Form finding method and system for circular plane hybrid cable truss structure

Abstract

The invention provides a shape finding method and system for a circular plane hybrid cable truss structure, and the method comprises the steps: dividing the hybrid cable truss structure into two sub-structures, namely an inner cable truss structure and an outer cable truss structure, respectively calculating the cable rod prestress of the inner cable truss structure and the outer cable truss structure and the vertical coordinates of a lower chord cable node; and if the change value of the vertical coordinates of the lower chord cable node and the support node meets the precision requirement, the shape finding analysis of the cable truss structure is completed. According to the method, a complex problem is converted into a simple problem, so that engineering design and researchers can conveniently carry out modeling and subsequent mechanical property analysis; according to the method, the calculation result is correct, the calculation precision is very high, and the prestress and the corresponding shape of the hybrid cable truss structure can be efficiently and accurately determined under the condition that the self-weight effect of the structure is considered.

Description

Technical Field

[0001] The invention relates to the field of large-span spatial structure design in construction engineering, and in particular to a form-finding method and system for a circular plane hybrid cable truss structure. Background Art

[0002] Cable truss structures are widely used in roof structures of large stadiums due to their light weight, high structural efficiency and convenient construction. Cable truss structures consist of two layers of cable nets, upper and lower, and intermediate rods (vertical rods or slings). Cable trusses require prestressing of cables and rods to have rigidity in order to withstand external loads. Therefore, the biggest challenge in the design of cable truss structures is to determine the prestress distribution and the corresponding shape, a process called form-finding analysis.

[0003] In addition, in terms of structural form, the upper and lower chords of the common cable truss structure intersect at one point at one end and intersect at the vertical rod at the other end; while the upper and lower chords of the hybrid cable truss structure intersect at one point at both ends. The upper and lower chords of the hybrid cable truss structure intersect at the inner circle ring cable in the inner circle and intersect at the support in the outer circle.

[0004] At present, the main methods used for form-finding analysis of cable truss structures include force density method, dynamic relaxation method, singular value decomposition method, finite element method, etc. However, these methods often require specific large-scale commercial software to perform form-finding analysis, making the corresponding solution process more complicated. In addition, some methods cannot consider the influence of the deadweight of the structure during the form-finding process, resulting in a large deviation of the structure shape in the prestressed state from the initial shape due to the inability to consider the deadweight of the structure.

[0005] Therefore, a solution is needed to efficiently and accurately determine the prestress and corresponding shape of the hybrid cable truss structure considering the self-weight of the structure. Summary of the invention

[0006] One purpose of the present application is to provide a shape-finding method and system for a circular planar hybrid cable truss structure, so as to solve the problem that the hybrid cable truss structure in the prior art has a large deviation from the initial shape in a prestressed state.

[0007] To achieve the above objectives, some embodiments of the present application provide a form-finding method for a circular plane hybrid cable truss structure, the method comprising the following steps:

[0008] Step 1: Split the hybrid cable truss structure into an inner cable truss structure and an outer cable truss structure; without considering the self-weight of the structure, according to the initial conditions, the prestress H0 of the inner ring cable and the prestress H0 of the upper ring cable k0 Calculating the prestress distribution of the initial shapes of the inner and outer cable truss structures;

[0009] Step 2: Select appropriate cross-sections for cables and rods according to the prestress distribution of the initial shape, distribute the weight of cables and rods evenly to the nodes at both ends of the rods, and calculate the equivalent node load F of the cable and rod self-weight i and F i ';

[0010] Step 3: Calculate the prestressing force T of the chord in the inner cable truss structure i and cable prestressing V i ;

[0011] Step 4: Calculate the prestressing force B of the lower chord of the inner cable truss structure i and the angle β between the lower chord and the horizontal plane i , and calculate the vertical coordinate Z of the lower ring cable node k0' k0' ;

[0012] Step 5: Determine Z k0' If the change value is not greater than 0.001 m, proceed to the next step; otherwise, adjust β1 and update F i and F i ', return to step 3 and recalculate until Z k0' The vertical coordinate change value is no more than 0.001 meters;

[0013] Step 6: Determine the change value of the vertical coordinates of other nodes of the lower chord. If the accuracy requirement is met, the form-finding analysis of the inner cable truss structure is completed. Otherwise, adjust the angle β1 between the lower chord and the horizontal plane under the initial condition, and update F i and F i ', return to step 3 and recalculate;

[0014] Step 7: Calculate the prestressing force T of the chord on the outer cable truss structure ki , vertical rod prestressing V k0 and cable prestressing V k(i-1) ;

[0015] Step 8: Calculate the prestressing force H of the outer cable truss structure k0 ', horizontal angle of lower chord β ki and lower chord prestressing B ki , and calculate the vertical coordinate Z of the support node kj ;

[0016] Step 9: Determine Z kj If the change value is not greater than 0.001 m, proceed to the next step; otherwise, adjust β k1 , and update F ki and F ki ', return to step 7 and recalculate until Z kjThe vertical coordinate change value is no more than 0.001 meters;

[0017] Step 10: Determine the change value of the vertical coordinates of other nodes of the lower chord. If the accuracy requirement is met, the form-finding analysis of the outer cable truss structure is completed. Otherwise, adjust β k1 , and update F i and F i ', return to step 7 and recalculate.

[0018] Furthermore, in step 3, the upper chord cable T of the inner cable truss structure is calculated. i and cable prestressing V i , and its calculation formula is as follows:

[0019] When i=1:

[0020] When i ≥ 2:

[0021] In the formula, α i and β1 are known quantities.

[0022] Furthermore, the calculation of the prestressing force B of the lower chord of the inner cable truss structure in step 4 is i The horizontal angle β with the lower chord i , and calculate the vertical coordinate Z of the lower ring cable node k0' k0′ , and its calculation formula is as follows:

[0023] When i=1:

[0024] When i ≥ 2:

[0025]

[0026] Where Z1 is the vertical coordinate of node 1, Δl i is the horizontal distance between the nodes i and i+1 of the lower chord; when j = k0', the calculation result is Z k0’ The vertical coordinate value of .

[0027] Furthermore, the change value ΔZ of the vertical coordinates of other nodes of the lower chord in step 6 is i’ Gradually converge to a small value, expressed as:

[0028] ΔZ i′ =Z i′，n -Z i′，n-1 ≤1×10 -3 m

[0029] In the formula, Z i′，n The vertical coordinate of node i' calculated in the nth iteration.

[0030] Furthermore, the calculation of the prestressing force T of the chord on the external cable truss structure in step 7 is ki , vertical rod prestressing V k0 and cable prestressing V k(i-1) , and its calculation formula is as follows:

[0031]

[0032] V k0 =-T j sinα j -T k1 sinα k1 -F k0

[0033] T ki =T k(i-1) cosa k(i-1) / cosα ki

[0034] V k(i-1) =T k(i-1) sinα k(i-1) -T ki sinα ki -F k(i-1)

[0035] In the formula, α ki is a known quantity; in addition, β k1 , T j And the prestressing force H of the upper ring cable k0 Set as initial condition.

[0036] Furthermore, in step 8, the prestressing force H of the ring cable under the outer cable truss structure is calculated. k0′ , horizontal angle of lower chord β ki and lower chord prestressing B ki , and calculate the vertical coordinate Z of the support node kj kj , and its calculation formula is as follows:

[0037]

[0038]

[0039] In the formula, B j Set as initial condition; Δl ki is the horizontal distance between the lower chord nodes k(i-1)′ and ki.

[0040] Furthermore, the change value ΔZ of the vertical coordinates of other nodes of the lower chord in step 10 is ki’ Gradually converge to a small value, expressed as:

[0041] ΔZ ki′ =Z ki′，n -Z ki′，n-1 ≤1×10 -3 m

[0042] In the formula, Z ki′，n It is the vertical coordinate of node ki′ calculated in the nth iteration.

[0043] On the other hand, a form-finding system for a circular plane hybrid cable truss structure is provided, the system comprising a memory for storing computer program instructions and a processor for executing the program instructions, wherein when the computer program instructions are executed by the processor, the system is triggered to execute the form-finding method for the circular plane hybrid cable truss structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the hybrid cable truss structure of the present invention;

[0045] Figure 2 It is a schematic diagram of the splitting of the hybrid cable truss structure of the present invention;

[0046] Figure 3 A calculation model diagram of an inner cable truss structure of a hybrid cable truss structure of the present invention;

[0047] Figure 4 A calculation model diagram of an outer cable truss structure of a hybrid cable truss structure of the present invention;

[0048] Figure 5 It is a flow chart of the hybrid cable truss structure form-finding method of the present invention;

[0049] Figure 6 It is a schematic diagram of the dimensions of an example of the hybrid cable truss structure of the present invention;

[0050] Figure 7 This is a schematic diagram of the initial shape of the hybrid cable truss structure of the present invention considering the deadweight of the structure. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0052] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0053] The embodiment of the present application proposes a form-finding method and system for a circular plane hybrid cable truss structure, which does not require professional form-finding analysis software and can be completed using a simple calculation table. The method can efficiently and accurately determine the prestress and corresponding shape of the circular plane hybrid cable truss structure under the action of the structure's own weight.

[0054] In some embodiments, Figure 1 As shown, the upper and lower chords of the hybrid cable truss structure intersect at one point at both ends, intersecting at the inner ring cable in the inner circle and intersecting at the support in the outer circle. The hybrid cable truss structure includes an upper ring cable, a lower ring cable, an upper chord cable, a lower chord cable, a sling, an inner ring cable and a vertical rod. The hybrid cable truss structure is split into an inner cable truss structure and an outer cable truss structure, as shown in FIG. Figure 2 This form-finding method is to split the hybrid cable truss structure into two substructures, the inner cable truss structure and the outer cable truss structure, and calculate and analyze them separately, that is, to convert a complex problem into a simple problem. The form-finding method of the two substructures is as follows:

[0055] 1. Form-finding method of internal cable truss structure

[0056] The calculation model of the internal cable truss structure can be simplified to a plane cable truss. Figure 1 and Figure 3 As shown in the figure, the inner cable truss structure is divided into two parts: the upper chord and the vertical rod, and the lower chord. i , B i , H0 represent the prestress of the upper chord, lower chord and inner ring cable respectively, F i and F i 'represent the equivalent nodal load of the cable-rod deadweight, α and βrepresent the angles between the upper and lower chords and the horizontal plane.

[0057] According to the node equilibrium relationship, two horizontal and vertical equilibrium equations are established for each node to solve the prestress of the upper chord, lower chord and sling. When i = 1:

[0058]

[0059] When i ≥ 2:

[0060]

[0061] When using the above calculation formula to solve, the initial shape of the upper chord needs to remain unchanged, that is, α i is a known quantity. In addition, β1 and H0 are required as initial conditions, V i Indicates the vertical cable prestressing.

[0062] After shape-finding calculation, the vertical coordinate Z of the lower chord node i’ It can be calculated by the following formula:

[0063]

[0064] Where: Z1 is the vertical coordinate of node 1, Δl i is the horizontal distance between nodes i and i+1 of the lower chord.

[0065] The vertical coordinate of the following chord node k0' is taken as the control value, and β1 is adjusted iteratively so that Z k0' In addition, during the iterative adjustment of β1, it is also necessary to ensure that the node coordinate change ΔZ of the lower chord i’ Gradually converge to a small value, expressed as:

[0066] ΔZ i' =Z i',n -Z i',n-1 ≤1×10 -3 m

[0067] Where: Z i',n The vertical coordinate of node i' calculated for the nth iteration.

[0068] In the process of adjusting β1, since the shape of the lower chord has changed, the equivalent node load F of the cable rod self-weight needs to be updated. i and F i '.

[0069] 2. Form-finding method of external cable truss structure

[0070] The calculation model of the external cable truss structure can be simplified to a plane cable truss, such as Figure 4 As shown in the figure, the outer cable truss is divided into two parts: the upper chord and the vertical rod, and the lower chord. The relevant calculation parameters are the same as the calculation model of the inner cable truss structure in the second step.

[0071] Establishing horizontal and vertical equilibrium equations for each node of the upper chord, the prestress T of the upper chord can be obtained. ki , vertical rod prestressing V k0 and cable prestressing V k(i-1) :

[0072]

[0073] Establishing horizontal and vertical equilibrium equations for each node of the lower chord, the prestressing force H of the lower hoop cable can be obtained: k0 ', horizontal angle of lower chord β ki and lower chord prestressing B ki :

[0074]

[0075] When using the above calculation formula to solve, the initial shape of the upper chord needs to remain unchanged, that is, α ki is a known quantity. In addition, k1 , T j , B j , and the prestressing force H of the middle upper ring cable k0 as initial conditions.

[0076] After shape-finding calculation, the vertical coordinate Z of the lower chord node ki’ The calculation is done by the following formula:

[0077]

[0078] Where: Z k0' is the vertical coordinate of node k0', Δl ki is the horizontal distance between the lower chord nodes k(i-1)' and ki'; when j = ki', it is Z ki’ The vertical coordinate value of .

[0079] Taking the vertical coordinate of the outer ring support node kj as the control value, β k1 Make Z kj The value of remains unchanged. In addition, when iteratively adjusting β k1 In the process, it is also necessary to ensure that the node coordinates of the lower chord change ΔZ ki’ Gradually converge to a small value, expressed as:

[0080] ΔZ ki' =Z ki',n -Z ki',n-1 ≤1×10 -3 m

[0081] Where: Z ki',n The vertical coordinate of node ki' calculated in the nth iteration.

[0082] In adjusting β k1 In the process of , the shape of the lower chord changes, and the equivalent node load F of the cable rod self-weight needs to be updated. ki and F ki '.

[0083] Some embodiments of the present application are based on the above circular plane hybrid cable truss structure form-finding method, such as Figure 5 As shown in Figure 1, the form-finding process includes the following steps:

[0084] Step 1: Split the hybrid cable truss structure into an inner cable truss structure and an outer cable truss structure; without considering the self-weight of the structure, according to the inner ring cable prestress H0 and the upper ring cable prestress H k0 Calculate the prestress distribution of the hybrid cable-truss structure in its initial shape.

[0085] Step 2: According to the initial shape of the prestress distribution, select the appropriate cross-sectional form for the cable and rod, so that the rod stress meets the relevant specifications. In the selected cross-section, the vertical rod is usually made of round steel tube. The weight of the cable and rod is evenly distributed to the nodes at both ends of the rod, and the equivalent node load F of the cable and rod self-weight is calculated. i and F i '.

[0086] Step 3: Calculate the prestress of the chords and suspenders in the internal cable truss structure according to H0, β1 and F i Calculate the prestressing force T of the upper chord i and cable prestressing V i .

[0087] Step 4: Calculate the prestress of the lower chord, the horizontal angle of the lower chord and the vertical coordinates of the lower chord node of the inner cable truss structure. i and F i 'Calculate the horizontal angle β of the lower chord i and lower chord prestressing B i , calculate the vertical coordinate Z of the lower ring cable k0' .

[0088] Step 5: Determine Z k0' If the change value of the initial coordinates is satisfied, proceed to the next step; otherwise, adjust β1 and update F i and F i ', return to step 3 and recalculate until Z k0' The vertical coordinate change is no more than 0.001m.

[0089] Step 6: Determine the change in the vertical coordinates of other nodes of the lower chord. If the accuracy requirements are met, the form-finding analysis of the inner cable truss structure is completed. Otherwise, adjust β1 and update F i and F i ', return to step 3 and recalculate.

[0090] Step 7: Calculate the prestressing of the chords, vertical rods and suspenders on the external cable truss structure according to H k0 , T j and F ki Calculate the prestressing force T of the upper chord ki , vertical rod prestressing V k0 and cable prestressing V k(i-1) .

[0091] Step 8: Calculate the prestress of the lower chord, the horizontal angle of the lower chord and the vertical coordinates of the support nodes of the external cable truss structure. k0 , B j , β k1 , V ki and F ki 'Calculate the prestressing force H of the lower chordk0 ', horizontal angle of lower chord β ki and lower chord prestressing B ki , calculate the vertical coordinate Z of the support node kj .

[0092] Step 9: Determine Z kj If the change value of the initial coordinates is satisfied, proceed to the next step; otherwise, adjust β k1 , and update F ki and F ki ', return to step 7 and recalculate until Z kj The vertical coordinate change is no more than 0.001m.

[0093] Step 10: Determine the change in the vertical coordinates of other nodes of the lower chord. If the accuracy requirements are met, the form-finding analysis of the external cable truss structure is completed. Otherwise, adjust β k1 , and update F i and F i ', return to step 7 and recalculate.

[0094] Example

[0095] The form-finding method and process are described by taking a circular plane hybrid cable truss structure as an example. The hybrid cable truss is divided into 36 equal parts along the circumferential direction, with a span of 200m, an inner ring diameter of 100m, an inner ring cable prestress H0 of 10000kN, and an upper ring cable prestress H1 of 17300kN. The geometric dimensions of the hybrid cable truss structure are as follows: Figure 6 shown.

[0096] The form-finding analysis process is as follows:

[0097] Step 1. Split the hybrid cable truss structure into an inner cable truss structure and an outer cable truss structure. Without considering the deadweight of the structure, calculate the initial prestress distribution of the inner and outer cable truss structures according to H0 and H1. The calculation results are shown in the third and fourth columns of Table 1.

[0098] Step 2. Select the cross-section of cables and rods according to the initial prestress distribution of the cable truss. Calculate the equivalent nodal loads F1~F5 and F2'~F5' of the cable and rod self-weight.

[0099] Step 3: Calculate the upper chord prestress T1, T2 and T3 and the sling prestress V2 and V3 according to H0, β1, F1, F2 and F3. The calculation results are shown in the fifth column of Table 1.

[0100] Step 4. Calculate the lower chord prestress B1, B2 and B3, the lower chord horizontal angles β2 and β3 according to H0, β1, V2, V3, F2' and F3'. The calculation results are shown in the fifth column of Table 1. Calculate the vertical displacement Z of the lower chord node 4' .

[0101] Step 5. Z 4' Compared with the initial coordinates, the change value does not meet the accuracy requirement. Adjust β1 to 0.98148α1, and update the equivalent node loads F1~F3 and F2'~F3' of the cable rod deadweight. At this time, Z 4' The vertical coordinate differs from the initial value by no more than 0.001m, meeting the accuracy requirements.

[0102] Step 6. The change values ​​of the vertical coordinates of other nodes of the lower chord of the inner cable truss structure all meet the accuracy requirements. The calculation results are shown in the third column of Table 2.

[0103] Step 7. Calculate the upper chord prestress T4 and T5, the vertical rod prestress V4 and the suspender cable prestress V5 based on H1, T3, F4 and F5. The calculation results are shown in the sixth column of Table 1.

[0104] Step 8. Calculate the lower hoop cable prestress H1', ​​the lower chord cable prestress B4 and B5, and the horizontal angle β6 of the lower chord cable based on V4, V5, B3, β5, F4' and F5'. The calculation results are shown in the sixth column of Table 1. Calculate the vertical displacement Z6 of support node 6.

[0105] Step 9. Compare Z6 with the initial coordinates, and its change value does not meet the accuracy requirements. Adjust β5 to 0.98549α5, and update the equivalent node loads F4~F5 and F4'~F5' of the cable rod deadweight. At this time, the vertical coordinate of Z6 differs from the initial value by no more than 0.001m, which meets the accuracy requirements.

[0106] Step 10. The change values ​​of the vertical coordinates of other nodes of the lower chord of the external cable truss structure all meet the accuracy requirements. The calculation results are shown in the fourth column of Table 2.

[0107] Table 1 Prestress calculation results

[0108]

[0109]

[0110] Table 2 Calculation results of vertical coordinates of lower chord

[0111]

[0112] Finite element software is used to verify the initial prestress calculation results. Figure 7 It is the vertical displacement of the hybrid cable truss structure in the equilibrium state under the action of its own weight and prestress. It can be seen from the results that the deviation between its vertical displacement and the initial state is very small, which shows that the cable truss structure maintains balance under the combined action of its own weight and prestress, and proves that the form-finding method and process proposed in the present invention have very high calculation accuracy.

[0113] Some embodiments of the present application also provide a form-finding system for a circular-plane hybrid cable truss structure, the system comprising a memory for storing computer program instructions and a processor for executing the program instructions, wherein when the computer program instructions are executed by the processor, the system is triggered to execute the aforementioned form-finding method for the circular-plane hybrid cable truss structure.

[0114] In summary, the form-finding method and system provided by the present application based on a circular plane hybrid cable truss structure has a simple calculation formula, and can complete the form-finding calculation using calculation tables such as Excel without the need for professional software, which is convenient for engineering designers and researchers to use for modeling and subsequent mechanical performance analysis. The calculation results of this method and process are correct and the calculation accuracy is very high after verification by professional software.

[0115] It should be noted that the present application can be implemented in software and / or a combination of software and hardware, for example, can be implemented using an application specific integrated circuit (ASIC), a general purpose computer or any other similar hardware device. In one embodiment, the software program of the present application can be executed by a processor to implement the steps or functions described above. Similarly, the software program of the present application (including relevant data structures) can be stored in a computer-readable recording medium, for example, a RAM memory, a magnetic or optical drive or a floppy disk and similar devices. In addition, some steps or functions of the present application can be implemented using hardware, for example, as a circuit that cooperates with a processor to perform each step or function.

[0116] In a typical configuration of the present application, the terminal and the network device each include one or more processors (CPU), input / output interface, network interface and memory.

[0117] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0118] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include non-transitory media such as modulated data signals and carrier waves.

[0119] In addition, a part of the present application may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present application through the operation of the computer. The program instruction for calling the method of the present application may be stored in a fixed or removable recording medium, and / or transmitted through a data stream in a broadcast or other signal-bearing medium, and / or stored in a working memory of a computer device that runs according to the program instruction. Here, according to an embodiment of the present application, a device is included, the device including a memory for storing computer program instructions and a processor for executing program instructions, wherein, when the computer program instruction is executed by the processor, the device is triggered to run the method and / or technical solution based on the aforementioned multiple embodiments according to the present application.

[0120] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or basic features of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present application is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present application. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in the device claim can also be implemented by one unit or device through software or hardware.

Claims

1. A form-finding method for a circular-plane hybrid cable truss structure, characterized in that: The following steps are involved: Step 1: Split the hybrid cable truss structure into an inner cable truss structure and an outer cable truss structure; without considering the self-weight of the structure, according to the initial conditions, the prestress H0 of the inner ring cable and the prestress H0 of the upper ring cable k0 Calculating the prestress distribution of the initial shapes of the inner and outer cable truss structures; Step 2: Select appropriate cross-sections for cables and rods according to the prestress distribution of the initial shape, distribute the weight of cables and rods evenly to the nodes at both ends of the rods, and calculate the equivalent node load F of the cable and rod self-weight i and F i '; Step 3: Calculate the prestressing force T of the chord in the inner cable truss structure i and cable prestressing V i ; Step 4: Calculate the prestressing force B of the lower chord of the inner cable truss structure i and the angle β between the lower chord and the horizontal plane i , and calculate the vertical coordinate Z of the lower ring cable node k0' k0' ; Step 5: Determine Z k0' If the change value is not greater than 0.001 m, proceed to the next step; otherwise, adjust β1 and update F i and F i ', return to step 3 and recalculate until Z k0' The vertical coordinate change value is no more than 0.001 meters; Step 6: Determine the change value of the vertical coordinates of other nodes of the lower chord. If the accuracy requirement is met, the form-finding analysis of the inner cable truss structure is completed. Otherwise, adjust the angle β1 between the lower chord and the horizontal plane under the initial condition, and update F i and F i ', return to step 3 and recalculate; Step 7: Calculate the prestressing force T of the chord on the outer cable truss structure ki , vertical rod prestressing V k0 and cable prestressing V k(i-1) ; Step 8: Calculate the prestressing force H of the outer cable truss structure k0 ', horizontal angle of lower chord β ki and lower chord prestressing B ki , and calculate the vertical coordinate Z of the support node kj ; Step 9: Determine Z kj If the change value is not greater than 0.001 m, proceed to the next step; otherwise, adjust β k1 , and update F ki and F ki ', return to step 7 and recalculate until Z kj The vertical coordinate change value is no more than 0.001 meters; Step 10: Determine the change value of the vertical coordinates of other nodes of the lower chord. If the accuracy requirement is met, the form-finding analysis of the outer cable truss structure is completed. Otherwise, adjust β k1 , and update F i and F i ', return to step 7 and recalculate.

2. The method according to claim 1, characterized in that In step 3, the upper chord cable T of the inner cable truss structure is calculated. i and cable prestressing V i , and its calculation formula is as follows: When i=1: When i ≥ 2: In the formula, α i and β1 are known quantities.

3. The method according to claim 2, characterized in that In step 4, the prestressing force B of the lower chord of the inner cable truss structure is calculated. i The horizontal angle β with the lower chord i , and calculate the vertical coordinate Z of the lower ring cable node k0' k0′ , and its calculation formula is as follows: When i=1: When i ≥ 2: Where Z1 is the vertical coordinate of node 1, Δl i is the horizontal distance between the nodes i and i+1 of the lower chord; when j = k0', the calculation result is Z k0’ The vertical coordinate value of .

4. The method according to claim 3, characterized in that: The change value ΔZ of the vertical coordinates of other nodes of the lower chord in step 6 i’ Gradually converge to a small value, expressed as: ΔZ i′ =Z i′,n -Z i′，n-1 ≤1×10 -3 m In the formula, Z i′，n The vertical coordinate of node i' calculated in the nth iteration.

5. The method according to claim 1, characterized in that In step 7, the prestressing force T of the chord cable on the external cable truss structure is calculated. ki , vertical rod prestressing V k0 and cable prestressing V k(i-1) , and its calculation formula is as follows: V k0 =-T j sina j -T k1 sinα k1 -F k0 T ki =T k(i-1) what is it k(i-1) / What ki V k(i-1) =T k(i-1) sinα k(i-1) -T ki sina ki -F k(i-1) In the formula, α ki is a known quantity; in addition, β k1 、T j And the prestressing force H of the upper ring cable k0 Set as initial condition.

6. The method according to claim 5, characterized in that In step 8, the prestressing force H of the ring cable under the outer cable truss structure is calculated. k0 ', horizontal angle of lower chord β ki and lower chord prestressing B ki , and calculate the vertical coordinate Z of the support node kj kj , and its calculation formula is as follows: In the formula, B j Set as initial condition; Δl ki is the horizontal distance between the lower chord nodes k(i-1)' and ki'.

7. The method according to claim 6, characterized in that The change value △Z of the vertical coordinates of other nodes of the lower chord in step 10 ki’ Gradually converge to a small value, expressed as: ΔZ ki′ =Z ki′,n -Z ki′,n-1 ≤1×10 -3 m In the formula, Z ki',n The vertical coordinate of node ki' calculated in the nth iteration.

8. A form-finding system for a circular-planar hybrid cable-truss structure, the system comprising a memory for storing computer program instructions and a processor for executing the program instructions, wherein: When the computer program instructions are executed by the processor, the system is triggered to execute the method according to any one of claims 1 to 7.

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