A shaking table test model design method and system

Abstract

The application discloses a shaking table test model design method and system, and belongs to the model design field.The method comprises the following steps: setting a scale ratio;reducing the original prestressed concrete-filled steel tube truss tower structure according to the scale ratio to obtain an initial model;constructing an ideal material test model of the original prestressed concrete-filled steel tube truss tower structure based on the initial model, and determining the target dynamic characteristic parameters of the ideal material test model; and matching the initial model with the target dynamic characteristic parameters in the stiffness and mass in a hierarchical equivalent and decoupling control mode to obtain a physical model.The low-order natural frequency and the corresponding vibration mode of the structure are taken as the core control indexes of the shaking table model design, the model design is avoided to be performed only according to the geometric scale or the local component parameters, the test model is consistent with the prototype structure at the low-order dynamic response level, and the engineering representativeness and the interpretation reliability of the test results are significantly improved.

Description

Technical Field

[0001] This application belongs to the field of model design, and specifically relates to a method and system for designing shaking table test models. Background Technology

[0002] With the increasing size of wind power equipment, onshore wind turbine towers are gradually evolving from traditional pure steel towers to new flexible tower structures. Prestressed concrete-tube truss towers, as a novel tall structural system, combine the high load-bearing capacity of concrete-tube steel structures, the efficient force transmission path of truss systems, and the advantages of prestressing in actively controlling structural stiffness. They are increasingly being applied to onshore wind turbine towers and large-scale engineering structures. Under seismic loading, the dynamic response of this type of structure exhibits a significant low-order mode dominance, with its overall dynamic behavior primarily controlled by the first few bending modes.

[0003] Shaking table testing, as an important physical simulation method for studying the dynamic characteristics and failure mechanisms of structures under seismic loading, plays an irreplaceable role in the seismic performance evaluation of such structures. However, due to limitations in the size, load-bearing capacity, and material processing conditions of shaking table equipment, prototype structures usually cannot be directly tested and must be simulated using scaled-down models.

[0004] Currently, the shaking table scaled-down model design method, for traditional single-column towers or homogeneous material structures, mostly adopts the principles of geometric and mass similarity, and derives residual similarity relationships to establish experimental models. However, for complex structures such as prestressed concrete-tube truss towers, which involve multiple materials, multiple member types, significant node eccentricity, and prestressing participating in the overall stress distribution, relying solely on traditional similarity theories or numerical calculations is insufficient to ensure that the scaled-down model remains consistent with the prototype structure at the low-order modal levels.

[0005] On the one hand, the combined stiffness formed by the synergistic action of steel-concrete composite and prestressed tendons is difficult to accurately simulate in scaled-down models; truss structures have diverse member types such as chords, web members, and diagonal members, and the contribution of each member to the overall stiffness varies significantly, making standardized scaling difficult; if steel-concrete composite is directly used in the model, it often faces problems such as complex processing technology and exceeding mass limits. On the other hand, existing technologies rarely use low-order natural frequencies as core control indicators for shaking table model design, and there is a lack of systematic methods for verifying and correcting dynamic characteristics through physical tests after the model is completed.

[0006] To address the aforementioned issues, this application provides a method and system for designing shaking table test models. Summary of the Invention

[0007] To address the above problems, this application provides a method for designing a shaking table test model, the method comprising: Set the scaling ratio; The prototype prestressed steel tube concrete truss tower structure was scaled down according to the scaling ratio to obtain the initial model; An ideal material test model for a prototype prestressed steel-concrete composite truss tower structure is constructed based on the initial model, and the target dynamic characteristic parameters of the ideal material test model are determined. The target dynamic characteristic parameters include the target low-order natural frequencies and the target equivalent total mass. By using hierarchical equivalence and decoupling control, the initial model is matched with the target dynamic characteristic parameters in terms of stiffness and mass, thus obtaining a solid model; Low-amplitude dynamic tests were conducted on the physical model to identify the low-order natural frequencies and compare them with the target low-order natural frequencies. The parameters of the entity model are corrected based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements.

[0008] According to some embodiments of this disclosure, the setting of the scaling ratio includes: The scaling ratio was set based on the geometric parameters and shaking table bearing capacity of the prototype prestressed steel tube concrete truss tower structure.

[0009] According to some embodiments of this disclosure, the expression for the scaling ratio is determined as follows:

[0010] in, Indicates the scaling ratio; Indicates the initial model feature size; This indicates the characteristic dimensions of the prototype prestressed steel tube concrete truss tower structure.

[0011] According to some embodiments of this disclosure, the ideal material test model is as follows: An ideal material test model is constructed based on the principles of axial stiffness similarity, mass similarity, and prestress equivalence. The prestress equivalence principle refers to equating the prestress effect in the prototype prestressed steel tube concrete truss tower structure with the axial stiffness parameter of the component.

[0012] According to some embodiments of this disclosure, the initial model is matched with the target dynamic characteristic parameters in terms of stiffness and mass through a hierarchical equivalent and decoupling control method, including: The composite material components of the prototype prestressed steel tube concrete truss tower structure are replaced by single homogeneous material components, and different stiffness equivalents are used in the design based on the differences in the contribution of different types of members to the overall low-order dynamic characteristics. After the stiffness design is completed, additional counterweights that do not participate in the structural stress are configured to make the overall mass of the initial model reach the target equivalent total mass, thus achieving mass matching.

[0013] According to some embodiments of this disclosure, different stiffness equivalences are used in the design based on the differences in the contribution of different types of rods to the overall low-order dynamic characteristics, including: Based on the target low-order natural frequencies and low-order mode shapes, the truss members are divided into main columns, horizontal trusses, and web members.

[0014] According to some embodiments of this disclosure, the main column, which serves as the primary bending member, is subjected to an equivalent design primarily based on bending stiffness. For the horizontal truss that provides axial constraint, perform an equivalent design for overall axial stiffness; For the web member, a cross section that meets the structural and stability requirements is selected, and no fine stiffness equivalence is performed for the low-order modes.

[0015] According to some embodiments of this disclosure, low-amplitude dynamic tests are conducted on a physical model to identify low-order natural frequencies, including: White noise excitation, frequency sweep excitation, or pulse excitation are applied to the solid model, vibration response is collected, and low-order natural frequencies of the solid model are obtained through modal parameter identification.

[0016] According to some embodiments of this disclosure, the parameters of the solid model are corrected based on the comparison results until the low-order natural frequencies of the solid model meet preset similarity requirements, including: When the deviation between the measured frequency and the target frequency exceeds the allowable range, the parameters of the entity model are corrected. After correction, the measured identification and comparison steps are repeated until the low-order natural frequencies of the entity model meet the preset similarity requirements.

[0017] This application also provides a shaking table test model design system, the system comprising: The settings module is used to set the scaling ratio; The scaling-down module is used to scale down the prototype prestressed steel tube concrete truss tower structure according to the scaling ratio to obtain the initial model; The parameter determination module is used to construct an ideal material test model of the prototype prestressed steel tube concrete truss tower structure based on the initial model, and to determine the target dynamic characteristic parameters of the ideal material test model; wherein, the target dynamic characteristic parameters include the target low-order natural frequencies and the target equivalent total mass; The solid model module is used to match the stiffness and mass of the initial model with the target dynamic characteristic parameters in a hierarchical equivalent and decoupled control manner, so as to obtain a solid model. The comparison module is used to conduct low-amplitude dynamic tests on the physical model, identify the low-order natural frequencies by measurement, and compare them with the target low-order natural frequencies. The correction module is used to correct the parameters of the entity model based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements.

[0018] Compared with the prior art, this application has the following advantages: (1) This application takes the low-order natural frequencies and corresponding mode shapes of the structure as the core control indicators for the design of the shaking table model, avoiding model design based solely on geometric scaling or local component parameters, so that the test model is consistent with the prototype structure at the low-order dynamic response level, significantly improving the engineering representativeness and interpretability of the test results.

[0019] (2) This application equates the prestressing effect in the prototype structure to the overall stiffness of the structure or the equivalent stiffness parameter of the component, rather than directly applying prestress in the scaled-down model. This avoids the problems of difficult prestressing construction, low control accuracy and poor repeatability under scaled-down conditions, making the processing, assembly and debugging process of the shaking table test model simpler and more reliable, and significantly improving the feasibility and stability of model manufacturing.

[0020] (3) This application introduces a pre-test modal inspection and parameter correction step. By measuring and comparing the natural frequency and mode shape of the model, the stiffness and mass parameters of the model are corrected in a timely manner. This avoids the problem of dynamic characteristic deviation caused by relying solely on theoretical calculation or one-time design in traditional methods, thereby effectively improving the matching accuracy and reliability between the low-order dynamic characteristics of the test model and the target value.

[0021] (4) This application proposes a systematic ideal model establishment, equivalent member and overall dynamic characteristic control method for each type of member, which is aimed at complex structural systems such as prestressed steel tube concrete truss towers with multiple member types, multiple node connection forms and significant node eccentricity. It can adapt to different structural layout forms and construction characteristics, has good versatility and scalability, and at the same time reduces the model production cost and experimental implementation risk, which is conducive to promotion and application.

[0022] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A diagram illustrating a shaking table test model design method according to an embodiment of this application is shown. Figure 2 A detailed flowchart of the shaking table test model design method according to an embodiment of this application is shown; Figure 3 A schematic diagram of a scaled-down model of a prestressed steel tube concrete truss tower according to an embodiment of this application is shown; Figure 4 A flowchart illustrating the calculation of target dynamic characteristics using an ideal truss model according to an embodiment of this application is shown. Figure 5 A schematic diagram of truss member classification according to an embodiment of this application is shown; Figure 6a A schematic diagram of a prototype prestressed steel-concrete composite column according to an embodiment of this application is shown; Figure 6b A schematic diagram showing the dimensions of the model steel pipe main column according to an embodiment of this application is provided; Figure 7 A system diagram of a shaking table test model design according to an embodiment of this application is shown; In the diagram: 1. Prestressed steel-concrete composite main column; 2. Horizontal truss; 3. Diagonal web member; 4. Top connection and node area; 5. Prototype steel pipe; 6. Prototype concrete; 7. Prototype prestressed cable; 8. Model steel pipe; 9. Outer diameter of model steel pipe; 10. Inner diameter of model steel pipe. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] like Figure 1 As shown, this application provides a method for designing a shaking table test model, the method comprising: Set the scaling ratio; The prototype prestressed steel tube concrete truss tower structure was scaled down according to the scaling ratio to obtain the initial model; An ideal material test model for a prototype prestressed steel-concrete composite truss tower structure is constructed based on the initial model, and the target dynamic characteristic parameters of the ideal material test model are determined. The target dynamic characteristic parameters include the target low-order natural frequencies and the target equivalent total mass. By using hierarchical equivalence and decoupling control, the initial model is matched with the target dynamic characteristic parameters in terms of stiffness and mass, thus obtaining a solid model; Low-amplitude dynamic tests were conducted on the physical model to identify the low-order natural frequencies and compare them with the target low-order natural frequencies. The parameters of the entity model are corrected based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements.

[0027] Specifically, the setting of the scaling ratio includes: The scaling ratio was set based on the geometric parameters and shaking table bearing capacity of the prototype prestressed steel tube concrete truss tower structure.

[0028] Specifically, the expression for determining the scaling ratio is:

[0029] in, Indicates the scaling ratio; Indicates the initial model feature size; This indicates the characteristic dimensions of the prototype prestressed steel tube concrete truss tower structure.

[0030] Specifically, the ideal material test model is as follows: An ideal material test model is constructed based on the principles of axial stiffness similarity, mass similarity, and prestress equivalence. The prestress equivalence principle refers to equating the prestress effect in the prototype prestressed steel tube concrete truss tower structure with the axial stiffness parameter of the component.

[0031] Specifically, by employing a hierarchical equivalent and decoupling control approach, the initial model is matched with the target dynamic characteristic parameters in terms of stiffness and mass, including: The composite material components of the prototype prestressed steel tube concrete truss tower structure are replaced by single homogeneous material components, and different stiffness equivalents are used in the design based on the differences in the contribution of different types of members to the overall low-order dynamic characteristics. After the stiffness design is completed, additional counterweights that do not participate in the structural stress are configured to make the overall mass of the initial model reach the target equivalent total mass, thus achieving mass matching.

[0032] Specifically, based on the different contributions of different types of members to the overall low-order dynamic characteristics, different stiffness equivalences are used in the design, including: Based on the target low-order natural frequencies and low-order mode shapes, the truss members are divided into main columns, horizontal trusses, and web members.

[0033] Specifically, the main column, which serves as the primary bending member, is subjected to an equivalent design primarily based on bending stiffness. For the horizontal truss that provides axial constraint, perform an equivalent design for overall axial stiffness; For the web member, a cross section that meets the structural and stability requirements is selected, and no fine stiffness equivalence is performed for the low-order modes.

[0034] Specifically, low-amplitude dynamic tests are conducted on the physical model to identify low-order natural frequencies, including: White noise excitation, frequency sweep excitation, or pulse excitation are applied to the solid model, vibration response is collected, and low-order natural frequencies of the solid model are obtained through modal parameter identification.

[0035] Specifically, the parameters of the entity model are corrected based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements, including: When the deviation between the measured frequency and the target frequency exceeds the allowable range, the parameters of the entity model are corrected. After correction, the measured identification and comparison steps are repeated until the low-order natural frequencies of the entity model meet the preset similarity requirements.

[0036] The purpose of this application is to provide a novel low-order modal shaking table test model design method for onshore wind power composite material foundation structures. The approach can be extended to other structures, specifically focusing on prestressed steel-concrete composite truss towers. The core of this application lies in: using low-order natural frequencies as the main similarity control index, equating the prestressing effect to structural stiffness, designing parameters through an ideal material truss model, and introducing a closed-loop experimental verification and parameter correction system after model completion. A prototype is designed using a 1:10 geometric scale as an example. Figure 2 As shown, the specific steps of the method are as follows: Step 1: Initial Scale and Identification of Similar Targets Based on the shaking table's bearing capacity and testing requirements, a geometrically scaled-down design was implemented for the prototype prestressed steel-concrete truss tower structure (hereinafter referred to as the "prototype structure"). The model maintains geometric similarity to the prototype structure in terms of overall height, member length, node arrangement, and truss topology. Figure 3 As shown. Here, we take a geometric scaling ratio of 1:10 as an example, that is:

[0037] in, It is a geometric scaling ratio; These are the feature dimensions of the prototype structure; The dimensions represent the structural features of the model.

[0038] Under the same gravitational field conditions, take the acceleration similarity ratio Low-order modal frequency similarity is used as the main dynamic similarity control index.

[0039] Step 2: Construction of Ideal Material Truss Model and Determination of Target Dynamic Characteristics like Figure 4As shown, based on the scaled-down geometric model, an ideal material truss model is constructed. That is, based on geometric scaling and similarity relationships, and assuming that the material is linearly elastic, continuous, and arbitrarily adjustable, it is a theoretical model used only to solve the natural frequency, mode shape, and equivalent stiffness level of the structural target.

[0040] The following similar principles are followed in this step: Axial stiffness similarity: Ensure that the axial stiffness of various bars is scaled according to similarity relationships; Quality similarity: Ensure that the overall quality level and height distribution meet similarity requirements; The prestress equivalence principle: prestress is introduced by equivalently increasing the axial stiffness of the component, that is, the additional stiffness generated by prestress in the prototype structure is included in the equivalent. Instead of applying prestress directly in the model, the prestress is applied in the model.

[0041] Based on the above similarity relationship, the target first and second natural frequencies, the target structural equivalent total mass, and the target equivalent stiffness level of the test model are calculated and determined as the basis for subsequent design and verification.

[0042] Step 3: Equivalent Selection of Processing Materials Within the low-order, small-amplitude dynamic response range of this shaking table test, and given the approximate rigidity of the nodes, the overall dynamic characteristics of the structure are primarily determined by the equivalent axial stiffness, bending stiffness, and mass distribution of the components, rather than by the specific material composition of the components. Therefore, a single material is used for the test, and the principle of the specific dynamic governing equations driving this determination is as follows: 1. The natural frequency is only at and Related The free vibration of any linear structure satisfies:

[0043] in, This is the quality matrix; Here is the stiffness matrix; U is acceleration; u is displacement; The natural frequency is determined by the eigenvalue problem:

[0044] in, This is the quality matrix; Here is the stiffness matrix; It is the angular frequency; For phase.

[0045] 2. Prestressing itself does not change the mass matrix; it only enters the stiffness matrix through geometric stiffness. At the same time, for those containing prestress The structure, linearized dynamic equations:

[0046] in, This is the quality matrix; For acceleration; Here is the material's elastic stiffness matrix; The geometric stiffness matrix (generated by prestress); denoted as prestress; u represents displacement.

[0047] 3. The Rayleigh quotient guarantees a strict equivalent of the natural frequencies of lower-order modes. As the low-order natural frequency corresponds to the minimum solution of the stiffness-to-mass ratio under the overall deformation path of the structure, the Rayleigh quotient is written as:

[0048] in, It is the angular frequency; It is a low-order dominant vibration mode; Here is the stiffness matrix; This is the quality matrix.

[0049] In the prototype structure:

[0050] in, The original angular frequency; K 原型 The stiffness matrix of the prototype; M 原型 The prototype mass matrix; It is a low-order dominant vibration mode; In the equivalent model:

[0051] Equivalent design guarantees:

[0052]

[0053] That must be true:

[0054] That is, as long as the generalized stiffness and generalized mass of the equivalent model are consistent with those of the prototype structure along the dominant deformation path, the Rayleigh quotient will be consistent, thus ensuring strict equivalence of the natural frequencies of the lower-order modes.

[0055] In summary, this experiment focuses on low-order modes. By adjusting the geometric parameters of a single-material component to make it equivalent to the prototype component in terms of key mechanical parameters, an equivalent substitution in dynamic behavior can be achieved.

[0056] The model truss members are all made of pure steel tubes, and steel tube concrete is not used. By adjusting parameters such as the outer diameter, wall thickness and whether the steel tubes are hollow, the axial stiffness is made equivalent to that of the prototype steel tube concrete members; if necessary, the bending stiffness is also made to meet the equivalent requirements by adjusting the cross-sectional parameters.

[0057] Step 4: Equivalent Design of Truss Members by Type Based on the target low-order natural frequencies and target equivalent stiffness levels calculated from the ideal model, the dominant deformation characteristics of the low-order modes are analyzed, various members in the truss structure are classified, and stiffness equivalent design is carried out for each.

[0058] like Figure 5 As shown, this prototype truss tower can be divided into four types of members: prestressed steel tube concrete main column 1, horizontal truss 2, diagonal web member 3, and top connection and node area 4.

[0059] The stiffness equivalence design of each type of member takes the prestressed steel tube concrete main column 1 as the core and prioritizes the realization of its bending stiffness equivalence; the axial stiffness equivalence of each layer of horizontal truss 2 is performed as a whole; the diagonal web members 3 only meet the requirements of axial stiffness and structural stability, and are not finely equivalent.

[0060] like Figure 6a As shown, the central grid area represents the prototype prestressed cable 7; the area with spots on the outside represents the concrete filling part, denoted as the prototype concrete 6; and the outermost annular area is denoted as the prototype steel pipe 5.

[0061] like Figure 6b As shown, the annular area filled with diagonal lines represents the model steel pipe 8, signifying the single homogeneous material used in the model. Based on the method of "hierarchical equivalence and decoupling control," the model abandons the complex concrete filling and directly uses the model steel pipe 8 as an equivalent replacement. Figure 6a The axial stiffness of the prototype component is reflected in the specific physical parameters of the model steel pipe outer diameter 9 and model steel pipe inner diameter 10, which are "adjusted by adjusting their outer diameter and wall thickness" for stiffness equivalent design. Among them, the model steel pipe outer diameter 9 is generally 20-100mm, and the model steel pipe inner diameter 10 is generally 10-80mm.

[0062] 1. Equivalent design of prestressed steel-concrete composite main columns In the low-order modes, the main column plays a central role in the overall bending; therefore, the equivalent objective is primarily bending stiffness, with axial stiffness as a secondary factor. (The prototype's main column bending stiffness is shown in the figure.) for:

[0063] The stiffness of the pure steel tube main column of the model is:

[0064] in, This is the scaling factor; the example uses 1:10. The bending stiffness of the main column in the prototype; For the bending stiffness of the steel pipe; Concrete provides flexural stiffness. For prestressed bending stiffness; This represents the bending stiffness of the model.

[0065] For each main column of the model, given the column length... Target stiffness Steel elastic modulus In this case, the moment of inertia of the cross section can be deduced. Then, the outer diameter of the steel pipe section is selected. With wall thickness ; .

[0066] 2. Equivalent design of horizontal trusses In low-order modes, the main function of the horizontal truss is to limit the relative displacement of the main columns and change the mode shape, without bearing overall bending; its primary function is axial constraint. Therefore, the equivalent objective is the equivalent axial stiffness of each story.

[0067] The axial stiffness of a single layer in the prototype is:

[0068] in, This refers to the axial stiffness of a single layer in the prototype. For single-column stiffness; The horizontal angle of a single column; The axial stiffness of this layer in the model is:

[0069] By determining a uniform rod diameter, the cross-sectional area and wall thickness of the horizontal truss can be derived by working backwards:

[0070] in, Let be the cross-sectional area of ​​a single rod; This is the length of a single rod.

[0071] 3. Diagonal web members and node connection area For diagonal web members and node connection areas, under the premise of satisfying overall geometric constraints and structural stability, section parameters with sufficient stiffness are selected, without performing fine stiffness equivalent design, so as to avoid unnecessary interference to low-order modes.

[0072] Step 5: Mass Equivalence and Counterweight Design After completing the stiffness equivalence design of the ideal model and the solid steel pipe model, the overall mass and mass distribution of the model are checked, and the consistency with the mass of the target model is achieved by counterweighting.

[0073] Based on the prototype structure mass and geometric scaling ratio, and in conjunction with similarity relationships, the target total mass of the shaking table test model is determined as follows:

[0074] in, The target total mass; For similar proportions; For prototype quality; After completing the design of the cross-sectional dimensions and node construction of the members, the mass of the solid steel pipe model was statistically analyzed, and its actual total mass was calculated:

[0075] in, This refers to the actual total mass; Density; For node quality; By comparing the quality of the physical model with the target quality, the total amount of counterweight required is determined. :

[0076] The arrangement of the counterweights should meet the following principles: uniform distribution along the height direction; not participating in the structural stress, not changing the stiffness of the members; and not damaging the structure of the node area.

[0077] After completing the counterweight arrangement, the overall dynamic characteristics of the model were verified, with a focus on checking whether the lower-order natural frequencies met the design objectives. The first-order natural frequency of the model can be approximated as: ; in, This is the first-order natural frequency; Equivalent stiffness; If the frequency deviation exceeds the allowable range, it can be corrected by fine-tuning the counterweight mass or locally redistributing the counterweight position until the model's dynamic characteristics meet the design requirements.

[0078] Step Six: Verification of Model Dynamic Characteristics Before Testing Before the formal seismic loading test, a low-amplitude dynamic test is conducted on the assembled physical model. Vibration responses under white noise excitation, frequency sweep excitation, or pulse excitation are collected, and modal parameter identification methods are used to identify the low-order natural frequencies of the model. These frequencies are then compared with the target low-order natural frequencies determined in the ideal model to determine whether the model's dynamic characteristics meet the similarity requirements.

[0079] Step 7: Adjust and confirm the parameters based on the test results to confirm the final model. When the identified low-order natural frequencies deviate from the target values ​​and exceed the allowable range, the model parameters are corrected. Correction methods include: adjusting the local member cross-sectional dimensions or wall thickness to correct the equivalent stiffness; adjusting the counterweight mass or distribution to correct the overall mass level; and locally strengthening or weakening the connection stiffness of the node area.

[0080] Repeat step seven after correction until the model’s low-order natural frequencies meet the preset similarity requirements. Confirm that the model can enter the formal shaking table ground motion loading test stage. Repeat this step if it exceeds the allowable range.

[0081] like Figure 7 As shown, this application also provides a shaking table test model design system, the system comprising: The settings module is used to set the scaling ratio; The scaling-down module is used to scale down the prototype prestressed steel tube concrete truss tower structure according to the scaling ratio to obtain the initial model; The parameter determination module is used to construct an ideal material test model of the prototype prestressed steel tube concrete truss tower structure based on the initial model, and to determine the target dynamic characteristic parameters of the ideal material test model; wherein, the target dynamic characteristic parameters include the target low-order natural frequencies and the target equivalent total mass; The solid model module is used to match the stiffness and mass of the initial model with the target dynamic characteristic parameters in a hierarchical equivalent and decoupled control manner, so as to obtain a solid model. The comparison module is used to conduct low-amplitude dynamic tests on the physical model, identify the low-order natural frequencies by measurement, and compare them with the target low-order natural frequencies. The correction module is used to correct the parameters of the entity model based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements.

[0082] Although this application 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for designing a shaking table test model, characterized in that, The method includes: Set the scaling ratio; The prototype prestressed steel tube concrete truss tower structure was scaled down according to the scaling ratio to obtain the initial model; An ideal material test model for a prototype prestressed steel-concrete composite truss tower structure is constructed based on the initial model, and the target dynamic characteristic parameters of the ideal material test model are determined. The target dynamic characteristic parameters include the target low-order natural frequencies and the target equivalent total mass. By using hierarchical equivalence and decoupling control, the initial model is matched with the target dynamic characteristic parameters in terms of stiffness and mass, thus obtaining a solid model; Low-amplitude dynamic tests were conducted on the physical model to identify the low-order natural frequencies and compare them with the target low-order natural frequencies. The parameters of the entity model are corrected based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements.

2. The shaking table test model design method according to claim 1, characterized in that, The set scaling ratio includes: The scaling ratio was set based on the geometric parameters and shaking table bearing capacity of the prototype prestressed steel tube concrete truss tower structure.

3. The shaking table test model design method according to claim 2, characterized in that, The expression for determining the scaling ratio is: in, Indicates the scaling ratio; Indicates the initial model feature size; This indicates the characteristic dimensions of the prototype prestressed steel tube concrete truss tower structure.

4. The shaking table test model design method according to claim 1, characterized in that, The ideal material test model is as follows: An ideal material test model is constructed based on the principles of axial stiffness similarity, mass similarity, and prestress equivalence. The prestress equivalence principle refers to equating the prestress effect in the prototype prestressed steel tube concrete truss tower structure with the axial stiffness parameter of the component.

5. The shaking table test model design method according to claim 1, characterized in that, By employing a hierarchical equivalent and decoupling control approach, the initial model is matched with the target dynamic characteristic parameters in terms of stiffness and mass, including: The composite material components of the prototype prestressed steel tube concrete truss tower structure are replaced by single homogeneous material components, and different stiffness equivalents are used in the design based on the differences in the contribution of different types of members to the overall low-order dynamic characteristics. After the stiffness design is completed, additional counterweights that do not participate in the structural stress are configured to make the overall mass of the initial model reach the target equivalent total mass, thus achieving mass matching.

6. The shaking table test model design method according to claim 1, characterized in that, Based on the different contributions of different types of members to the overall low-order dynamic characteristics, different stiffness equivalences are used in the design, including: Based on the target low-order natural frequencies and low-order mode shapes, the truss members are divided into main columns, horizontal trusses, and web members.

7. The shaking table test model design method according to claim 6, characterized in that, For the main column, which is the main bending member, an equivalent design based on bending stiffness is performed. For the horizontal truss that provides axial constraint, perform an equivalent design for overall axial stiffness; For the web member, a cross section that meets the structural and stability requirements is selected, and no fine stiffness equivalence is performed for the low-order modes.

8. The shaking table test model design method according to claim 1, characterized in that, Low-amplitude dynamic tests were conducted on the physical model to identify low-order natural frequencies, including: White noise excitation, frequency sweep excitation, or pulse excitation are applied to the solid model, vibration response is collected, and low-order natural frequencies of the solid model are obtained through modal parameter identification.

9. The shaking table test model design method according to claim 1, characterized in that, The parameters of the entity model are corrected based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements, including: When the deviation between the measured frequency and the target frequency exceeds the allowable range, the parameters of the entity model are corrected. After correction, the measured identification and comparison steps are repeated until the low-order natural frequencies of the entity model meet the preset similarity requirements.

10. A shaking table test model design system, characterized in that, The system includes: The settings module is used to set the scaling ratio; The scaling-down module is used to scale down the prototype prestressed steel tube concrete truss tower structure according to the scaling ratio to obtain the initial model; The parameter determination module is used to construct an ideal material test model of the prototype prestressed steel tube concrete truss tower structure based on the initial model, and to determine the target dynamic characteristic parameters of the ideal material test model; wherein, the target dynamic characteristic parameters include the target low-order natural frequencies and the target equivalent total mass; The solid model module is used to match the stiffness and mass of the initial model with the target dynamic characteristic parameters in a hierarchical equivalent and decoupled control manner, so as to obtain a solid model. The comparison module is used to conduct low-amplitude dynamic tests on the physical model, identify the low-order natural frequencies by measurement, and compare them with the target low-order natural frequencies. The correction module is used to correct the parameters of the entity model based on the comparison results until the low-order natural frequencies of the entity model meet the preset similarity requirements.

Images