A continuously adjustable attack angle and frequency bending-torsional coupling vibration wind tunnel test device

Abstract

The present application relates to the technical field of bridge wind tunnel test device, and particularly relates to a continuous adjustable bending-torsion coupling vibration wind tunnel test device of attack angle and frequency, which comprises a test model, a vertical bending adjuster, a torsion attack angle adjuster and a rigid rod, the rigid rod is arranged through the test model, the torsion center line of the test model and the axis of the rigid rod are arranged in line, the vertical bending adjuster and the torsion attack angle adjuster are connected with the rigid rod, and the vertical bending adjuster is connected with an external supporting device; the vertical bending adjuster is used for adjusting the vertical bending vibration frequency of the test model; and the torsion attack angle adjuster is used for adjusting the torsion vibration frequency and the attack angle of the test model. The device has the advantages that the vertical bending adjuster and the torsion attack angle adjuster are independently supported and do not interfere with each other, the stiffness of the vertical bending and the torsion of the test model is completely independent and has very good linearity, the vertical bending and the torsion vibration frequency are independently and continuously adjustable, and the initial attack angle is conveniently and continuously adjustable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge wind tunnel test device, in particular to a continuously adjustable attack angle and frequency of the bending-torsional coupling vibration wind tunnel test device. BACKGROUND

[0002] The bridge section model wind tunnel test is a key means for the bridge wind resistance research, and is also an important wind tunnel test device for measuring the aerodynamic derivatives, aerodynamic admittance and flutter, and vortex-induced resonance response of the bridge structure.

[0003] In the past, the initial attack angle adjustment of the section model wind tunnel test usually needs to unlock the attack angle adjustment device, and then use the disc, chain wheel or wheel hub fixed with the model to adjust the attack angle of the model, that is, adjust the initial meshing position of the disc and the toothed plate, or use the initial pre-rotation method of the chain wheel or the initial pre-rotation method of the wheel hub to adjust the initial attack angle. Since the model is fixed with the disc, chain wheel or wheel hub, the self-weight is large, which is very time-consuming and laborious, and the attack angle value is unknown during the adjustment process, so the measurement device needs to be repeatedly corrected and adjusted to reach the target attack angle value. This not only is tedious, but also the model may vibrate or be unstable during the final locking process, the error is large, and more importantly, it cannot realize the continuous, quantitative and accurate adjustment of the initial attack angle value of the test.

[0004] In the past, the greater the spring stiffness, the greater the vertical bending and torsional stiffness provided by the spring for the section model, and the greater the vibration frequency of the model. However, the vibration frequencies of different bridges under different wind speeds are different. In order to set the stiffness in line with the characteristics in each test, the vertical bending and torsional stiffness can be directly adjusted by making spring devices matched with each test and adjusting the spring spacing, or the torsional and vertical bending stiffness can be indirectly adjusted by making different types of wheel hubs and fiber ropes, and then adjusting the vertical bending and torsional vibration frequency of the model. However, this is not only tedious and time-consuming, but also expensive to make multiple types of springs, wheel hubs and fiber ropes, and the springs, wheel hubs and fiber ropes used in one test cannot be used again in other tests, which is poor in economy, and more importantly, it cannot realize the independent continuous adjustment of the vertical bending and torsional vibration frequency.

[0005] In the past, when the torsional amplitude is large, the vertical spring will obviously tilt laterally, and the geometric stiffness of the spring changes nonlinearly, especially the torsional stiffness provided by the vertical spring has complex nonlinear characteristics with the amplitude, so the vertical and torsional stiffness of the bending-torsional coupling vibration system will no longer remain constant, thereby causing unacceptable errors to the subsequent test results.

[0006] Therefore, how to conveniently and continuously adjust the initial attack angle, realize the independent and continuous adjustment of the vertical bending and torsional vibration frequency, and ensure the vertical bending and torsional coupling linear vibration is a problem to be solved in the field. SUMMARY

[0007] In order to solve the above problems, the application provides a bending-torsional coupling vibration wind tunnel test device with continuously adjustable attack angle and frequency, and the specific technical scheme is as follows.

[0008] A bending-torsional coupling vibration wind tunnel test device with continuously adjustable attack angle and frequency, comprising a test model, a vertical bending adjuster, a torsional attack angle adjuster and a rigid rod, the rigid rod is arranged through the test model, the torsional center line of the test model and the axis of the rigid rod are arranged in line, the rigid rod is rotatably connected with a first connecting piece, the torsional attack angle adjuster comprises a second connecting piece and the rigid rod is adjustably connected with the second connecting piece, the first connecting piece is located between the test model and the second connecting piece, the first connecting piece is connected with the vertical bending adjuster, the vertical bending adjuster is connected with the torsional attack angle adjuster, and the vertical bending adjuster is connected with an external supporting device.

[0009] The vertical bending adjuster is used for adjusting the vertical bending vibration frequency of the test model.

[0010] The torsional attack angle adjuster is used for adjusting the torsional vibration frequency and attack angle of the test model.

[0011] Preferably, the vertical bending adjuster comprises a vertical bending beam and an adjusting piece arranged to slide along the length direction of the vertical bending beam, the end of the vertical bending beam is connected with the first connecting piece, and the adjusting piece is connected with the external supporting device.

[0012] Preferably, the vertical bending beam is a vertical bending steel beam, and a sliding groove for continuously adjusting the adjusting piece is formed in the vertical bending steel beam.

[0013] Preferably, the adjusting piece comprises a bolt anchor and a fixed support arranged on the bolt anchor, the bolt anchor realizes the continuous adjustment of the position of the adjusting piece along the length direction of the sliding groove through a bolt and a nut, and the fixed support is used for connecting the external supporting device.

[0014] Preferably, the first connecting piece is connected with the rigid rod through a rotating assembly, the rotating assembly comprises a bearing and a bearing anchor, the bearing is arranged on the rigid rod, and the bearing anchor is connected with the first connecting piece and the vertical bending adjuster.

[0015] Preferably, the torsional attack angle adjuster further comprises a torsional beam and an adjustable connecting rod, one end of the torsional beam is fixedly arranged on the first connecting piece, the other end is adjustably connected with the adjustable connecting rod, and the end of the adjustable connecting rod away from the torsional beam is fixedly connected with the second connecting piece.

[0016] Preferably, the torsion beam is a torsion steel bar, the adjustable connecting rod is a threaded rod, and the end of the threaded rod is adjustably arranged on the waist-shaped hole through a bolt, for adjusting the distance between the torsion steel bar and the second connecting member.

[0017] Preferably, the threaded rod is provided with a scale value along the length direction of the threaded rod, and the scale value is used to assist in adjusting the initial angle of attack value of the test model.

[0018] The technical scheme of the present application has the following beneficial effects:

[0019] (1) The present application converts the effective length of the threaded rod between the torsion steel bar and the second connecting member and the initial angle of attack value, so that they correspond to each other, and the required angle value is displayed on the side surface of the threaded rod, so that the effective length of the threaded rod can be continuously adjusted quantitatively, the initial torsion angle of the model is continuously changed, and the initial angle of attack of the test is conveniently and accurately controlled. In the past, when adjusting the initial angle of attack of the segment model wind tunnel test, the angle adjustment device needs to be unlocked first, and then the model is adjusted by using the disc, sprocket or hub fixed to the model, that is, the initial meshing position of the disc and the toothed plate is adjusted, or the initial angle of attack is adjusted by the initial pre-rotation method of the sprocket or the initial pre-rotation method of the hub. The present application solves the problem of tedious adjustment of the initial angle of attack in the past segment model wind tunnel test, improves the stability of the test model, reduces the test error, and realizes a wind tunnel test device that can continuously adjust the angle of attack.

[0020] (2) The vertical bending steel beam and the torsion steel bar in the device are independently supported and do not interfere with each other, and provide completely independent and very good linearity stiffness for the torsion and vertical bending movement degrees of the bridge segment model, so that the vertical bending and torsion vibration frequencies can be independently and continuously adjusted by continuously adjusting the effective length of the vertical bending steel beam and the torsion steel bar, saving time and effort, and achieving rapid and zero-cost changes in frequency. In the past segment model wind tunnel test, the greater the stiffness of the spring, the greater the vertical bending and torsion stiffness provided for the segment model, and the greater the vibration frequency of the model. Replacing the spring or other components is tedious, time-consuming and labor-intensive, and the cost of producing multiple types of springs, hubs and fiber ropes is expensive. The spring, hub and fiber rope used in one test cannot be used again in other tests, and the economy is poor. The present application solves the problem that the existing wind tunnel test device cannot independently and continuously adjust the vertical bending and torsion vibration frequencies.

[0021] (3) The present application ensures that the test model does not have lateral displacement except vertical displacement during vibration by constraining the spanwise and lateral directions of the model by the vertical bending steel beams, and the vertical bending and torsional two degrees of freedom are independently supported, so that the linear geometric stiffness condition is met during vibration, the vertical bending and torsional vibration frequencies are always constant, and the accuracy of the bridge wind resistance test can be ensured. If there is only single-degree-of-freedom vertical bending vibration, the vertical bending steel beams at both ends of the test model vibrate and deform in the same direction. If there is only single-degree-of-freedom torsional vibration, the torsional steel bars at both ends of the test model vibrate and deform in the same direction. If there is vertical bending and torsional coupling vibration, the two linear stiffness cantilever beams will linearly superimpose the above vibration deformations. In the past, when the torsional amplitude is large, the vertical spring will tilt obviously, the geometric stiffness of the spring will change nonlinearly, and the torsional stiffness provided by the vertical spring will have complex nonlinear characteristics with the amplitude, so the vertical and torsional stiffness of the bending-torsional coupling vibration system will no longer remain constant, thereby causing unacceptable errors in subsequent test results.

[0022] (4) The present application can conveniently obtain any required vertical bending and torsional vibration frequency by independently and continuously adjusting the effective length of the vertical bending steel beam and the torsional steel beam, and can easily realize simulation tests of very many different working conditions by combining different vertical bending and torsional vibration frequencies with different initial attack angle values. In the past, when performing specified working condition tests, it is necessary to not only adjust the attack angle to the specified value, but also replace the specified type of spring or hub, fiber rope, etc. to adjust the vertical bending and torsional vibration frequencies to the required values for the test working condition, which is tedious and the vertical bending stiffness and the torsional stiffness are not independent. When the vertical bending stiffness is changed, the torsional stiffness will also change, which makes it difficult to achieve certain specific working conditions, such as experimental working conditions with a higher or lower vertical bending and torsional vibration frequency ratio.

[0023] In addition to the objects, features, and advantages described above, the present application has other objects, features, and advantages. The present application will be described in further detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The drawings illustrate one preferred embodiment of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0025] Figure 1 is a structural schematic diagram of the bending-torsional coupling vibration wind tunnel test device in the preferred embodiment of the present application;

[0026] Figure 2 is Figure 1 is a front view of the combination of the rigid rod, the bearing, the bearing anchor, the vertical bending steel beam, the first connecting piece, and the torsional steel bar in

[0027] Figure 3 is Figure 1 is

[0028] Figure 4 is Figure 2 is

[0029] Figure 5 is Figure 1 is

[0030] Figure 6 is Figure 1 is

[0031] Wherein, 1-test model; 2-rigid rod; 3-bearing; 4-bearing anchor; 5-vertical bent steel beam; 6-bolt anchor; 7-fixed support; 8-first connecting piece; 9-torsion steel strip; 10-threaded rod; 11-second connecting piece. DETAILED DESCRIPTION

[0032] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the claims.

[0033] Embodiment:

[0034] Referring to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , the embodiment discloses a bend-torsion coupling vibration wind tunnel test device with continuous attack angle and frequency, comprising a test model 1, a vertical bending regulator, a torsion attack angle regulator and a rigid rod 2, the rigid rod 2 is arranged through the test model 1, the torsion center line of the test model 1 and the axis of the rigid rod 2 are arranged in line, the rigid rod 2 is rotatably connected with a first connecting piece 8, the torsion attack angle regulator comprises a second connecting piece 11 and the rigid rod 2 is adjustably connected with the second connecting piece 11, the first connecting piece 8 is located between the test model 1 and the second connecting piece 11, the first connecting piece 8 is connected with the vertical bending regulator, the vertical bending regulator is connected with the torsion attack angle regulator, and the vertical bending regulator is connected with an external support device.

[0035] In one specific embodiment, the rigid rod 2 is arranged through the test model 1, and the lengths of the rigid rods 2 at both ends of the test model 1 are the same, in addition, a set of first connecting pieces 8, vertical bending regulators and torsion attack angle regulators are respectively arranged on the rigid rods 2 at both ends of the test model 1.

[0036] In one embodiment, the second connecting member 11 is provided with a bolt hole and is fixed on the rigid rod 2 by a bolt. During the preparation of the test, the position of the second connecting member 11 can be adjusted and then fixed by the bolt.

[0037] It should be noted that the vertical bending adjuster is connected with the external support through the fixed support 7, and the torsional attack angle adjuster is used to provide torsional stiffness for the device itself. Specifically, when the test model 1 is twisted, the second connecting member 11 is twisted by the same angle, thereby driving the torsional attack angle adjuster to be bent, that is, the bending stiffness of the torsional attack angle adjuster indirectly provides the torsional stiffness of the test model 1.

[0038] It should be noted that the first connecting member 8 is connected with the rigid rod 2 through a rotating assembly, the rotating assembly includes a bearing 3 and a bearing anchor 4, the bearing 3 is arranged on the rigid rod 2, and the bearing anchor 4 is connected with the first connecting member 8 and the vertical bending adjuster.

[0039] The vertical bending adjuster is used to adjust the vertical bending vibration frequency of the test model 1. In this embodiment, the vertical bending adjuster preferably includes a vertical bending beam and an adjusting member arranged to slide along the length direction of the vertical bending beam, the end of the vertical bending beam is connected with the first connecting member 8, and the adjusting member is connected with the external support device.

[0040] Preferably, the vertical bending beam is a vertical bending steel beam 5, which provides vertical stiffness for the test model 1, limits the longitudinal and transverse displacement of the test model 1, and further ensures that the test model 1 does not vibrate laterally except vertically during vibration. Further, a sliding groove for continuous adjustment of the adjusting member is arranged on the vertical bending steel beam 5. In this embodiment, the adjusting member preferably includes a bolt anchor 6 and a fixed support 7 arranged on the bolt anchor 6, the bolt anchor 6 is used to continuously adjust the position of the adjusting member along the length direction of the sliding groove through a bolt and a nut, and the fixed support 7 is used to connect the external support device.

[0041] Further, as shown in the mechanical schematic diagram of the bending-torsional coupling vibration of the bridge test model: Figure 6

[0042] The dashed line represents the initial state of the test model and the device, at this time, the vertical bending steel beam and the torsional steel strip are not bent and deformed (the model is in a static state and does not vibrate);

[0043] The solid line represents the actual state of the deformed test model and the device, at this time, the vertical bending steel beam and the torsional steel strip are bent to provide vertical bending and torsional stiffness (the model is subjected to vertical bending and torsional coupling vibration);

[0044] a is the effective length of the torsional steel strip, and b is the effective length of the vertical bending steel beam;

[0045] ​c is the effective length of the threaded rod;

[0046] α is the bending angle of the torsional steel strip, and β is the bending angle of the vertical bending steel beam;

[0047] Δh is the vertical bending vibration displacement of the model, and θ is the model torsional vibration angle;

[0048] The vertical bending steel beam and the torsional steel strip are independently supported and do not interfere with each other. During vibration, the model generates a vertical bending vibration displacement Δh, so that the vertical bending steel beam is bent and a tangent angle β is generated at the force point. The model generates a torsional vibration angle θ, so that the second connecting member generates a torsional angle θ, so that the torsional steel strip is bent and a tangent angle α is generated at the force point. Thus, the torsional and vertical bending movement degrees of freedom of the bridge segment model are provided with completely independent and very good linear stiffness, and the linear geometric stiffness condition is met during vibration.

[0049] It should be noted that the vertical bending stiffness of the device in the embodiment is determined by the effective length b of the vertical bending steel beam 5 and the external support device. That is, the vertical bending stiffness adjustment is associated with the outside, and the torsional stiffness is adjusted by changing the effective length a of the torsional attack angle adjuster. That is, the torsional stiffness adjustment is not associated with the outside. In addition, the vertical bending stiffness of the vertical bending steel beam 5 is proportional to the frequency (the greater the vertical bending stiffness, the greater the frequency), so the vertical bending frequency can be adjusted by continuously adjusting the effective length b of the vertical bending steel beam 5.

[0050] The torsional attack angle adjuster is used to adjust the torsional vibration frequency and attack angle of the test model 1. The preferred torsional attack angle adjuster in the embodiment further comprises a torsional beam and an adjustable connecting rod. One end of the torsional beam is fixedly arranged on the first connecting member 8, and the other end is adjustably connected to the adjustable connecting rod. The end of the adjustable connecting rod away from the torsional beam is fixedly connected to the second connecting member 11. The second connecting member 11 is moved along the shaft of the rigid rod to the required stiffness. After the first connecting member is fixed, the threaded rod 10 is finally fixed, thereby changing the effective length of the torsional steel strip.

[0051] Preferably, the torsional beam is a torsional steel strip 9, a waist-shaped hole is formed in the torsional steel strip 9, and the adjustable connecting rod is a threaded rod 10. The end of the threaded rod 10 is adjustably arranged on the waist-shaped hole through a bolt, and is used to adjust the distance between the torsional steel strip 9 and the second connecting member 11 (i.e. the effective length c of the threaded rod). In the embodiment, one end of the torsional steel strip 9 is connected to the vertical bending steel beam 5 through the first connecting member 8, and the other end is connected to the second connecting member 11 through the threaded rod 10. The second connecting member 11 is synchronous with the torsional angle of the test model 1, so the linear stiffness of the torsional steel strip 9 can be converted into torsional stiffness. In the embodiment, the threaded rod 10 has two functions, i.e. adjusting the attack angle and adjusting the torsional frequency.

[0052] Preferably, the threaded rod is provided with scale values along the length direction of the threaded rod, which are used to assist in adjusting the initial angle of attack value of the test model 1. In a specific embodiment, the scale values are converted to correspond to the initial angle of attack value, i.e. the initial angle of attack value and the scale value on the threaded rod are in one-to-one correspondence. In this embodiment, by adjusting the vertical anchoring position of the threaded rod, the effective length c of the threaded rod between the second connecting piece 11 and the torsion steel strip 9 can be quantitatively and continuously changed, so that the initial rotation of the second connecting piece 11 drives the test model 1 to continuously rotate by the same angle, thereby achieving the effect of more convenient and accurate adjustment of the initial angle of attack.

[0053] Further, for the torsion steel strip 9, by adjusting the horizontal anchoring position of the threaded rod 10 and the torsion steel strip 9, the effective length (torsional stiffness) of the torsion steel strip 9 is changed, and the torsional frequency adjustment principle is consistent with the vertical bending frequency adjustment. The second connecting piece 11 in this embodiment is continuously adjustable along the axis of the rigid rod 2, and the final fixed position of the second connecting piece 11 is determined by the required torsional stiffness, i.e. the effective length of the torsion steel strip 9.

[0054] In this embodiment, by providing a sliding groove between the vertical bending steel beam 5 and the bolt anchoring piece 6 and the fixed support 7, and between the torsion steel strip 9 and the threaded rod 10, the effective lengths of the vertical bending steel beam 5 and the torsion steel strip 9 are independently and continuously adjustable, and the vertical bending stiffness and the torsional stiffness are independently and continuously adjustable, thereby enabling the vertical bending and torsional vibration frequencies to be independently and continuously adjustable.

[0055] In summary, the device of the present application has extremely wide application range, and compared with the previous wind tunnel test device, the structure is novel, the operation is convenient, the initial angle of attack, the vertical bending and the torsional vibration frequency are continuously adjustable, and the accuracy of the wind tunnel test results is further improved.

[0056] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A wind tunnel test apparatus for bending-torsional coupled vibration with continuously adjustable angle of attack and frequency, characterized in that, The test model (1), vertical bending adjuster, torsional angle of attack adjuster, and rigid rod (2) are included. The rigid rod (2) is set through the test model (1). The torsional center line of the test model (1) and the axis of the rigid rod (2) are collinear. The rigid rod (2) is rotatably connected to a first connecting piece (8). The torsional angle of attack adjuster includes a second connecting piece (11) and the rigid rod (2) is adjustablely connected to the second connecting piece (11). The first connecting piece (8) is located between the test model (1) and the second connecting piece (11). One end of the first connecting piece (8) is connected to the vertical bending adjuster, and the other end of the first connecting piece (8) is connected to the torsional angle of attack adjuster. The vertical bending adjuster is connected to an external support device. The vertical bending adjuster is used to adjust the vertical bending vibration frequency of the test model (1); The torsional angle of attack adjuster is used to adjust the torsional vibration frequency and angle of attack of the test model (1); The vertical bending adjuster includes a vertical bending beam and an adjusting member that is slidably arranged along the length of the vertical bending beam. The end of the vertical bending beam is connected to a first connecting member (8), and the adjusting member is connected to an external support device. The torsion angle of attack adjuster also includes a torsion beam and an adjustable connecting rod. One end of the torsion beam is fixedly mounted on the first connecting member (8), and the other end is adjustablely connected to the adjustable connecting rod. The end of the adjustable connecting rod away from the torsion beam is fixedly connected to the second connecting member (11). The torsion beam is a torsion steel bar (9), and the torsion steel bar (9) has a waist-shaped hole. The adjustable connecting rod is a threaded rod (10), and the end of the threaded rod (10) is adjustablely set on the waist-shaped hole by a bolt, which is used to adjust the distance between the torsion steel bar (9) and the second connecting piece (11). The threaded rod has a scale value along its own length direction, and the scale is used to help adjust the initial angle of attack value of the test model (1).

2. The bending-torsional coupled vibration wind tunnel test apparatus according to claim 1, characterized in that, The vertical curved beam is a vertical curved steel beam (5), and a groove is provided on the vertical curved steel beam for continuous adjustment of the adjusting component.

3. The bending-torsional coupled vibration wind tunnel test apparatus according to claim 2, characterized in that, The adjusting component includes a bolt anchor (6) and a fixed support (7) provided on the bolt anchor. The bolt anchor (6) enables the adjusting component to continuously adjust its position along the length of the groove through bolts and nuts. The fixed support (7) is used to connect an external support device.

4. The bending-torsional coupled vibration wind tunnel test apparatus according to any one of claims 1-3, characterized in that, The first connector (8) is connected to the rigid rod (2) via a rotating assembly, the rotating assembly including a bearing (3) and a bearing anchor (4), the bearing (3) being disposed on the rigid rod (2), and the bearing anchor (4) connecting the first connector (8) and the vertical bend adjuster.

Images