Particle damping inertia amplification vibration reduction device and superstructure raft

Abstract

The application discloses a granular damping inertia amplification damping device and a superstructure raft, two hinged bases are arranged at a preset interval; a rigid lever is provided with a first hinge joint and a second hinge joint, the first hinge joint is connected with the first hinged base, the second hinge joint is connected with the second hinged base, so that the rigid lever can rotate around the connecting shaft of the hinged base; a container is fixedly connected to one end of the rigid lever which is not provided with a hinge joint, and the container is filled with bulk granules. The raft has 2D periodicity in a horizontal plane; the granular damping inertia amplification damping device is periodically arranged on the lower surface of the front panel of the raft, excellent low-frequency broadband damping effect can be achieved, and the valuable upper surface equipment installation space is not occupied.

Description

Technical Field

[0001] This invention belongs to the field of ship structure vibration and noise control technology, specifically relating to a composite vibration reduction device for suppressing low-frequency broadband vibration of ship rafts, and particularly a raft superstructure vibration reduction device that combines a lever-type inertial amplification mechanism with particle damping technology. Background Technology

[0002] The ship's raft is a crucial vibration isolation platform for the ship's propulsion system, and it is prone to low-frequency broadband vibrations under the wide-frequency excitation of the main engine, auxiliary engines, etc. These vibrations can not only be transmitted to the hull through the structure, causing cabin noise, but also affect the normal operation of the precision equipment on board. Therefore, effective low-frequency broadband vibration control of the ship's raft is of great significance for improving the ship's stealth, comfort, and equipment reliability.

[0003] Traditional vibration control methods for raft structures mainly include increasing structural damping and installing tuned dynamic vibration absorbers. These methods often have limitations: increasing damping materials is beneficial for broadband vibration reduction, but its effect on low-frequency vibration reduction is limited; dynamic vibration absorbers are usually only effective for narrow-band frequencies, and a large additional mass is required to achieve low-frequency vibration reduction targets. In particular, it is important to consider that the upper surface of the raft's front panel is typically equipped with various devices, limiting installation space.

[0004] Phononic crystals based on metamaterials offer a new approach to structural vibration control. Initially, phononic crystals based on the Bragg scattering principle had bandgap frequencies dependent on the periodic size of the structure. Achieving low-frequency bandgap required bulky structures, making them impractical. Subsequently, locally resonant phononic crystals (or acoustic metamaterials) achieved low-frequency bandgap at small sizes by introducing resonant units at the subwavelength scale. However, to obtain even lower resonant frequencies, locally resonant units often rely on heavy mass blocks or extremely soft springs, which is also detrimental to lightweight structural design and cannot achieve broadband vibration reduction outside the bandgap, limiting their application in weight-sensitive fields such as shipbuilding.

[0005] To achieve low-frequency broadband control without significantly increasing weight, inertial amplification mechanisms have been proposed. However, the vibration reduction performance of metamaterials based on inertial amplification mainly relies on suppressing the propagation of elastic waves within a specific bandgap frequency range. Once the excitation frequency deviates from the bandgap, the attenuation effect drops sharply, making it difficult to cope with broadband random vibrations commonly encountered in engineering.

[0006] There are also applications of particle damping, but under low-intensity vibration (especially low-frequency vibration), the particle movement is insufficient, resulting in a slow start-up of the damping effect and low efficiency.

[0007] Therefore, existing ship raft vibration reduction technology faces a dual challenge: on the one hand, traditional damping or resonance methods are difficult to balance low frequency and lightweight; on the other hand, although inertial amplification metamaterials can be lightweight and low frequency, their bandwidth is limited, while particle damping, although wide bandwidth, is inefficient under low frequency weak excitation. Summary of the Invention

[0008] The present invention aims to overcome the shortcomings of the prior art and provide a particle damping inertial amplification vibration reduction device and a superstructure raft frame, which achieves excellent low-frequency broadband vibration reduction effect without occupying valuable upper surface equipment installation space.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction, comprising: Two hinged bases are set at a preset interval; A rigid lever is provided with a first hinge point and a second hinge point. The first hinge point is connected to a first hinge base, and the second hinge point is connected to a second hinge base, so that the rigid lever can rotate about the connecting axis of the hinge base. A container is fixedly connected to the end of the rigid lever that is not hinged, and the container is filled with loose particles.

[0010] Based on the principles of lever kinematics, the minute vertical displacement of the raft frame at its two hinge points is amplified into a larger vertical displacement of the container. This inertial amplification effect, through periodic design, can generate a significant vibrational bandgap within a specific low-frequency range, strongly suppressing the propagation of bending waves in that frequency band. Simultaneously, the amplified motion of the container violently agitates the internal particles, placing them in a high-kinetic-energy state. Frequent collisions and friction occur between particles and between particles and the container's inner wall, converting a large amount of vibrational mechanical energy into heat energy, which is then dissipated. This damping effect remains highly efficient across an extremely wide frequency band, from low to mid-high frequencies.

[0011] In the above technical solution, the total length of the rigid lever is greater than the length between its two hinge points, and the ratio of the two constitutes the inertial amplification ratio.

[0012] In the above technical solution, the hinged base is fixed to the lower surface of the vibration damping foundation by welding, bonding or bolting, so that the rigid lever and the container are suspended without contacting the upper vibration damping foundation.

[0013] In the above technical solution, the rigid lever is a lightweight rigid rod made of metal or composite material.

[0014] In the above technical solution, the hinge base is made of lightweight metal or composite material.

[0015] In the above technical solution, the material of the granular particles is metal. Preferably, the diameter is 0.5mm to 5mm.

[0016] In the above technical solution, the filling rate of the granular material in the container is 50% to 90%.

[0017] In the above technical solution, the container is fixed to the end of the rigid lever by welding, bonding or threaded connection.

[0018] In the above technical solution, the rigid lever and the hinge base are hinged by a pin.

[0019] In the above technical solution, the pin is fixed to the hinge base by welding or bonding.

[0020] In the above technical solution, the vibration reduction foundation has two-dimensional periodicity in the horizontal plane.

[0021] The working principle of the device is as follows: when the vibration of the equipment is transmitted to the ship's raft frame, the vibration is transmitted to the rigid lever through two hinged bases. Since the distance between the two hinge points on the lever is less than the actual length of the lever segment, the small displacement of the raft frame is converted into a larger acceleration motion at the lever end (i.e., the container) by the inertial amplification mechanism. This mechanism is equivalent to significantly increasing the added mass of the system, thereby forming a band gap for vibration propagation in the target low-frequency band, effectively suppressing the transmission of bending waves in this frequency band. At the same time, the amplified motion of the container violently agitates the internal loose particles, greatly enhancing the particle damping effect. The collisions and friction between particles and between particles and the container wall dissipate vibration energy over a very wide frequency range, compensating for the insufficient attenuation outside the band gap of the pure inertial amplification mechanism. In addition, by periodically arranging the periodic raft frame on the lower surface of the front panel, a raft frame superstructure with a significant low-frequency band gap and efficient broadband damping is formed, achieving excellent low-frequency broadband vibration reduction effect without occupying valuable upper surface equipment installation space.

[0022] Based on the aforementioned vibration reduction device, this invention provides a particle-damped inertial amplification superstructure raft frame with low-frequency broadband vibration reduction function. The specific technical solution is as follows: A particle-damped inertial amplification superstructure raft with low-frequency broadband vibration reduction function, employing the aforementioned particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction, wherein: The raft structure as a whole exhibits two-dimensional periodicity in the horizontal plane; Multiple particle-damped inertial amplification vibration reduction devices capable of low-frequency broadband vibration reduction are periodically arranged on the lower surface of the raft frame front panel.

[0023] Rafts are typically ship rafts. They can also be used in similar scenarios, such as vibration-damping platforms with space at the bottom and equipment on top. By periodically arranging these rafts on the lower surface of the raft's front panel, a raft superstructure with significant low-frequency bandgap and efficient broadband damping is formed, achieving excellent low-frequency broadband vibration reduction without occupying valuable upper surface space for equipment installation.

[0024] In the above technical solution, a number of arrayed lattice cavities are provided at the bottom of the raft frame, and a particle damping inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction is provided on the lower surface of the front panel of the raft frame in each cavity.

[0025] In the above technical solution, two hinged bases are fixed at a preset interval to the lower surface of the front panel of the raft frame inside each cavity.

[0026] In the above technical solution, each cavity is interconnected along both the horizontal transverse direction and the horizontal longitudinal direction.

[0027] The device works as follows: when the vibration of the equipment is transmitted to the ship's raft frame, it is transmitted to a rigid lever through two hinged bases. Since the distance between the two hinge points on the lever is less than the actual length of that segment of the lever, the minute displacement of the raft frame is converted into a larger acceleration motion at the lever end (i.e., the container) by the inertial amplification mechanism. This mechanism is equivalent to significantly increasing the added mass of the system, thereby creating a band gap for vibration propagation in the target low-frequency band, effectively suppressing the transmission of bending waves within that band. Simultaneously, the amplified motion of the container violently agitates the internal loose particles, greatly enhancing the particle damping effect. The collisions and friction between particles and between particles and the container wall dissipate vibrational energy over a very wide frequency range, compensating for the insufficient attenuation outside the band gap of the pure inertial amplification mechanism.

[0028] Therefore, this invention discloses a particle-damped inertial amplification vibration reduction device and a superstructure raft frame with low-frequency broadband vibration reduction function. By periodically arranging this device in an array on the lower surface of the front panel of the periodic raft frame, a superstructure device with low-frequency broadband vibration suppression function is formed.

[0029] The beneficial effects of this invention are: This device innovatively integrates a lever-type inertial amplification mechanism with a particle damper and a periodic raft frame. Through the inertial amplification effect, it reduces the system response frequency and generates a low-frequency bandgap. Simultaneously, the amplification of the container's motion fully activates the wideband energy dissipation potential of the particle damper, achieving synergistic effects. In particular, the ingenious integration of the inertial amplification mechanism, the particle system, and the periodic raft frame effectively avoids spatial interference with the equipment on the upper surface.

[0030] This invention integrates the inertial amplification effect, particle damping effect, and periodic structure bandgap effect: a lever mechanism amplifies the minute vibration displacement of the raft frame, causing the particle container to undergo large-amplitude acceleration motion, thereby significantly improving the system's equivalent mass. Simultaneously, the increased amplitude of motion enhances collision and frictional dissipation between particles, improving the system's broadband damping and vibration reduction performance. Utilizing a two-dimensional periodic array arrangement, the structure possesses typical low-frequency vibration bandgap characteristics, effectively suppressing low-frequency broadband vibrations.

[0031] In terms of structural design, this invention uses a support rod hinged to form a lever effect with the container particles and is fixed to a periodic object, introducing a low-frequency bandgap vibration reduction mechanism to form an integrated raft frame with low-frequency broadband vibration reduction. This directly absorbs and dissipates the vibration energy of the raft frame, achieving a better absorption effect than the commonly used inverted spring lever structure.

[0032] Meanwhile, the enhanced motion response of the container can effectively excite the motion of the bulk particles, and through collisions and friction between particles and between particles and the container wall, vibrational energy is efficiently dissipated over a wide frequency range. This overcomes the technical reality that under low-intensity vibration (especially low-frequency vibration), insufficient particle motion leads to a slow start-up of the damping effect and low efficiency.

[0033] This particle-damped inertial amplification raft frame has a high degree of integration and does not occupy additional equipment space, making it particularly suitable for low-frequency broadband vibration suppression of ship raft frames. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the inertial magnification particle damping raft superstructure according to an embodiment of the present invention; Figure 2 yes Figure 1 A three-dimensional half-section view (viewed from below); Figure 3 This is a schematic diagram of the inertial amplification particle damping mechanism according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the lever hinge structure according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the container structure according to an embodiment of the present invention; Figure 6 This is a structural diagram of the particle-damped inertial magnification superstructure raft frame installation according to an embodiment of the present invention; Figure 7 This is the particle-damped inertial amplification superstructure raft band structure of this invention. Figure 8 This is a comparison diagram of the particle-damped inertial amplification superstructure raft frame and the vibration reduction effect of the raft frame according to an embodiment of the present invention; Figure 9 This is a comparison of the average vibration transmission in different regions of an embodiment of the present invention.

[0035] In the diagram: 1-Periodic raft frame; 2-Inertial amplification particle damping mechanism; 3-Hinged base; 4-Cylindrical pin; 5-Lightweight lever; 6-Container; 7-Particle; 8-Hollow container; 9-Container lid; 10-Screw. 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.

[0037] Example 1 like Figure 1 and Figure 2 As shown, the multiple vibration-damping inertial amplification particle damping mechanisms 2 provided by the present invention are periodically arranged on the lower surface of the front panel of the periodic raft 1, forming a complete raft superstructure device with low-frequency broadband vibration reduction. This arrangement makes full use of the idle space at the bottom of the periodic raft and completely avoids interference with the installation and maintenance of equipment on the upper surface of the periodic raft.

[0038] like Figure 3 and Figure 4 As shown, the single inertial amplification particle damping mechanism 2 mainly consists of two hinged bases 3, a cylindrical pin 4, a lightweight lever 5, a container 6, and loose particles 7 filled in the container. The two hinged bases 3 are fixed upside down to the lower surface of the front panel of the raft frame 1 by welding, bonding, or bolting, so that the lightweight lever 5 and the container 6 are suspended upside down and do not touch the front panel of the raft frame 1; the pin is fixed to the hinged base by welding or bonding.

[0039] The lightweight lever 5 is typically made of a high-rigidity, lightweight material (such as aluminum alloy) and has two hinge points. These two hinge points are connected to two hinge bases 3 respectively via cylindrical pins 4, allowing the lightweight lever 5 to rotate freely about the axis of the cylindrical pins 4. Let the distance between the two hinge points be... l 1. The total length of the lightweight lever 5 is l 2. Thus, the inertial magnification ratio is defined. u = l 2 / l 1. Container 6 is fixedly connected to the end of lightweight lever 5.

[0040] like Figure 5 As shown, the container 6 is specifically composed of: a hollow container 8, a container lid 9, and screws 10 for fastening.

[0041] The container 6 is filled with loose particles 7. The loose particles 7 are preferably metal spheres (such as stainless steel beads) with a diameter of 1-5 mm, and the filling rate can be adjusted between 50% and 90%. The loose particles 7 are the core component constituting the particle damping effect.

[0042] Working process: When the equipment vibration is transmitted to the periodic raft frame 1, the vibration is transmitted to the lightweight lever 5 through two hinged bases 3 fixed to the lower surface. According to the lever kinematics principle, the small vertical displacements w1 and w2 of the raft frame at the two hinge points are amplified into a larger vertical displacement w of the container 6. m Their relationship satisfies w m =(1- u w1+ u w2. This inertial amplification effect makes the small added mass of container 6 and its internal particles 7 appear larger. m The particle 0 exhibits an equivalent inertia far greater than its own, thus generating a significant vibrational bandgap in a specific low-frequency range, strongly suppressing the propagation of flexural waves in that frequency band. Simultaneously, the amplified motion of container 6 violently agitates the internal particles 7, placing them in a high-kinetic-energy state. Frequent collisions and friction occur between particles and between particles and the container's inner wall, converting a large amount of vibrational mechanical energy into heat energy, which is then dissipated. This damping effect remains highly efficient across an extremely wide frequency band, from low to mid-high frequencies.

[0043] By optimizing the lattice constant and inertial amplification ratio of the array design u Parameters such as particle material, particle size, and filling rate can be customized for the main vibration excitation frequency band of a specific ship to achieve the best low-frequency broadband vibration reduction effect.

[0044] Example 2 To verify the effectiveness of this design, the following was designed: Figure 6 The particle-damped inertial amplification superstructure raft 1 is shown. The raft 1 is provided with several arrayed lattice cavities, and each cavity is interconnected along the horizontal transverse and horizontal longitudinal directions.

[0045] Raft 1 is made of steel, with an elastic modulus E=200GPa and a density of 7850kg / m³. 3 Poisson's ratio v = 0.3. Inertial magnification ratio. u =3. The total mass of the particles and container is 0.132 kg. The particle filling rate is 60% (mass 0.042 kg). The transverse lattice constant of the raft is 140 mm, the longitudinal lattice constant is 100 mm, the thickness of the top and bottom panels in the unit cell is 1 mm, the thickness of the side panels is 0.5 mm, and the height is 150 mm.

[0046] The bandgap position of the particle-damped inertial amplification superstructure raft is as follows: Figure 6 As shown, it can be observed that the particle-damped inertial amplification superstructure raft has a typical low-frequency bandgap.

[0047] Further structural vibration response, such as Figure 7 As shown, compared to the raft structure, the vibration transmission curve of the particle-damped inertial amplification superstructure raft exhibits a significant attenuation at the band gap position.

[0048] For better comparison, based on the band gap position, such as Figure 8 As shown, the transmission curve was divided into three regions, and the average transmission ratio of each region was calculated. The results are as follows. Figure 9 As shown.

[0049] It can be seen that the average vibration transmission ratio of the particle-damped inertial amplification superstructure raft is significantly lower than that of the raft in all three intervals; therefore, the introduction of the particle-damped inertial amplification superstructure device can achieve significant low-frequency broadband vibration reduction of the raft.

[0050] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction, characterized in that... include: Two hinged bases are set at a preset interval; A rigid lever is provided with a first hinge point and a second hinge point. The first hinge point is connected to a first hinge base, and the second hinge point is connected to a second hinge base, so that the rigid lever can rotate about the connecting axis of the hinge base. A container is fixedly connected to the end of the rigid lever that is not hinged, and the container is filled with loose particles.

2. The particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction according to claim 1, characterized in that... The total length of a rigid lever is greater than the length between its two hinge points, and the ratio of the two constitutes the inertia amplification ratio.

3. The particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction according to claim 1, characterized in that... The hinged base is fixed to the lower surface of the vibration damping foundation, so that the rigid lever and the container are suspended without contacting the upper vibration damping foundation.

4. The particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction according to claim 1, characterized in that... The rigid lever is a lightweight rigid rod made of metal or composite material.

5. The particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction according to claim 1, characterized in that... The hinge base is made of lightweight metal or composite material.

6. The particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction according to claim 1, characterized in that... The fill rate of the bulk particles in the container is 50% to 90%.

7. The particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction according to claim 1, characterized in that... The vibration-damping foundation has two-dimensional periodicity in the horizontal plane.

8. A particle-damped inertial amplification superstructure raft with low-frequency broadband vibration reduction function, characterized in that... The particle-damped inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction according to any one of claims 1-7, wherein: The raft structure as a whole exhibits two-dimensional periodicity in the horizontal plane; Multiple particle-damped inertial amplification vibration reduction devices capable of low-frequency broadband vibration reduction are periodically arranged on the lower surface of the raft frame front panel.

9. The particle-damped inertial amplification superstructure raft with low-frequency broadband vibration reduction function according to claim 8, characterized in that... The bottom of the raft frame is provided with several arrayed lattice cavities, and a particle damping inertial amplification vibration reduction device capable of low-frequency broadband vibration reduction is provided on the lower surface of the front panel of the raft frame in each cavity.

10. The particle-damped inertial amplification superstructure raft with low-frequency broadband vibration reduction function according to claim 8, characterized in that... Two hinged bases are fixed at a preset interval to the lower surface of the raft frame front panel inside each cavity.

Images