A variable stiffness rate independent negative stiffness viscoelastic damping passive vibration reduction system

Abstract

The present application belongs to the technical field of vibration control, and discloses a variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system, which comprises a negative stiffness unit and a viscoelastic damping unit, wherein: the negative stiffness unit comprises a body frame, two air cylinders, a central connecting block and two groups of sliding assemblies, the body frame comprises a first connecting end plate and two side plates, one end of each air cylinder is hinged to a side plate; the central connecting block comprises two ear plates, each air cylinder is connected with a sliding assembly through an ear plate; the viscoelastic damping unit comprises an oil damper, a double-acting air cylinder and a second connecting end plate, one end of the oil damper is hinged to the first connecting end plate, the other end of the oil damper is hinged to one end of the central connecting block, one end of the double-acting air cylinder is connected with the central connecting block, and the other end of the double-acting air cylinder is connected with the second connecting end plate through a piston. The present application solves the technical problems that the prior art is difficult to meet the requirements of size, mechanical properties and usability.

Description

Technical Field

[0001] This invention belongs to the field of vibration control technology, and more specifically, relates to a variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system. Background Technology

[0002] Vibration control technology has been applied to various engineering fields to reduce or eliminate structural vibrations caused by various factors (such as wind loads, seismic loads, train loads, etc.). However, how to effectively reduce vibration response in the face of vibration sources with complex frequency domain components has always been one of the key issues in the field of vibration control.

[0003] To better control vibrations caused by complex vibration source inputs, vibration damping systems should possess good adaptive control characteristics. Compared to traditional vibration damping systems, those with rate-independent characteristics (i.e., output force independent of frequency) can provide greater control force under low-frequency excitation to further control displacement, while requiring less control force under high-frequency excitation to avoid increasing the acceleration response of the controlled system. Therefore, implementing a passive vibration damping system with rate-independent control characteristics can effectively improve vibration control performance under excitations with complex frequency domain components. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system, which is used to solve the technical problem that the existing technology is unable to simultaneously meet the requirements of volume, mechanical performance and usability.

[0005] To achieve the above objectives, this application provides a variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system, comprising a negative stiffness unit and a viscoelastic damping unit, wherein: the negative stiffness unit includes a main frame, two cylinders, a central connecting block, and two sets of sliding components; the main frame includes a first connecting end plate and two side plates disposed on one side of the first connecting end plate, with one end of each cylinder hinged to one side plate; the central connecting block includes two ear plates, with the other end of each cylinder connected to a sliding component via one ear plate, and the cylinder hinged to the ear plate; the two sets of sliding components are respectively connected to one side plate; the viscoelastic damping unit includes an oil damper, a double-acting cylinder, and a second connecting end plate; one end of the oil damper is hinged to the first connecting end plate, and the other end of the oil damper is hinged to one end of the central connecting block; one end of the double-acting cylinder is connected to the other end of the central connecting block, and the other end of the double-acting cylinder is connected to the second connecting end plate via a piston.

[0006] Preferably, the sliding assembly includes a slider and a slide rail, the slide rail being fixedly connected to the side plate, and the slider being fixedly connected to the ear plate of the central connecting block.

[0007] Preferably, the system also includes a gas supply unit, which includes two high-pressure gas tanks. Each high-pressure gas tank includes two gas pipelines, one of which is connected to a cylinder and the other is connected to a double-acting cylinder.

[0008] Preferably, the chambers on both sides of the piston in the double-acting cylinder are respectively connected to the pipeline of a high-pressure gas tank.

[0009] Preferably, the two high-pressure gas tanks are fixed to the first connecting end plate and are centrally symmetrical along the axis of the oil damper.

[0010] Preferably, in the balanced state, the two cylinders are perpendicular to the side plate, and both cylinders have pre-pressure.

[0011] Preferably, there are multiple double-acting cylinders, which are symmetrically arranged along the axis of the oil damper; in a further preferred embodiment, the two lugs of the central connecting block are symmetrically arranged along the axis of the oil damper.

[0012] Preferably, based on the controlled system, the parameters of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system should satisfy the following conditions to achieve the rate-independent characteristic of the control force:

[0013] K N =-βk,K M =2βk,c M =βk / ω0

[0014] Among them, c M K is the linear damping coefficient of a law-independent, negative stiffness, viscoelastic damping passive vibration reduction system. M K is the linear positive stiffness coefficient of a rate-independent negative stiffness viscoelastic damping passive vibration reduction system. N β is the linear negative stiffness coefficient of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system, k is the stiffness of the controlled system, ω0 is the frequency of the controlled system, and β is the design damping ratio of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system.

[0015] Preferably, the nonlinear damping coefficient of the oil damper satisfies:

[0016]

[0017] Among them, c M Γ is the linear damping coefficient of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system of this application, α is the preset damping index of the oil damper, Γ is the gamma function, and v is the preset target velocity.

[0018] Preferably, the initial pressure P of the cylinder i Stroke D and piston head area A i Satisfy the following formula:

[0019]

[0020] Where i is the cylinder number, i=1 is the first cylinder 8, i=2 is the second cylinder, and k N i (x) represents the negative stiffness provided by the i-th cylinder under different displacements x, P i Let A be the initial pressure of the i-th cylinder, D be the stroke of the first and second cylinders, and A be the initial pressure of the i-th cylinder. i Let b be the piston head area of ​​the i-th cylinder. i Let b be the compression volume retention rate of the i-th cylinder. i =(1-DA) i / V i ) n L h L is the sum of the lengths of the connecting hinges on the first and second cylinders. p Let L be the total length of the first and second cylinders after compression at their equilibrium positions, and μ be the dimensionless relative displacement of the central connecting block, μ = x / (L). p +L h ), x is the horizontal displacement of the central connecting block relative to the equilibrium position, g is the dimensionless length ratio, g=(L p +L h ) / D, where n is the gas compressibility polytropic index, V i Let x be the preset total volume of the i-th cylinder and the high-pressure gas tank and chamber connected to it. max The preset maximum travel distance;

[0021] The area A on both sides of the piston in a double-acting cylinder f and A s satisfy:

[0022]

[0023] Among them, A f Let A be the area of ​​the piston without the piston rod. s This is the area of ​​the piston on the side with the piston rod.

[0024] In summary, compared with the prior art, the variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system provided by the present invention has the following beneficial effects:

[0025] 1. This application includes an oil damper for energy dissipation. Specifically, the cylinder and the oil damper are connected via a central connecting block. The cylinder provides the oil damper with a force that acts as negative stiffness, assisting the oil damper in energy dissipation. The double-acting cylinder is connected to the central connecting block to achieve the function of a tuning spring. Furthermore, by adjusting the negative stiffness coefficient of the negative stiffness unit, the damping coefficient of the oil damper, and the positive stiffness coefficient of the double-acting cylinder, rate-independent control can be achieved, thus realizing a rate-independent negative stiffness viscoelastic damping passive vibration reduction system.

[0026] 2. The two chambers inside the double-acting cylinder are also connected to different high-pressure cylinder tanks, so that the equivalent stiffness of the double-acting cylinder changes synchronously with the negative stiffness provided by the cylinder when the cylinder moves, giving the damping system a wider tuning frequency range and good adaptability.

[0027] 3. This application uses a cylinder to provide negative stiffness. The compressed gas has a large stiffness coefficient and a higher compression ratio. The cylinder can achieve a negative stiffness effect with higher linearity and mechanical properties than traditional springs in the direction of movement.

[0028] 4. By designing the key parameters of each component to ensure that they conform to the rate-independent control characteristic parameter relationship, and at the same time ensuring that the stiffness relationship conforms to the rate-independent control characteristic parameter relationship within the stroke range, a rate-independent negative stiffness viscoelastic damping passive vibration reduction system with variable stiffness is realized. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to an embodiment of this application;

[0030] Figure 2 This is a right view of a variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to an embodiment of this application.

[0031] Figure 3 This is a schematic diagram of the structure of a double-acting cylinder according to an embodiment of this application;

[0032] Figure 4 This is the equivalent model of the variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system of this application;

[0033] Figure 5 This application describes the rate-independent control characteristics of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system with variable stiffness.

[0034] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0035] 1-First connecting end plate; 2-Side plate; 3-Connecting rib; 4-Slider; 5-Slide rail; 6-First connecting ear; 7-Oil damper; 8-First cylinder; 9-Second cylinder; 10-Central connecting block; 11-Double-acting cylinder; 12-Cavity connecting pipe; 13-Second connecting end plate; 14-Second connecting ear; 15-First high-pressure gas tank; 16-Second high-pressure gas tank; 17-First pipeline; 18-Second pipeline; 19-Third pipeline; 20-Fourth pipeline; 21-Connecting hinge; 22-First chamber; 23-Second chamber; 24-Piston. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0037] This application discloses a variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system, which includes a negative stiffness unit and a viscoelastic damping unit.

[0038] The negative stiffness unit includes a main frame, two cylinders, a central connecting block, and two sets of sliding components. The main frame includes a first connecting end plate 1 and side plates 2 on both sides of the first connecting end plate 1. One end of each cylinder is hinged to one side plate 2. The central connecting block 10 includes two ear plates. The other end of each cylinder is connected to a sliding component through one ear plate. The cylinder is hinged to the ear plate. The two sets of sliding components are respectively connected to one side plate 2.

[0039] In this embodiment, the main frame includes a first connecting end plate 1 and two side plates 2 disposed on one side of the first connecting end plate 1. The two side plates 2 are fixedly connected by connecting ribs 3. A first connecting lug 6 is provided on the other side of the first connecting end plate 1. The two side plates 2 are arranged symmetrically with respect to the central axis of the first connecting end plate 1.

[0040] Two cylinders, namely cylinder 8 and cylinder 9, are perpendicular to the two side plates 2 in the balanced state, and both cylinders have pre-pressure. One end of cylinder 8 and cylinder 9 are respectively hinged to the two side plates 2 via connecting hinge 21.

[0041] The sliding assembly includes a slider 4 and a slide rail 5. The slide rail 5 is fixed to the side plate 2, and the slider 4 slides on the slide rail 5. The central connecting block 10 includes two ear plates, which are centrally symmetrically arranged with respect to the axis of the central connecting block 10, so that the two ear plates can be fixed to the two sets of sliding assemblies. The other ends of the two cylinders are respectively hinged to the two ear plates.

[0042] The viscoelastic damping unit includes an oil damper 7, a double-acting cylinder 11, and a second connecting end plate 13. One end of the oil damper 7 is hinged to the first connecting end plate 1, and the other end of the oil damper 7 is hinged to one end of the central connecting block 10. One end of the double-acting cylinder 11 is connected to the other end of the central connecting block 10, and the other end of the double-acting cylinder 11 is connected to the second connecting end plate 13 through a piston.

[0043] In this embodiment, one end of the oil damper 7 is hinged to the first connecting end plate 1 via a connecting hinge. The other end of the oil damper 7 is hinged to one end of the axis of the central connecting block 10 via a connecting hinge.

[0044] In a further preferred embodiment, the system also includes a gas supply unit comprising two high-pressure gas tanks, namely a first high-pressure gas tank 15 and a second high-pressure gas tank 16. Each high-pressure gas tank includes two gas pipelines, one of which is connected to a cylinder and the other is connected to a double-acting cylinder 11. That is, the first high-pressure gas tank 15 includes a first pipeline 17 and a second pipeline 18, and the second high-pressure gas tank 16 includes a third pipeline 19 and a fourth pipeline 20. The first pipeline 17 is connected to the first cylinder 8, and the third pipeline 19 is connected to the second cylinder 9.

[0045] In a further preferred embodiment, the double-acting cylinder 11 is provided with a piston 24, which divides the double-acting cylinder 11 into a first chamber 22 and a second chamber 23. The other end of the piston 24 is connected to a second connecting end plate 13, and the second connecting end plate 13 is provided with a second connecting lug 14.

[0046] In a further preferred embodiment, the chambers on both sides of the piston inside the double-acting cylinder 11 are respectively connected to the pipelines of a high-pressure gas tank. The first chamber 22 and the second chamber 23 of the multiple double-acting cylinders 11 are respectively connected through a cavity connecting pipe. The first chamber 22 of the double-acting cylinder 11 is connected to the first high-pressure gas tank 15 through a second pipeline 18, and the second chamber 23 of the double-acting cylinder 11 is connected to the second high-pressure gas tank 16 through a fourth pipeline 20.

[0047] In a further preferred embodiment, the two high-pressure gas tanks are fixed to the first connecting end plate 1 and are centrally symmetrical along the axis of the oil damper 7. After the first cylinder 8 and the second cylinder 9 leave the equilibrium position, they reduce the pressure inside the first high-pressure gas tank 15 and the second high-pressure gas tank 16, thereby simultaneously reducing the pressure in the first chamber 22 and the second chamber 23 of the double-acting cylinder 11, thus realizing the change in the translational stiffness of the double-acting cylinder.

[0048] In a further preferred embodiment, in the balanced state, the two cylinders are perpendicular to the side plate 2, and both cylinders have pre-pressure.

[0049] In a further preferred embodiment, there are multiple double-acting cylinders 11, which are symmetrically arranged along the axis of the oil damper 7 and connected by a cavity connecting pipe 12.

[0050] The second connecting end plate 13 is connected to the outside. When the second connecting end plate 13 moves, it drives the central connecting block 10 to move through the double-acting cylinder 11. When the central connecting block 10 moves, it drives the oil damper 7 to move to dissipate energy. When the central connecting block 10 moves, it drives the first cylinder 8 and the second cylinder 9. When the first cylinder 8 and the second cylinder 9 move, they provide force along the direction of movement to achieve a negative stiffness effect and assist the oil damper 7 in moving. The slider 4 and the guide rail 5 ensure that the central connecting block 10 moves along the axis of the device.

[0051] The key parameter design steps for this variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system are as follows:

[0052] (1) Based on the characteristic parameters of the controlled system and the design damping ratio, the parameters of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system of this application are calculated. At the same time, based on the design stroke of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system, the negative stiffness coefficient and the positive stiffness coefficient of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system are made equal at the maximum stroke.

[0053] Based on the controlled system, the parameters of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system should satisfy the following:

[0054] K N =-βk,K M =2βk,c M =βk / ω0

[0055] Design goals:

[0056] Where k is the stiffness of the controlled system, ω0 is the frequency of the controlled system, β is the design damping ratio of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system, and c M K is the linear damping coefficient of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system of this application. N K represents the total negative stiffness at the equilibrium position of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system of this application. M For the equivalent positive stiffness of the double-acting cylinder at the equilibrium position of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system of this application, k N i (x) represents the negative stiffness provided by the i-th cylinder under different displacements x, k M (x) represents the positive stiffness provided by the double-acting cylinder at different displacements x, where x max The maximum displacement is designed for the central connecting block 10.

[0057] (2) The nonlinear damping coefficient of the oil damper 7 is designed according to the linear viscous damping design formula.

[0058] The nonlinear damping coefficient of oil damper 7 should satisfy:

[0059]

[0060] Among them, c M The linear damping coefficient of the passive vibration reduction system with negative stiffness and independent rate of this application has been obtained by the above step (1), where α is the preset damping index of the oil damper, Γ is the gamma function, and v is the preset target speed.

[0061] (3) Initial pressure P of the cylinder i Stroke D and piston head area A i In the design, the negative stiffness provided by the i-th cylinder should satisfy:

[0062]

[0063] Where i is the cylinder number, i=1 is the first cylinder 8, i=2 is the second cylinder 9, P i Let A be the initial pressure of the i-th cylinder, D be the stroke of the first cylinder 8 and the second cylinder 9, and A be the initial pressure of the i-th cylinder. i Let b be the piston head area of ​​the i-th cylinder. i Let b be the compression volume retention rate of the i-th cylinder. i =(1-DA) i / V i ) n L h L is the sum of the lengths of the connecting hinges 21 on the first and second cylinders. p The total length of the first and second cylinders after compression at the equilibrium position is μ = x / (L) p +L h μ is the dimensionless relative displacement of the central connecting block 10, x is the horizontal displacement of the central connecting block relative to the equilibrium position, g is the dimensionless length ratio, and g = (L p +L h ) / D, where n is the gas compressibility polytropic index, V i Let be the total volume of the i-th cylinder and the high-pressure gas tank and chamber connected to it.

[0064] When x is 0 and x max Then, by combining the formulas from step (1) above, the initial pressure P of the cylinder can be obtained. i Stroke D and piston head area A i .

[0065] (4) Calculate the area A on both sides of the piston of the double-acting cylinder 11.f and A s .

[0066]

[0067] Similarly, when x is 0 and x max At the same time, the area A on both sides of the piston of the double-acting cylinder 11 in step (1) above is combined. f and A s A f Let A be the area of ​​the piston 24 without the piston rod. s The area of ​​piston 24 on the piston rod side.

[0068] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A variable stiffness rate-independent negative stiffness viscoelastic damping passive vibration reduction system, characterized in that, It includes negative stiffness elements and viscoelastic damping elements, wherein: The negative stiffness unit includes a main frame, two cylinders, a central connecting block, and two sets of sliding components. The main frame includes a first connecting end plate (1) and two side plates (2) located on one side of the first connecting end plate (1). One end of each cylinder is hinged to one side plate (2). The central connecting block (10) includes two ear plates. The other end of each cylinder is connected to a sliding component through one ear plate. The cylinder is hinged to the ear plate. The two sets of sliding components are respectively connected to one side plate (2). The viscoelastic damping unit includes an oil damper (7), a double-acting cylinder (11), and a second connecting end plate (13). One end of the oil damper (7) is hinged to the first connecting end plate (1), and the other end of the oil damper (7) is hinged to one end of the central connecting block (10). One end of the double-acting cylinder (11) is connected to the other end of the central connecting block (10), and the other end of the double-acting cylinder (11) is connected to the second connecting end plate (13) through a piston. It also includes a gas supply unit, which includes two high-pressure gas tanks, namely a first high-pressure gas tank (15) and a second high-pressure gas tank (16). Each high-pressure gas tank includes two gas pipelines, one of which is connected to a cylinder and the other is connected to a double-acting cylinder (11). The chambers on both sides of the piston in the double-acting cylinder (11) are respectively connected to the pipelines of a high-pressure gas tank.

2. The rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to claim 1, characterized in that, The sliding assembly includes a slider (4) and a slide rail (5). The slide rail (5) is fixedly connected to the side plate (2), and the slider (4) is fixedly connected to the ear plate of the central connecting block (10).

3. The rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to claim 1, characterized in that, Two high-pressure gas tanks are fixed on the first connecting end plate (1) and are centrally symmetrical along the axis of the oil damper (7).

4. The rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to claim 1, characterized in that, In the balanced state, the two cylinders are perpendicular to the side plate (2) and both have pre-pressure.

5. The rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to claim 1, characterized in that, There are multiple double-acting cylinders (11), and the multiple double-acting cylinders (11) are arranged symmetrically along the axis of the oil damper (7); the two ear plates of the central connecting block (10) are arranged symmetrically along the axis of the oil damper (7).

6. The rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to any one of claims 1 to 5, characterized in that, According to the controlled system, the parameters of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system should satisfy: To achieve the rate-independent characteristic of control force; among which, c M The linear damping coefficient of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system is given. K M The linear positive stiffness coefficient of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system is given. K N The linear negative stiffness coefficient of the rate-independent negative stiffness viscoelastic damping passive vibration reduction system is given. k For the stiffness of the controlled system, For the frequency of the controlled system, The design damping ratio for a rate-independent negative stiffness viscoelastic damping passive vibration reduction system.

7. The rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to claim 6, characterized in that, Nonlinear damping coefficient of oil damper (7) satisfy: in, c M For a rate-independent, negative stiffness, viscoelastic damping passive vibration reduction system, the linear damping coefficient is given. α Here, Γ is the preset damping index of the oil damper, and Γ is the gamma function. v The preset target rate.

8. The rate-independent negative stiffness viscoelastic damping passive vibration reduction system according to claim 6, characterized in that, Initial pressure of the cylinder P i ,journey D and piston head area A i Satisfy the following formula: in, i Number the cylinder. i =1 is the first cylinder (8). i =2 is the second cylinder (9). k N i ( x ) is the first i The negative stiffness provided by the cylinder at different displacements x. P i For the first i The initial pressure of each cylinder, D For the strokes of the first cylinder (8) and the second cylinder (9), A i For the first i Piston head area of ​​each cylinder b i Let i be the compression volume retention rate of the i-th cylinder. , L h The sum of the lengths of the connecting hinges (21) on the first cylinder (8) and the second cylinder (9) is the total length. L p The total length of the first cylinder (8) and the second cylinder (9) after compression at the equilibrium position. μ The dimensionless relative displacement of the central connecting block (10) is given. , x This represents the horizontal displacement of the central connecting block relative to its equilibrium position. g The length ratio is dimensionless. , where n is the gas compressibility polytropic index. V i For the first i The preset total volume of each cylinder and its connected high-pressure gas tank and chamber. x max The preset maximum travel distance; The area on both sides of the piston (24) of the double-acting cylinder (11) A f and A s satisfy: in, A f The area of ​​the piston (24) without the piston rod. A s Let be the area of ​​the piston (24) on the piston rod side.

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