Truss suspension bridge aeroelastic model and design method

Abstract

This invention discloses an aeroelastic model of a truss suspension bridge, comprising an outer casing and a frame system within the casing. The frame system includes: an upper suspension member comprising at least one upper core beam extending longitudinally; a lower suspension member comprising at least two lower core beams spaced parallel to each other laterally, extending longitudinally; and a load-bearing mechanism comprising multiple load-bearing components. Each load-bearing component includes an upper rigid arm, one lower rigid arm, a load-bearing frame, and another lower rigid arm arranged sequentially along the longitudinal direction. The upper rigid arm is connected to the upper suspension member, and both lower rigid arms are connected to the lower suspension member. The load-bearing frame is connected to both the upper and lower suspension members. This invention enables the simulation effect of the aeroelastic model structure in wind tunnel tests to more closely approximate the vibration mode of actual bridges, achieving high simulation accuracy. Furthermore, the structure and design method are simple and easy to operate, while providing a reasonable simulation basis for the central slotting of the main beam of a double-deck bridge truss.

Description

Technical Field

[0001] This invention relates to the field of bridge wind engineering research technology, and in particular to an aeroelastic model of a truss suspension bridge and its design method. Background Technology

[0002] For long-span suspension bridges, wind resistance is extremely sensitive, and structural wind-induced stability can be a controlling factor in the design of ultra-long-span suspension bridges. Wind tunnel tests are often used during the structural design process to verify wind resistance and guide the design. Traditional aeroelastic modeling methods simulate the stiffness of the main girder using a single core beam within the girder. However, for double-deck trusses, the offset core beam can affect the torsional center of the cross-section, causing vibration pattern deviations and impacting test results. For four-cable truss suspension bridges, the connection structure is complex. If a Π-shaped spring is used to simulate the main girder stiffness, the external spring connection can affect the aerodynamic shape of the structure, altering the wind flow and causing significant discrepancies between the aeroelastic test results and the actual bridge wind vibration response, resulting in aerodynamic simulation errors. Furthermore, the design, fabrication, and installation of Π-shaped spring parameters are quite complex. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide an aeroelastic model of a truss suspension bridge and its design method.

[0004] To achieve the above objectives, an embodiment of the present invention provides the following technical solution:

[0005] An aeroelastic model of a truss suspension bridge includes an outer garment and a frame system disposed within the outer garment, the frame system comprising:

[0006] The upper lifting component includes at least one upper core beam extending longitudinally;

[0007] The lower lifting component includes at least two lower core beams that are arranged parallel to each other in the transverse direction and the lower core beams extend in the longitudinal direction.

[0008] The bearing mechanism includes multiple bearing components. Each bearing component includes an upper rigid arm, one lower rigid arm, a bearing frame, and another lower rigid arm arranged longitudinally. The upper rigid arm is connected to the upper lifting member, and both lower rigid arms are connected to the lower lifting member. The bearing frame is connected to the upper lifting member and the lower lifting member respectively.

[0009] As a further improvement of the present invention, the bearing frame includes two horizontal rigid arms arranged parallel to each other in the vertical direction and two vertical rigid arms arranged parallel to each other in the transverse direction. Each of the vertical rigid arms is connected between the two horizontal rigid arms, one of the horizontal rigid arms is connected to the upper lifting member, and the other horizontal rigid arm is connected to the lower lifting member.

[0010] A design method for an aeroelastic model of a truss suspension bridge includes the following steps:

[0011] (1) Calculate the target stiffness and target mass values ​​of the aeroelastic model;

[0012] (2) Calculate the actual stiffness and actual mass of the aeroelastic model;

[0013] (3) Compare the target stiffness value and the actual stiffness value of the aeroelastic model. Based on the comparison results, adjust the geometric parameters of the frame system so that the absolute value of the error between the target stiffness value and the actual stiffness value is less than 3%.

[0014] (4) Compare the target mass value and the actual mass value of the aeroelastic model. When the actual mass value is less than the target mass value, set an additional counterweight and calculate the mass and lateral spacing of the additional counterweight.

[0015] As a further improvement of the present invention, in step (1), stiffness includes bending stiffness and torsional stiffness, and mass includes mass per meter and moment of inertia.

[0016] As a further improvement of the present invention, the formula for calculating the target stiffness value of the aeroelastic model is as follows:

[0017]

[0018]

[0019] In the formula, EI is the bending stiffness, GJ is the torsional stiffness, subscripts M and P represent the aeroelastic model and the actual bridge, respectively, and n is the reciprocal of the geometric scaling ratio.

[0020] The formula for calculating the target mass value of the aeroelastic model is as follows:

[0021]

[0022]

[0023] In the formula, m is the mass per meter, I is the moment of inertia, subscripts M and P represent the aeroelastic model and the actual bridge, respectively, and n is the reciprocal of the geometric scaling ratio.

[0024] As a further improvement of the present invention, in step (2), the method for calculating the actual stiffness and actual mass values ​​of the aeroelastic model includes the following steps:

[0025] (2.1) Set the initial values ​​of the geometric parameters of the frame system;

[0026] (2.2) Establish the cantilever beam finite element model of the frame system based on the initial values ​​of the geometric parameters, calculate the bending frequency and torsional frequency of the frame system using the cantilever dynamic method, and then calculate the actual stiffness and actual mass values ​​of the aeroelastic model.

[0027] As a further improvement of the present invention, the geometric parameters include the width B1 and height H1 of the upper core beam, the width B2 and height H2 of the lower core beam, the lateral spacing Δs2 between adjacent lower core beams, the width b1 and height h1 of the upper rigid arm, the width b2 and height h2 of the lower rigid arm, and the width b3, height h3, and lateral spacing Δs3 of the bearing frame.

[0028] As a further improvement of the present invention, the formula for calculating the actual value of stiffness is as follows:

[0029]

[0030]

[0031] In the formula, ω b ω is the bending frequency. t Where is the torsional frequency, m is the actual mass per meter, I is the actual mass moment of inertia, L is the length of the cantilever beam, EI is the actual bending stiffness, and GJ is the actual torsional stiffness.

[0032] The formula for calculating the actual mass value is:

[0033]

[0034]

[0035] In the formula, ρ is the material density, and A i Let L be the cross-sectional area of ​​the i-th member. i Let D be the length of the i-th member. i Let m be the distance of the i-th member from the centroid of the cross section, m be the actual mass per meter, and I be the actual moment of inertia.

[0036] As a further improvement of the present invention, in step (3), the influence matrix method is used to calculate the influence matrix of each geometric parameter on the actual value of stiffness, and then the initial value of each geometric parameter is adjusted.

[0037] As a further improvement of the present invention, in step (4), the formula for calculating the mass of the additional counterweight is:

[0038] △m=m M -m 外衣 -m 框架系统

[0039] △I=I M -I 外衣 -I框架系统

[0040] In the formula, Δm is the mass per meter of the additional counterweight, and m M Let m be the target mass per meter for the aeroelastic model. 外衣 The actual mass per meter of the outer garment, in meters. 框架系统 The actual mass per meter of the frame system; ΔI is the moment of inertia of the added counterweight, I M I is the target value of the mass moment of inertia of the aeroelastic model. 外衣 I is the actual value of the moment of inertia of the outer garment. 框架系统 This represents the actual value of the mass moment of inertia of the frame system.

[0041] The formula for calculating the lateral spacing ΔD of the additional counterweights is:

[0042]

[0043] In the formula, △D is the transverse bridge distance between one pair of counterweights of the additional counterweight, △m is the mass per meter of the additional counterweight, and △I is the moment of inertia of the additional counterweight.

[0044] The beneficial effects of this invention are:

[0045] This invention employs a frame system to simulate the stiffness and mass of an aeroelastic model of a truss suspension bridge. It solves the problems of torsional center offset and mass eccentricity in truss simulations caused by previous single-core beam stiffness systems, and minimizes aerodynamic shape interference. This makes the simulation effect of the aeroelastic model structure in wind tunnel tests closer to the vibration mode of the actual bridge, with high simulation accuracy. The structure and design method are simple and easy to operate, and it also provides a reasonable simulation basis for the central slotting of the main beam of a double-deck bridge truss. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of the framework system according to a preferred embodiment of the present invention;

[0048] Figure 2 This is a schematic cross-sectional view of the frame system at the load-bearing frame according to a preferred embodiment of the present invention;

[0049] Figure 3 This is a side view of the frame system according to a preferred embodiment of the present invention;

[0050] Figure 4 This is a top view of the frame system according to a preferred embodiment of the present invention;

[0051] Figure 5 This is a longitudinal side view of the connection between the upper rigid arm and the upper core beam in a preferred embodiment of the present invention;

[0052] Figure 6 This is a longitudinal side view of the lower rigid arm connecting to two lower core beams in a preferred embodiment of the present invention;

[0053] Figure 7 This is a longitudinal side view of the connection between the load-bearing frame and the upper core beam and two lower core beams according to a preferred embodiment of the present invention.

[0054] Figure 8 This is a cross-sectional view of the aeroelastic model at the bearing frame according to a preferred embodiment of the present invention;

[0055] Figure 9 A top view of a preferred embodiment of the present invention, showing the upper core beam positioned below the upper bridge deck of the outer garment;

[0056] Figure 10 A top view of a preferred embodiment of the present invention showing two lower core beams positioned below the lower bridge deck of the outer garment;

[0057] In the diagram: 1. Aeroelastic model, 11. Outer garment, 111. Upper bridge deck, 112. Lower bridge deck, Frame system 12, 2. Upper core beam, 3. Lower core beam, 41. Upper rigid arm, 42. Lower rigid arm, 43. Bearing frame, 431. Horizontal rigid arm, 432. Vertical rigid arm. Detailed Implementation

[0058] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0059] Please see Figure 1 , Figure 3 , Figures 8-10This application discloses an aeroelastic model 1 of a truss suspension bridge, including an outer garment 11 and a frame system 12 disposed within the outer garment 11. The frame system 12 includes: an upper suspension member, which includes at least one upper core beam 2 extending longitudinally; a lower suspension member, which includes at least two lower core beams 3 arranged parallel to each other in the transverse direction, extending longitudinally; and a load-bearing mechanism, which includes multiple load-bearing components. Each load-bearing component includes an upper rigid arm 41, one lower rigid arm 42, a load-bearing frame 43, and another lower rigid arm 42 arranged sequentially in the longitudinal direction. The upper rigid arm 41 is connected to the upper suspension member, and both lower rigid arms 42 are connected to the lower suspension member. The load-bearing frame 43 is connected to the upper suspension member and the lower suspension member, respectively.

[0060] Specifically, the upper lifting component includes an upper core beam 2, and the lower lifting component includes two lower core beams 3. The upper rigid arm 41 is connected to the upper core beam 2, and the two lower rigid arms 42 are both connected to the two lower core beams 3. Each lower rigid arm 42 is laterally connected to the two lower core beams 3, and the load-bearing frame 43 is connected to the upper core beam 2 and the two lower core beams 3 respectively.

[0061] Please see Figure 2 The load-bearing frame 43 includes two horizontal rigid arms 431 arranged parallel to each other in the vertical direction and two vertical rigid arms 432 arranged parallel to each other in the transverse direction. Each vertical rigid arm 432 is connected between the two horizontal rigid arms 431. One horizontal rigid arm 431 is connected to the upper lifting member, and the other horizontal rigid arm 431 is connected to the lower lifting member. Specifically, one horizontal rigid arm 431 is connected to the upper core beam 2, and the other horizontal rigid arm 431 is transversely spanned and connected to the two lower core beams 3.

[0062] The outer casing 11 provides the aerodynamic shape, and the frame system 12 provides rigidity. (See also...) Figures 8-10 The upper core beam 2 of the frame system 12 is located below the upper bridge deck 111 of the outer garment 11, and the two lower core beams 3 of the frame system 12 are located below the lower bridge deck 112 of the outer garment 11. The frame system 1 is connected to the upper bridge deck 111 via an upper rigid arm 41, and to the lower bridge deck 112 via a lower rigid arm 42. One horizontal rigid arm 431 of the load-bearing frame 43 is connected to the upper bridge deck 111, and the other horizontal rigid arm 431 is connected to the lower bridge deck 112, thus connecting the frame system 1 to the outer garment 11. The outer garment 11 can be made of acrylic sheet, high-quality board, ABS sheet, or balsa wood to simulate aerodynamic shape. The frame system 12 can be made of steel or aluminum to simulate stiffness.

[0063] This application also discloses a design method for an aeroelastic model 1 of a truss suspension bridge, including the following steps:

[0064] (1) Calculate the stiffness target value and mass target value of aeroelastic model 1.

[0065] Stiffness includes bending stiffness and torsional stiffness; bending stiffness includes vertical bending stiffness and lateral bending stiffness; mass includes mass per meter and moment of inertia.

[0066] The formula for calculating the target stiffness value of aeroelastic model 1 is as follows:

[0067]

[0068]

[0069] In the formula, EI represents the bending stiffness, GJ represents the torsional stiffness, subscripts M and P represent the aeroelastic model and the actual bridge, respectively, and n is the reciprocal of the geometric scaling ratio. Then (EI) M (GJ) M Let E and E represent the target values ​​for bending stiffness and torsional stiffness of the aeroelastic model, respectively. P (GJ) P These represent the bending stiffness and torsional stiffness of the actual bridge, respectively.

[0070] Finite element analysis was performed using a finite element model of the actual bridge structure to obtain the bending frequency and torsional frequency. The bending stiffness (EI) of the actual bridge was then calculated based on these bending and torsional frequencies. P and torsional stiffness (GJ) P Then, using the formula for calculating the target stiffness value, the target bending stiffness value (EI) is determined based on the geometric scaling ratio. M And the target value of torsional stiffness (GJ) M .

[0071] The formula for calculating the target mass value of aeroelastic model 1 is as follows:

[0072]

[0073]

[0074] In the formula, m is the mass per meter, I is the moment of inertia, subscripts M and P represent the aeroelastic model and the actual bridge, respectively, and n is the reciprocal of the geometric scaling ratio. Then m M I M Let m represent the target mass per meter and the target moment of inertia of the aeroelastic model, respectively. p I p These represent the mass per meter of the actual bridge and the moment of inertia, respectively.

[0075] Based on the actual bridge structure's mass per meter (m) p and mass moment of inertia I p The target mass per meter m of aeroelastic model 1 is determined by geometric scaling. M and the target value of mass moment of inertia IM .

[0076] (2) Calculate the actual stiffness and actual mass of aeroelastic model 1.

[0077] Specifically, the calculation method for the actual values ​​of stiffness and mass of the aeroelastic model includes the following steps:

[0078] (2.1) Set the initial values ​​of the geometric parameters of the frame system 12;

[0079] (2.2) Based on the initial values ​​of the geometric parameters, establish the cantilever beam finite element model of the frame system 12, calculate the bending frequency and torsional frequency of the frame system 12 by the cantilever dynamic method, and then calculate the actual stiffness and actual mass of the aeroelastic model 1.

[0080] Please see Figures 4-7 The geometric parameters include the width B1 and height H1 of the upper core beam 2, the width B2 and height H2 of the lower core beam 3, the lateral spacing Δs2 between adjacent lower core beams 3, the width b1 and height h1 of the upper rigid arm 41, the width b2 and height h2 of the lower rigid arm 42, and the width b3, height h3, and lateral spacing Δs3 of the bearing frame 43. The lateral spacing Δs2 between adjacent lower core beams 3 is the distance between the centerlines of the two lower core beams 3; the width b3 and height h3 of the bearing frame 43 are the width b3 and height h3 of the horizontal rigid arm 431; and the lateral spacing Δs3 of the bearing frame 43 is the distance between the centerlines of the two vertical rigid arms 432.

[0081] The formula for calculating the actual value of stiffness is:

[0082]

[0083]

[0084] In the formula, ω b The first-order bending frequency, ω t denoted as the first-order torsional frequency, m as the actual mass per meter, I as the actual mass moment of inertia, L as the length of the cantilever beam, EI as the actual bending stiffness, and GJ as the actual torsional stiffness.

[0085] The formula for calculating the actual mass value is:

[0086]

[0087]

[0088] In the formula, ρ is the material density, and A i Let L be the cross-sectional area of ​​the i-th member. i Let D be the length of the i-th member. iLet m be the distance of the i-th member from the centroid of the cross section, m be the actual mass per meter, and I be the actual moment of inertia. The outer garment 11 and the frame system 12 can be equivalently represented as multiple connected members. The mass per meter of the outer garment 11 and the frame system 12 can be calculated by multiplying the density, cross-sectional area, and length of each member.

[0089] (3) Compare the target stiffness value of aeroelastic model 1 with the actual stiffness value. Based on the comparison results, adjust the geometric parameters of frame system 12 so that the absolute value of the error between the target stiffness value and the actual stiffness value is less than 3%.

[0090] Specifically, the influence matrix method is used to calculate the influence matrix of each geometric parameter on the actual stiffness value, and then the initial values ​​of each geometric parameter are adjusted. In other words, by adjusting the initial values ​​of the geometric parameters of the frame system 12, the calculated actual bending stiffness value EI is made closer to the target bending stiffness value (EI). M The absolute value of the error is less than 3%, and the actual value of torsional stiffness GJ is made to match the target value of torsional stiffness (GJ). M The absolute value of the error is less than 3%.

[0091] Actual bending stiffness EI and target bending stiffness (EI) M The formula for calculating the error γ1 is as follows:

[0092]

[0093] In the formula, EI is the actual value of bending stiffness, (EI) M This represents the target value for bending stiffness.

[0094] Actual torsional stiffness GJ and target torsional stiffness (GJ) M The formula for calculating the error γ2 is as follows:

[0095]

[0096] In the formula, GJ is the actual value of torsional stiffness, (GJ) M The target value for torsional stiffness.

[0097] (4) Compare the target mass value with the actual mass value of aeroelastic model 1. When the actual mass value is less than the target mass value, set additional counterweights and calculate the mass and lateral spacing of the additional counterweights. When the actual mass value is greater than the target mass value, the initial values ​​of the geometric parameters of frame system 12 need to be adjusted.

[0098] Specifically, the mass of the additional counterweight and the lateral spacing are calculated based on the deviation between the target mass and the actual mass. The formula for calculating the mass of the additional counterweight is:

[0099] △m=m M -m外衣 -m 框架系统

[0100] △I=I M -I 外衣 -I 框架系统

[0101] In the formula, Δm is the mass per meter of the additional counterweight, and m M Let m be the target mass per meter for the aeroelastic model. 外衣 The actual mass per meter of the outer garment, in meters. 框架系统 The actual mass per meter of the frame system; ΔI is the moment of inertia of the added counterweight, I M I is the target value of the mass moment of inertia of the aeroelastic model. 外衣 I is the actual value of the moment of inertia of the outer garment. 框架系统 This represents the actual value of the mass moment of inertia of the frame system.

[0102] m 外衣 m 框架系统 I 外衣 I 框架系统 It can be obtained through the formula for calculating the actual mass value.

[0103] The formula for calculating the lateral spacing ΔD of the additional counterweights is:

[0104]

[0105] In the formula, △D is the transverse bridge distance between one pair of counterweights of the additional counterweight, △m is the mass per meter of the additional counterweight, and △I is the moment of inertia of the additional counterweight.

[0106] The additional counterweights include multiple pairs of counterweights, which are arranged longitudinally at N positions on the outer garment 11. Each position has one pair of counterweights, and the mass of each counterweight is...

[0107] The method of the present invention adjusts the geometric parameters of the frame system 12 so that the bending stiffness EI and torsional stiffness GJ of the aeroelastic model 1 reach the target value of bending stiffness (EI). M Target value for torsional stiffness (GJ) M Simultaneously, this ensures that the mass per meter *m* and moment of inertia *I* of aeroelastic model 1 reach the target mass per meter *m*. M and I M This ensures that the aeroelastic model 1 and the actual bridge structure satisfy a scale relationship.

[0108] Dynamic characteristic tests were conducted on the fabricated full-bridge aeroelastic model 1 to verify the accuracy of the frame system 12 in dynamic characteristic simulation. Displacement sensors were positioned laterally on the aeroelastic model 1 to measure the lateral bending mode, while vertical bending and torsional modes were fixed vertically to the ground. Different artificial excitation methods were used to induce the aforementioned modes based on their characteristics. Then, through displacement amplitude-frequency analysis and phase-frequency analysis at each measuring point, the frequencies and mode shapes of each mode of the aeroelastic model 1 were determined.

[0109] The results of the dynamic characteristic tests on the tested modes are summarized in Table 1 below. For the first two modes of the three degrees of freedom of the full-bridge aeroelastic model 1, the errors between the frequencies and the design target values ​​are all within ±5%. Except for the slightly larger damping of the first and second vertical bends, the damping ratios of the other modes are approximately close to 5‰, verifying the accuracy of the simulation of the frame system 12.

[0110] Table 1. Dynamic performance test results

[0111]

[0112] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0113] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An aeroelastic model of a truss suspension bridge comprising a skin and a frame system disposed within the skin, characterized in that, The framework system includes: The upper lifting component includes at least one upper core beam extending longitudinally; The lower lifting component includes at least two lower core beams that are arranged parallel to each other in the transverse direction and the lower core beams extend in the longitudinal direction. The bearing mechanism includes multiple bearing components. Each bearing component includes an upper rigid arm, one lower rigid arm, a bearing frame, and another lower rigid arm arranged longitudinally. The upper rigid arm is connected to the upper lifting member, and both lower rigid arms are connected to the lower lifting member. The bearing frame is connected to the upper lifting member and the lower lifting member respectively.

2. The aeroelastic model of a truss suspension bridge according to claim 1, characterized in that, The support frame includes two horizontal rigid arms arranged parallel to each other in the vertical direction and two vertical rigid arms arranged parallel to each other in the transverse direction. Each vertical rigid arm is connected between the two horizontal rigid arms. One of the horizontal rigid arms is connected to the upper lifting member, and the other horizontal rigid arm is connected to the lower lifting member.

3. A design method for an aeroelastic model of a truss suspension bridge as described in any one of claims 1-2, characterized in that, Includes the following steps: (1) Calculate the target stiffness and target mass values ​​of the aeroelastic model; (2) Calculate the actual stiffness and actual mass of the aeroelastic model; (3) Compare the target stiffness value and the actual stiffness value of the aeroelastic model. Based on the comparison results, adjust the geometric parameters of the frame system so that the absolute value of the error between the target stiffness value and the actual stiffness value is less than 3%. (4) Compare the target mass value and the actual mass value of the aeroelastic model. When the actual mass value is less than the target mass value, set an additional counterweight and calculate the mass and lateral spacing of the additional counterweight.

4. The method of designing an aeroelastic model of a truss suspension bridge according to claim 3, wherein In step (1), stiffness includes bending stiffness and torsional stiffness, and mass includes mass per meter and moment of inertia.

5. The design method for the aeroelastic model of a truss suspension bridge according to claim 4, characterized in that, The formula for calculating the target stiffness value of the aeroelastic model is as follows: In the formula, EI is the bending stiffness, GJ is the torsional stiffness, subscripts M and P represent the aeroelastic model and the actual bridge, respectively, and n is the reciprocal of the geometric scaling ratio. The formula for calculating the target mass value of the aeroelastic model is as follows: In the formula, m is the mass per meter, I is the moment of inertia, subscripts M and P represent the aeroelastic model and the actual bridge, respectively, and n is the reciprocal of the geometric scaling ratio.

6. The design method for the aeroelastic model of a truss suspension bridge according to claim 3, characterized in that, In step (2), the calculation method for the actual stiffness and actual mass values ​​of the aeroelastic model includes the following steps: (2.1) Set the initial values ​​of the geometric parameters of the frame system; (2.2) Establish the cantilever beam finite element model of the frame system based on the initial values ​​of the geometric parameters, calculate the bending frequency and torsional frequency of the frame system using the cantilever dynamic method, and then calculate the actual stiffness and actual mass values ​​of the aeroelastic model.

7. The method of designing an aeroelastic model of a truss suspension bridge according to claim 6, wherein The geometric parameters include the width B1 and height H1 of the upper core beam, the width B2 and height H2 of the lower core beam, the lateral spacing Δs2 between adjacent lower core beams, the width b1 and height h1 of the upper rigid arm, the width b2 and height h2 of the lower rigid arm, and the width b3, height h3, and lateral spacing Δs3 of the load-bearing frame.

8. The method of designing an aeroelastic model of a truss suspension bridge according to claim 6, wherein, The formula for calculating the actual value of stiffness is: In the formula, ω b ω is the bending frequency. t Where is the torsional frequency, m is the actual mass per meter, I is the actual mass moment of inertia, L is the length of the cantilever beam, EI is the actual bending stiffness, and GJ is the actual torsional stiffness. The formula for calculating the actual mass value is: In the formula, ρ is the material density, and A i Let L be the cross-sectional area of ​​the i-th member. i Let D be the length of the i-th member. i Let m be the distance of the i-th member from the centroid of the cross section, m be the actual mass per meter, and I be the actual moment of inertia.

9. The method of designing an aeroelastic model of a truss suspension bridge according to claim 3, wherein, In step (3), the influence matrix method is used to calculate the influence matrix of each geometric parameter on the actual value of stiffness, and then the initial values ​​of each geometric parameter are adjusted.

10. The method of designing an aeroelastic model of a truss suspension bridge as defined in claim 3, wherein In step (4), the formula for calculating the mass of the additional counterweight is: Δm = m M -m 外衣 -m 框架系统 △I=I M -I 外衣 -I 框架系统 In the formula, Δm is the mass per meter of the additional counterweight, and m M Let m be the target mass per meter for the aeroelastic model. 外衣 The actual mass per meter of the outer garment, in meters. 框架系统 The actual mass per meter of the frame system; ΔI is the moment of inertia of the added counterweight, I M I is the target value of the mass moment of inertia of the aeroelastic model. 外衣 I is the actual value of the moment of inertia of the outer garment. 框架系统 This represents the actual value of the mass moment of inertia of the frame system. The formula for calculating the lateral spacing ΔD of the additional counterweights is: In the formula, △D is the transverse bridge distance between one pair of counterweights of the additional counterweight, △m is the mass per meter of the additional counterweight, and △I is the moment of inertia of the additional counterweight.

Images