Three-way magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span space structure and control method thereof

Abstract

This invention relates to the field of vibration control technology for civil engineering structures. It discloses a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures and its control method. The bearing includes a top plate and a bottom plate. A middle plate is fixed to the bottom of the horizontally stacked magnetorheological elastomer vibration isolation / vibration unit. A vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit is fixed to the bottom plate and slidably connected to the inner side of the middle plate. The control method uses sensors to collect the structural response in real time, identifying three operating conditions: high-frequency micro-vibration, low-frequency moderate vibration, and large earthquake safety. It automatically switches control modes to achieve coordinated adaptive control of vertical damping and horizontal stiffness and damping. This invention combines high static load-bearing capacity with low dynamic stiffness, enabling triaxial decoupling and multi-mode intelligent coordinated control, and is suitable for broadband vibration control of roof supports for large-span spatial structures.

Description

Technical Field

[0001] This invention relates to the field of vibration control technology for civil engineering structures, specifically to a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures and its control method. Background Technology

[0002] Large-span spatial structures (such as stadiums, airport terminals, convention centers, and railway stations) are an important form of modern public buildings. They are characterized by large spans, low stiffness, low damping, and dense natural frequencies. Under multi-source excitation such as wind loads, equipment vibrations, and seismic forces, vibration problems are particularly prominent. Large-span spatial structures are typical vertical vibration-sensitive structures, and their vertical vibration response is often not negligible. This places higher demands on the safety and comfort of the structure. Therefore, vibration control of large-span spatial structures, especially multi-dimensional vibration isolation / seismic technology at roof supports, has become a research hotspot in the field of vibration control of civil engineering structures.

[0003] In recent years, the application of seismic isolation technology in large-span spatial structures has gradually developed towards three-dimensional seismic isolation, which simultaneously reduces horizontal and vertical vibrations. However, three-dimensional seismic isolation bearings generally face the contradiction between the vertical bearing capacity requirement and the seismic isolation flexibility requirement. That is, how to achieve a low dynamic stiffness to obtain a good vibration isolation effect while ensuring sufficient static bearing capacity. This contradiction is particularly prominent in large-span spatial structures because the self-weight of the roof structure and the dead load of the roof are large, which puts strict requirements on the vertical static bearing capacity of the bearings. At the same time, the roof is a typical low-frequency sensitive structure, requiring the bearings to have sufficiently low vertical dynamic stiffness to isolate micro-amplitude vibrations.

[0004] Quasi-zero stiffness vibration isolation technology achieves a balance between high static load-bearing capacity and low dynamic stiffness by connecting positive stiffness elastic elements in parallel with negative stiffness mechanisms. This represents a cutting-edge technology in low-frequency vibration isolation. Magnetorheological elastomers (MREs) are intelligent materials composed of a polymer matrix and micron-sized soft magnetic particles. Under an applied magnetic field, their shear modulus and damping can undergo continuous and reversible changes within milliseconds. By fabricating MREs into thin layers and alternately stacking them with steel plates, and then winding excitation coils around them, a laminated MRE seismic isolation bearing is formed, enabling active or semi-active control of horizontal shear stiffness and damping.

[0005] Despite the significant advantages of each of the aforementioned technologies, their integrated application in the field of triaxial intelligent vibration isolation / seismic isolation for large-span spatial structures still faces the following common technical challenges that urgently need to be addressed: (1) How to achieve vertical quasi-zero stiffness characteristics to isolate low-frequency micro-vibrations while ensuring the high static load support capacity of large-span roofs, and maintain quasi-zero stiffness under load variation conditions; (2) How to achieve physical and functional decoupling of vertical and horizontal vibration isolation / seismic functions, and on this basis, construct a multi-mode collaborative control strategy; (3) How to provide the support with the ability to adjust the stiffness and damping parameters in real time according to the amplitude and spectral characteristics of the external excitation in order to cope with broadband excitation from micro-vibration to strong earthquake; (4) How to deal with the risk of uplift caused by wind suction and earthquake overturning moment of large-span roofs, as well as the risk of collision damage under extreme displacement conditions. Summary of the Invention

[0006] The purpose of this invention is to provide a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing and its control method for large-span spatial structures. This bearing can achieve vertical quasi-zero stiffness characteristics to isolate low-frequency micro-vibrations while ensuring the high static load support capacity of large-span roofs, and actively adjust damping to dissipate energy when the load changes. At the same time, through the decoupling layout of the horizontally stacked magnetorheological elastomer and the vertical magnetorheological quasi-zero stiffness unit, the physical and functional separation of vertical and horizontal vibration isolation / seismic functions is achieved. Through embedded sensors and controllers, the bearing has the ability to adjust mechanical parameters in real time according to the amplitude and spectral characteristics of external excitation to cope with broadband excitation from micro-vibrations to strong earthquakes. Through integrated anti-pull-out locking and soft limiting devices, it effectively copes with the risk of upward pull-out of large-span roofs under wind suction and seismic overturning moment, as well as the risk of collision damage under extreme displacement.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures, comprising a top plate and a bottom plate. A horizontally stacked magnetorheological elastomer vibration isolation / vibration unit is rotatably connected to the bottom of the top plate. A middle plate is fixed to the bottom of the horizontally stacked magnetorheological elastomer vibration isolation / vibration unit. A vertically magnetorheological quasi-zero stiffness vibration isolation / vibration unit is fixed to the bottom plate. The vertically magnetorheological quasi-zero stiffness vibration isolation / vibration unit is slidably connected to the inner side of the middle plate.

[0008] Preferably, the horizontally stacked magnetorheological elastomer vibration isolation / vibration unit includes a stacked magnetorheological elastomer, which is composed of alternating stacks of magnetorheological elastomer and magnetically conductive steel plates. A permanent magnet is fixed on the inner side of the stacked magnetorheological elastomer, and a first coil is surrounded on the outer side of the stacked magnetorheological elastomer.

[0009] Preferably, a steel yoke is provided on the outer side of the first coil, and the steel yoke and the internal magnetic conductive steel plate form a closed magnetic circuit.

[0010] Preferably, the bottom of the top plate is fixed with a horizontal slide rail A, and the top of the steel yoke is slidably connected within the horizontal slide rail A.

[0011] Preferably, the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit includes a negative stiffness unit, and the negative stiffness unit includes a compression spring. The compression spring is fixed on the two inner walls of the base plate, and a connecting plate is fixed to the inner end of the compression spring. Horizontal slide rails B are symmetrically fixed on both sides of the bottom inner wall of the base plate. The connecting plate is slidably connected in the horizontal slide rails B. Disc springs are symmetrically fixed on both sides of the bottom inner wall of the base plate. The middle plate is fixed on the top of the two disc springs. A connecting rod is hinged between the connecting plate and the middle plate.

[0012] Preferably, a magnetorheological damper is fixed at the middle of the bottom of the base plate, and the magnetorheological damper includes a cylinder, a piston block is slidably connected inside the cylinder, and a piston rod is hinged to the top of the middle plate, the piston rod passing through the top of the cylinder and connected to the piston block.

[0013] Preferably, a second coil is wound inside the piston block, the cylinder is filled with magnetorheological fluid, and a throttling orifice is provided on the piston block.

[0014] Preferably, a vertical slide rail is fixed to the outer side of the base plate, and the vertical slide rail is rotatably connected to the inner wall of the middle plate.

[0015] Preferably, four pull-out locking buckles are evenly fixed on the outer circumference of the base plate, and the pull-out locking buckles are slidably connected to the inner wall of the middle plate. The pull-out locking buckles adopt an I-shaped slot embedded structure.

[0016] A control method for a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures includes the following steps: Step 1: The device is equipped with an intelligent control system, which includes a sensor network, a core controller, a current driver, and a communication module. The sensor network includes accelerometers, displacement sensors, and force sensors deployed at the top and bottom of the supports and key nodes of the large-span roof structure. Sensor data acquisition and signal processing: Accelerometers, displacement sensors, and force sensors are used to collect the acceleration, displacement, and vertical load data of the structure in real time. The collected signals are amplified, filtered, and converted from analog to digital before being sent to the core controller. Step 2, Operating Condition Identification: The core controller extracts features from the preprocessed data, including vibration amplitude, dominant frequency, duration, and bandwidth. It uses a preset classification algorithm to identify the current external excitation type in real time and classifies the operating condition into one of the following three categories: high-frequency micro-vibration mode, low-frequency medium-vibration mode, and large-earthquake safety mode. Step 3: Control Mode Switching and Cooperative Control: Based on the operating condition identification results, the core controller outputs corresponding control commands to the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit and the horizontal laminated magnetorheological elastomer vibration isolation / vibration unit, respectively. When identified as a high-frequency micro-vibration mode: in the vertical direction, the quasi-zero stiffness isolation unit is kept working near the static equilibrium position, and the magnetorheological damper is in a low-damping state; in the horizontal direction, the laminated magnetorheological elastomer isolation / vibration unit is switched to a high-stiffness state. When identified as a low-frequency medium vibration mode: In the vertical direction, the quasi-zero stiffness vibration isolation unit continues to work normally, and the magnetorheological damper switches to the variable damping state, dynamically adjusting the damping force according to the real-time vibration response; In the horizontal direction, the laminated magnetorheological elastomer vibration isolation / vibration unit enters the real-time adjustment state, continuously adjusting the shear stiffness and damping through the coordinated control of the first coil and the permanent magnet. When identified as a major earthquake safety mode: In the vertical direction, if the detected upward displacement exceeds the preset threshold, the anti-pull-out latch is automatically activated, and the magnetorheological damper is supplied with the maximum current to provide maximum damping; in the horizontal direction, the laminated magnetorheological elastomer vibration isolation / seismic unit switches to a low stiffness state. Step 4: Closed-loop feedback and real-time adjustment: The core controller continuously receives sensor feedback signals, monitors the displacement, acceleration and force response of the support in real time, compares them with the control target value, and dynamically adjusts the current value output to the magnetorheological damper and the laminated magnetorheological elastomer for excitation. Step 5: Repeat the process: Return to Step 1 and continue to collect data, identify operating conditions, switch modes, and perform closed-loop control until the system stops running.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures ensures high static load support capacity for large-span roofs while making the vertical dynamic stiffness near the static equilibrium position approach zero, effectively isolating low-frequency micro-amplitude vibrations.

[0018] 2. This triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures achieves physical separation of vertical compression motion and horizontal shear motion, avoiding the complex coupling effect between the vertical and horizontal directions in traditional three-dimensional bearings. The vibration isolation / seismic performance in each direction can be designed and controlled independently. In the vertical direction, a magnetorheological damper is connected in parallel with a quasi-zero stiffness unit to achieve continuous and reversible adjustment of the damping force, effectively suppressing the response amplification of the quasi-zero stiffness system near the resonance region. In the horizontal direction, a laminated magnetorheological elastomer is used to achieve real-time adjustment of stiffness and damping, improving the vibration isolation / seismic performance of the system under broadband excitation.

[0019] 3. This triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures, through an embedded sensor network and core controller, can identify different working conditions such as micro-vibration, wind vibration, small and medium earthquakes, and large earthquakes in real time, and automatically switch to the optimal control mode, realizing active identification and intelligent control, and greatly improving the bearing's adaptability to complex and variable external excitations.

[0020] 4. This triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures integrates an anti-pull-out lock that is decoupled from vertical movement under normal conditions, without interfering with the quasi-zero stiffness vibration isolation performance. It is automatically activated when wind suction or seismic overturning moment causes upward pull, effectively preventing the bearing from detaching.

[0021] 5. This triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures has a high degree of system integration, a regular overall shape, and is compatible with the installation of existing building bearings, making it easy to promote and apply in large-span spatial structure projects. Attached Figure Description

[0022] Figure 1 This is a frontal cross-sectional view of the present invention. Figure 2 This is a schematic diagram of the magnetorheological damper structure of the present invention; Figure 3 This is a schematic diagram of the connection structure between the plate and the pull-out locking buckle in this invention; Figure 4 This is the control flowchart of the present invention; Figure 5 This is a schematic diagram of the mechanical model of the present invention; Figure 6 This is a schematic diagram of the installation nodes of the present invention.

[0023] In the diagram: 1. Top plate; 2. Horizontal layered magnetorheological elastomer vibration isolation / vibration unit; 201. Layered magnetorheological elastomer; 202. Permanent magnet; 203. First coil; 204. Steel yoke; 205. Horizontal slide rail A; 3. Middle plate; 4. Vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit; 41. Negative stiffness unit; 411. Compression spring; 412. Connecting plate; 413. Horizontal slide rail B; 414. Connecting rod; 42. Disc spring; 43. Magnetorheological damper; 431. Cylinder; 432. Piston rod; 433. Piston block; 434. Second coil; 435. Magnetorheological fluid; 44. Vertical slide rail; 45. Anti-pull-out lock; 5. Base plate. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0025] Please see Figures 1-6This invention provides a technical solution: a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures, comprising a top plate 1 and a bottom plate 5. A horizontally stacked magnetorheological elastomer vibration isolation / vibration unit 2 is rotatably connected to the bottom of the top plate 1. A middle plate 3 is fixed to the bottom of the horizontally stacked magnetorheological elastomer vibration isolation / vibration unit 2. A vertically magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 is fixed on the bottom plate 5. The vertically magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 is slidably connected to the inner side of the middle plate 3. The top plate 1 is located at the uppermost end of the bearing, and its upper surface is provided with bolt holes or welding interfaces for fixed connection with the lower chord ball node or bearing node plate of the large-span roof space frame structure. The base plate 5 is located at the lowest end of the support, and its lower surface is also equipped with a connection interface for fixed connection with the pre-embedded steel plate or anchor bolts at the top of the lower support column. The middle plate 3 is set between the horizontally stacked magnetorheological elastomer vibration isolation / vibration unit 2 and the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4. When the support is subjected to a horizontal load, the horizontally stacked magnetorheological elastomer vibration isolation / vibration unit 2 can slide freely relative to the top plate 1 through the horizontal slide rail A205, while the vertical load is smoothly transferred to the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 below through the middle plate 3. When the support is subjected to a vertical load, the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 can slide freely relative to the base plate 5 through the vertical slide rail 44. This achieves physical and functional decoupling of horizontal and vertical movements, ensuring that the vibration isolation / vibration performance in each direction is independently controllable.

[0026] In this embodiment, as Figure 1 As shown, the horizontally oriented laminated magnetorheological elastomer (MRE) vibration isolation / vibration unit 2 includes a laminated MRE 201, which is composed of alternating layers of MRE and magnetically conductive steel plates. A permanent magnet 202 is fixed to the inner side of the laminated MRE 201, and a first coil 203 surrounds the outer side of the laminated MRE 201. The horizontally oriented laminated MRE vibration isolation / vibration unit 2 undertakes horizontal shear deformation and achieves active adjustment of horizontal stiffness and damping. The laminated MRE 201 is formed by alternating layers of MRE and magnetically conductive steel plates, followed by high-temperature and high-pressure vulcanization bonding to form a cylindrical or rectangular columnar composite. The magnetically conductive steel plate acts as a mechanical constraint element, limiting the lateral bulging deformation of the MRE thin layer under vertical pressure, ensuring the vertical bearing stiffness of the support, and also acts as a magnetic circuit conduction element participating in the formation of a closed magnetic circuit. The first coil 203 is connected to an external current driver via a wire.

[0027] In this embodiment, as Figure 1 As shown, a steel yoke 204 is provided on the outside of the first coil 203, and the steel yoke 204 and the internal magnetic conductive steel plate form a closed magnetic circuit. The steel yoke 204, the magnetic conductive steel plate and the permanent magnet 202 together form a closed magnetic circuit, so that the magnetic field generated by the first coil 203 is concentrated inside the laminated magnetorheological elastic body 201.

[0028] In this embodiment, as Figure 1 As shown, a horizontal slide rail A205 is fixed at the bottom of the top plate 1, and the top of the steel yoke 204 is slidably connected inside the horizontal slide rail A205. The horizontal slide rail A205 adopts a linear guide pair to constrain the direction of horizontal shearing motion.

[0029] In this embodiment, as Figure 1 As shown, the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 includes a negative stiffness unit 41, and the negative stiffness unit 41 includes a compression spring 411. The compression spring 411 is fixed on the two inner walls of the base plate 5, and the inner end of the compression spring 411 is fixed with a connecting plate 412. Horizontal slide rails B413 are symmetrically fixed on both sides of the bottom of the base plate 5. The connecting plate 412 is slidably connected in the horizontal slide rails B413. Disc springs 42 are symmetrically fixed on both sides of the bottom of the base plate 5. The middle plate 3 is fixed on the top of the two disc springs 42. A connecting rod 414 is hinged between the connecting plate 412 and the middle plate 3. The vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 bears the vertical static load of the roof and isolates vertical vibration.

[0030] The disc spring 42, as a positive stiffness element, is vertically positioned at the center of the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4. The disc spring 42 is composed of multiple disc-shaped spring plates arranged in a paired or stacked manner. The specifications of the disc spring 42 are determined according to the design static load of the large-span roof. The disc spring 42 bears the roof static load transmitted from the middle plate 3, and the compression of the disc spring 42 at the static equilibrium position is determined according to the design bearing capacity.

[0031] The negative stiffness unit 41 is used to provide vertical negative stiffness, which cancels out the positive stiffness of the disc spring 42 near the static equilibrium position, achieving quasi-zero stiffness characteristics.

[0032] The specifications of the compression spring 411 are determined according to the required negative stiffness. The horizontal slide rail B413 is used to constrain the horizontal movement direction of the connecting plate 412, ensuring that it can only slide back and forth in the horizontal direction. The connecting plate 412 is provided with a slider or roller that cooperates with the horizontal slide rail B413 to reduce motion friction.

[0033] Link 414 is a rigid member, and its length and inclination angle are determined according to the negative stiffness design curve.

[0034] When the support undergoes vertical displacement, the vertical moving component drives the upper hinge point of the connecting rod 414 to move synchronously. The connecting rod 414 converts the vertical motion into the horizontal motion of the connecting plate 412, which in turn compresses or stretches the compression spring 411. The restoring force of the compression spring 411, after being decomposed by the connecting rod 414, generates a component force in the vertical direction in the same direction as the displacement, i.e., a negative stiffness force. This negative stiffness force cancels out the positive stiffness force provided by the disc spring 42 near the static equilibrium position, causing the vertical dynamic stiffness of the support to approach zero within a certain stroke range near the static equilibrium position.

[0035] To achieve near-zero stiffness characteristics, the stiffness, preload, and geometric parameters of the compression spring 411 and the disc spring 42 should meet the following matching relationship: the absolute value of the negative stiffness generated by the negative stiffness mechanism in the vertical direction is equal to or slightly smaller than the positive stiffness of the disc spring 42 at the static equilibrium position, so as to ensure that the overall stiffness of the system is always non-negative and avoid stiffness instability.

[0036] In this embodiment, as Figure 1 and Figure 2 As shown, a magnetorheological damper 43 is fixed in the middle of the bottom of the base plate 5. The magnetorheological damper 43 includes a cylinder 431, a piston block 433 is slidably connected inside the cylinder 431, and a piston rod 432 is hinged to the top of the middle plate 3. The piston rod 432 passes through the top of the cylinder 431 and is connected to the piston block 433. The magnetorheological damper 43 is arranged in parallel with the disc spring 42 to provide an actively adjustable vertical damping force. The magnetorheological damper 43 adopts a double-rod or single-rod structure. The piston rod 432 moves synchronously with the vertical moving parts. The piston block 433 is fixed in the middle of the piston rod 432, dividing the inner cavity of the cylinder 431 into upper and lower chambers.

[0037] In this embodiment, as Figure 1 and Figure 2 As shown, a second coil 434 is wound inside the piston block 433, and the cylinder 431 is filled with magnetorheological fluid 435. A throttling orifice is provided on the piston block 433. Under the action of an external magnetic field, the yield stress of the magnetorheological fluid 435 can undergo continuous and reversible changes within milliseconds. The throttling orifice allows the magnetorheological fluid 435 to flow between the two chambers.

[0038] The second coil 434 is wound inside the piston block 433 to shorten the magnetic circuit length and improve the magnetic field efficiency. The second coil 434 is connected to an external current driver via a wire. When current flows through the second coil 434, the generated magnetic field passes perpendicularly through the damping channel where the throttling orifice is located, causing the magnetorheological fluid 435 in the channel to undergo a magnetorheological effect, thereby changing its shear yield stress and adjusting the damping force output by the damper. By controlling the magnitude of the current in the second coil 434, the damping force can be continuously adjusted.

[0039] In this embodiment, as Figure 1 As shown, a vertical slide rail 44 is fixed to the outer side of the base plate 5, and the vertical slide rail 44 is rotatably connected to the inner wall of the middle plate 3 to constrain the movement direction of the vertical moving parts and ensure the stability of the vertical load. In this embodiment, the vertical slide rail 44 is a linear ball bearing guide sleeve, whose inner surface mates with the outer cylindrical surface of the vertical moving parts, resulting in a low coefficient of friction and high movement accuracy.

[0040] In this embodiment, as Figure 1 and Figure 3 As shown, four pull-out locking buckles 45 are uniformly fixed to the outer circumference of the base plate 5, and the pull-out locking buckles 45 are slidably connected to the inner wall of the middle plate 3. The pull-out locking buckles 45 adopt an I-shaped slot-embedded structure. The pull-out locking buckles 45 are used to provide pull-out restraint when the support is under tension. The pull-out locking buckles 45 adopt an I-shaped slot-embedded structure: a transversely extending I-shaped flange is provided at the upper end of the vertical moving part, and symmetrical L-shaped blocks are provided on both sides at the corresponding position below the middle plate 3. A slot-shaped space is formed between the two blocks to accommodate the I-shaped flange. Under normal vibration isolation conditions, the I-shaped flange can move freely vertically in the slot-shaped space, and a preset gap is maintained between it and the horizontal contact surface of the L-shaped block, which does not interfere with the quasi-zero stiffness vibration isolation performance. When the support is subjected to wind suction or seismic overturning moment and the upward displacement exceeds the gap threshold, the upper surface of the I-shaped flange contacts the lower surface of the L-shaped block to form a geometric lock and withstand the upward pull-out force. Rubber pads can be attached to the contact surfaces of the L-shaped stop and the I-shaped flange to achieve soft contact cushioning and reduce the impact during locking.

[0041] According to another aspect of the present invention, a control method for a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures is provided, comprising the following steps: Step 1: Sensor data acquisition and signal processing.

[0042] Accelerometers, displacement sensors, and force sensors deployed at the top and bottom of the supports and key nodes of the large-span roof structure collect multi-source data in real time, including the structure's acceleration response, displacement response, and vertical load. Additionally, anemometers deployed on the roof or towers and regional earthquake early warning signals can be connected as auxiliary criteria for determining operating conditions. The raw sensor signals are amplified, subjected to anti-aliasing low-pass filtering, and converted from analog to digital by the signal conditioning module before being sent to the core controller.

[0043] Step 2: Operating condition identification.

[0044] The core controller extracts features from the preprocessed multi-source data. Extracted feature parameters include the root mean square value of vibration acceleration, peak acceleration, dominant frequency, duration, and bandwidth. A pre-defined classification algorithm is used to identify the current type of external excitation in real time, determining the type of external excitation currently being experienced by the structure.

[0045] Based on the identification results, the operating conditions are divided into one of the following three categories: High-frequency micro-vibration mode: The excitation frequency is relatively high (>5Hz) and the amplitude is relatively small, corresponding to micro-excitations such as equipment vibration and personnel activity; Low-frequency moderate vibration mode: The excitation frequency is relatively low (0.5~5Hz) and the amplitude is moderate, corresponding to wind load, small and medium earthquakes, etc. Major earthquake safety mode: When the excitation amplitude exceeds the preset major earthquake threshold or an earthquake early warning signal is received, it corresponds to extreme conditions such as rare earthquakes or strong winds.

[0046] Step 3: Control mode switching and collaborative control.

[0047] Based on the mode judgment result, the core controller automatically switches to the corresponding control mode and outputs corresponding control commands to the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 and the horizontal laminated magnetorheological elastomer vibration isolation / vibration unit 2 respectively: 1. When identified as a high-frequency micro-vibration mode: In the vertical direction, the quasi-zero stiffness vibration isolation unit is kept working near the static equilibrium position. The disc spring 42 and the negative stiffness unit 41 form a quasi-zero stiffness characteristic near the static equilibrium position, and use their high static and low dynamic characteristics to isolate high-frequency micro-amplitude vibrations. The second coil 434 of the magnetorheological damper 43 is supplied with a low current and adopts a low damping state to avoid excessive energy consumption affecting the quasi-zero stiffness vibration isolation effect.

[0048] In the horizontal direction, the first coil 203 of the laminated magnetorheological elastomer vibration isolation / vibration unit 2 is supplied with a positive current, which switches the support to a high stiffness state, restricts the slight horizontal displacement, and suppresses structural swaying.

[0049] 2. When identified as a low-frequency intermediate vibration mode: In the vertical direction, the quasi-zero stiffness vibration isolation unit continues to work normally, and the disc spring 42 and the negative stiffness unit 41 maintain quasi-zero stiffness characteristics near the static equilibrium position; the magnetorheological damper 43 switches to the variable damping state, and the core controller runs the control algorithm to dynamically adjust the current in the second coil 434 according to the amplitude and frequency of the real-time vibration response to optimize the energy consumption effect.

[0050] In the horizontal direction, the laminated magnetorheological elastomer vibration isolation / vibration unit 2 enters a real-time adjustment state. Through the coordinated control of the first coil 203 and the permanent magnet 202, the core controller adjusts the current in the first coil 203 in real time according to the horizontal vibration response, continuously adjusting the shear stiffness and damping to achieve adaptive matching of stiffness and damping.

[0051] 3. When identified as a major earthquake safety mode: In the vertical direction, if the upward displacement is detected to exceed the preset threshold, the anti-pull-out latch 45 is automatically activated, and the I-shaped flange contacts and locks with the L-shaped stop block to prevent the support from being pulled out under strong earthquake or wind suction. The second coil 434 of the magnetorheological damper 43 is supplied with the maximum current to provide maximum damping to dissipate the energy of violent vibration.

[0052] In the horizontal direction, the support enters an ultra-low stiffness state, and the laminated magnetorheological elastomer vibration isolation / seismic unit 2 switches to a low stiffness state, extending the seismic isolation period and maximizing the isolation of strong earthquake energy input.

[0053] Step 4: Closed-loop feedback and real-time adjustment.

[0054] In each of the above control modes, the core controller continuously receives sensor feedback signals, monitors the displacement, acceleration, and force response of the support in real time, compares them with the control target values, and dynamically adjusts the current values ​​output to the second coil 434 of the magnetorheological damper 43 and the excitation first coil 203 of the laminated magnetorheological elastomer 201 through a closed-loop control algorithm. The current driver has an internal current sampling feedback loop, which monitors the output current in real time through a sampling resistor and a differential amplifier, feeding it back to the core controller to form a closed-loop control, ensuring the accuracy and stability of the output current. Simultaneously, the core controller uploads the support operating status, working condition identification results, and control parameters to the host computer monitoring system in real time, enabling remote monitoring and early warning.

[0055] Step 5: Execute repeatedly.

[0056] Return to step one and continue data acquisition, operating condition identification, mode switching, and closed-loop control to form a complete closed-loop feedback control cycle until the system stops running.

[0057] To further clarify the mechanical principles and engineering applications of this invention, Figure 5 A schematic diagram of the overall mechanical model of the triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing is given. Figure 6 The typical installation location of this support in a large-span spatial grid structure is shown.

[0058] like Figure 5As shown, the mechanical model of the bearing is composed of horizontal and vertical vibration isolation / seismic units through spatial decoupling, achieving independent control in three directions. The horizontal unit is equivalent to a parallel combination of a horizontal variable spring and a horizontal variable damper, where both spring stiffness and damping coefficient can be actively adjusted via a magnetic field. The vertical unit adopts a quasi-zero stiffness system, consisting of three parallel parts: a vertical positive stiffness spring providing static load capacity; a negative stiffness spring (often implemented using inclined springs, pre-compressed buckling beams, or spring-linkage mechanisms), generating negative stiffness near the static equilibrium position to cancel out the positive stiffness; and a vertical variable damper for active energy dissipation. The horizontal and vertical units are connected orthogonally or decoupled in the mechanical model, together forming a three-dimensional seismic isolation bearing model with three-dimensional adaptive stiffness and damping adjustment capabilities.

[0059] like Figure 6 As shown, the support is installed between the roof and the lower supporting structure of the large-span spatial grid structure. Figure 6 In the middle, the superstructure is a typical spatial grid structure (such as a space frame or grid shell), including chords and web members; the substructure consists of supporting columns or piers. The support body ( Figure 1 As shown, the supports are arranged at the support nodes of the grid structure. Specifically, the top plate of the support is fixedly connected to the lower chord ball joint or the support node plate, and the bottom plate of the support is fixedly connected to the pre-embedded steel plate or anchor bolts at the top of the column. This installation method ensures that the vertical static load transfer, horizontal shear sliding, and pull-out locking functions of the support are effectively utilized, while also facilitating the placement of sensors and the lead-out of control lines. Example

[0060] This embodiment is basically the same as Embodiment 1, except that the negative stiffness unit 41 in the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 is specifically implemented.

[0061] In this embodiment, the negative stiffness unit 41 uses a pre-compressed buckling beam structure instead of the compression spring 411-linkage 414 mechanism. Specifically, two sets of pre-compressed buckling steel strips are symmetrically arranged on both sides of the disc spring 42. The two ends of the steel strips are fixed to the support housing, and the middle is connected to the vertical moving member through a connector. The steel strips are in a pre-compressed buckling state in the initial state. When the vertical moving member deviates from the static equilibrium position, the restoring force of the buckling steel strips generates a component force in the vertical direction in the same direction as the displacement, providing negative stiffness.

[0062] This embodiment is basically the same as Embodiment 1, except that the negative stiffness unit 41 in the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit 4 is specifically implemented.

[0063] In this embodiment, the negative stiffness unit 41 uses a pre-compressed buckling beam structure instead of the compression spring 411-linkage 414 mechanism. Specifically, two sets of pre-compressed buckling steel strips are symmetrically arranged on both sides of the disc spring 42. The two ends of the steel strips are fixed to the support housing, and the middle is connected to the vertical moving member through a connector. The steel strips are in a pre-compressed buckling state in the initial state. When the vertical moving member deviates from the static equilibrium position, the restoring force of the buckling steel strips generates a component force in the vertical direction in the same direction as the displacement, providing negative stiffness. Example

[0064] This embodiment is basically the same as Embodiment 1, except for the specific implementation of the pull-out lock 45.

[0065] In this embodiment, the pull-out locking buckle 45 adopts a pre-reserved gap ratchet structure instead of an I-shaped slotted structure. Specifically, a one-way ratchet groove is machined on the outer cylindrical surface of the vertical moving part, and a pre-compressed spring wedge is installed at the corresponding position below the middle plate 3. Under normal vibration isolation conditions, a preset gap is maintained between the wedge and the ratchet groove, and they are completely decoupled; when the upward pull-out displacement exceeds the gap threshold, the wedge is quickly pushed into the groove under the action of spring force, forming a geometric lock; after the tension disappears, the support is pressed back under the action of gravity, and the wedge slides out along the inclined surface of the groove, automatically unlocking.

[0066] Working Principle: The layered magnetorheological elastomer 201 is formed by alternating layers of magnetorheological elastomer (MRE) and magnetically conductive steel plates, bonded together by high-temperature and high-pressure vulcanization, creating a cylindrical or rectangular columnar composite. The magnetically conductive steel plate acts as a mechanical constraint element, limiting the lateral bulging deformation of the MRE layers under vertical pressure, ensuring the vertical load-bearing stiffness of the support, and also participates in the formation of the closed magnetic circuit as a magnetic circuit conduction element. The steel yoke 204, the magnetically conductive steel plate, and the permanent magnet 202 together form a closed magnetic circuit, concentrating the magnetic field generated by the energization of the first coil 203 within the layered magnetorheological elastomer 201. The horizontal slide rail A205 is used to constrain the direction of horizontal shear motion. The disc spring 42 bears the roof static load transmitted from the middle plate 3, and the compression of the disc spring 42 at the static equilibrium position is determined according to the design load-bearing capacity. The negative stiffness unit 41 provides vertical negative stiffness, which cancels out the positive stiffness of the disc spring 42 near the static equilibrium position, achieving quasi-zero stiffness characteristics. The horizontal slide rail B413 is used to constrain the horizontal movement direction of the connecting plate 412, ensuring that it can only slide back and forth in the horizontal direction. The connecting rod 414 converts the vertical motion into the horizontal motion of the connecting plate 412. The magnetorheological damper 43 is arranged in parallel with the disc spring 42 to provide an actively adjustable vertical damping force. The piston rod 432 moves synchronously with the vertical moving part, and the piston block 433 divides the inner cavity of the cylinder 431 into upper and lower chambers. When current is passed through the second coil 434, the generated magnetic field passes vertically through the damping channel where the throttling orifice is located, causing the magnetorheological fluid 435 in the channel to undergo a magnetorheological effect, and its shear yield stress changes accordingly, thereby adjusting the damping force output by the damper. By controlling the current in the second coil 434, the damping force can be continuously adjusted.

[0067] The pull-out locking buckle 45 adopts an I-shaped slotted structure: a transversely extending I-shaped flange is provided at the upper end of the vertical moving part, and symmetrical L-shaped blocks are provided on both sides at the corresponding position below the middle plate 3, forming a slotted space between the two blocks to accommodate the I-shaped flange. Under normal vibration isolation conditions, the I-shaped flange can move freely vertically within the slotted space, maintaining a preset gap between its horizontal contact surface with the L-shaped blocks, without interfering with the quasi-zero stiffness vibration isolation performance; when the support is subjected to wind suction or seismic overturning moment, resulting in an upward pull-out displacement exceeding the gap threshold, the upper surface of the I-shaped flange contacts the lower surface of the L-shaped blocks, forming a geometric lock and bearing the upward pull-out force.

[0068] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures, comprising a top plate (1) and a bottom plate (5), characterized in that: The bottom of the top plate (1) is rotatably connected to a horizontally stacked magnetorheological elastomer vibration isolation / vibration unit (2), and the bottom of the horizontally stacked magnetorheological elastomer vibration isolation / vibration unit (2) is fixed with a middle plate (3). The bottom plate (5) is fixed with a vertically magnetorheological quasi-zero stiffness vibration isolation / vibration unit (4), and the vertically magnetorheological quasi-zero stiffness vibration isolation / vibration unit (4) is slidably connected to the inner side of the middle plate (3).

2. The triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 1, characterized in that: The horizontally stacked magnetorheological elastomer vibration isolation / vibration unit (2) includes a stacked magnetorheological elastomer (201), and the stacked magnetorheological elastomer (201) is composed of alternating stacks of magnetorheological elastomer and magnetically conductive steel plate. A permanent magnet (202) is fixed on the inner side of the stacked magnetorheological elastomer (201), and a first coil (203) is surrounded on the outer side of the stacked magnetorheological elastomer (201).

3. The triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 2, characterized in that: A steel yoke (204) is provided on the outside of the first coil (203), and the steel yoke (204) and the internal magnetic steel plate form a closed magnetic circuit.

4. The triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 3, characterized in that: The bottom of the top plate (1) is fixed with a horizontal slide rail A (205), and the top of the steel yoke (204) is slidably connected in the horizontal slide rail A (205).

5. The triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 1, characterized in that: The vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit (4) includes a negative stiffness unit (41), and the negative stiffness unit (41) includes a compression spring (411). The compression spring (411) is fixed on the two inner walls of the base plate (5), and the inner end of the compression spring (411) is fixed with a connecting plate (412). The bottom of the base plate (5) is symmetrically fixed with horizontal slide rails B (413) on both sides. The connecting plate (412) is slidably connected in the horizontal slide rails B (413). The bottom of the base plate (5) is symmetrically fixed with disc springs (42) on both sides. The middle plate (3) is fixed on the top of the two disc springs (42). The connecting plate (412) and the middle plate (3) are hinged with a connecting rod (414).

6. A triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 2, characterized in that: A magnetorheological damper (43) is fixed at the middle of the bottom of the base plate (5), and the magnetorheological damper (43) includes a cylinder (431). A piston block (433) is slidably connected inside the cylinder (431). A piston rod (432) is hinged to the top of the middle plate (3). The piston rod (432) passes through the top of the cylinder (431) and is connected to the piston block (433).

7. A triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 6, characterized in that: The piston block (433) has a second coil (434) wound inside, the cylinder (431) is filled with magnetorheological fluid (435), and the piston block (433) has a throttling orifice.

8. A triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 1, characterized in that: A vertical slide rail (44) is fixed to the outer side of the base plate (5), and the vertical slide rail (44) is rotatably connected to the inner wall of the middle plate (3).

9. A triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures according to claim 6, characterized in that: Four pull-out buckles (45) are evenly fixed on the outer circumference of the base plate (5), and the pull-out buckles (45) are slidably connected to the inner wall of the middle plate (3). The pull-out buckles (45) adopt an I-shaped slot embedded structure.

10. A control method for a triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures, applicable to the triaxial magnetorheological quasi-zero stiffness intelligent vibration isolation bearing for large-span spatial structures as described in claim 9, characterized in that... Includes the following steps: Step 1: The device is equipped with an intelligent control system, which includes a sensor network, a core controller, a current driver, and a communication module. The sensor network includes accelerometers, displacement sensors, and force sensors deployed at the top and bottom of the supports and key nodes of the large-span roof structure. Sensor data acquisition and signal processing: Accelerometers, displacement sensors, and force sensors are used to collect the acceleration, displacement, and vertical load data of the structure in real time. The collected signals are amplified, filtered, and converted from analog to digital before being sent to the core controller. Step 2, Operating Condition Identification: The core controller extracts features from the preprocessed data, including vibration amplitude, dominant frequency, duration, and bandwidth. It uses a preset classification algorithm to identify the current external excitation type in real time and classifies the operating condition into one of the following three categories: high-frequency micro-vibration mode, low-frequency medium-vibration mode, and large-earthquake safety mode. Step 3, Control Mode Switching and Cooperative Control: Based on the operating condition identification results, the core controller outputs corresponding control commands to the vertical magnetorheological quasi-zero stiffness vibration isolation / vibration unit (4) and the horizontal laminated magnetorheological elastomer vibration isolation / vibration unit (2), respectively: When identified as a high-frequency micro-vibration mode: in the vertical direction, the quasi-zero stiffness isolation unit is kept working near the static equilibrium position, and the magnetorheological damper (43) adopts a low-damping state; in the horizontal direction, the laminated magnetorheological elastomer isolation / vibration unit (2) is switched to a high-stiffness state. When identified as a low-frequency vibration mode: in the vertical direction, the quasi-zero stiffness isolation unit continues to work normally, and the magnetorheological damper (43) switches to the variable damping state, dynamically adjusting the damping force according to the real-time vibration response; in the horizontal direction, the laminated magnetorheological elastomer isolation / vibration unit (2) enters the real-time adjustment state, and continuously adjusts the shear stiffness and damping through the coordinated control of the first coil (203) and the permanent magnet (202); When identified as a major earthquake safety mode: in the vertical direction, if the upward displacement is detected to exceed the preset threshold, the anti-pull-out latch (45) is automatically activated, and the magnetorheological damper (43) is supplied with the maximum current to provide maximum damping; in the horizontal direction, the laminated magnetorheological elastomer isolation / vibration unit (2) switches to a low stiffness state. Step 4, Closed-loop feedback and real-time adjustment: The core controller continuously receives sensor feedback signals, monitors the displacement, acceleration and force response of the support in real time, compares them with the control target value, and dynamically adjusts the current value output to the magnetorheological damper (43) and the second excitation coil (434) of the laminated magnetorheological elastomer (201); Step 5: Repeat the process: Return to Step 1 and continue to collect data, identify operating conditions, switch modes, and perform closed-loop control until the system stops running.

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