Vibration excitation device, method for determining design parameters of vibration excitation device, and vibration reduction device

Abstract

The present invention discloses an excitation device, a method for determining the design parameters of the excitation device, and a vibration reduction device, which relate to the field of excitation and vibration reduction technology, and include: a container, a mass block, a spring group, an exciter, and a controller. Damping liquid is stored inside the container, the mass block is immersed in the damping liquid, at least one pipeline is provided inside the mass block, the spring group includes at least one spring, one end of each spring is connected to the container and the other end is connected to the mass block, the exciter is connected to the mass block, and the controller is configured as follows: the controller is used to control the exciter to drive the mass block to move up and down in the damping liquid, so that the container and the structure to be excited vibrate at a preset excitation target. The present invention immerses the mass block in the damping liquid, and at least one pipeline is provided inside the mass block, and the buoyancy of the floating body and the additional inertial mass of the liquid are introduced to balance the deadweight of the mass block and provide damping, so as to achieve the ultra-low frequency excitation function while overcoming the problem of excessive static elongation and usage of the spring.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration excitation and vibration reduction, and in particular to a vibration excitation device, a method for determining design parameters of the vibration excitation device, and a vibration reduction device. Background Art

[0002] With the progress of building materials and modern construction technology, the current and future bridges are developing in the direction of being thinner, taller, softer and more beautiful, and several kilometer-level super-large span bridges have emerged. The increase in bridge spans has led to the increasingly obvious characteristics of bridge structures being soft and slender, with low damping and low natural frequency. Under the action of pulsating wind, people, vehicles and earthquakes, various forms of vibration are prone to occur. These vibrations will not only cause discomfort to personnel, structural shaking, structural fatigue and other problems, but will even have a great impact on the safety of the bridge and cause adverse social negative impacts. For example, the vortex-induced vibration phenomenon of the Yingwuzhou Yangtze River Bridge and the Humen Bridge that appeared in 2020 had a vibration frequency of less than 0.4Hz, which is already in the category of ultra-low frequency vibration.

[0003] At present, there are few special excitation equipment suitable for ultra-low frequency excitation of large-span bridges at home and abroad. Most bridge excitation equipment has defects such as narrow working frequency range and uncontrollable excitation. Large excitation equipment has disadvantages such as complex structure, bulky equipment and high cost. It is difficult to obtain a sufficiently large excitation force under low frequency (<0.5Hz) state, and it is difficult to directly apply it to actual bridge safety diagnosis, and it is impossible to provide a reliable basis for the design of vibration reduction measures.

[0004] Tuned mass damper (TMD) mainly includes three components: spring, mass and damper, which has a very obvious inhibitory effect on structural vibration. However, when conventional TMD is used for ultra-low frequency vibration reduction, it is difficult to deal with the contradiction between the low stiffness of the spring and the weight of the balancing mass block. If the weight of the mass block is balanced directly by the spring elastic force, the static elongation of the spring is:

[0005]

[0006] In the formula, δ is the static elongation of the spring (in m), m is the mass of the mass block (in kg), k is the spring stiffness (in N / m), g is the acceleration of gravity (in m / s2), and f is the damper frequency (in Hz). It can be seen from the above formula that the static elongation δ of the spring is inversely proportional to the square of the frequency f. As the frequency decreases, the static elongation of the spring will increase rapidly, and the space occupied by the TMD will also increase rapidly. In order to achieve such a large elongation and ensure that the stress of the spring wire meets the design specification requirements, the diameter and total length of the spring wire will also increase rapidly, resulting in a rapid increase in its mass. Calculations show that the spring elongation required for conventional TMD to reach 0.3Hz and 0.1Hz is 2.76m and 24.82m respectively. Under the premise that the deadweight of the active mass remains unchanged, the smaller the frequency, the smaller the stiffness of the spring. In order to resist the deadweight, it can only be achieved through large deformation. For the actual bridge structure, the clearance position of the main beam that allows TMD is about 2 to 3m. In addition, due to the large static elongation of the spring, the initial stress of the spring is large, resulting in a sharp increase in the amount of spring steel. For example, the spring amount of the 0.2Hz design main frequency TMD reaches 50% of the mass block. Therefore, for ultra-low frequency TMD, according to the conventional solution, the static elongation and amount of the spring are too large, and the spring cannot be designed. Summary of the invention

[0007] The embodiments of the present invention provide a vibration excitation device, a method for determining the design parameters of the vibration excitation device, and a vibration reduction device to solve the technical problem in the related art that the static elongation and usage of the spring of the existing vibration excitation device to achieve ultra-low frequency vibration are too large.

[0008] In a first aspect, a vibration excitation device is provided, comprising:

[0009] A container, in which damping fluid is stored, and the container is used to be connected to the structure to be excited;

[0010] A mass block, which is immersed in the damping fluid, and at least one pipeline is provided inside the mass block;

[0011] A spring group, comprising at least one spring, wherein one end of each spring is connected to the container and the other end is connected to the mass block;

[0012] an exciter connected to the mass block;

[0013] A controller configured to:

[0014] The controller is used to control the exciter to drive the mass block to move up and down in the damping liquid, so that the container and the structure to be excited vibrate at a preset excitation target.

[0015] In some embodiments, the excitation device further comprises:

[0016] The first sensor and the second sensor are respectively arranged on the container and the mass block, and the first sensor and the second sensor are respectively used to detect vibration parameters of the container and the mass block, and send the vibration parameters of the container and the mass block to the controller.

[0017] In some embodiments, the exciter is a turbine pump, and the turbine pump is disposed in the pipeline.

[0018] In some embodiments, the vibrator is a telescopic cylinder, one end of which is connected to the container and the other end of which is connected to the mass block.

[0019] In some embodiments, limiting wheels are provided on both sides of the mass block.

[0020] In some embodiments, the container is a sealed container.

[0021] In a second aspect, a method for determining design parameters of an excitation device is provided, comprising the following steps:

[0022] Determine the exciting force amplitude F, velocity amplitude ν1, acceleration amplitude A1 and exciting frequency f1 of the exciter according to the preset excitation target of the structure to be excited, and determine the minimum power P of the exciter according to the exciting force amplitude F and velocity amplitude ν1 of the exciter;

[0023] Determine the mass m, velocity amplitude ν2, acceleration amplitude A2 and vibration frequency f2 of the mass block according to the exciting force amplitude F of the exciter;

[0024] Determine the static deformation δ of the spring group according to the velocity amplitude ν2, acceleration amplitude A2 and allowable installation height of the mass block;

[0025] Determine the additional inertia mass Δm of the liquid based on the pipeline inside the mass block;

[0026] Determine the stiffness k of the spring group according to the mass m of the mass block, the vibration frequency f2 and the additional inertia mass Δm of the liquid;

[0027] The volume V of the mass block is determined according to the formula: the mass m of the mass block, the static deformation δ of the spring group, and the stiffness k.

[0028] In some embodiments, the step of determining the additional inertia mass Δm of the liquid according to the pipeline inside the mass block includes:

[0029] According to the formula Determine the additional inertia mass Δm of the liquid;

[0030] Where s is the cross-sectional area of ​​the pipeline, n is the number of pipelines, l is the length of each pipeline, S is the cross-sectional area of ​​the container, and ρ is the density of the damping fluid.

[0031] In some embodiments, the step of determining the volume V of the mass block according to the formula of the mass m of the mass block, the static deformation δ of the spring group and the stiffness k comprises:

[0032] The volume V of the mass block is determined according to the formula m·g=ρ·g·V+k·δ.

[0033] In a third aspect, a vibration reduction device is provided, comprising the aforementioned vibration excitation device.

[0034] The beneficial effects brought about by the technical solution provided by the present invention include:

[0035] An embodiment of the present invention provides an excitation device, a method for determining the design parameters of the excitation device, and a vibration reduction device. The excitation device immerses a mass block in a damping liquid, and sets at least one pipeline inside the mass block to introduce the buoyancy of a floating body and the additional inertial mass of the liquid, so as to balance the deadweight of the mass block and provide damping, thereby realizing an ultra-low frequency excitation function and overcoming the problems of excessive static elongation and usage of the spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A schematic structural diagram of a vibration excitation device provided by an embodiment of the present invention;

[0038] Figure 2 Another structural diagram provided for an embodiment of the present invention;

[0039] Figure 3 Another structural diagram provided for an embodiment of the present invention;

[0040] Figure 4 Another structural diagram provided for an embodiment of the present invention;

[0041] Figure 5 A schematic cross-sectional view of a mass block provided by an embodiment of the present invention;

[0042] Figure 6 Another cross-sectional schematic diagram of a mass block provided by an embodiment of the present invention;

[0043] Figure 7 Another cross-sectional schematic diagram of a mass block provided by an embodiment of the present invention;

[0044] Figure 8Another cross-sectional schematic diagram of a mass block provided by an embodiment of the present invention;

[0045] Fig. 9 A schematic diagram of the implementation of vibration excitation or vibration reduction provided by an embodiment of the present invention;

[0046] In the figure:

[0047] 1. Container;

[0048] 2. Mass block; 21. Pipeline;

[0049] 3. Spring set;

[0050] 4. Vibrator;

[0051] 5. Controller;

[0052] 6. Limiting wheel;

[0053] 7. Damping fluid;

[0054] 8. First sensor;

[0055] 9. Second sensor. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] The embodiment of the present invention provides a vibration excitation device, which can solve the technical problem that the static elongation and usage of the spring of the existing vibration excitation device are too large to achieve ultra-low frequency vibration.

[0058] See also Figure 1 As shown, an embodiment of the present invention provides a vibration excitation device, including: a container 1, a mass block 2, a spring group 3, an exciter 4 and a controller 5.

[0059] The container 1 stores damping fluid 7, and the container 1 is used to connect to the structure to be excited. The mass block 2 is immersed in the damping fluid 7. At least one pipeline 21 is provided inside the mass block 2. The spring group 3 includes at least one spring, and one end of each spring is connected to the container 1 and the other end is connected to the mass block 2. The exciter 4 is connected to the mass block 2.

[0060] The controller 5 is configured as follows: the controller 5 is used to control the exciter 4 to drive the mass block 2 to move up and down in the damping liquid 7, so that the container 1 and the structure to be excited vibrate at a preset excitation target.

[0061] The excitation device in the embodiment of the present invention immerses the mass block in the damping liquid, and sets at least one pipeline inside the mass block to introduce the buoyancy of the float and the additional inertia mass of the liquid, balance the deadweight of the mass block and provide damping, thereby realizing the ultra-low frequency excitation function and overcoming the problems of excessive static elongation and usage of the spring.

[0062] As an optional implementation, in an embodiment of the invention, the excitation device further includes: a first sensor 8 and a second sensor 9, the first sensor 8 and the second sensor 9 are respectively arranged on the container 1 and the mass block 2, the first sensor 8 and the second sensor 9 are respectively used to detect the vibration parameters of the container 1 and the mass block 2, and send the vibration parameters of the container 1 and the mass block 2 to the controller 5. Specifically, the controller 5 analyzes the vibration main frequency and phase difference of the mass block 2 and the container 1 (connected to the structure to be excited) through the test data of the first sensor 8 and the second sensor 9, and then feeds back to the exciter 4 for active control to adjust the excitation frequency, amplitude, etc.

[0063] As an optional implementation, in an embodiment of the invention, the exciter 4 is a turbine pump, and the turbine pump is arranged in the pipeline 21.

[0064] Specifically, see Figure 1 As shown, the pipeline 21 can be a threaded pipe. Figure 2 As shown, the pipeline 21 can be a straight pipe, and there can be multiple pipelines 21. By blocking part of the pipeline 21, the additional inertia mass of the liquid can be adjusted to adjust the main frequency of the excitation. The number of the turbo pumps can also be matched according to the number of the pipelines 21. The straight pipe can be a round straight pipe or a square straight pipe, and the mass block 2 can be a square or a round one, see Figures 5 to 8 shown.

[0065] As an optional implementation, in an embodiment of the invention, see Figure 3 and Figure 4 As shown, the exciter 4 may be a telescopic cylinder, one end of which is connected to the container 1 and the other end of which is connected to the mass block 2 .

[0066] As an optional implementation, in an embodiment of the invention, see Figure 1 As shown, both sides of the mass block 2 are provided with limiting wheels 6 which abut against the inner wall of the container 1. The limiting wheels 6 are installed on both sides of the mass block to prevent the mass block 2 from hitting the container 1 and ensure the gap between the side of the mass block 2 and the container 1, thereby reducing the system damping.

[0067] As an optional implementation, in an embodiment of the invention, see Figure 1 As shown, the container 1 is a closed container, which provides support for the spring and a sealed environment for the entire device and has good durability.

[0068] In addition, the mass block 2 is completely immersed in the damping liquid 7 to ensure that the buoyancy and damping are fixed values ​​and do not affect the change in the elongation of the spring group 3. The damping liquid 7 can be water, silicone oil, etc., and the damping ratio can be adjusted by the viscosity of different liquids.

[0069] An embodiment of the present invention provides a method for determining design parameters of an excitation device, comprising the following steps:

[0070] Determine the exciting force amplitude F, velocity amplitude ν1, acceleration amplitude A1 and exciting frequency f1 of the exciter 4 according to the preset excitation target of the structure to be excited, and determine the minimum power P of the exciter 4 according to the exciting force amplitude F and velocity amplitude ν1 of the exciter 4;

[0071] Determine the mass m, velocity amplitude ν2, acceleration amplitude A2 and vibration frequency f2 of the mass block 2 according to the exciting force amplitude F of the exciter 4;

[0072] Determine the static deformation δ of the spring group 3 according to the velocity amplitude ν2, the acceleration amplitude A2 and the allowable installation height of the mass block 2;

[0073] Determine the additional inertia mass Δm of the liquid according to the pipeline 21 inside the mass block 2;

[0074] Determine the stiffness k of the spring group 3 according to the mass m of the mass block 2, the vibration frequency f2 and the additional inertia mass Δm of the liquid;

[0075] The volume V of the mass block 2 is determined according to the formula: the mass m of the mass block 2, the static deformation δ of the spring group 3, and the stiffness k.

[0076] As an optional implementation, in an embodiment of the invention, the step of determining the additional inertia mass Δm of the liquid according to the pipeline 21 inside the mass block 2 includes:

[0077] According to the formula Determine the additional inertia mass Δm of the liquid;

[0078] Wherein, s is the cross-sectional area of ​​the pipeline, n is the number of pipelines 21 , l is the length of each pipeline 21 , S is the cross-sectional area of ​​the container 1 , and ρ is the density of the damping fluid 7 .

[0079] As an optional implementation, in an embodiment of the invention, the step of determining the volume V of the mass block 2 according to the formula of the mass m of the mass block 2, the static deformation δ of the spring group 3 and the stiffness k comprises:

[0080] The volume V of the mass 2 is determined according to the formula m·g=ρ·g·V+k·δ.

[0081] The embodiment of the present invention provides a vibration reduction device, including the aforementioned vibration excitation device. The vibration excitation device can be fixed for structural vibration control, and can also be equipped with a flatbed trailer and a lifting jack, see Fig. 9 As shown, it is used for temporary structural excitation and vibration reduction load tests, such as rapid control of vortex-induced vibration of long-span suspension bridges and modal parameter identification of bridge load tests.

[0082] For example, an implementation case of the excitation device: the first-order vertical bending frequency of a large-span cable-stayed main beam is about 0.25Hz. In order to accurately identify its natural frequency, the bridge external excitation method is adopted. The required simple harmonic excitation force amplitude is designed to be 10kN, the excitation time is 5 minutes, and the excitation frequency is 0.25Hz. It can excite the main beam vertically up and down 100mm. The natural frequency can be accurately tested through the free attenuation of the bridge. The total weight of the design mass block is 10 tons, and the acceleration is 1m / s 2 , the mass block stroke is 0.41m. For easy installation, the spring extension is designed to be 1.5m, the mass block stroke is 0.5m, and in order to meet the excitation main frequency of 0.25Hz, the total stiffness of spring group 3 is designed to be 2467N / m, 12 tension springs are used, and the stiffness of a single tension spring is 206N / m; the design liquid is water, and the density is 1000kg / m 3 , mass block is 20m 3 , a square mass block is used; the static elongation of the spring is 1.655m, the static equilibrium position is 2.175m, and the mass block stroke is 0.41m, which meets the design excitation force requirements. The exciter 4 is a telescopic cylinder with a minimum power of 15.7kW and a rod length of 1m. The first sensor 8 and the second sensor 9 on the main beam (which has been connected to the container 1 as a whole) and the mass block 2 are actively excited through the controller 5 to exert the optimal excitation effect of the excitation device.

[0083] For example, an implementation case of a vibration reduction device: the main frequency of vortex-induced vibration of a large-span suspension bridge is 0.3Hz, the main beam clearance is 2.5m, the required total weight of mass block 2 is 60 tons, and the damping ratio is 5%. For the convenience of installation, mass block 2 is discretized into 30 2-ton mass blocks, the elongation of spring group 3 is designed to be 1.2m, and the stroke of mass block 2 is 0.3m. In order to meet the control main frequency of 0.3Hz, the total stiffness of spring group 3 is designed to be 2132N / m, 4 tension springs are used, and the stiffness of a single tension spring is 533N / m. The additional inertia mass of the liquid is 400kg, and the mass block weighs 2000kg; in order to meet the spring elongation of 1.2m, the damping liquid is designed to be water with a density of 1000kg / m 3 , the equivalent density of the mass block is 2000kg / m 3, the displacement volume is 2m3, a cylindrical float is used, the cross-sectional area is 1m2, and the spiral pipe diameter is 0.005m 2 , the length is 2m, the additional inertia mass of the liquid is 400kg, and the required damping ratio of 5% is obtained by adjusting the length, width and height ratio of the float; the static elongation of the spring is 1.15m, the static equilibrium position is 1.65m, the stroke of the mass block is 0.3m, and with the frame hook, the total installation height can be controlled within 2.5m, meeting the design requirements. In order to better play the control role of the damper, the first sensor 8 and the second sensor 9 are installed on the main beam (which has been connected to the container 1 as a whole) and the mass block 2, and the exciter 4 is a telescopic cylinder. The exciter 4 is designed to have a 1m output rod length and an output amplitude of 1kN. The controller 5 is actively excited to achieve the optimal vibration reduction effect.

[0084] In the description of the present invention, it should be noted that the terms "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0085] It should be noted that, in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0086] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A method for determining design parameters of an excitation device, characterized in that: The excitation device comprises: A container (1) having a damping fluid (7) stored therein, wherein the container (1) is used to be connected to a structure to be excited; A mass block (2) immersed in the damping liquid (7), wherein a plurality of pipelines (21) are provided inside the mass block (2); A spring group (3), comprising at least one spring, each of the springs having one end connected to the container (1) and the other end connected to the mass block (2); An exciter (4) connected to the mass block (2); A controller (5) is configured to: The controller (5) is used to control the vibration exciter (4) to drive the mass block (2) to move up and down in the damping liquid (7), so that the container (1) and the structure to be excited vibrate at a preset excitation target; The exciter (4) is a turbine pump, which is arranged in the pipeline (21). The number of the turbine pumps matches the number of the pipelines (21), and a portion of the pipeline (21) is blocked to adjust the additional inertia mass of the liquid. The method for determining the design parameters of the vibration excitation device comprises the following steps: Determine the amplitude of the exciting force of the exciter (4) according to the preset exciting target of the structure to be excited , velocity amplitude , acceleration amplitude and excitation frequency , and according to the amplitude of the exciting force of the exciter (4) , velocity amplitude Determine the minimum power of the exciter (4) ; According to the amplitude of the exciting force of the exciter (4) Determine the mass of the mass (2) , velocity amplitude , acceleration amplitude and vibration frequency ; According to the velocity amplitude of mass (2) , acceleration amplitude The static deformation of the spring assembly (3) is determined by the permissible installation height ; Determine the additional inertia mass of the liquid based on the pipe (21) inside the mass block (2) ; According to the mass of mass block (2) , vibration frequency and additional inertia mass of liquid Determine the stiffness of the spring assembly (3) ; According to the formula, the mass of the mass block (2) , static deformation of spring group (3) and stiffness Determine the volume of mass (2) .

2. The method for determining the design parameters of the vibration device according to claim 1, characterized in that: The excitation device also includes: A first sensor (8) and a second sensor (9) are respectively arranged on the container (1) and the mass block (2); the first sensor (8) and the second sensor (9) are respectively used to detect vibration parameters of the container (1) and the mass block (2), and send the vibration parameters of the container (1) and the mass block (2) to the controller (5).

3. The method for determining the design parameters of the vibration excitation device according to claim 1, characterized in that: Limiting wheels (6) are provided on both sides of the mass block (2).

4. The method for determining the design parameters of the vibration excitation device according to claim 1, characterized in that: The container (1) is a sealed container.

5. The method for determining the design parameters of the vibration device according to claim 1, characterized in that: The mass of the mass block according to formula (2) , static deformation of spring group (3) and stiffness Determine the volume of mass (2) The steps include: According to the formula Determine the volume of mass (2) .

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