Active and passive synergistic magnetorheological shear thickening fluid damper

Abstract

The active and passive synergistic magnetorheological shear thickening fluid damper comprises a damper shell, the inner wall of the damper shell is slidably connected with a piston, the periphery of the piston is integrated with a self-adaptive synergistic sleeve, the self-adaptive synergistic sleeve comprises a sleeve-shaped base body electrically connected with an exciting coil, the base body has both magnetic conductivity and electrical conductivity, and the base body is provided with a magnetic core and a magnetic core; a plurality of self-adaptive flow channel units which extend in the axial direction and are arranged at intervals in the circumferential direction are constructed on the outer wall of the sleeve-shaped base body, and each self-adaptive flow channel unit is composed of a concave part formed in the base body and an elastic filling body filled in the concave part; the invention belongs to the technical field of dampers, and achieves the technical effects that by integrating the conductive metal sleeve, the ribs and the shell ring belt and optimizing the wedge geometry of the groove and the sealing block, deep collaboration of a multi-physical field energy consumption mechanism is achieved; when the piston moves, the ribs and the annular belt cut magnetic induction lines to generate eddy current damping, and additional passive energy consumption which is linearly related to the speed and free of abrasion is provided.

Description

Technical Field

[0001] This invention relates to the field of damper technology, specifically to an active-passive coordinated magnetorheological shear thickening liquid damper. Background Technology

[0002] In modern civil engineering, bridge engineering, and vibration isolation of precision equipment, dampers, as a key energy dissipation and vibration reduction device, play a crucial role in dissipating external vibration energy and ensuring structural safety and comfort. Traditional passive dampers, such as viscous dampers, have fixed damping characteristics during the design phase and cannot be adjusted in real time according to changes in external loads. Therefore, their vibration reduction efficiency is often limited when dealing with earthquakes or wind-induced vibrations with complex spectral components and variable amplitudes. To overcome this shortcoming, dampers based on intelligent fluids have emerged. Among them, magnetorheological fluid dampers can quickly and reversibly change their damping force by adjusting the external magnetic field, demonstrating good semi-active control potential. However, it relies entirely on an external power source and control system, and degrades to a low-damping state once power is lost, posing a safety hazard. On the other hand, as a purely passive device, the shear-thickening liquid damper can exhibit a significant increase in viscosity at high shear rates and has excellent passive energy dissipation capabilities, but its characteristics are also not adjustable in real time and it has a weak response to low-frequency micro-amplitude vibrations. In recent years, some studies have attempted to combine the magnetorheological effect with the shear-thickening effect in order to obtain a composite intelligent fluid damper that has both adjustability and high energy dissipation potential. However, most existing solutions simply mix the two fluids without achieving deep synergy and complementarity of the two effects from the perspective of the internal mechanical structure of the damper. As a result, their overall performance is often just a simple superposition of the two characteristics, or even mutually restrictive. For example, the fixed fluid gap design makes it difficult to optimize the magnetic field distribution and flow field morphology, and cannot adaptively adjust according to the impact intensity. Under extreme conditions, there may be insufficient damping force or response lag, which limits the further improvement of its intelligent adaptability and reliability under wide-band and variable amplitude complex loads. Therefore, it does not meet the existing requirements, so we propose an active-passive coordinated magnetorheological shear thickening liquid damper. Summary of the Invention

[0003] Therefore, the present invention provides an active-passive coordinated magnetorheological shear thickening liquid damper to solve the above-mentioned problems in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, a passive-active coordinated magnetorheological shear thickening fluid damper includes a damper housing, a piston slidably connected to the inner wall of the damper housing, a piston rod fixedly connected to the middle of the piston, an excitation coil mounted on the piston, the interior of the damper housing being filled with a magnetorheological shear thickening fluid, and a wiring channel provided on the inner wall of the piston rod, through which the wire of the excitation coil passes and is led out to be connected to an external power source; characterized in that an adaptive coordinated sleeve is integrated on the outer periphery of the piston, the adaptive coordinated sleeve comprising: A sleeve-shaped substrate electrically connected to the excitation coil, the substrate being both magnetically and electrically conductive; The outer wall of the sleeve-shaped substrate is constructed with multiple adaptive flow channel units that extend axially and are arranged at intervals in the circumferential direction. The adaptive flow channel unit is composed of a recess opened on the substrate and an elastic filler filling the recess. Among them, magnetic ribs made of sleeve-shaped matrix material are formed between adjacent adaptive flow channel units; Under fluid pressure, the elastic filler can undergo elastic deformation toward the interior of the recess, thereby dynamically changing the geometry and cross-sectional area of ​​the fluid channel formed by the outer edge of the adjacent magnetic ribs, the surface of the elastic filler, and the inner wall of the damper housing. An inductive coupling section is provided on the inner wall of the damper housing in the region corresponding to the piston's stroke.

[0005] Furthermore, the sleeve-shaped substrate is a metal sleeve fixedly fitted onto the outer wall of the piston, which is connected to the excitation coil through internal wires to form a current loop and a magnetic path.

[0006] Furthermore, the recess in the adaptive flow channel unit is a vertical groove formed on the outer wall of the sleeve-shaped substrate, and the elastic filler is a flexible sealing block embedded and fixed in the vertical groove.

[0007] Furthermore, the thickness of the flexible sealing block is designed to decrease in a gradient from its root to its free end.

[0008] Furthermore, the flexible sealing block is made of polyurethane elastomer or silicone rubber elastomer.

[0009] Furthermore, the cross-sectional shape of the vertical groove and the flexible sealing block inside it is a wedge shape with the width gradually decreasing from the inside to the outside.

[0010] Furthermore, the magnetic rib is an axially extending rib that, as part of the sleeve-shaped substrate, possesses both magnetic and electrical conductivity.

[0011] Furthermore, the inductive coupling part is an annular band embedded and fixed to the inner wall of the damper housing, and the annular band is made of a highly conductive material.

[0012] Furthermore, the deformation of the elastic filler under fluid pressure changes the distance between the outer edge of the magnetic rib and the inductive coupling part, thereby adjusting the magnetic coupling strength between them.

[0013] Furthermore, the excitation coil is arranged around the inside of the piston.

[0014] Furthermore, the metal sleeve and the piston body are fixed by an interference fit or by a key connection.

[0015] Furthermore, the damper housing includes a damper shell, with bushing one and bushing two fixedly connected to both ends of the damper shell, and an extension tube fixedly connected to the end of the damper shell away from bushing one. One end of the piston rod passes through bushing one and is fixedly connected to pin one, while the other end passes through bushing two and extends into the extension tube. Pin two is fixedly installed at the end of the extension tube away from the damper shell.

[0016] The present invention has the following advantages: 1. This active-passive coordinated magnetorheological shear thickening liquid damper achieves effective focusing and enhancement of the magnetic field by introducing a metal sleeve electrically connected to the excitation coil and a rigid rib structure formed thereon. This design concentrates and guides the originally relatively uniformly dispersed magnetic field lines to the top of the ribs, forming a local high magnetic flux density region between the ribs and the shell or ring. This structural innovation significantly enhances the magnetorheological effect in the key operating range, thereby enabling a larger range of damping force adjustment with a smaller excitation current. This greatly improves the energy efficiency and response sensitivity of the active control mode, overcoming the shortcomings of low magnetic field utilization and low adjustment efficiency in traditional structures. 2. This active-passive coordinated magnetorheological shear thickening fluid damper constructs an adaptive flow channel through a flexible sealing block and its gradient thickness design set in the vertical groove of the metal sleeve. The flexible sealing block constitutes the dynamic boundary of the fluid channel, and its deformation under stress is directly related to the external load intensity. Under low-frequency micro-amplitude vibration, it maintains its shape to maintain a narrow gap, optimizing low-speed shear and magnetic field conditions. Under high-speed impact, it elastically bends to expand the flow channel, achieving instantaneous pressure relief and protection. This process simultaneously mechanically adjusts the magnetic pole gap, forming a negative feedback loop of "increased pressure → wider flow channel / increased magnetic gap → weakened magnetic field → greater reliance on passive energy dissipation". This significantly improves the damper's adaptive capability and overall stability in the face of uncertain impacts. 3. This active-passive synergistic magnetorheological shear thickening fluid damper achieves deep synergy of multi-physics energy dissipation mechanisms by integrating conductive metal sleeves, ribs, and shell rings, and optimizing the wedge geometry of the grooves and sealing blocks. During piston movement, the ribs and rings cut magnetic field lines to generate eddy current damping, providing an additional passive energy dissipation that is linearly related to velocity and wear-free, effectively filling the damping force saturation zone that may occur in the shear thickening fluid at extremely high speeds. At the same time, the wedge design not only guides the flow field to be smoother and improves shear efficiency, but also makes the deformation of the flexible sealing block more controllable and the stress distribution more reasonable, further improving the linearity of magnetic field regulation feedback and component durability. These structural measures ensure that the three effects of shear thickening, magnetorheology, and eddy current damping are no longer isolated, but intertwined and complementary in space and time, jointly extending the effective operating frequency band of the damper to both high and low ends, ensuring efficient, smooth, and reliable comprehensive vibration reduction performance across the entire operating range from daily micro-vibrations to extreme impacts. Attached Figure Description

[0017] Figure 1 This is a front view of an active-passive coordinated magnetorheological shear thickening fluid damper proposed in this invention; Figure 2 for Figure 1 A cross-sectional view; Figure 3 This is the main view of the metal sleeve; Figure 4 for Figure 3 A schematic diagram of the decomposition process; Figure 5 for Figure 3 A front sectional view; Figure 6 for Figure 3 Top view of the piston.

[0018] In the diagram: 11. Damper housing; 12. Bushing 1; 13. Bushing 2; 14. Extension tube; 15. Piston rod; 16. Pin 1; 17. Pin 2; 18. Excitation coil; 110. Piston; 111. Fluid gap; 21. Metal sleeve; 22. Vertical wedge groove; 23. Flexible seal; 24. Rib; 25. Ring belt; Detailed Implementation

[0019] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0020] Example 1; Reference Figure 1 - Figure 3 A passive-active coordinated magnetorheological shear thickening fluid damper includes a damper housing 11. Two bushings, a first bushing 12 and a second bushing 13, for sealing are fixedly connected to both ends of the damper housing 11. An extension tube 14 is fixedly connected to the end of the damper housing 11 away from the first bushing 12. A piston 110 is slidably connected to the inner wall of the damper housing 11. A piston rod 15 is fixedly connected to the middle of the piston 110. One end of the piston rod 15 passes through the first bushing 12 and is fixedly connected to a pin head 16, while the other end extends through the second bushing 13. Inside the extension tube 14, a pin 17 is fixedly installed at one end of the extension tube 14 away from the damper housing 11. There is an annular gap between the outer wall of the piston 110 and the inner wall of the damper housing 11. This annular gap is a fluid gap 111 for liquid flow. An excitation coil 18 is installed on the piston 110. The inner wall of the damper housing 11 is filled with magnetorheological shear thickening liquid. A wiring channel is provided inside the piston rod 15. The wire of the excitation coil 18 passes through the channel and is led out from the side wall of the piston rod 15 to connect to an external power source. Furthermore: the magnetorheological shear thickening fluid is a composite smart fluid, which is composed of a magnetorheological material and a shear thickening fluid; wherein, the magnetorheological material includes soft magnetic particles, a carrier liquid and a dispersant; the shear thickening fluid includes nanoscale particles and a base carrier liquid; the composite material has both magnetorheological properties and shear rate thickening properties. Furthermore: the excitation coil 18 is arranged around the internal cavity of the piston 110. After the coil is energized, a controllable magnetic field can be formed in the fluid gap 111 around the piston 110. The direction of the magnetic field is basically perpendicular to the direction of piston movement, so it can effectively act on the magnetorheological shear thickening liquid in the gap. In use, the device is installed between floors of a building structure or between beams and piers of a bridge via pins 16 and 17 at both ends. When the piston rod 15 is subjected to external vibration or impact, the piston 110 reciprocates within the damper housing 11, pushing the magnetorheological shear thickening fluid 19 through the fluid gap 111. At this time, the damper can simultaneously exert both passive and active damping effects: in passive mode, the viscosity of the shear thickening fluid increases significantly due to high-speed shearing, thereby dissipating energy; in active mode, the magnetic field strength can be adjusted in real time by controlling the current of the excitation coil 18 through an external power supply, causing the particles in the magnetorheological fluid to form a chain-like structure, further changing the fluid viscosity and damping characteristics. The two mechanisms work together to achieve a wide-bandwidth, adaptive, and adjustable damping effect. Working principle: The core of this damper is based on the composite intelligent fluid characteristics of magnetorheological fluid and shear thickening fluid. In the absence of a magnetic field, the fluid mainly exhibits shear thickening behavior—as the piston speed increases, the shear rate of the fluid increases, leading to a sharp increase in its apparent viscosity and generating a strong passive energy dissipation effect. When the excitation coil 18 is energized, a magnetic field perpendicular to the fluid flow direction is generated. The magnetic particles in the magnetorheological fluid arrange themselves into chains along the magnetic field lines, increasing the fluid flow resistance. The active and passive effects are not simply superimposed, but rather mutually reinforced through structural design and fluid synergy: the magnetic field can regulate the critical shear rate of shear thickening, while shear flow also affects the formation and destruction rate of the magnetorheological structure, thereby achieving faster, smoother, and wider-range damping force adjustment over a wide frequency range. Example 2: Similar to Embodiment 1, however, the piston structure in Embodiment 1 is relatively simple, with a fixed fluid gap, resulting in a relatively uniform but not focused magnetic field distribution. Furthermore, its adaptive adjustment capability is limited under extreme conditions (such as ultra-high-speed impact or low-frequency micro-amplitude vibration). Moreover, referring to… Figure 1 - Figure 6 A passive-active coordinated magnetorheological shear thickening liquid damper has a metal sleeve 21 fixedly fitted on the outer periphery of the piston 110. The metal sleeve 21 is made of a material with good magnetic permeability and electrical conductivity (such as silicon steel with surface conductive treatment), and is electrically connected to the excitation coil 18 through internal circuitry, so that it can serve as part of the magnetic circuit (pole shoe) and carry current when energized. The outer wall of the metal sleeve 21 is uniformly provided with several axially extending vertical grooves 22 along the circumference; each vertical groove 22 is provided with a flexible sealing block 23; the root of the flexible sealing block 23 (i.e., the side near the center of the piston 110) is fixedly connected to the bottom of the vertical groove 22, and its thickness is designed to decrease gradually from the inside to the outside (i.e., from the root to the free end), so that the stiffness of the flexible sealing block 23 gradually decreases from the inside to the outside (the flexible sealing block 23 can be made of high-performance polyurethane or silicone rubber elastomer, which has the characteristics of high elasticity, fatigue resistance and compatibility with working fluid); by opening these vertical grooves 22, the solid part of the metal sleeve 21 naturally forms multiple axial, magnetic and electrical rigid ribs 24 between adjacent grooves; in addition, on the inner wall of the damper housing 11, in the area corresponding to the movement stroke of the piston 110, a ring band 25 made of highly conductive and magnetic material (such as copper or aluminum alloy) is embedded and fixed. Working principle: By integrating a metal sleeve 21, a flexible sealing block 23, and a conductive ring band 25, a composite intelligent piston system integrating magnetic field focusing, flow channel self-adaptation, and eddy current damping is constructed; its working principle and the resulting synergistic effects are as follows: When the excitation coil 18 is energized, the current flows through the metal sleeve 21. Since the metal sleeve 21 is made of magnetically conductive material, the rigid ribs 24 on it become efficient magnetic poles, which can concentrate the magnetic field lines generated by the excitation coil 18 and guide them outward, forming a high-intensity, localized magnetic field region between the top of the ribs 24 and the damper housing 11. Compared with the more uniform magnetic field in Embodiment 1, this significantly improves the magnetic flux density in the key area of ​​the fluid gap 111, making the magnetorheological effect more sensitive and efficient, and achieving stronger active adjustment capability with a smaller current. The flexible seal 23 forms a variable boundary for fluid flowing through the piston 110. When the piston 110 moves at a low speed or the fluid pressure is low, the flexible seal 23 maintains its original shape due to its elasticity, forming a relatively narrow flow channel together with the outer edge of the rigid rib 24. This is beneficial for generating sufficient shear at low speeds to initiate passive energy dissipation and maintaining a small magnetic gap to enhance the magnetic field. When encountering high-speed impacts or a surge in fluid pressure, the high-pressure fluid acts on the inclined surface of the flexible seal 23, forcing it to deform elastically and bend into the vertical groove. This instantly increases the flow channel cross-section, achieving a dual effect: firstly, it acts as a pressure relief valve to avoid excessively high damping force peaks and protect the mechanical structure; secondly, it automatically adjusts the gap between the magnetic pole (top of the rib 24) and the opposite conductive ring 25. The greater the pressure, the larger the gap, and the weaker the magnetic field. This forms a purely mechanical negative feedback regulation, making the system more reliant on passive energy dissipation under high loads and automatically optimizing the magnetic field conditions when fine adjustment is needed. When the piston 110 moves at high speed, the magnetically conductive metal sleeve 21 (especially its rib 24 portion) moves relative to the ring 25 embedded in the damper housing 11. Even without an external excitation current, the weak leakage flux of the excitation coil 18 is cut by the rib 24, thereby inducing eddy currents in the conductive ring 25. These eddy currents generate a damping force that is always opposite to the direction of piston 110's movement. This mechanism provides a completely passive, contactless, and wear-free additional damping force, the magnitude of which is proportional to the piston 110's speed. It effectively compensates for the damping force saturation or plateau effect that may occur in the magnetorheological shear thickener at extremely high speeds, and broadens the high-frequency and high-efficiency operating range of the damper. Example 3: Similar to Example 2, this example features a refined design of the vertical groove and the geometric configuration of the flexible block to further optimize the flow field morphology, improve the controllability of the flexible block deformation, and enhance the synergistic efficiency with the magnetic field. Furthermore, referring to… Figure 1 - Figure 6 A passive-active coordinated magnetorheological shear thickening liquid damper, wherein the vertical groove 22 on the outer wall of the metal sleeve 21 and the flexible sealing block 23 embedded inside it are both designed to have a wedge shape with a gradually decreasing width from the inside to the outside (i.e. from the bottom of the groove to the opening direction).

[0021] Working principle: This wedge design is not a simple change in shape; its core improvement principle is as follows: The wedge-shaped vertical groove 22 and the flexible sealing block 23 together form a flow channel with a cross-sectional area that changes smoothly along the flow direction (radial). When the piston moves, the fluid enters this wedge-shaped gap and will produce a controllable acceleration or deceleration effect due to the change in the flow cross-section. The wedge-shaped structure with decreasing width means that the material width is greatest at the root of the flexible block 23, gradually narrowing towards the free end; this geometric feature brings two key improvements: 1. The wider root provides stable support and greater initial stiffness, while the narrower tip makes it more prone to directional elastic deformation, primarily bending, under fluid pressure. 2. The wedge-shaped structure facilitates the smooth transfer and dispersion of stress from the wide root to the narrow free end, avoiding the sharp concentration of stress in local areas (especially at the root fixation point); combined with the gradient thickness design described in Example 2 (the thickness also decreases from the inside to the outside), the fatigue resistance and service life of the flexible sealing block 23 under long-term and repeated deformation are further improved.

Claims

1. A passive-active coordinated magnetorheological shear thickening fluid damper, comprising a damper housing, a piston slidably connected to the inner wall of the damper housing, a piston rod fixedly connected to the middle of the piston, an excitation coil mounted on the piston, the interior of the damper housing being filled with a magnetorheological shear thickening fluid, and a wiring channel provided on the inner wall of the piston rod, through which the wire of the excitation coil passes and is led out to connect to an external power source; characterized in that, The piston is integrated with an adaptive coordination sleeve on its outer periphery, the adaptive coordination sleeve comprising: A sleeve-shaped substrate electrically connected to the excitation coil, the substrate being both magnetically and electrically conductive; The outer wall of the sleeve-shaped substrate is constructed with multiple adaptive flow channel units that extend axially and are arranged at intervals in the circumferential direction. The adaptive flow channel unit is composed of a recess opened on the substrate and an elastic filler filling the recess. Among them, magnetic ribs made of sleeve-shaped matrix material are formed between adjacent adaptive flow channel units; Under fluid pressure, the elastic filler can undergo elastic deformation toward the interior of the recess, thereby dynamically changing the geometry and cross-sectional area of ​​the fluid channel formed by the outer edge of the adjacent magnetic ribs, the surface of the elastic filler, and the inner wall of the damper housing. An inductive coupling section is provided on the inner wall of the damper housing in the region corresponding to the piston's stroke.

2. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 1, characterized in that, The sleeve-shaped substrate is a metal sleeve that is fixedly sleeved on the outer wall of the piston. It is connected to the excitation coil through internal wires to form a current loop and a magnetic path.

3. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 2, characterized in that, The recess in the adaptive flow channel unit is a vertical groove formed on the outer wall of the sleeve-shaped substrate, and the elastic filler is a flexible sealing block embedded and fixed in the vertical groove.

4. The active-passive coordinated magnetorheological shear thickening liquid damper according to claim 3, characterized in that, The thickness of the flexible sealing block is designed to decrease gradually from its root to its free end.

5. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 4, characterized in that, The flexible sealing block is made of polyurethane elastomer or silicone rubber elastomer.

6. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 5, characterized in that, The cross-sectional shape of the vertical groove and the flexible sealing block inside it is a wedge shape with the width gradually decreasing from the inside to the outside.

7. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 6, characterized in that, The magnetic ribs are axially extending ribs that, as part of a sleeve-shaped substrate, possess both magnetic and electrical conductivity.

8. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 7, characterized in that, The inductive coupling part is an annular band embedded and fixed to the inner wall of the damper housing, and the annular band is made of a highly conductive material.

9. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 1, characterized in that, The deformation of the elastic filler under fluid pressure changes the distance between the outer edge of the magnetic rib and the inductive coupling part, thereby adjusting the magnetic coupling strength between them.

10. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 1, characterized in that, The excitation coil is arranged around the inside of the piston.

11. The active-passive coordinated magnetorheological shear thickening fluid damper according to claim 10, characterized in that, The metal sleeve is fixed to the piston body by an interference fit or by a key connection.

12. The active-passive coordinated magnetorheological shear thickening liquid damper according to claim 1, characterized in that, The damper housing includes a damper shell, with bushing one and bushing two fixedly connected to both ends of the damper shell, and an extension tube fixedly connected to the end of the damper shell away from bushing one. One end of the piston rod passes through bushing one and is fixedly connected to pin one, while the other end passes through bushing two and extends into the extension tube. Pin two is fixedly installed at the end of the extension tube away from the damper shell.

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