Cable force identification method for truss string structures based on spatial morphology and dynamic characteristics

Abstract

The present disclosure relates to a method for identifying cable forces in a chord-truss structure based on spatial form and dynamic characteristics. The method includes determining a first dynamic characteristic for the chord-truss structure, the first dynamic characteristic corresponding to the actual dynamic characteristic of the corresponding cable in the chord-truss structure; determining a second spatial form for the chord-truss structure based on the first spatial form of the corresponding cable in the chord-truss structure; obtaining a model for the chord-truss structure based on the second spatial form; determining a second dynamic characteristic corresponding to the chord-truss structure using the model; and identifying the cable force for the corresponding cable based on the first dynamic characteristic and the second dynamic characteristic. In this way, the measurement error can be significantly reduced and the accuracy of cable force measurement can be improved. The present disclosure uses fewer parameters and can achieve accurate cable stress with minimal error through less calculation, and has strong operability.

Description

Technical Field

[0001] The present disclosure generally relates to the field of building technology, and in particular to a cable force identification method for a truss string structure based on spatial form and dynamic characteristics. Background Art

[0002] As a new structural form, truss-string structures have been increasingly widely used in practical engineering applications in recent years. Cables are a crucial component of truss-string structures. Monitoring cable tension is crucial for ensuring that prestressing meets design targets during construction and that the structure remains safe during operation. Changes in cable tension not only affect the overall shape of the structure but also its internal forces. Cable failure can lead to a significant degradation of structural stiffness, potentially causing the entire structure to fail.

[0003] Current techniques for measuring cable tension can use vibration and strain methods. However, these methods often suffer from large measurement errors (e.g., 5% or even higher), resulting in inaccurate cable tension measurements and limited identification accuracy. Furthermore, these measurements are typically static measurements of truss-string structures and are unable to dynamically monitor changes during construction and use. Therefore, a method for identifying cable tension in truss-string structures is needed that can at least partially address these issues. Summary of the Invention

[0004] The purpose of the present disclosure is to provide a cable force identification method for a truss string structure based on spatial morphology and dynamic characteristics, so as to at least partially solve the above-mentioned problems existing in the prior art.

[0005] According to a first aspect of the present disclosure, a method for identifying cable forces in a truss-chord structure based on spatial form and dynamic characteristics is provided. The method comprises: determining a first dynamic characteristic for the truss-chord structure, the first dynamic characteristic corresponding to the actual dynamic characteristic of a corresponding cable in the truss-chord structure; determining a second spatial form for the truss-chord structure based on the first spatial form of the corresponding cable in the truss-chord structure; obtaining a model for the truss-chord structure based on the second spatial form; determining a second dynamic characteristic corresponding to the truss-chord structure using the model; and identifying the cable forces in the corresponding cables based on the first and second dynamic characteristics.

[0006] In some embodiments, identifying the cable force for the corresponding cable based on the first dynamic characteristic and the second dynamic characteristic may include: fitting the first dynamic characteristic and the second dynamic characteristic; and determining the cable force for the corresponding cable based on a result of the fitting.

[0007] In some embodiments, fitting the first dynamic characteristic and the second dynamic characteristic may include: performing a best square approximation calculation on the first dynamic characteristic and the second dynamic characteristic to obtain a best square approximation error for the first dynamic characteristic and for the second dynamic characteristic; and obtaining a cable force for the corresponding cable in response to determining the minimum value of the best square approximation error.

[0008] In some embodiments, performing a best square approximation calculation on the first dynamic characteristic and the second dynamic characteristic to obtain a best square approximation error for the first dynamic characteristic and the second dynamic characteristic may include: the second dynamic characteristic is f(x) and the first dynamic characteristic is f′(x), setting δ(x)=f(x)-f′(x), then the best square approximation error is:

[0009]

[0010] in, is a subset of the entire interval of the string truss structure.

[0011] In some embodiments, the minimum value is determined based on: f(x) is a subset of the overall interval, and the nth-order best square approximation polynomial is found in H.

[0012] at this time and

[0013] Represent G using matrix H n =G(1,x,···x n ) corresponds to the matrix, then

[0014]

[0015] but

[0016] Let Ha = d k ,a=(a0,a1,…a n ) T , Solution is the optimal square approximation polynomial; and

[0017] Sure to obtain the cable force for the corresponding cable;

[0018] Among them, k and j represent any item between the 1st and nth items, d k express and f, a is the best square approximation polynomial coefficient, G is (1, x, ···x n ) generates the matrix, where H is the Hilbert matrix.

[0019] In some embodiments, the first spatial form can be obtained via laser scanning.

[0020] In some embodiments, identifying the cable force of the corresponding cable may include: identifying the cable force of the corresponding cable during at least one of a construction process and a use process.

[0021] In some embodiments, obtaining a model for the truss chord structure based on the second spatial form may include: obtaining the model for the truss chord structure via finite element software.

[0022] In some embodiments, the first spatial form may be variable at different stages during the construction process; and / or the first spatial form may be variable at different stages during the use process.

[0023] In some embodiments, determining the first dynamic characteristic of the truss-chord structure may include: measuring the dynamic characteristics of a chord-supported structure strut of the truss-chord structure to obtain the first dynamic characteristic of the truss-chord structure.

[0024] The various embodiments of the present disclosure can achieve at least the following beneficial effects:

[0025] (1) Through the cable force identification method disclosed in the present invention, the error rate can be lower than 1%, which significantly reduces the measurement error, improves the accuracy of cable force identification, and better serves engineering practice.

[0026] (2) The cable tension identification method disclosed in the present invention can not only statically monitor the use process of the truss string structure, but also dynamically monitor the cable tension conditions of the truss string structure during the construction process and use process, and can ensure that the prestressing force in the construction stage reaches the design target and the structural safety in the use stage.

[0027] (3) Provide a specific application of the best square approximation method in the field of cable tension measurement technology for truss string structures, which greatly improves the accuracy of cable tension measurement.

[0028] (4) The best square approximation calculation method adopted in the present disclosure has a small number of functions and parameters, so that accurate cable stress can be obtained with minimal error through less calculation, and the operability is strong.

[0029] It should be understood that the contents described in the Summary of the Invention section are not intended to limit the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other objects, features and advantages of the embodiments of the present disclosure will become readily understood by reading the following detailed description with reference to the accompanying drawings, in which several embodiments of the present disclosure are shown by way of example and not limitation, in which:

[0031] Figure 1 is a schematic diagram illustrating a truss string structure according to some embodiments of the present disclosure;

[0032] Figure 2 1 is a schematic flow chart showing a cable force testing method according to an embodiment of the present disclosure.

[0033] In the various drawings, the same or corresponding reference numerals denote the same or corresponding parts. DETAILED DESCRIPTION

[0034] The following describes embodiments of the present disclosure in more detail with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for illustrative purposes only and are not intended to limit the scope of protection of the present disclosure.

[0035] In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to." The term "based on" should be understood as "based at least in part on." The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment." The terms "first," "second," etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0036] The present disclosure can scan the spatial form of the structure, model and calculate the structural dynamic characteristics, measure the structural dynamic characteristics, and fit the two dynamic characteristics. The cable force corresponding to the minimum error is the cable force. In a specific embodiment of the present disclosure, during the construction and use of the cables, the spatial form of the cables in the truss-string structure can be first scanned with a laser to determine the spatial form of the truss-string structure during construction and use, and the spatial form analysis can be performed. The truss-string structure can then be modeled using finite element software, and the dynamic characteristics of the truss-string structure can be analyzed. The actual dynamic characteristics of the truss-string structure can then be measured, and the calculated and measured dynamic characteristics can be fit together to calculate the cable forces based on the fitting results.

[0037] The following will be combined with the Figure 1 To the attached Figure 2 The embodiments of the present disclosure are described in detail.

[0038] Figure 1 Schematic diagram showing a truss string structure according to some embodiments of the present disclosure. Figure 1 As shown, the truss-string structure is a long-span prestressed spatial structural system. Its structural system consists of rigid components with high bending stiffness and high-strength cables. Its low weight allows it to span large spaces. As a semi-rigid structure, the overall stiffness of the truss-string structure is determined by both the cross-sectional dimensions of the rigid components and the spatial geometry of the structural system. The overall stiffness and geometry are closely related to the construction process. The stiffness of the structural system is relatively weak before it is formed. Therefore, a rational construction plan for the truss-string structure and strict control of the construction process are essential.

[0039] Unlike rigid components, cables in string-and-string structures are highly stressed and can only withstand tension, not compression. Generally, the connections between the struts, the upper chord, and the cables are hinged. If any section of the cable fails, the strain energy is rapidly released, causing the entire cable to fail completely. This failure, in turn, causes all struts to rotate and fail. Therefore, cable construction and cable force monitoring are key aspects of string-and-string truss structures. Cable force must ensure that the prestressing meets the design target during construction and that the structure remains safe throughout operation.

[0040] Figure 2 This is a schematic flow chart showing a method for testing cable force according to an embodiment of the present disclosure. Figure 2 Exemplary embodiments according to the present disclosure are introduced.

[0041] In some embodiments, in order to identify the cable tension of the truss string structure, a first dynamic characteristic of the truss string structure may be determined, where the first dynamic characteristic corresponds to the actual dynamic characteristic of the corresponding cable in the truss string structure. This step may correspond to Figure 2In block 101, the first dynamic characteristic may correspond to a measured dynamic characteristic. In some embodiments, specifically, the dynamic characteristics of the chord-supported struts of the chord-truss structure may be measured to obtain the first dynamic characteristic specific to the chord-truss structure. It should be understood that any suitable method in the art may be used to measure the first dynamic characteristic, and this disclosure is not limited thereto.

[0042] It should be noted that the structural dynamic characteristics are inherent characteristics of the structure, including natural frequency (natural vibration period), damping, and mode shape, which are only related to the mass, stiffness and material of the structure. Mode shape refers to the basic form of structural vibration. Generally, there are several modes for each number of layers of the structure, which corresponds to several periods. Usually, the first mode shape is dominant, and the other high modes decay quickly. For example, the commonly used base shear method is calculated based on the first mode shape. Damping usually refers to the damping ratio, which refers to the ratio of the structural vibration damping coefficient to the critical damping coefficient, and is also inherent in the structure itself.

[0043] In some embodiments, a second spatial form of the truss-chord structure is determined based on the first spatial form of the corresponding cable in the truss-chord structure. This step may correspond to Figure 2 Specifically, laser scanning can be used to obtain the first spatial form of the corresponding cable and the second spatial form for the string-truss structure, or the first spatial form of the corresponding cable can be obtained by laser scanning, and then the second spatial form can be obtained based on the first spatial form.

[0044] Subsequently, a model for the truss string structure can be obtained based on the second spatial form, and the second dynamic characteristics corresponding to the truss string structure can be determined using the model. The second dynamic characteristics are simulated dynamic characteristics obtained using the model. This step can correspond to Figure 2 In block 105, in some embodiments, for example, a model for the truss string structure may be obtained via finite element software.

[0045] Furthermore, the cable force for the corresponding cable can be identified based on the first dynamic characteristic and the second dynamic characteristic. Figure 2 In boxes 107 and 109, the first dynamic characteristic and the second dynamic characteristic can be fitted, that is, the measured dynamic characteristic of the structure and the simulated dynamic characteristic can be fitted, and at box 109, the first dynamic characteristic and the second dynamic characteristic can be subjected to best square approximation calculation to obtain the best square approximation errors for the first dynamic characteristic and the second dynamic characteristic, and in response to determining the minimum value of the best square approximation error, the cable force for the corresponding cable is obtained.

[0046] In some embodiments, the cable tension measured for the corresponding cable can be either the cable tension during construction or the cable tension during use. In fact, the disclosed method can dynamically detect either or both of the cable tension during construction and use, depending on project requirements. This allows for not only static monitoring of the truss-string structure during use, but also dynamic monitoring of the cable tension during construction and use, ensuring that prestressing during construction meets design goals and that the structure is safe during use.

[0047] In one embodiment, the best squared approximation error for the first and second dynamic characteristics can be obtained using the following specific calculation method. This calculation method uses a small number of functions and parameters, resulting in accurate cable stress determination with minimal error, while requiring minimal computational effort. Furthermore, experimental verification has shown that this cable force identification method can achieve an error rate below 1%, significantly reducing measurement error and improving cable force identification accuracy.

[0048] In this embodiment, the second dynamic characteristic may be f(x) and the first dynamic characteristic may be f′(x). Let δ(x)=f(x)-f′(x), then the error of the best square approximation is:

[0049]

[0050] in, It can be a subset of the entire interval of the string-truss structure.

[0051] In this embodiment, the minimum value can be determined based on the following method: f(x) is a subset of the overall interval, and the nth-order best square approximation polynomial is found in H.

[0052] at this time and

[0053] Represent G using matrix H n =G(1,x,···x n ) corresponds to the matrix, then

[0054]

[0055] but

[0056] Let Ha = d k ,a=(a0,a1,…a n ) T , Solution That is the optimal square approximation polynomial.

[0057] Furthermore, it can be determined to obtain the cable force for the corresponding cable;

[0058] In the above equation, k and j represent any item between the 1st and nth items, and d k express and f, a is the best square approximation polynomial coefficient, G is (1, x, ···x n ) generates the matrix, where H is the Hilbert matrix.

[0059] It can be seen that in a preferred embodiment, the cable force identification method of a truss string structure based on spatial morphology and dynamic characteristics can be implemented in the following manner: during the construction and use of the cables of the truss string structure, the spatial morphology of the cables in the truss string structure is first scanned with a laser to determine the spatial morphology of the truss string structure during construction and use, and the spatial morphology is analyzed. Then, the truss string structure is modeled using finite element software, and the dynamic characteristics of the truss string structure are analyzed. Then, the actual dynamic characteristics of the truss string structure are measured, the calculated and measured dynamic characteristics are fitted, and the cable force is calculated based on the fitting results. In such an embodiment, the error rate of the cable force identification method can be lower than 1%, which significantly reduces the measurement error, improves the accuracy of cable force identification, and better serves engineering practice; the cable force identification method can not only statically monitor the use process of the chord truss structure, but also dynamically monitor the cable force conditions of the chord truss structure during the construction process and use process, and can ensure that the prestressing in the construction stage reaches the design target and the structure is safe in the use stage; the method provides a specific application of the best square approximation method in the field of chord truss cable force measurement technology, which greatly improves the cable force measurement accuracy and fills the technical gap in this field; the method disclosed in the present invention adopts the best square approximation calculation method with a small number of functions and parameters, so that with a small amount of calculation, it is possible to obtain accurate cable stress with extremely small errors, and has strong operability.

[0060] It should be noted that the methods of the above equations provide specific best square approximation error calculation methods and achieve specific technical effects, which are preferred methods of the present disclosure, but are not specific limitations of the present disclosure. It should be understood that those skilled in the art, inspired by the present disclosure, may also adopt any other suitable best square approximation method to determine the cable forces of a string-truss structure based on its spatial morphology and dynamic characteristics.

[0061] Although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this disclosure. Certain features described in the context of separate embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable subcombination.

[0062] In addition, although adopting specific order to describe each operation, this should be understood as requiring such operation to be carried out in the specific order shown or in sequential order, or requiring that all illustrated operations should be carried out to obtain desired results. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although comprising some specific implementation details in the above discussion, these should not be interpreted as limiting the scope of the present disclosure. Some features described in the context of separate embodiment can also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation also can be implemented in a plurality of implementations individually or in the mode of any suitable subcombination.

[0063] While various embodiments of the present disclosure have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A cable force identification method for a truss string structure based on spatial morphology and dynamic characteristics, characterized in that: include: determining a first dynamic characteristic for the truss-chord structure, the first dynamic characteristic corresponding to an actual dynamic characteristic of a corresponding cable in the truss-chord structure; determining a second spatial form for the truss-chord structure based on the first spatial form of the corresponding cable in the truss-chord structure; Based on the second spatial form, a model for the truss string structure is obtained; Determining a second dynamic characteristic corresponding to the truss string structure using the model; as well as Identifying a cable force for the corresponding cable based on the first dynamic characteristic and the second dynamic characteristic includes: The first dynamic characteristic and the second dynamic characteristic are subjected to a best square approximation calculation to obtain best square approximation errors for the first dynamic characteristic and the second dynamic characteristic, and in response to determining a minimum value of the best square approximation error, a cable force for the corresponding cable is obtained; wherein, The best squared approximation error is obtained as follows: The second dynamic characteristic is f(x) and the first dynamic characteristic is f′(x). Let δ(x)=f(x)-f′(x). Then the error of the best square approximation is: in, is a subset of the dynamic characteristic interval of the truss string structure; and wherein, The minimum value is obtained as follows: Pick f(x) is a subset of the overall interval, and the nth-order best square approximation polynomial is found in H. at this time and Represent G using matrix H n =G(1,x,···x n ) corresponds to the matrix, then but Let Ha = d k ,a=(a0,a1,…a n ) T , Solution is the optimal square approximation polynomial; and Sure to obtain the cable force for the corresponding cable; Among them, k and j represent any item between the 1st and nth items, d k express and f, a is the best square approximation polynomial coefficient, G is (1, x, ···x n ) generates the matrix, where H is the Hilbert matrix.

2. The method according to claim 1, characterized in that The first spatial form is obtained through laser scanning.

3. The method according to claim 1, characterized in that Identifying the cable forces for the respective cables includes: The cable force of at least one of the cable during construction and during use is identified.

4. The method according to claim 1, wherein Based on the second spatial form, a model for the truss string structure is obtained, including: The model of the truss string structure is obtained through finite element software.

5. The method according to claim 1, wherein The first spatial form changes at different stages of the construction process; and / or The first spatial form changes at different stages during use.

6. The method according to claim 1, wherein Determining a first dynamic characteristic of the truss string structure includes: The dynamic characteristics of the chord-supported structure struts of the chord-truss structure are measured to obtain first dynamic characteristics of the chord-truss structure.

Images