plate joints can only achieve in-plane connections between aluminum alloy components and are not suitable for spatial connections. Therefore, traditional aluminum alloy structures usually adopt a single-layer grid shell form, unable to form a double-layer system. Furthermore, the bending stiffness and load-bearing capacity of plate joints are limited. Therefore, single-layer aluminum alloy grid shells are mostly used in large-span structures with relatively small loads and cannot meet the design requirements of large-span heavy loads. When there are requirements for large-span heavy loads, aluminum alloys often need to adopt a truss form, using upper and lower chord members and diagonal web members to create a truss effect to overcome the shortcomings of low strength and stiffness in aluminum alloys.

[0003] For example, the invention patent application (application number 202311553597.8), entitled "A Fully Assembled Hinged Node Aluminum Alloy Double-Layer Mesh Structure and Its Forming Method," proposes a fully hinged aluminum alloy node. This node achieves a truss effect by setting a central rod and diagonal web members that are hinged to both the upper and lower mesh layers within the double-layer aluminum alloy mesh structure, thereby increasing the load-bearing capacity of the aluminum alloy structure. The main difference between this invention and the mesh shell node proposed in this invention is the use of a fully hinged node. Therefore, in structural arrangement, it is necessary to ensure that the in-plane meshes of the upper and lower mesh shells form a stable triangular mesh or to set multiple through-plane support systems along the radial direction. In contrast, the mesh shell system proposed in this invention, using a three-dimensional rigid-connected fully assembled node, is a fully rigid-connected system. Only vertical web members are needed between the upper and lower mesh shells to form a reliable hollow effect, eliminating the need for diagonal web members. Simultaneously, the upper and lower mesh shells also form a rigid mesh in-plane, eliminating the need for an in-plane support system, significantly reducing the number of members and lowering the assembly difficulty.

[0004] The aluminum alloy mesh node in the invention application (application number 202311554032.1) "A Fully Assembled Aluminum Alloy Mesh Node and Mesh Structure and Its Forming Method" achieves rigid connection of the chord by connecting the flanges of the chord with the upper and lower cover plates. However, since the vertical web members are only connected to the web of the chord and not to the flanges of the chord or the upper and lower cover plates, the connection between the vertical web members and the chord is still a hinged or limited stiffness connection. It is still necessary to set diagonal web members between the upper and lower mesh shells to ensure the structural bearing capacity. This is fundamentally different from the three-dimensional rigid fully assembled node proposed in this invention.

[0005] In the invention patent application (application number 201510154267.0) "Prestressed Bolted Assembled Double-Layer Aluminum Alloy Reticulated Shell Structure", prestressed cable-stayed tendons arranged between the upper and lower reticulated shells are used instead of diagonal web members. However, the prestressed cable-stayed tendons are connected to the connecting plate that is pre-installed on the cover plate. The application does not specify the connection method between the connecting plate and the cover plate. However, this connection structure cannot be processed by aluminum alloy extrusion. It can be assumed that the connecting plate and the cover plate need to be connected by welding, which reduces the design strength of the aluminum alloy.

[0006] By studying and comparing the invention applications of the aforementioned scholars, it can be found that when the vertical web members are hinged, a large number of diagonal web members need to be installed between the upper and lower grid shells. At the same time, a large number of fasteners are required to connect the members, reducing construction feasibility and limiting the engineering application of aluminum alloy structures. Besides hinged systems, some scholars have also attempted to adopt other structural forms.

[0007] For example, the invention patent application (application number 202411783597.1) "Fully Assembled Core Column Node Aluminum Alloy Space Grid Structure" uses a through-type vertical web bar (core column). The vertical web bar is composed of cross ribs, ring ribs, and branches. The branches of the vertical web bar are connected to the cover plate of the node through angle aluminum connectors. However, this node has the following problems in actual engineering applications:

[0008] The rib-ring type reticulated shell structure system consists of radial and circumferential grid members. The webs of the radial grid members on both sides of the node can be kept in a plane (generally a plumb plane formed by the vertical and radial lines), while the webs of the circumferential grid members on both sides of the node cannot be kept in a plane. Furthermore, in addition to the circumferential angle, the two circumferential members also have a torsion angle along their own axial direction. If the branches of the vertical web members are to be used to connect the circumferential members on both sides of the node simultaneously, the branches of the vertical web members must have a spatial torsion angle, which cannot be achieved by aluminum alloy extrusion. Only welding the branches or eliminating the connection between the circumferential member web and the vertical web member can be used, both of which weaken the load-bearing capacity of the node and the entire structure. Unlike this node, the node of this invention uses T-shaped connectors or angle aluminum connectors to connect the web of the circumferential grid members to the web plane of the I-shaped vertical web members. This connection method is not affected by the torsion angle.

[0009] Although the vertical web members of this node are equipped with ring ribs, they are mainly connected to the surrounding members through branch plates. This construction method makes the torsional stiffness of the vertical web members dependent on the out-of-plane bending resistance of the branch plates. However, the out-of-plane bending resistance of plates is generally weak, resulting in very weak torsional stiffness of the vertical web members. This makes it unsuitable for structures requiring high torsional stiffness in the vertical web members. This invention uses an I-shaped cross-section as the web members, and connects the upper and lower flanges of the I-shaped cross-section to the node plate through connectors. The shear and in-plane bending resistance of the upper and lower flanges ensure reliable torsional stiffness of the vertical web members.

[0010] Compared to the I-shaped vertical web members used in this invention, which can achieve a connection of equal bending stiffness between the vertical web members and the chord members of the reticulated shell, this node uses branches to connect with the chord members of the reticulated shell. Although the presence of ring ribs gives the vertical web members a certain bending stiffness, when bending, the position of the ring ribs is closer to the neutral axis of the vertical web members than that of the branches. Under the same vertical web member width, its bending stiffness is much weaker than that of the I-shaped vertical web members used in this invention.

[0011] The invention patent application (application number 202311549839.6), entitled "An Aluminum Alloy Grid Structure Node System and its Curtain Wall System and Forming Method," uses pins to constrain the relative deformation between the vertical web members (central connector) and the node cover plate, and utilizes web connecting plates with a central arc and straight sides to connect the vertical web members to the web members of the chord members. This node has good adaptability to structures where the grid members are in the same plane, but when applied to grid shell structures with spatial corners in the grid members, the following problems arise:

[0012] 1. For reticulated shell structures with spatial curvature, such as spherical reticulated shells, ellipsoidal reticulated shells, and freeform reticulated shells, there is usually a spatial angle between two adjacent members at the grid nodes, resulting in a spatial angle between the webs of adjacent members. In this case, the shape of the web connecting plate that connects the adjacent members and the curved surface of the vertical web members is very complex and cannot be manufactured using aluminum alloy extrusion.

[0013] 2. In the direction along the pin axis, the pin can indeed limit the position of the cover plate and the vertical web member, thus achieving a rigid connection between the vertical web member and the chord member. However, in the direction perpendicular to the pin axis, the cover plates on both sides of the vertical web member can rotate around the pin axis, making it impossible to achieve a rigid connection between the vertical web member and the chord member in this direction.

[0014] The invention patent (authorization announcement number: CN 103590488 B) "Bolted Assembly Double-Layer Aluminum Alloy Reticulated Shell Structure" uses an aluminum alloy node that is simultaneously connected to the upper and lower cover plates of the node via a central rib tube and vertical web members, achieving a rigid connection between the vertical web members and the chord members. However, the rib plates of the central rib tube need to be pre-welded, and rib plates also need to be pre-welded to the vertical web members, thus not achieving a fully assembled connection. Furthermore, the load-bearing capacity of the aluminum alloy material in the heat-affected zone of the weld is reduced. When applied to reticulated shell structures with high load-bearing capacity requirements, this node will be significantly limited.

[0015] The information disclosed in this background section is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0016] The purpose of this invention is to provide a double-layer hollow aluminum alloy mesh shell structure to solve the problems existing in the prior art.

[0017] To achieve the above objectives, the present invention adopts the following technical solution:

[0018] This invention provides a double-layer hollow aluminum alloy mesh shell structure, comprising: an upper aluminum alloy mesh shell, a lower aluminum alloy mesh shell, and vertical web members connecting the upper and lower aluminum alloy mesh shells;

[0019] The vertical web members and the upper and lower aluminum alloy grid shell components all adopt aluminum alloy I-shaped open sections, and are connected to the upper and lower grid shells through three-dimensional rigid fully assembled nodes. In both the radial and circumferential directions of the rib ring grid, reliable bending stiffness and bending moment transfer capacity between the upper and lower grid shells are achieved, forming a hollow truss effect.

[0020] Both the upper and lower aluminum alloy mesh shells adopt a rib-ring type mesh with varying density.

[0021] There are no diagonal braces between the upper and lower aluminum alloy mesh shells.

[0022] Furthermore, the spacing of the circumferential members of the density-varying rib ring grid remains consistent, and the spacing of the radial members gradually decreases from the outside to the inside. When the spacing of the radial members is less than a set threshold, the number of circumferential grids is reduced, and two circumferential grids are merged into one circumferential grid. At the same time, circumferential diagonal members are set for transition to avoid interruption of radial force flow.

[0023] Furthermore, the three-dimensional rigid-connected fully assembled node adopts a fully assembled connection, and the bending stiffness of the node after assembly is not lower than the minimum bending stiffness of all the grid shell members and vertical web members connected to it.

[0024] Furthermore, in addition to radial members, circumferential members, and circumferential diagonal members, support members are also provided in the plane of the upper and lower reticulated shells along the radial direction.

[0025] Furthermore, the three-dimensional rigid-connection fully assembled nodes are divided into two basic types, with type one being a typical node (such as...). Figure 2 As shown), it is used to connect radial members, circumferential members, and vertical web members. Type II, in addition to connecting radial members, circumferential members, and vertical web members, also connects supporting members or circumferential diagonal members and other diagonal members (such as...). Figure 8 (as shown);

[0026] The node consists of an upper node plate, a lower node plate, and angle aluminum as connecting components, connecting radial members, circumferential members, vertical web members, and diagonal members;

[0027] The upper and lower node plates of the node are each provided with an I-shaped opening that matches the I-shaped cross-section of the vertical web member, and the vertical web member passes through the upper and lower node plates;

[0028] The upper and lower flanges of the vertical web member are connected to the upper and lower node plates and the upper and lower flanges of the radial member respectively through angle aluminum and fasteners. The flanges, node plates and angle aluminum of the radial member are connected by the same set of fasteners.

[0029] The web of the radial member is connected to the upper and lower flanges of the vertical web member by double-angle aluminum and fasteners.

[0030] The web of the circumferential member is connected to the web of the vertical member via double-angle aluminum or T-shaped aluminum and fasteners; the upper and lower flanges of the circumferential member are connected to the upper and lower node plates respectively via fasteners.

[0031] The upper and lower flanges of the inclined member are connected to the upper and lower node plates respectively by fasteners, while the web of the inclined member is not connected.

[0032] The fasteners can be bearing bolts or grooved rivets made of stainless steel or titanium alloy.

[0033] A design method for a double-layer hollow aluminum alloy mesh shell structure includes a mesh forming method and a mechanical analysis method.

[0034] By adopting the above technical solution, the present invention has the following beneficial effects:

[0035] This invention provides a double-layer hollow aluminum alloy grid shell structure and its design method. The structure employs a density-variable rib-ring mesh, and the use of three-dimensional rigid-connected fully assembled aluminum alloy nodes avoids the need for diagonal bracing between the upper and lower layers, significantly reducing the number of structural members and simplifying the assembly process. The corresponding design method accurately calculates the strength and stiffness of the grid shell, providing a reliable basis for the component design of this type of shell. Compared to common single-layer aluminum alloy grid shells and aluminum alloy space frames, the double-layer hollow aluminum alloy grid shell structure offers greater spanning capacity, higher load-bearing capacity, and greater adaptability to architectural forms. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram comparing a standard ribbed ring mesh with a ribbed ring mesh of varying density.

[0038] Figure 2 This is an assembly schematic diagram of a three-dimensional rigid-joint fully assembled aluminum alloy node type provided by the present invention.

[0039] Figure 3 This is a disassembly diagram of a three-dimensional rigid-joint fully assembled aluminum alloy node type provided by the present invention.

[0040] Figure 4 This is a schematic diagram of a three-dimensional rigid-connected fully assembled aluminum alloy node type 1 provided by the present invention, used for upper and lower reticulated shells.

[0041] Figure 5 This is a top view of a three-dimensional rigid-joint fully assembled aluminum alloy node type one provided by the present invention.

[0042] Figure 6 This is a front view of a three-dimensional rigid-joint fully assembled aluminum alloy node type 1 provided by the present invention.

[0043] Figure 7 This is a side view of a three-dimensional rigid-joint fully assembled aluminum alloy node type 1 provided by the present invention.

[0044] Figure 8 This is a schematic diagram of the assembly of a three-dimensional rigid-joint fully assembled aluminum alloy node of type two provided by the present invention.

[0045] Figure 9 This is a disassembly diagram of a three-dimensional rigid-joint fully assembled aluminum alloy node type two provided by the present invention.

[0046] Figure 10 This is a schematic diagram of the three-dimensional rigid-connected fully assembled aluminum alloy node type II provided by the present invention when used in upper and lower reticulated shells.

[0047] Figure 11 This is a top view of a three-dimensional rigid-joint fully assembled aluminum alloy node type two provided by the present invention.

[0048] Figure 12 This is a front view of the second type of three-dimensional rigid-joint fully assembled aluminum alloy node provided by the present invention.

[0049] Figure 13 This is a side view of a three-dimensional rigid-joint fully assembled aluminum alloy node type two provided by the present invention.

[0050] Figure 14 This is an isometric schematic diagram of the double-layer hollow aluminum alloy mesh shell structure provided by the present invention.

[0051] Figure 15 This is a top view schematic diagram of the double-layer hollow aluminum alloy mesh shell structure provided by the present invention.

[0052] Figure 16 This is a side view of the double-layer hollow aluminum alloy mesh shell structure provided by the present invention.

[0053] Figure 17 The flowchart shows the mesh forming method in the design method of the double-layer hollow aluminum alloy mesh shell structure provided by the present invention.

[0054] Figure 18 The flowchart shows the mechanical analysis method in the design method of the double-layer hollow aluminum alloy reticulated shell structure provided by the present invention.

[0055] Figure 19 The overall flowchart of the design method for the double-layer hollow aluminum alloy mesh shell structure provided by the present invention.

[0056] Icons: 1-Standard rib-ring type grid; 2-Rib-ring type grid with varying density; 3-Vertical web member; 4-Radial member; 5-Circumferential member; 6-Diagonal member; 7-Upper node plate; 8-Lower node plate; 9-Upper shell node; 10-Lower shell node; 11-Angle aluminum connector; 12-T-shaped aluminum connector; 13-Double angle aluminum connector; 14-Fastener; 101-Location using node type one; 102-Location using node type two. Detailed Implementation

[0057] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0059] Figure 1 The specific structural forms of the standard rib-ring type 1 and the density-variable rib-ring type 2 are provided.

[0060] Combination Figures 2-16 As shown, this embodiment provides a double-layer hollow aluminum alloy mesh shell structure, characterized in that it includes: an upper aluminum alloy mesh shell, a lower aluminum alloy mesh shell, and a vertical web rod 3 connecting the upper and lower aluminum alloy mesh shells;

[0061] The vertical web members and the upper and lower aluminum alloy grid shell components all adopt aluminum alloy I-shaped open sections, and are connected to the upper and lower grid shells through three-dimensional rigid fully assembled nodes. In both the radial and circumferential directions of the rib ring grid, reliable bending stiffness and bending moment transfer capacity between the upper and lower grid shells are achieved, forming a hollow truss effect.

[0062] Both the upper and lower aluminum alloy mesh shells adopt a rib-ring type mesh with varying density.

[0063] There are no diagonal braces between the upper and lower aluminum alloy mesh shells.

[0064] In this embodiment, the spacing of the circumferential members of the density-varying rib ring grid remains consistent, and the spacing of the radial members gradually decreases from the outside to the inside. When the spacing of the radial members is less than a set threshold, the number of circumferential grids is reduced, and two circumferential grids are merged into one circumferential grid. At the same time, circumferential diagonal members are set for transition to avoid interruption of radial force flow.

[0065] In this embodiment, the three-dimensional rigid-connected fully assembled node adopts a fully assembled connection, and the bending stiffness of the node after assembly is not lower than the minimum bending stiffness of all the grid shell members and vertical web members connected to it.

[0066] In this embodiment, in addition to the radial members 4, the circumferential members 5, and the circumferential diagonal members, support members are also provided in the plane of the upper and lower reticulated shells along the radial direction. Upper reticulated shell nodes 9 are formed on the upper reticulated shell, and lower reticulated shell nodes 10 are formed on the lower reticulated shell.

[0067] In this embodiment, the three-dimensional rigid-connection fully assembled node is divided into two basic types, with type one being a typical node ( Figure 15 The location marked is 101, which uses node type one to connect radial members, circumferential members, and vertical web members. Type two, in addition to connecting radial members, circumferential members, and vertical web members, also connects support members or circumferential diagonal members, etc. Figure 15 The node position (102) using node type two is marked in the text.

[0068] The node consists of an upper node plate 7, a lower node plate 8, and an angle aluminum as connecting components, connecting radial members, circumferential members, vertical web members, and diagonal members 6;

[0069] The upper and lower node plates of the node are each provided with an I-shaped opening that matches the I-shaped cross-section of the vertical web member, and the vertical web member passes through the upper and lower node plates;

[0070] The upper and lower flanges of the vertical web member are connected to the upper and lower node plates and the upper and lower flanges of the radial member respectively through the angle aluminum connector 11 and fastener 14. The flanges of the radial member, the node plate, and the angle aluminum are connected by the same set of fasteners.

[0071] The web of the radial member is connected to the upper and lower flanges of the vertical web member via double-angle aluminum connectors 13 and fasteners.

[0072] The web of the circumferential member is connected to the web of the vertical member via double-angle aluminum or T-shaped aluminum connectors 12 and fasteners; the upper and lower flanges of the circumferential member are connected to the upper and lower node plates respectively via fasteners.

[0073] The upper and lower flanges of the inclined member are connected to the upper and lower node plates respectively by fasteners, while the web of the inclined member is not connected.

[0074] The fasteners can be bearing bolts or grooved rivets made of stainless steel or titanium alloy.

[0075] Combination Figures 17-19 As shown, this embodiment also provides a design method for a double-layer hollow aluminum alloy mesh shell structure, specifically including a mesh forming method and a mechanical analysis method:

[0076] The mesh forming method includes the following steps:

[0077] S1. Determine the design conditions, including the thickness, span, sag, and surface geometry of the double-layer reticulated shell, as well as the maximum circumferential grid spacing L. max_c and minimum value L min_c Maximum radial grid spacing L max_r and minimum value L min_r ;

[0078] S2. Calculate the length L of the outermost edge of the reticulated shell. circum and the length L from the vertex to the edge of the reticulated shell radial ;

[0079] S3, Calculation And for N ′ Take an even integer N and calculate And for M ′ Take the integer M;

[0080] S4. Divide the reticulated shell surface radially into M equal parts from the outside in, resulting in M ​​loops of length l. i (i = 1, 2, ..., M);

[0081] S5, Calculation If r i <L min_c If the result is positive, divide the ring into N equal parts and execute step S6; otherwise, let N = 2 × N and repeat step S5.

[0082] S6. When the number of circumferential division points is the same, radial mesh members are generated; when the number of circumferential division points is not the same, diagonal mesh members are generated.

[0083] S7. Statistical analysis of the distances d1, d2, ..., d between the outer vertex and the inner member of the oblique grid. ( , let d m =max(d1,d2,…,d ( ), k is the number of diagonal grid cycles, if d m ≤L max_r Execute step S8; otherwise, decrease the spacing of the ring containing the diagonal mesh and increase the spacing of other rings, and repeat steps S5-S7.

[0084] S8. Connect the circumferentially divided points to generate circumferential mesh members;

[0085] S9. Generate in-plane support members radially at the position of the grid symmetry axis;

[0086] S10. Project the generated mesh nodes along the normal of the curved surface onto another curved surface, and generate radial mesh rods, circumferential mesh rods, oblique mesh rods and support rods according to the same topological relationship. Connect the projected nodes and the projected nodes to form vertical web rods, and the mesh forming is completed.

[0087] The mechanical analysis method includes the following steps:

[0088] S1. Based on the geometries of the reticulated shell obtained by the mesh forming method, a finite element analysis model of the double-layer hollow reticulated shell is established.

[0089] S2. Perform finite element analysis and determine whether the stiffness and bearing capacity of the structure can meet the design specifications. If both meet the design specifications, proceed to step S3; otherwise, return to adjust the cross section of the reticulated shell.

[0090] S3. Calculate the number of fasteners for each member according to the current reticulated shell cross-section specifications and the principle of equal strength: For radial and circumferential members, the sum of the shear strength of all flange fasteners shall not be less than the yield strength of the flange, the sum of the shear strength of all web fasteners shall not be less than the yield strength of the web, and for diagonal members, the sum of the shear strength of all flange fasteners shall not be less than the yield strength of the flange, and no fasteners shall be provided for the web.

[0091] S4. Arrange the fasteners according to the requirements of the fastener hole spacing and the distance from the fastener to the edge of the plate in the specification;

[0092] S5. After completing the fastener arrangement for each member, calculate the radial stiffness K of the node region of the member considering the node construction. radial Linear stiffness K of the nodal region of the circumferential member circum Linear stiffness K of the oblique member node area dia2 :

[0093] The total length of the rod is L elem It is divided into node areas at both ends and a middle member area.

[0094] The node region length is L con =L i +L o ,

[0095] The length of the middle member is L mid =L ekem -2·L con ,

[0096] For radial members:

[0097] Linear stiffness K of the middle member area radial_ori2 Calculations are performed based on the cross-section of the component;

[0098] The linear stiffness of the node region comprises three stages: the fastener embedding stage, the fastener slippage stage, and the fastener bearing stage. The linear stiffness of these three stages is described by a three-segment curve, as follows:

[0099]

[0100] In the formula:

[0101]

[0102] H is the height of the vertical web member section;

[0103]

[0104] In the formula:

[0105] L o =L ′ +2·0.5·d0,L ′ The total width of the fasteners is the projected length of the distance between the innermost and outermost fasteners in the direction of the rod.

[0106]

[0107] Where j Jlan2e The number of flange fastener rows for the member, along the width of the member;

[0108]

[0109] Where j HeI The number of rows of web fasteners in the member, along the width of the member;

[0110]

[0111] Among them, the shape factor κ≈0.9 for the circular cross-section.

[0112] G is the shear modulus of the fastener.

[0113] n is the number of rows, along the direction of the rod.

[0114]

[0115] d0 is the diameter of the fastener.

[0116] t Jlan2e For the flange thickness of the rod,

[0117] t pla\e The thickness of the upper and lower node plates;

[0118] For circumferential members:

[0119] Linear stiffness K of the middle member area circum_ori2 Calculations are performed based on the cross-section of the component;

[0120] The linear stiffness of the node region comprises three stages: the fastener embedding stage, the fastener slippage stage, and the fastener bearing stage. The linear stiffness of these three stages is described by a three-segment curve, where F and δ represent the force and displacement values ​​corresponding to the transition from the current stage to the next stage, respectively.

[0121]

[0122] In the formula:

[0123] Ki =K ipla\e +K iHeI

[0124]

[0125] L i =L + 2·d0 - 0.5·d0, where L is the total width of the fasteners, that is, the projected length of the distance between the innermost and outermost fasteners in the direction of the rod.

[0126] t p The thickness of the upper and lower node plates,

[0127] B is the flange width of the member.

[0128] E is the elastic modulus of aluminum alloy.

[0129] H cp Minimum height for double-angle aluminum or T-shaped aluminum connectors.

[0130] t cp The total thickness of the double-angle aluminum or T-shaped aluminum connector.

[0131]

[0132] In the formula:

[0133] L o =L ′ +2·0.5·d0,L ′ The total width of the fastener is the projected length of the distance between the innermost and outermost fasteners in the direction of the rod.

[0134]

[0135] Where j Jlan2e The number of flange fastener rows for the member, along the width of the member;

[0136]

[0137] Where j HeI The number of rows of web fasteners in the member, along the width of the member;

[0138]

[0139] The shape factor κ ≈ 0.9 for the circular cross-section.

[0140] n is the number of rows (along the direction of the rod).

[0141]

[0142] The shape factor κ ≈ 0.9 for the circular cross-section.

[0143] G is the shear modulus of the fastener.

[0144] n is the number of rows, along the width of the member.

[0145]

[0146] d0 is the diameter of the fastener.

[0147] t Jlan2e For the flange thickness of the rod,

[0148] t pka\e The thickness of the upper and lower node plates;

[0149] For diagonal members:

[0150] Linear stiffness K of the middle member area dia2_ori2 Calculations are performed based on the cross-section of the component;

[0151] The linear stiffness of the node region comprises three stages: the fastener embedding stage, the fastener slippage stage, and the fastener bearing stage. The linear stiffness of these three stages is described by a three-segment curve, where F and δ represent the force and displacement values ​​corresponding to the transition from the current stage to the next stage, respectively.

[0152]

[0153] In the formula:

[0154]

[0155] L i =L+2·d0-0.5·d0

[0156]

[0157] In the formula:

[0158] L i =L+2·d0-0.5·d0, where L is the total width of the fastener, that is, the projected length of the distance between the innermost and outermost fasteners in the direction of the rod.

[0159]

[0160] Where j Jlan2e The number of flange fastener rows for the member, along the width of the member;

[0161]

[0162] The shape factor κ ≈ 0.9 for the circular cross-section.

[0163] G is the shear modulus of the fastener.

[0164] n is the number of rows, along the direction of the rod.

[0165]

[0166] d0 is the diameter of the fastener.

[0167] t Jlan2e For the flange thickness of the rod,

[0168] t pla\e The thickness of the upper and lower node plates;

[0169] S6. Consider the linear stiffness K of the radial member node region in the overall finite element calculation model. radial Linear stiffness K of the nodal region of the circumferential member circum Linear stiffness K of the oblique member node area dia2 And perform overall finite element analysis of the structure to obtain the deformation D of the structure and the internal forces of all members;

[0170] S7. Based on the obtained deformation and internal force, determine whether the stiffness and bearing capacity of the structure can meet the design specifications. If both meet the design specifications, proceed to step S3; otherwise, return to adjust the cross section of the reticulated shell.

[0171] S8. Perform an overall stability check on the structure considering the stiffness of the nodal area to obtain the stability bearing capacity coefficient. If the obtained stability bearing capacity coefficient meets the design index, the design ends; otherwise, adjust the member cross-section and repeat S3-S8.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double-layer hollow aluminum alloy mesh shell structure, characterized in that, include: Upper aluminum alloy mesh shell, lower aluminum alloy mesh shell, and vertical web members connecting the upper and lower aluminum alloy mesh shells; The vertical web members and the upper and lower aluminum alloy grid shell components all adopt aluminum alloy I-shaped open sections, and are connected to the upper and lower grid shells through three-dimensional rigid fully assembled nodes. In both the radial and circumferential directions of the rib ring grid, reliable bending stiffness and bending moment transfer capacity between the upper and lower grid shells are achieved, forming a hollow truss effect. Both the upper and lower aluminum alloy mesh shells adopt a rib-ring type mesh with varying density. There are no diagonal braces between the upper and lower aluminum alloy mesh shells.

2. The double-layer hollow aluminum alloy mesh shell structure according to claim 1, characterized in that, The spacing of the circumferential members in the density-varying rib ring grid remains consistent, while the spacing of the radial members gradually decreases from the outside to the inside. When the spacing of the radial members is less than a set threshold, the number of circumferential grids is reduced, and two circumferential grids are merged into one. At the same time, circumferential diagonal members are set for transition to avoid interruption of radial force flow.

3. The double-layer hollow aluminum alloy mesh shell structure according to claim 1, characterized in that, The three-dimensional rigid-connected fully assembled node adopts a fully assembled connection, and the bending stiffness of the node after assembly is not lower than the minimum bending stiffness of all the grid shell members and vertical web members connected to it.

4. The double-layer hollow aluminum alloy mesh shell structure according to claim 1, characterized in that, In addition to radial members, circumferential members, and circumferential diagonal members, support members are also provided in the plane of the upper and lower reticulated shells along the radial direction.

5. The double-layer hollow aluminum alloy mesh shell structure according to claim 1, characterized in that, The three-dimensional rigid-connected fully assembled nodes are divided into two basic types. Type 1 is a typical node (as shown in Figure 2), which is used to connect radial members, circumferential members and vertical web members. Type 2, in addition to connecting radial members, circumferential members and vertical web members, also connects support members or circumferential diagonal members and other diagonal members (as shown in Figure 8). The node consists of an upper node plate, a lower node plate, and angle aluminum as connecting components, connecting radial members, circumferential members, vertical web members, and diagonal members; The upper and lower node plates of the node are each provided with an I-shaped opening that matches the I-shaped cross-section of the vertical web member, and the vertical web member passes through the upper and lower node plates; The upper and lower flanges of the vertical web member are connected to the upper and lower node plates and the upper and lower flanges of the radial member respectively through angle aluminum and fasteners. The flanges, node plates and angle aluminum of the radial member are connected by the same set of fasteners. The web of the radial member is connected to the upper and lower flanges of the vertical web member by double-angle aluminum and fasteners. The web of the circumferential member is connected to the web of the vertical member via double-angle aluminum or T-shaped aluminum and fasteners; the upper and lower flanges of the circumferential member are connected to the upper and lower node plates respectively via fasteners. The upper and lower flanges of the inclined member are connected to the upper and lower node plates respectively by fasteners, while the web of the inclined member is not connected. The fasteners can be bearing bolts or grooved rivets made of stainless steel or titanium alloy.

6. A design method applicable to the double-layer hollow aluminum alloy mesh shell structure according to any one of claims 1-5, characterized in that, Including mesh forming methods and mechanical analysis methods: The mesh forming method includes the following steps: S1. Determine the design conditions, including the thickness, span, sag, and surface geometry of the double-layer reticulated shell, as well as the maximum circumferential grid spacing L. max_c and minimum value L min_c Maximum radial grid spacing L max_r and minimum value L min_r ; S2. Calculate the length L of the outermost edge of the reticulated shell. circum The length L from the vertex to the edge of the reticulated shell radial ; S3, Calculation And for N ′ Take an even integer N and calculate And for M ′ Take the integer M; S4. Divide the reticulated shell surface radially into M equal parts from the outside in, resulting in M ​​loops of length l. i (i = 1, 2, ..., M); S5, Calculation If r i <L min_c If the result is positive, divide the ring into N equal parts and execute step S6; otherwise, let N = 2 × N and repeat step S5. S6. When the number of circumferential division points is the same, radial mesh members are generated; when the number of circumferential division points is not the same, diagonal mesh members are generated. S7. Statistical analysis of the distances d1, d2, ..., d between the outer vertex and the inner member of the oblique grid. ( , let d m =max(d1,d2,…,d ( ), k is the number of diagonal grid cycles, if d m ≤L max_r Execute step S8; otherwise, decrease the spacing of the ring containing the diagonal mesh and increase the spacing of other rings, and repeat steps S5-S7. S8. Connect the circumferentially divided points to generate circumferential mesh members; S9. Generate in-plane support members radially at the position of the grid symmetry axis; S10. Project the generated mesh nodes along the normal of the curved surface onto another curved surface, and generate radial mesh rods, circumferential mesh rods, oblique mesh rods and support rods according to the same topological relationship. Connect the projected nodes and the projected nodes to form vertical web rods, and the mesh forming is completed. The mechanical analysis method includes the following steps: S1. Based on the geometries of the reticulated shell obtained by the mesh forming method, a finite element analysis model of the double-layer hollow reticulated shell is established. S2. Perform finite element analysis and determine whether the stiffness and bearing capacity of the structure can meet the design specifications. If both meet the design specifications, proceed to step S3; otherwise, return to adjust the cross section of the reticulated shell. S3. Calculate the number of fasteners for each member according to the current reticulated shell cross-section specifications and the principle of equal strength: For radial and circumferential members, the sum of the shear strength of all flange fasteners shall not be less than the yield strength of the flange, the sum of the shear strength of all web fasteners shall not be less than the yield strength of the web, and for diagonal members, the sum of the shear strength of all flange fasteners shall not be less than the yield strength of the flange, and no fasteners shall be provided for the web. S4. Arrange the fasteners according to the requirements of the fastener hole spacing and the distance from the fastener to the edge of the plate in the specification; S5. After completing the fastener arrangement for each member, calculate the radial stiffness K of the node region of the member considering the node construction. radial Linear stiffness K of the nodal region of the circumferential member circum Linear stiffness K of the oblique member node area dia2 : The total length of the rod is L elem It is divided into node areas at both ends and a middle member area. The node region length is L con =L i +L o , The length of the middle member is L mid =L elem -2·L con , For radial members: Linear stiffness K of the middle member area radial_ori2 Calculations are performed based on the cross-section of the component; The linear stiffness of the node region comprises three stages: the fastener embedding stage, the fastener slippage stage, and the fastener bearing stage. The linear stiffness of these three stages is described by a three-segment curve, as follows: In the formula: H is the height of the vertical web member section; In the formula: L o =L ′ +2·0.5·d0,L ′ The total width of the fasteners is the projected length of the distance between the innermost and outermost fasteners in the direction of the rod. Where j Jlan2e The number of flange fastener rows for the member, along the width of the member; Where j HeI The number of rows of web fasteners in the member, along the width of the member; Among them, the shape factor κ≈0.9 for the circular cross-section. G is the shear modulus of the fastener. n is the number of rows, along the direction of the rod. d0 is the diameter of the fastener. t Jlan2e For the flange thickness of the rod, t pla\e The thickness of the upper and lower node plates; For circumferential members: Linear stiffness K of the middle member area circum_ori2 Calculations are performed based on the cross-section of the component; The linear stiffness of the node region comprises three stages: the fastener embedding stage, the fastener slippage stage, and the fastener bearing stage. The linear stiffness of these three stages is described by a three-segment curve, where F and δ represent the force and displacement values ​​corresponding to the transition from the current stage to the next stage, respectively. In the formula: K i =K ipla\e +K iHeI L i =L + 2·d0 - 0.5·d0, where L is the total width of the fasteners, that is, the projected length of the distance between the innermost and outermost fasteners in the direction of the rod. t p The thickness of the upper and lower node plates, B is the flange width of the member. E is the elastic modulus of aluminum alloy. H cp Minimum height for double-angle aluminum or T-shaped aluminum connectors. t cp The total thickness of the double-angle aluminum or T-shaped aluminum connector. In the formula: L o =L ′ +2·0.5·d0,L ′ The total width of the fastener is the projected length of the distance between the innermost and outermost fasteners in the direction of the rod. Where j Jlan2e The number of flange fastener rows for the member, along the width of the member; Where j HeI The number of rows of web fasteners in the member, along the width of the member; The shape factor κ ≈ 0.9 for the circular cross-section. n is the number of rows (along the direction of the rod). The shape factor κ ≈ 0.9 for the circular cross-section. G is the shear modulus of the fastener. n is the number of rows, along the width of the member. d0 is the diameter of the fastener. t Jlan2e For the flange thickness of the rod, t pka\e The thickness of the upper and lower node plates; For diagonal members: Linear stiffness K of the middle member area dia2_ori2 Calculations are performed based on the cross-section of the component; The linear stiffness of the node region comprises three stages: the fastener embedding stage, the fastener slippage stage, and the fastener bearing stage. The linear stiffness of these three stages is described by a three-segment curve, where F and δ represent the force and displacement values ​​corresponding to the transition from the current stage to the next stage, respectively. In the formula: L i < L+2·d0-0.5·d0 In the formula: L i =L+2·d0-0.5·d0, where L is the total width of the fastener, that is, the projected length of the distance between the innermost and outermost fasteners in the direction of the rod. Where j Jlan2e The number of flange fastener rows for the member, along the width of the member; The shape factor κ ≈ 0.9 for the circular cross-section. G is the shear modulus of the fastener. n is the number of rows, along the direction of the rod. d0 is the diameter of the fastener. t Jlan2e For the flange thickness of the rod, t pla\e The thickness of the upper and lower node plates; S6. Consider the linear stiffness K of the radial member node region in the overall finite element calculation model. radial Linear stiffness K of the nodal region of the circumferential member circum Linear stiffness K of the oblique member node area dia2 And perform overall finite element analysis of the structure to obtain the deformation D of the structure and the internal forces of all members; S7. Based on the obtained deformation and internal force, determine whether the stiffness and bearing capacity of the structure can meet the design specifications. If both meet the design specifications, proceed to step S3; otherwise, return to adjust the cross section of the reticulated shell. S8. Perform an overall stability check on the structure considering the stiffness of the nodal area to obtain the stability bearing capacity coefficient. If the obtained stability bearing capacity coefficient meets the design index, the design ends; otherwise, adjust the member cross-section and repeat S3-S8.

Images