METHOD FOR MANUFACTURING NON-MAGNETIC SPATIAL LATTICED SHELL STRUCTURE COMPOSED OF CARBON FIBER PLATE MEMBERS

Abstract

A method for manufacturing a non-magnetic spatial latticed shell structure composed of carbon fiber plate members. The load-bearing member of the latticed shell structure is made of non-magnetic carbon fiber plate, and joints are made of non-magnetic titanium alloy material. The magnetic shielding layer is provided on the roofing system above the structural layer, and a non-magnetic space with a magnetic field strength lower than 1 nT is formed inside the structure. The load-bearing members are fixed by two carbon fiber limb plates in the form of inter-limb connection and forms an hollow rectangular built-up section; and the joint comprises a titanium alloy gusset plate, a titanium alloy bolt group, and a carbon fiber limb plate; the magnetic shielding layer of the roofing system comprises a shielding layer pad, a shielding layer, a shielding laminate, a buffer layer, a permalloy plate, and a batten.

Claims

1. A method for manufacturing a non-magnetic spatial latticed shell structure composed of carbon fiber plate members, wherein load-bearing members of the non-magnetic spatial latticed shell structure are made of non-magnetic carbon fiber plates, and a joint of the non-magnetic spatial latticed shell structure is made of a non-magnetic titanium alloy material, a magnetic shielding layer is provided on a roofing system above a structural layer, and a non-magnetic space with a magnetic field strength lower than 1 nT is formed inside the non-magnetic spatial latticed shell structure.

2. The method for manufacturing the non-magnetic spatial latticed shell structure composed of the carbon fiber plate members according to claim 1, wherein the non-magnetic spatial latticed shell structure uses carbon fiber double-limb plate members as the main load-bearing members, and the carbon fiber double-limb plate members are manufactured by a following method: arranging two carbon fiber limb plates with a length of l, a thickness of t and a width of b in parallel at a distance h, and fixing the carbon fiber limb plates at an interval of d by inter-limb connections, thereby forming a hollow rectangular cross-section built-up member, wherein equivalent slenderness ratios for internal force verification are calculated as follows: $\mathrm{weak}\mathrm{axis}\mathrm{slenderness}\mathrm{ratio}:{}_{hy}={}_g{}_{t}2\sqrt{3}\sqrt{\frac{2l^{2}t}{{\left(2t+h\right)}^3}+\frac{d^2}{t^2}}$ $\mathrm{strong}\mathrm{axis}\mathrm{slenderness}\mathrm{ratio}:{}_{hx}=\frac{2\sqrt{3}}{b}$ where .sub.g represents a reduction factor related to a geometric size of the carbon fiber limb plate, and is to be determined based on an axial compression test of a double-limb spliced carbon fiber plate; and .sub.t represents a reduction factor related to an interlaminar shear strength of the carbon fiber limb plate, and needs to be determined based on the axial compression test of the double-limb spliced carbon fiber plate.

3. The method for manufacturing the non-magnetic spatial latticed shell structure composed of the carbon fiber plate members according to claim 1, wherein the joint comprises a cross-shaped titanium alloy plate, a titanium alloy bolt group and a carbon fiber limb plate, and is manufactured by a following method: fixing the carbon fiber limb plate and the cross-shaped titanium alloy plate using the titanium alloy bolt group in a frictional connection manner to form a titanium alloy joint, wherein a failure process of the titanium alloy joint when subjected to a moment load presents four stages of bonding-sliding-strengthening-failure, and wherein a joint rotation stiffness in the sliding and failure stages is relatively weak, and a joint rotation stiffness K.sub.1 in the bonding stage and a joint rotation stiffness a joint rotation stiffness in the strengthening stage are designed and calculated as follows: $K_1=\frac{{\mathrm{Et}}_j{b}_j^3}{12l_j}$ $K_3=\frac{1}{\begin{array}{c}\frac{12l_j}{{\mathrm{Et}}_j{b}_j^3}+\frac{{\left(\frac{d_b}{t}\right)}^2\frac{{\left(2t+t_j\right)}^3}{192{\mathrm{EI}}_b}\left[1+\frac{63.84{\mathrm{EI}}_b}{G{A_b\left(2t_m+t_j\right)}^2}\right]}{.Math.r_i^2}+\\ \frac{E+E_c}{24{}_b{}_t{d}_b{f}_u.Math.r_i^2}\end{array}}$ ${}_b=\min \left\{\frac{0.25e_b}{d}+0.5,\frac{0.25p_b}{d}+0.375\right\}1\text{.25}$ ${}_t=\frac{1.5t_j}{16}2.5$ where E represents an elastic modulus of titanium alloy; t.sub.j represents a thickness of the cross-shaped titanium alloy plate; b.sub.j represents a width of the cross-shaped titanium alloy plate; l.sub.j represents an effective length of the cross-shaped titanium alloy plates; d.sub.b represents a diameter of titanium alloy bolts; t represents a thickness of the carbon fiber limb plates; t.sub.m represents a thickness of the carbon fiber limb plates; I.sub.b represents a moment of inertia of the titanium alloy bolts; GA.sub.b represents a section shear stiffness of the titanium alloy bolts; r.sub.i.sup.2 represents a sum of squares of distances from respective bolts in the titanium alloy bolt group to a group center; E.sub.c represents an elastic modulus of carbon fiber; .sub.b and .sub.t represent coefficient values related to a bolt hole; f.sub.u represents a ultimate tensile strength of the cross-shaped titanium alloy plates; e.sub.b represents a minimum distance from a center of bolt holes to an edge of the cross-shaped titanium alloy plates; and p.sub.b represents a bolt hole spacing.

4. The method for manufacturing the non-magnetic spatial latticed shell structure composed of the carbon fiber plate members according to claim 2, wherein the magnetic shielding layer of the roofing system is made of permalloy, and is manufactured by a following method: sequentially installing a shielding layer pad, a shielding layer, a shielding laminate, a buffer layer, a permalloy plate and a batten on the carbon fiber double-limb plate member by fixing with titanium alloy bolts or screws.

5. The method for manufacturing the non-magnetic spatial latticed shell structure composed of the carbon fiber plate members according to claim 1, wherein a span of the spatial latticed shell structure is greater than or equal to 30 m.

6. The method for manufacturing the non-magnetic spatial latticed shell structure composed of the carbon fiber plate members according to claim 3, wherein a contact surface of the cross-shaped titanium alloy plate and a contact surface of the carbon fiber limb plate are both sandblasted to improve a friction between the carbon fiber limb plate and the cross-shaped titanium alloy plate.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly explain the embodiments of the present disclosure or the technical solution in the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0020] FIG. 1 is a schematic structural diagram of a space latticed shell for ribbed-type spherical latticed shells.

[0021] FIG. 2 is the composition and geometric dimension diagram of a carbon fiber plate member.

[0022] FIG. 3 is a schematic diagram of the load-displacement curve of a joint.

[0023] FIG. 4 is a schematic diagram of a joint.

[0024] FIG. 5 is a schematic structural diagram of the magnetic shielding layer of the roofing system.

[0025] FIG. 6 is a schematic diagram of the integral latticed shell structure and its basic components.

DESCRIPTION OF EMBODIMENTS

[0026] A preferred embodiments of the present disclosure will be described in detail below with reference to the drawings, so that the advantages and features of the present disclosure can be more easily understood by those skilled in the art, and the protection scope of the present disclosure can be more clearly defined. The concrete implementation process of manufacturing the non-magnetic spatial latticed shell structure is as follows:

[0027] (1) According to the requirements of the actual building, the geometric modeling of the structure is designed. In this implementation process, taking a spherical latticed shell structure as an example, a ribbed-type (as shown in FIG. 1) is divided. In the latticed shell structure, a carbon fiber double-limb plate member composed of two parallel carbon fiber limb plates by inter-limb connection are used as load-bearing members. Inter-limb connection is to fixedly connect the two parallel carbon fiber limb plates through several fixed limb plates with equal spacing, and connect them with titanium alloy joints and titanium alloy bolts. The titanium alloy joint consists of a cross-shaped titanium alloy gusset plate, a titanium alloy bolt group and a carbon fiber limb plate, and the carbon fiber limb plate and the cross-shaped titanium alloy gusset plate are fixed by a frictional connection mode through the titanium alloy bolt group. The contact surfaces of the cruciform titanium alloy gusset plates and the carbon fiber limb plates are all sandblasted to improve the friction between the carbon fiber limb plates and the cruciform titanium alloy gusset plates.

[0028] (2) A numerical model is established according to the lattice structure. Then, the initial cross-sectional dimensions of carbon fiber double-limb plate members and the initial dimensions of the double-limb connection structure (as shown in FIG. 2) are set. After that, the material properties of related members and joints are set. Finally, the moment-rotation curve of the joint rotational stiffness is preliminarily set according to the engineering requirements (as shown in FIG. 3).

[0029] (3) The static linear elasticity of the structure is calculated according to the known load conditions and support conditions, and the deflection and displacement of the structure are obtained. The building requirements are compared with relevant design specifications to check whether they meet the requirements. If they do not meet the requirements, the member size or joint rotation stiffness in step (2) is recalculated and the above steps are repeated.

[0030] (4) According to the known load conditions and support conditions, the elastoplastic static calculation of the structure considering double nonlinearity is carried out to obtain the ultimate bearing capacity of the structure, and the building requirements are compared with relevant design specifications to check whether they meet the requirements. If they do not meet the requirements, the component size or joint rotational stiffness in step (2) is recalculated and the above steps are repeated.

[0031] (5) The load information at the end of the member in the static calculation result is extracted, the strength and stability are checked according to the following equivalent slenderness ratio formula of the component, the building requirements are compared with relevant design specifications to check whether they meet the requirements. If they do not meet the requirements, the component size is recalculated in step (2), and the above steps are repeated:

[00003]$\mathrm{weak}\mathrm{axis}\mathrm{slenderness}\mathrm{ratio}:{}_{hy}={}_g{}_{t}2\sqrt{3}\sqrt{\frac{2l^{2}t}{{\left(2t+h\right)}^3}+\frac{d^2}{t^2}}$$\mathrm{strong}\mathrm{axis}\mathrm{slenderness}\mathrm{ratio}:{}_{hx}=\frac{2\sqrt{3}}{b}$

where l is the length of the carbon fiber limb plate, t is the thickness of the carbon fiber limb plate, b is the width of the carbon fiber limb plate, h is the distance between two parallel carbon fiber limb plates, and dis the distance between fixed limb plates, .sub.g is a reduction factor related to a geometric size of the carbon fiber limb plate, which is to be determined according to an axial compression test of a double-limb spliced carbon fiber plate .sub.t is a reduction factor related to an interlaminar shear strength of the carbon fiber limb plate, which needs to be determined according to the axial compression test of the double-limb spliced carbon fiber plate.

[0032] (6) According to the moment-rotation angle curve of the joint rotational stiffness in step (2), the size and structure of the joint and bolt arrangement are obtained according to the following formula (as shown in FIG. 4). The failure process of the titanium alloy joint bearing a bending moment load presents four stages: bonding-sliding-strengthening-failure, in which the joint rotational stiffness in the sliding and failure stages is weak. The design of the joints is checked according to the actual structure and the structural requirements of relevant codes. If it does not meet the requirements, the moment-rotation curve of the joint stiffness in step (2) is recalculated and the above steps are repeated.

[00004]$K_1=\frac{{\mathrm{Et}}_j{b}_j^3}{12l_j}$$K_3=\frac{1}{\begin{array}{c}\frac{12l_j}{{\mathrm{Et}}_j{b}_j^3}+\frac{{\left(\frac{d_b}{t}\right)}^2\frac{{\left(2t+t_j\right)}^3}{192{\mathrm{EI}}_b}\left[1+\frac{63.84{\mathrm{EI}}_b}{G{A_b\left(2t_m+t_j\right)}^2}\right]}{.Math.r_i^2}+\\ \frac{E+E_c}{24{}_b{}_t{d}_b{f}_u.Math.r_i^2}\end{array}}$${}_b=\min \left\{\frac{0.25e_b}{d}+0.5,\frac{0.25p_b}{d}+0.375\right\}1\text{.25}$${}_t=\frac{1.5t_j}{16}2.5$

where E represents the elastic modulus of titanium alloy; t.sub.j represents the thickness of the cross-shaped titanium alloy plate; b.sub.j represents the width of the cross-shaped titanium alloy plate; l.sub.j represents the effective length of the cross-shaped titanium alloy plates; d.sub.b represents the diameter of the titanium alloy bolts; t represents the thickness of the carbon fiber limb plates; t.sub.m represents the thickness of the carbon fiber limb plates; I.sub.b represents the moment of inertia of the titanium alloy bolts; GA.sub.b represents the section shear stiffness of the titanium alloy bolts; r.sub.i.sup.2 represents the sum of squares of distances from respective bolts in the titanium alloy bolt group to the group center; E.sub.c represents the elastic modulus of carbon fiber; .sub.b and .sub.t represent coefficient values related to the bolt hole; f.sub.u represents the ultimate tensile strength of the cross-shaped titanium alloy plates; e.sub.b represents the minimum distance from the center of the bolt holes to the edge of the cross-shaped titanium alloy plates; and p.sub.b represents the bolt hole spacing.

[0033] (7) On the basis of the above design parameters, a magnetically shielded roofing system is disposed. A shielding layer pad, a shielding layer, a shielding laminate, a buffer layer, a permalloy plate, a batten and other components are sequentially installed on the carbon fiber plate member to form a roofing system (as shown in FIG. 5). Permalloy plates with magnetic shielding properties are densely distributed in the roofing system above the structural layer, a space with magnetic field strength less than 1 nT is formed inside the latticed shell, and the space inside the latticed shell has the characteristics of near zero remanence.

[0034] (8) Finally, an embodiment of the method for manufacturing a non-magnetic spatial latticed shell structure is obtained (as shown in FIG. 6).

[0035] The above embodiment is only a preferred embodiment of the present disclosure, which does not limit the patent scope of the present disclosure. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present disclosure, or directly or indirectly applied to other related technical fields, are equally included in the scope of the present disclosure.