Vibration isolation device and wind tunnel test system for high angle of attack wind tunnel test

Abstract

The present invention discloses a high-angle-of-attack wind tunnel test vibration-absorbing device and a wind tunnel test system, comprising a symmetrically arranged L-shaped member, a shell, a spring steel sheet and a counterweight; wherein the shell has a long side and a short side, and the L-shaped member is fixed to the short side of the shell; the L-shaped member comprises a first molded member and a second molded member, the front end of the spring steel sheet is inserted from the middle part of the shell, and the end of the spring steel sheet is located outside the shell and clamped by the first molded member and the second molded member; the counterweight is located at the free end of the spring steel sheet. The vibration-absorbing device does not require external energy input, nor does it require a complex control rate design, nor does it require modification of the support system, and the frequency and damping of the vibration-absorbing device can be adjusted according to different models, thereby improving the efficiency of the vibration-absorbing device, making it easy to disassemble, and having high safety and reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of wind tunnel tests, and in particular relates to a vibration elimination device for high-angle-of-attack wind tunnel tests and a wind tunnel test system. Background Art

[0002] Wind tunnel testing is an indispensable way to obtain aerodynamic data in the process of aircraft development. The wind tunnel model and its support system are the motion mechanisms that realize the change of the attitude angle of the aircraft model in the wind tunnel test. Usually, a long cantilever support rod structure is used to reduce its turbulence interference on the flow field and provide good dynamic test characteristics. However, such a structure is usually a multi-degree-of-freedom, low-damping elastic system. Because a balance is needed to measure aerodynamic forces, the entire wind tunnel model system has low stiffness characteristics and is prone to vibration. Especially in the large angle of attack test of the aircraft, large-amplitude abnormal vibrations often occur, which not only affects the quality of the test data, limits the test state range, but also seriously threatens the safety of the wind tunnel.

[0003] In order to reduce the vibration of the model in domestic wind tunnels, the traditional method is mainly to change the dynamic characteristics of the support system by changing the mass of the support rod or the model, but this method is costly and time-consuming. At present, the active vibration reduction control method based on piezoelectric ceramic actuators is the main research at home and abroad. The main patents include CN201310196950.1 and CN201710475080.X, but this method has the problems of complex system, high cost and easy divergence of the system. Patent CN201821445672.3 attempts to arrange a mass stiffness system at the root of the support rod, but the defect of this device is that it can only slow down the vibration but cannot fundamentally solve the problem of model vibration, and the support rod needs to be replaced for different models, resulting in increased costs. Patent CN202010144762.4 adds liquid mercury to the inside of the model support rod to dissipate energy through liquid shaking. This method has high processing requirements, and mercury is toxic. Once leaked, it will threaten the health of experimental operators.

[0004] Through research, it was found that the abnormal vibration of the model in the high-angle-of-attack wind tunnel test is mainly a single-degree-of-freedom flutter problem. This abnormal vibration caused by structural modal instability is very sensitive to the frequency and damping of the vibration reduction device, which results in many vibration absorbers of the same type failing to achieve the vibration reduction effect. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The purpose of the present invention is to overcome the defects of the existing wind tunnel model vibration reduction technology system, which is complex, expensive and cannot reduce vibration under all working conditions. On the basis of fully understanding the vibration mechanism of the wind tunnel model, a large angle of attack wind tunnel test vibration reduction device is provided, which can effectively improve the structural stability of the model system with a simple and practical structure, and achieve vibration reduction by adjusting the damping and frequency, thereby ensuring the accuracy of the wind tunnel test data and improving the safety of the test.

[0007] (II) Technical solution

[0008] To achieve the above-mentioned purpose, the high-angle-of-attack wind tunnel test vibration absorption device of the present invention comprises a symmetrically arranged L-shaped member, a shell, a spring steel sheet and a counterweight; wherein the shell has a long side and a short side, and the L-shaped member is fixed to the short side of the shell; the L-shaped member comprises a first mold member and a second mold member, the front end of the spring steel sheet is inserted from the middle part of the shell, and the end of the spring steel sheet is located outside the shell and clamped by the first mold member and the second mold member; the counterweight is located at the free end of the spring steel sheet.

[0009] Furthermore, damping member 1 and damping member 2 are arranged on both sides of the spring steel sheet, and damping member 1 and damping member 2 are symmetrically arranged on both sides of the spring steel sheet.

[0010] Furthermore, a side of the damping element 1 close to the spring steel sheet is in close contact with the spring steel sheet, and a side of the damping element 2 close to the spring steel sheet is in close contact with the spring steel sheet.

[0011] Furthermore, a first pressing plate is provided on the side of the damping member 1 away from the spring steel sheet, and a second pressing plate is provided on the side of the damping member 2 away from the spring steel sheet; the first pressing plate is connected to the damping member 1 through a first adjusting screw; and the second pressing plate is connected to the damping member 2 through a second adjusting screw.

[0012] Furthermore, there is an even number of the first adjusting screws, which are symmetrically distributed at both ends of the first pressing plate; there is an even number of the second adjusting screws, which are symmetrically distributed at both ends of the second pressing plate.

[0013] Furthermore, the damping member 1 and the damping member 2 are arranged at a middle position in the shell.

[0014] The invention also discloses a wind tunnel test device, comprising a scimitar mechanism, a model support rod and a test model, wherein the high-angle-of-attack wind tunnel test vibration elimination device as described above is arranged inside the test model.

[0015] Furthermore, the high-angle-of-attack wind tunnel test vibration isolation device adjusts the compression degree of damping element one by rotating the first adjusting screw, thereby achieving an adjustable damping range of damping element one; similarly, the high-angle-of-attack wind tunnel test vibration isolation device adjusts the compression degree of damping element two by rotating the second adjusting screw, thereby achieving an adjustable damping range of damping element two.

[0016] Furthermore, when the frequency of the high-angle-of-attack wind tunnel test vibration elimination device is consistent with the vibration frequency of the test model, vibration elimination of the test model is achieved.

[0017] (III) Beneficial effects

[0018] Compared with the prior art, the technical solution of the present invention has the following advantages: 1. Compared with the traditional piezoelectric ceramic damper, the vibration damping device does not require external energy input, nor does it require complex control rate design, and the cost is lower; 2. Compared with the damper arranged at the root of the model support, the vibration damping device is arranged inside the model, which is the position with the largest amplitude, and can be effectively coupled with the model system to achieve the vibration damping effect, without the need to modify the support system, and the frequency and damping of the vibration damping device can be adjusted according to different models, thereby improving the efficiency of the vibration damping device; 3. Compared with the liquid damper in which the cavity is processed on the support rod and liquid mercury is injected, the vibration damping device does not need to redesign and modify the entire model system. It is installed inside the model as an additional mechanism, which is easy to disassemble, and has higher safety and reliability than liquid mercury. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the overall structure of a high angle of attack wind tunnel test vibration elimination device and a wind tunnel test device provided for an embodiment of the present invention;

[0020] Figure 2 It is a top view of the vibration reduction device for high angle of attack wind tunnel test of the present invention;

[0021] Figure 3 The present invention is based on Figure 2 AA direction profile;

[0022] Figure 4 The present invention is based on Figure 2 BB direction cross-section diagram.

[0023] In the figure: 1.1, scimitar mechanism; 1.2, model support rod; 1.3, test model; 1.4, vibration reduction device; 2.1, mold part 1; 2.2, mold part 2; 2.3, spring steel sheet; 2.4, counterweight; 2.5, housing; 3.1, first adjusting screw; 3.2, second adjusting screw; 3.3, damping part 1; 3.4, damping part 2; 3.5, first pressing plate; 3.6, second pressing plate. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] like Figures 1 to 4As shown, the high angle of attack wind tunnel test vibration absorption device 1.4 of the present invention comprises a symmetrically arranged L-shaped member, an outer shell 2.5, a spring steel sheet 2.3 and a counterweight 2.4; wherein the outer shell 2.5 has a long side and a short side, and the L-shaped member is fixed to the short side of the outer shell 2.5; the L-shaped member comprises a profile 1 2.1 and a profile 2 2.2, the front end of the spring steel sheet 2.3 is inserted from the middle part of the outer shell 2.5, and the end of the spring steel sheet 2.3 is located outside the outer shell 2.5 and clamped by the profile 1 2.1 and the profile 2 2.2; the counterweight 2.4 is located at the free end of the spring steel sheet 2.3, and when the counterweight 2.4 is determined, the structural frequency characteristics of the vibration absorption device 1.4 can be changed by adjusting the length of the spring steel sheet 2.3.

[0026] A damping member 1 3.3 and a damping member 2 3.4 are arranged on both sides of the spring steel sheet 2.3 located in the inner cavity of the housing 2.5. The damping member 1 3.3 and the damping member 2 3.4 are symmetrically arranged on both sides of the spring steel sheet 2.3.

[0027] The side of the damping member 1 3.3 close to the spring steel sheet 2.3 is in close contact with the spring steel sheet 2.3, and the side of the damping member 2 3.4 close to the spring steel sheet 2.3 is in close contact with the spring steel sheet 2.3. The damping material can be selected from soft damping materials such as foam and rubber.

[0028] The first pressing plate 3.5 is provided on the side of the damping member 1 3.3 away from the spring steel sheet 2.3, and the second pressing plate 3.6 is provided on the side of the damping member 2 3.4 away from the spring steel sheet 2.3; the first pressing plate 3.5 is connected to the damping member 1 3.3 through the first adjusting screw 3.1; the second pressing plate 3.6 is connected to the damping member 2 3.4 through the second adjusting screw 3.2. The compression amount of the damping material is adjusted by adjusting the position of the pressing plate through the screw, thereby changing the damping characteristics.

[0029] The first adjusting screws 3.1 have an even number and are symmetrically distributed at both ends of the first pressing plate 3.5; the second adjusting screws 3.2 have an even number and are symmetrically distributed at both ends of the second pressing plate 3.6.

[0030] The damping element 1 3.3 and the damping element 2 3.4 are arranged at a middle position in the housing 2.5.

[0031] The present invention further discloses a wind tunnel test device, comprising a scimitar mechanism 1.1, a model support rod 1.2 and a test model 1.3, and the above-mentioned high-angle-of-attack wind tunnel test vibration reduction device 1.4.

[0032] The high-angle-of-attack wind tunnel test vibration absorption device 1.4 adjusts the compression degree of the damping member 1 3.3 by rotating the first adjusting screw 3.1, thereby achieving an adjustable damping range of the damping member 1 3.3; similarly, the high-angle-of-attack wind tunnel test vibration absorption device 1.4 adjusts the compression degree of the damping member 2 3.4 by rotating the second adjusting screw 3.2, thereby achieving an adjustable damping range of the damping member 2 3.4.

[0033] When the frequency of the high-angle-of-attack wind tunnel test vibration-damping device 1.4 is consistent with the vibration frequency of the test model 1.3, the vibration of the test model 1.3 is eliminated.

[0034] Working principle:

[0035] When the angle of attack is large, the structural mode and flow mode of the model support rod and the test model combination are coupled, resulting in structural modal instability, resulting in large-scale vibration. At this time, the spring steel sheet will bend and deform repeatedly, and the counterweight block at the free end of the spring steel sheet will also make an approximate single-degree-of-freedom reciprocating motion, and the kinetic energy will be converted into internal energy through the dissipation of the damping material. Through fluid-solid coupling analysis, it is easy to know that when the vibration frequency of the vibration reduction device is coupled with the model support frequency, the structural modal stability of the entire wind tunnel model system can be improved, thereby achieving the effect of vibration reduction. Specifically, by rotating the adjusting screw, the compression degree of damping element one and damping element two can be changed, thereby achieving damping adjustment. When the test model and the model support rod are at a large angle of attack, reciprocating oscillations similar to sinking and floating are likely to occur under the action of the wind tunnel flow. The counterweight block and spring steel sheet of the vibration-isolating device will also produce reciprocating vibrations in the same direction. At the same time, the damping material is stretched and / or compressed, converting kinetic energy into internal energy. When the frequency of the vibration-isolating device is close to the frequency of the model support system, the stability of the entire model system can be greatly improved, thereby achieving vibration isolation of the wind tunnel test model.

[0036] The device of the present invention can adjust the frequency and damping, effectively suppress the vibration of the wind tunnel model, has a simple structure, is easy to install and has a low cost.

[0037] In summary, the above-mentioned embodiments are not limitative embodiments of the present invention, and any modifications or equivalent variations made by those skilled in the art on the basis of the essential contents of the present invention are within the technical scope of the present invention.

Claims

1. A vibration reduction device for high angle of attack wind tunnel test, characterized in that: It includes a symmetrically arranged L-shaped member, a housing, a spring steel sheet and a counterweight; The shell has a long side and a short side, and the L-shaped member is fixed to the short side of the shell; the L-shaped member includes a profile 1 and a profile 2, the front end of the spring steel sheet is inserted from the middle part of the shell, and the end of the spring steel sheet is located outside the shell and clamped by the profile 1 and the profile 2; damping member 1 and damping member 2 are arranged on both sides of the spring steel sheet, and the damping member 1 and damping member 2 are symmetrically arranged on both sides of the spring steel sheet; the side of the damping member 1 close to the spring steel sheet is tightly fitted with the spring steel sheet, and the side of the damping member 2 close to the spring steel sheet is tightly fitted with the spring steel sheet; the side of the damping member 1 away from the spring steel sheet is provided with a first pressing sheet, and the side of the damping member 2 away from the spring steel sheet is provided with a second pressing sheet; the first pressing sheet is connected to the damping member 1 through a first adjusting screw; the second pressing sheet is connected to the damping member 2 through a second adjusting screw; The counterweight is located at the free end of the spring steel sheet.

2. The vibration reduction device for high angle of attack wind tunnel test according to claim 1, characterized in that: The first adjusting screws have an even number and are symmetrically distributed at both ends of the first pressing plate; the second adjusting screws have an even number and are symmetrically distributed at both ends of the second pressing plate.

3. The vibration reduction device for high angle of attack wind tunnel test according to claim 1, characterized in that: The damping member 1 and the damping member 2 are arranged at the middle position in the shell.

4. A wind tunnel test device, comprising a scimitar mechanism, a model support rod and a test model, characterized in that: A high-angle-of-attack wind tunnel test vibration reduction device as described in any one of claims 1 to 3 is arranged inside the test model.

5. The wind tunnel test device according to claim 4, characterized in that: The high-angle-of-attack wind tunnel test vibration isolation device adjusts the compression degree of damping element one by rotating the first adjusting screw, thereby achieving an adjustable damping range of damping element one; similarly, the high-angle-of-attack wind tunnel test vibration isolation device adjusts the compression degree of damping element two by rotating the second adjusting screw, thereby achieving an adjustable damping range of damping element two.

6. The wind tunnel test device according to claim 5, characterized in that: When the frequency of the high-angle-of-attack wind tunnel test vibration elimination device is consistent with the vibration frequency of the test model, the vibration elimination of the test model is achieved.

Images