Adjustable negative stiffness damping vibration attenuation device and mounting method thereof

Abstract

The invention relates to an adjustable negative stiffness damping vibration attenuation device and a mounting method thereof, and belongs to the field of structural vibration control. Comprising an adjustable negative stiffness component and a viscous damper component. The adjustable negative stiffness component comprises a connecting plate, a movable shaft, a fixed rod, a fixed plate, a sleeve, a connecting piece, a roller, a cam structure, a movable bedplate, an outer annular magnet, an inner annular magnet, a precision gasket and a shaft check ring; the viscous damper component comprises a front lug ring, a damper main body and a rear lug ring; according to the wide-displacement-domain magnetostriction-cam roller type adjustable negative stiffness damping vibration attenuation device, the dual advantages of a magnetostriction negative stiffness mechanism and a cam roller negative stiffness mechanism are creatively fused, stable negative stiffness can be achieved in a wide displacement domain, the negative stiffness characteristic is adjustable, different working condition requirements can be met, and the vibration attenuation effect is good. Due to the unique negative stiffness damping characteristic, the vibration damper has a wide application prospect in vibration control of structures such as buildings and bridges.

Description

Technical Field

[0001] The present invention relates to an adjustable negative stiffness damping vibration reduction device and an installation method thereof, in particular to a wide displacement range magneto-cam roller type adjustable negative stiffness damping vibration reduction device and an installation method thereof, belonging to the field of structural vibration control. Background Art

[0002] Vibration is a widespread problem in fields such as civil engineering and bridge engineering, seriously impacting the safety and functionality of structures. For example, high-rise buildings can generate excessive vibration responses under external excitations such as earthquakes and wind loads. This vibration not only significantly reduces the comfort of occupants, but also affects the proper operation of precision equipment and, in severe cases, can damage structural components and structures. According to vibration control theory, passive vibration control methods for engineering structures can be primarily categorized into three types: energy dissipation, vibration isolation, and energy absorption. Energy dissipation devices (such as viscous dampers, metal friction dampers, and viscoelastic dampers) reduce the structural vibration response by dissipating vibration energy. However, these damping devices typically exhibit positive or zero stiffness. While they can effectively control the structural displacement response, they inevitably increase the shear and acceleration responses, creating an engineering dilemma.

[0003] To address this critical issue, negative stiffness damping vibration reduction technology has gradually emerged and garnered widespread attention in recent years. By configuring a negative stiffness mechanism and damping elements in parallel, negative stiffness damping devices can address the multiple requirements of structural vibration control. On the one hand, the negative stiffness mechanism provides negative stiffness within a specific displacement range, effectively reducing the overall stiffness of the structural system, extending the structure's natural vibration period, and significantly reducing the structural shear and acceleration responses. On the other hand, the parallel damping elements effectively suppress the increased displacement caused by the reduced stiffness. This collaborative working mechanism ultimately achieves multi-objective coordinated control of the structural shear, displacement, and acceleration responses, providing a new approach to addressing the technical bottleneck of traditional vibration reduction devices, which often focus on one thing but neglect another.

[0004] However, existing negative stiffness and negative stiffness damping devices still face key challenges that need to be addressed: First, the negative stiffness-displacement curve of existing negative stiffness mechanisms is usually fixed and cannot be adjusted, making it difficult to adapt to changes in structural parameters or vibration environments, and their adaptability and flexibility are clearly insufficient. Second, the negative stiffness operating range is limited, and most negative stiffness mechanisms can only maintain stable negative stiffness characteristics within a relatively small displacement range. In addition, the negative stiffness-displacement curve has a large gradient, resulting in significant changes in negative stiffness characteristics with displacement. These technical bottlenecks have restricted the promotion and application of negative stiffness damping devices in practical engineering projects. Summary of the Invention

[0005] In response to the above-mentioned defects of the prior art, the present invention proposes an adjustable negative stiffness damping vibration reduction device and an installation method thereof. The adjustable negative stiffness damping vibration reduction device is a wide-displacement magneto-cam roller type adjustable negative stiffness damping vibration reduction device with a wide negative stiffness area and adjustable negative stiffness characteristics, which is used to solve the above-mentioned problems of non-adjustable negative stiffness characteristics and limited negative stiffness working range.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] An adjustable negative stiffness damping vibration reduction device is a wide-displacement magneto-cam roller type adjustable negative stiffness damping vibration reduction device, comprising an adjustable negative stiffness component and a viscous damper component. The adjustable negative stiffness component and the viscous damper component are arranged in a docking manner along the central axis, and the two are connected by high-strength bolts to ensure that the two deform synchronously and the deformation amount is the same.

[0008] The adjustable negative stiffness component includes a connecting plate, a movable shaft, a fixed rod, a fixed plate, a sleeve, a connecting piece, a roller, a cam structure, a movable platform, an outer annular magnet, and an inner annular magnet; the connecting plate, the fixed rod, and the fixed plate are connected to form an integral frame; the movable shaft, the sleeve, the connecting piece, and the roller are symmetrically arranged on the left and right sides of the cam structure, and a fixed rod extends from the top of the cam structure and is connected to the movable platform;

[0009] The connecting plate is fixedly connected to the sleeve; the inner annular magnet is precisely assembled on the movable shaft, and the axial position is adjusted by the precision gasket on the movable shaft, and the axial position locking is achieved by a shaft retaining ring, and the inner annular magnet and the movable shaft are clearance-fitted; the outer annular magnet is installed inside the sleeve, one end face of the outer annular magnet is close to the inner end face of the sleeve, and the other side of the outer annular magnet is limited by the connecting plate, and the outer annular magnet and the sleeve are clearance-fitted; the inner annular magnet and the outer annular magnet are concentrically arranged and there is a preset offset between the two along the axial direction, that is, the inner annular magnet is biased towards the direction of the cam structure relative to the outer annular magnet, and the offset can be adjusted by a precision gasket; the inner annular magnet and the outer annular magnet are both magnetized in the same direction along the movable shaft direction; the fixed rod and the fixed plate are fixedly connected to the upper and lower ends of the connecting plate respectively; the movable shaft is fixedly connected to the connecting piece, and the roller is fixed in the reserved position of the connecting piece. The groove on the inner side of the roller keeps in contact with the contour of the cam structure and realizes relative movement;

[0010] The viscous damper component includes a front earring, a damper body and a rear earring; the front earring is usually connected to the piston rod end of the damper body through threaded fitting (which can be supplemented by a set screw to prevent loosening), and the rear earring is typically connected to the cylinder end of the damper body by welding.

[0011] Furthermore, bolt holes are reserved in the connecting plate, movable shaft, fixed rod, fixed plate, sleeve, connecting piece, cam structure and movable platform.

[0012] Furthermore, the movable shaft is a stepped cylindrical structure with two variable cross-section designs, wherein the first variable cross-section is used for positioning and installing the inner ring magnet, and the second variable cross-section is used for clearance fit with the opening on the connecting plate; the large diameter end face of the movable shaft is fixedly connected to the connecting part of the roller by high-strength bolts, and the small diameter end of the movable shaft forms a clearance fit with the opening on the connecting plate.

[0013] Furthermore, when the inner ring magnet moves toward the cam direction, that is, when it moves away from the outer ring magnet, a nonlinear force-displacement relationship can be achieved between the two; the axial position of the inner ring magnet on the movable shaft can be adjusted by a precision gasket, and the axial position can be locked by a shaft retaining ring to achieve precise control of the axial initial relative position of the inner ring magnet and the outer ring magnet, thereby achieving adjustable nonlinear force.

[0014] Furthermore, the sleeve is a variable-section circular ring structure, and its inner cavity is provided with a positioning installation position for the outer ring magnet. One end of the sleeve is fixedly connected to the connecting plate by a high-strength bolt, and the opening at the other end forms a clearance fit with the movable shaft.

[0015] Furthermore, the cam structure adopts a bilaterally symmetrical cam design, and its thickness is smaller than the inner groove of the roller to ensure non-interference relative movement between the roller and the cam structure profile, thereby ensuring the movement accuracy and stability of the mechanism.

[0016] Furthermore, when the cam structure moves from the equilibrium position, the inner annular magnet moves along the moving shaft toward the center line of the cam structure, and the two magnets produce relative axial displacement. Their unidirectional magnetization characteristics induce repulsive force, and the repulsive force-displacement has a nonlinear relationship. The repulsive force is converted into pressure applied to the cam structure through the moving shaft and roller, further promoting the movement of the cam structure, thereby producing a significant negative stiffness characteristic.

[0017] Furthermore, except for the outer annular magnet and the inner annular magnet in the adjustable negative stiffness component, and the viscous liquid and sealing ring in the viscous damper component, the remaining structural components are all made of stainless steel; to ensure smooth movement, reduce friction and facilitate installation, the small diameter end of the movable shaft and the opening on the connecting plate, the inner annular magnet and the first variable cross-section of the movable shaft, and the outer annular magnet and the inside of the sleeve are all clearance-fitted, and the fitting surfaces are precision-machined to ensure surface smoothness.

[0018] Furthermore, the connecting plate and the sleeve are fixedly connected by high-strength bolts; the fixing rod and the fixing plate are respectively fixedly connected to the upper and lower ends of the connecting plate by high-strength bolts; the movable platform is fixedly connected to the two side surfaces of the cam structure by L-shaped angle brackets and high-strength bolts; the movable shaft is fixedly connected to the connecting piece by high-strength bolts, and the roller is fixedly connected to the connecting piece by high-strength bolts; the movable platform is rigidly connected to the main body of the engineering structure by high-strength bolts; and the fixing plate is fixedly connected to the supporting structure by high-strength bolts. The connection parts of the movable platform and the fixed plate include but are not limited to: key connection parts such as the connection nodes between adjacent layers of the building structure, the joints between the bridge body and the auxiliary structure, and the interface transition zone of the building's external envelope structure bearing system or the multi-stage shock absorption system.

[0019] The installation method of the above-mentioned adjustable negative stiffness damping vibration reduction device includes the following steps:

[0020] S1: Fix the inner ring magnet on the moving shaft, and reserve axial space for installing the precision gasket and shaft retaining ring;

[0021] S2: Pass the small diameter end of the moving shaft through the round hole on the connecting plate, and install a shaft sleeve on the small diameter end of the moving shaft passing through the back of the connecting plate, and tighten the end with a nut;

[0022] S3: Fix the outer ring magnet in the sleeve, then pass the sleeve through the large diameter end of the movable shaft, and finally fix it to the connecting plate with high-strength bolts;

[0023] S4: Fix the moving shaft and the connecting piece with high-strength bolts, and then complete the assembly of the connecting piece and the roller;

[0024] S5: Use high-strength bolts to connect and fix the connecting plate and the fixing plate;

[0025] S6: Use high-strength bolts to connect and fix the fixing rod and the connecting plate;

[0026] S7: Assemble the cam structure and the movable platen using L-shaped angle brackets and high-strength bolts. Finally, insert the cam part into the inner groove of the roller. Adjust the position of the cam structure so that its widest part contacts the roller. This completes the assembly of the adjustable negative stiffness component.

[0027] S8: Assemble the viscous damper component and the adjustable negative stiffness component, wherein the cam structure and the front earring are connected and fixed by high-strength bolts, and the fixing plate and both sides of the rear earring are connected and fixed by L-shaped angle brackets and high-strength bolts.

[0028] After adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0029] 1. The present invention proposes a wide-displacement magnetostrictive-cam roller-type adjustable negative stiffness damping vibration reduction device and its installation method. Through the synergistic action of coaxially arranged inner and outer ring magnets and a cam roller mechanism, an innovative composite negative stiffness mechanism is formed, which can achieve adjustable negative stiffness characteristics over a wide displacement range. Specifically, when the inner ring magnet moves toward the cam and away from the outer ring magnet, it is subjected to a nonlinear repulsive force exerted by the outer ring magnet. This force is transmitted to the roller via a movable shaft and then acts on the cam structure. The combined force of the two rollers on the cam structure further promotes the movement of the cam structure, generating negative stiffness. Research has shown that compared to linear force, the nonlinear force generated by the inner and outer ring magnets acting on the cam structure can significantly widen the negative stiffness range. In addition, the initial axial offset distance between the inner and outer ring magnets can be adjusted using precision gaskets, thereby changing the initial force applied by the roller on the cam structure. This allows for adjustable negative stiffness without changing the structural dimensions of the device, improving the adaptability and flexibility of the device.

[0030] 2. The cam structure of the present invention adopts a bilaterally symmetrical design to ensure the stability of the device under reciprocating vibration. In addition, the cam structure can be designed into various forms of curves, such as circular arc shape, trigonometric function shape, and shape with an initial zero stiffness segment. By adjusting the curve of the cam structure, the mechanical properties of the device can be adjusted to meet the needs of different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 Schematic diagram of the adjustable negative stiffness component of the present invention;

[0033] Figure 3 For the present invention Figure 1 Exploded diagram;

[0034] Figure 4 This is a schematic diagram of the relative installation positions of the movable shaft, precision gasket and shaft retaining ring of the present invention;

[0035] Figure 5 Schematic diagram of the viscous damper components of the present invention;

[0036] Figure 6 It is a partial cross-sectional schematic diagram of the adjustable negative stiffness component of the present invention;

[0037] Figure 7 This is a schematic diagram of the sleeve structure of the present invention;

[0038] Figure 8 This is a schematic diagram of the contact between the roller and the cam structure of the present invention;

[0039] Figure 9Schematic diagram of the inner and outer ring magnet poles of the present invention;

[0040] Figure 10 Schematic diagram of the cam-roller contact motion of the present invention;

[0041] Figure 11 The figure is a comparison diagram of the dimensionless stiffness-dimensionless displacement relationship curves of the device of the present invention (i.e., the force acting on the cam structure is nonlinear) and the traditional negative stiffness device (i.e., the force acting on the cam structure is linear). DETAILED DESCRIPTION

[0042] The following is combined with Figure 1-11 The present invention will be further described in detail with specific implementations to facilitate a clear understanding of the present invention, but they do not constitute a limitation to the present invention.

[0043] Example 1

[0044] like Figure 1-5 As shown, a wide-displacement magneto-cam roller type adjustable negative stiffness damping vibration reduction device of this embodiment includes an adjustable negative stiffness component 1 and a viscous damper component 2. The adjustable negative stiffness component 1 and the viscous damper component 2 are arranged in a docking manner along the central axis, and the two are connected by high-strength bolts to ensure that the two are deformed synchronously and the deformation amount is the same.

[0045] The adjustable negative stiffness component 1 includes a connecting plate 3, a movable shaft 4, a fixed rod 5, a fixed plate 6, a sleeve 7, a connector 8, a roller 9, a cam structure 10, a movable platform 11, an outer ring magnet 12, and an inner ring magnet 13. The connecting plate 3, the fixed rod 5, and the fixed plate 6 are connected to form an overall frame. The movable shaft 4, the sleeve 7, the connector 8, and the roller 9 are symmetrically arranged on the left and right sides of the cam structure 10. The top of the cam structure 10 extends between the two fixed rods 5 and is connected to the movable platform 11. The movable platform 11 is rigidly connected to the main body of the engineering structure through high-strength bolts; the fixed plate 6 is fixedly connected to the supporting structure through high-strength bolts. The connection parts of the movable platform 11 and the fixed plate 6 include but are not limited to: key connection parts such as the connection nodes between adjacent layers of the building structure, the joints between the bridge body and the auxiliary structure, and the interface transition zone of the building's external envelope structure bearing system or the multi-stage shock absorption system.

[0046] like Figure 4As shown, the movable shaft 4 is a stepped cylindrical structure with two variable cross-section designs, wherein the first variable cross-section is used for positioning and installing the inner annular magnet 13, and the second variable cross-section is used for clearance fit with the opening on the connecting plate 3; the large-diameter end face of the movable shaft 4 is fixedly connected to the roller connector 8 by a high-strength bolt, and the small-diameter end of the movable shaft 4 forms a clearance fit with the opening on the connecting plate 3; the axial position of the inner annular magnet 13 on the movable shaft 4 can be adjusted by a precision gasket 14, and the axial position can be locked by a shaft retaining ring 15 to achieve precise control of the axial initial relative position of the inner annular magnet 13 and the outer annular magnet 12, thereby achieving adjustable nonlinear force; the shaft retaining ring 15 meets the technical requirements of the national standard "Standard Type A Elastic Retaining Ring for Shafts GB / T 894.1-2017", which can ensure the axial fixation reliability of the inner annular magnet 13.

[0047] like Figure 5 As shown, the viscous damper component 2 includes a front earring 16, a damper body 17 and a rear earring 18; the front earring 16 is usually connected to the piston rod end of the damper body 17 by threaded fitting (which may be assisted by a set screw to prevent loosening), and the rear earring 18 is typically connected to the cylinder end of the damper body 17 by welding.

[0048] like Figure 6 As shown, the connecting plate 3 is fixedly connected to the sleeve 7; the inner annular magnet 13 is precisely assembled on the movable shaft 4, and the axial position is adjusted by the precision gasket 14 on the movable shaft 4, and the axial position is locked by the shaft retaining ring 15, and the inner annular magnet 13 and the movable shaft 4 are in a clearance fit; the outer annular magnet 12 is installed inside the sleeve 7, one end face of the outer annular magnet 12 is close to the inner end face of the sleeve 7, and the other side of the outer annular magnet 12 is limited by the connecting plate 3, and the outer annular magnet 12 and the sleeve 7 are in a clearance fit; the inner annular magnet 13, the outer annular magnet The iron 12 is designed with a concentric arrangement, and there is a preset offset between the two along the axial direction, that is, the inner annular magnet 13 is biased towards the cam structure 10 relative to the outer annular magnet 12, and the offset can be adjusted by the precision gasket 14; the inner annular magnet 13 and the outer annular magnet 12 are magnetized in the same direction along the moving axis 4; the fixed rod 5 and the fixed plate 6 are fixedly connected to the upper and lower ends of the connecting plate 3 respectively; the moving axis 4 is fixedly connected to the connecting member 8, and the roller 9 is fixed to the reserved position of the connecting member 8. The groove on the inner side of the roller 9 keeps in contact with the contour of the cam structure 10 and realizes relative movement.

[0049] like Figure 7 As shown, the sleeve 7 is a variable cross-section circular ring structure, and its inner cavity is provided with a positioning installation position for the outer ring magnet 12. One end of the sleeve 7 is fixedly connected to the connecting plate 3 by a high-strength bolt, and the opening at the other end forms a clearance fit with the movable shaft 4.

[0050] like Figure 8 As shown, the cam structure 10 adopts a bilaterally symmetrical cam design, and its thickness is slightly smaller than the inner groove of the roller 9 to ensure that the roller and the cam structure 10 have no interference with the relative motion, ensuring the movement accuracy and stability of the mechanism. Figure 6 As shown, when the cam structure 10 moves from the equilibrium position, the inner annular magnet 13 moves along the movable shaft 4 toward the center line of the cam structure 10, and the two magnets produce relative axial displacement. Their unidirectional magnetization characteristics induce repulsive force, and the repulsive force-displacement has a nonlinear relationship. The repulsive force is converted into pressure applied to the cam structure 10 through the movable shaft 4 and the roller 9, further promoting the movement of the cam structure 10, thereby producing a significant negative stiffness characteristic.

[0051] In this embodiment, bolt holes are reserved for the connecting plate 3, movable shaft 4, fixed rod 5, fixed plate 6, sleeve 7, connector 8, cam structure 10, and movable platform 11. The connecting plate 3 is fixedly connected to the sleeve 7 via high-strength bolts; the fixed rod 5 and fixed plate 6 are respectively fixedly connected to the upper and lower ends of the connecting plate 3 via high-strength bolts; the movable platform 11 is fixedly connected to the two side surfaces of the cam structure 10 via L-shaped angle brackets and high-strength bolts; the movable shaft 4 is fixedly connected to the connector 8 via high-strength bolts, and the roller 9 is fixedly connected to the connector 8 via high-strength bolts.

[0052] In addition, in this embodiment, except for the outer annular magnet 12 and the inner annular magnet 13 in the adjustable negative stiffness component 1, and the viscous liquid and the sealing ring in the viscous damper component 2, the remaining structural components are all made of stainless steel. To ensure smooth movement, reduce friction and facilitate installation, the small-diameter end of the movable shaft 4 and the opening on the connecting plate 3, the inner annular magnet 13 and the first variable cross-section of the movable shaft 4, and the outer annular magnet 12 and the inside of the sleeve 7 are all clearance-fitted, and the mating surfaces are precision-machined to ensure surface smoothness.

[0053] Example 2

[0054] In this embodiment, the Coulomb model is used to calculate the magnetic force between the inner and outer ring magnets, as shown in FIG. Figure 9 As shown, the inner annular magnet 13 and the outer annular magnet 12 are simplified as three-dimensional toroidal surfaces with uniform electromagnetic poles on their surfaces, and a single magnetic pole carries a net magnetic charge. The two end faces of each annular magnet are respectively a magnetic pole, and the net magnetic charges on their surfaces are +σ* and -σ*, respectively. P1 and P2 are two arbitrary magnetic monopoles from the surface of the inner annular magnet 13 and the surface of the outer annular magnet 12, respectively. L1 and L2 are the heights of the inner annular magnet 13 and the outer annular magnet 12, respectively. r1 and r2 are the distances from the center of the circle on the end faces of P1 and P2, respectively. R 2in is the inner radius of the outer ring magnet 12, R 2out is the outer radius of the outer ring magnet 12, R 1in and R1out are the inner radius and outer radius of the inner ring magnet 13 respectively; H is the distance difference between the inner ring magnet 13 and the outer ring magnet 12 in the Z-axis direction; θ1 and θ2 are the polar angles of P1 and P2 respectively, that is, the angles of the radius lines r1 and r2 rotated counterclockwise from the positive direction of the X-axis to P1 and P2.

[0055] The force in the Z direction between the left end face of the inner ring magnet 13 and the right end face of the outer ring magnet 12 can be shown as:

[0056]

[0057] Where μ0 is the vacuum permeability, which is 4π×10 -7 Tm / A, and are the net magnetic charges on the end faces of the inner and outer ring magnets respectively; where h 12' is the distance difference between P1 and P2 in the Z-axis direction; the force between the inner and outer ring magnets in the Z-axis direction is the sum of the interactions between the two end faces of the inner ring magnet 13 and the two end faces of the outer ring magnet 12. There are four possible interactions between the four end faces of the inner and outer ring magnets, and the corresponding four distance differences are calculated as follows:

[0058] h 11′ =H+L1 / 2-L2 / 2

[0059] h 12′ =H+L1 / 2+L2 / 2 Formula 2

[0060] h 21′ =H-L1 / 2-L2 / 2

[0061] h 22′ =H-L1 / 2+L2 / 2

[0062] therefore, Figure 9 The repulsive force of the outer annular magnet 12 on the inner annular magnet 13 shown in FIG is calculated by the following formula:

[0063]

[0064] The following are the parameters selected in this example: L1=25mm,L2=25mm,R 1in =10mm, R 1out =15mm, R 2in =20mm, R 2out =30mm.

[0065] like Figure 10Assume that the cam structure 10 moves upward by x from its initial equilibrium position under external excitation. The right roller 9 is used as an example for motion state and force analysis. The right roller 9 moves downward and leftward relative to the cam structure 10, driving the inner ring magnet 13 to move leftward by z relative to the outer ring magnet 12 via the movable shaft 4. The positive direction of the Z axis is defined as the positive direction of the force. The outer ring magnet 12 exerts a repulsive force f on the inner ring magnet 13. h , driving the roller 9 to apply an upward and leftward pressure to the cam structure 10. Similarly, the left roller 9 will apply an upward and rightward pressure to the cam structure 10. The leftward and rightward pressures cancel each other out. Therefore, only upward pressure is applied to the cam structure 10. The force is consistent with the movement direction of the cam structure 10, which can further promote the movement of the cam structure 10, thereby generating negative stiffness.

[0066] The nonlinear force-displacement relationship between the inner and outer ring magnets can be obtained by calculating from Equation 3. The nonlinear force-displacement relationship between the inner and outer ring magnets can be obtained by simplifying the fitting:

[0067] f h =-0.06068z 3 +17.7z Formula 4

[0068] in

[0069] z=[δ+(R1+R2)(1-cosθ)] Formula 5

[0070] Wherein, δ is the initial distance difference between the inner annular magnet 13 and the outer annular magnet 12 in the positive direction of the Z axis, that is, when the widest part of the cam structure 10 contacts the roller 9, the initial offset of the inner annular magnet 13 relative to the outer annular magnet 12 in the direction of the cam structure, R1 is the radius of the roller 9, and R2 is the cam radius of the cam structure 10.

[0071] Overall force analysis of adjustable negative stiffness component 1, with the negative direction of the X-axis as the positive direction of the force:

[0072] f(x)=-2f h tanθ Equation 6

[0073] in

[0074]

[0075] Substitute equations 4, 5, and 7 into equation 6, and we get:

[0076]

[0077] Among them, k h is f in formula 4 h The stiffness-displacement relationship between the inner and outer ring magnets obtained by taking the derivative of z is k h =-0.18204z2 +17.7.

[0078] Dimensionless, let

[0079]

[0080] The dimensionless force-dimensionless displacement relationship expression of the adjustable negative stiffness component 1 can be obtained as follows:

[0081]

[0082] After derivation, the dimensionless stiffness-dimensionless displacement relationship expression of the adjustable negative stiffness component 1 is as follows:

[0083]

[0084] Among them, R1=12mm, R2=50mm, and δ=7.2mm are selected.

[0085] like Figure 11 As shown, by comparing the dimensionless stiffness-dimensionless displacement relationship curve of the adjustable negative stiffness component 1 of the device of the present invention, i.e., the nonlinear force-displacement relationship in the horizontal direction, and the dimensionless stiffness-dimensionless displacement relationship curve of the traditional negative stiffness device, i.e., the linear force-displacement relationship in the horizontal direction, it can be clearly seen that the device of the present invention can achieve a wider range of negative stiffness.

[0086] The center lines of the adjustable negative stiffness component 1 and the viscous damper component 2 coincide with each other. The adjustable negative stiffness component 1 and the viscous damper component 2 are connected by high-strength bolts and deform synchronously with the same amount of deformation.

[0087] Example 3

[0088] The installation method of a wide-displacement magneto-cam roller type adjustable negative stiffness damping vibration reduction device in the above-mentioned embodiment 1 comprises the following steps:

[0089] S1: Fix the inner ring magnet 13 on the movable shaft 4, and reserve axial space for installing the precision gasket 14 and the shaft retaining ring 15;

[0090] S2: Pass the small diameter end of the movable shaft 4 through the circular hole on the connecting plate 3, and install a sleeve on the small diameter end of the movable shaft 4 passing through the back of the connecting plate 3, and tighten the end with a nut;

[0091] S3: Fix the outer ring magnet 12 in the sleeve 7, then pass the sleeve 7 through the large diameter end of the movable shaft 4, and finally fix it to the connecting plate 3 with high-strength bolts;

[0092] S4: Fix the movable shaft 4 and the connecting member 8 with high-strength bolts, and then complete the assembly of the connecting member 8 and the roller 9;

[0093] S5: Use high-strength bolts to connect and fix the connecting plate 3 and the fixing plate 6, that is, fix them symmetrically on both sides;

[0094] S6: Use high-strength bolts to connect and fix the fixing rod 5 to the connecting plate 3;

[0095] S7: Assemble the cam structure 10 and the movable platen 11 using L-shaped angle brackets and high-strength bolts. Finally, insert the cam portion into the inner groove of the roller 9. Adjust the position of the cam structure 10 so that its widest part contacts the roller 9. This completes the assembly of the adjustable negative stiffness component 1.

[0096] S8: Assemble the viscous damper component 2 and the adjustable negative stiffness component 1, wherein the cam structure 10 and the front earring 16 are connected and fixed by high-strength bolts, and the fixing plate 6 and the two sides of the rear earring (18) are connected and fixed by L-shaped angle codes and high-strength bolts.

[0097] The above is merely a preferred embodiment of the present invention and does not constitute any formal limitation on the structure of the present invention. The layout and number of the present invention are not limited to this example and can be optimized according to actual engineering practices. Any modifications, equivalent changes, and decorations to the above embodiment based on the technical principles of the present invention that do not depart from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An adjustable negative stiffness damping vibration reduction device, which is a wide-displacement magneto-cam roller type adjustable negative stiffness damping vibration reduction device, characterized by: The invention comprises an adjustable negative stiffness component (1) and a viscous damper component (2), wherein the adjustable negative stiffness component (1) and the viscous damper component (2) are arranged in a butt joint along a central axis and are connected by high-strength bolts to ensure that the two components deform synchronously and in the same amount. The adjustable negative stiffness component (1) comprises a connecting plate (3), a movable shaft (4), a fixed rod (5), a fixed plate (6), a sleeve (7), a connecting piece (8), a roller (9), a cam structure (10), a movable platform (11), an outer annular magnet (12), and an inner annular magnet (13); the connecting plate (3), the fixed rod (5), and the fixed plate (6) are connected to form an integral frame; the movable shaft (4), the sleeve (7), the connecting piece (8), and the roller (9) are symmetrically arranged on the left and right sides of the cam structure (10); the top of the cam structure (10) extends out of the fixed rod (5) and is connected to the movable platform (11); The connecting plate (3) is fixedly connected to the sleeve (7); the inner annular magnet (13) is precisely assembled on the movable shaft (4), and the axial position is adjusted by the precision gasket (14) on the movable shaft (4), and the axial position is locked by the shaft retaining ring (15), and the inner annular magnet (13) and the movable shaft (4) are in a clearance fit; the outer annular magnet (12) is installed inside the sleeve (7), one end face of the outer annular magnet (12) is close to the inner end face of the sleeve (7), and the other side of the outer annular magnet (12) is limited by the connecting plate (3), and the outer annular magnet (12) and the sleeve (7) are in a clearance fit; the inner annular magnet (13) and the outer annular magnet (12) are in a clearance fit The iron (12) is designed to be arranged concentrically, and there is a preset offset between the two along the axial direction, that is, the inner annular magnet (13) is biased towards the cam structure (10) relative to the outer annular magnet (12), and the offset can be adjusted by a precision gasket (14); the inner annular magnet (13) and the outer annular magnet (12) are both magnetized in the same direction along the direction of the moving shaft (4); the fixed rod (5) and the fixed plate (6) are fixedly connected to the upper and lower ends of the connecting plate (3) respectively; the moving shaft (4) is fixedly connected to the connecting member (8), and the roller (9) is fixed to a reserved position of the connecting member (8), and the groove on the inner side of the roller (9) keeps in contact with the contour of the cam structure (10) to achieve relative movement; The viscous damper component (2) includes a front earring (16), a damper body (17) and a rear earring (18); the front earring (16) is usually connected to the piston rod end of the damper body (17) by threaded engagement, and the rear earring (18) is typically connected to the cylinder end of the damper body (17) by welding.

2. The adjustable negative stiffness damping vibration reduction device according to claim 1, characterized in that: Bolt holes are reserved in the connecting plate (3), movable shaft (4), fixed rod (5), fixed plate (6), sleeve (7), connecting piece (8), cam structure (10), and movable platform (11).

3. The adjustable negative stiffness damping vibration reduction device according to claim 1, characterized in that: The movable shaft (4) is a stepped cylindrical structure with two variable cross-section designs, wherein the first variable cross-section is used for positioning and installing the inner annular magnet (13), and the second variable cross-section is used for clearance fit with the opening on the connecting plate (3); the large diameter end face of the movable shaft (4) is fixedly connected to the connecting piece (8) of the roller (9) by high-strength bolts, and the small diameter end of the movable shaft (4) forms a clearance fit with the opening on the connecting plate (3).

4. The adjustable negative stiffness damping vibration reduction device according to claim 3, characterized in that: When the inner annular magnet (13) moves in the direction of the cam, that is, moves away from the outer annular magnet (12), a nonlinear force-displacement relationship can be achieved between the two; the axial position of the inner annular magnet (13) on the movable shaft (4) can be adjusted by a precision gasket (14), and the axial position can be locked by a shaft retaining ring (15) to achieve precise control of the axial initial relative position of the inner annular magnet (13) and the outer annular magnet (12), thereby achieving adjustable nonlinear force.

5. The adjustable negative stiffness damping vibration reduction device according to claim 4, characterized in that: The sleeve (7) is a variable cross-section circular ring structure, and its inner cavity is provided with a positioning installation position for the outer ring magnet (12). One end of the sleeve (7) is fixedly connected to the connecting plate (3) by a high-strength bolt, and the opening at the other end forms a clearance fit with the movable shaft (4).

6. The adjustable negative stiffness damping vibration reduction device according to claim 5, characterized in that: The cam structure (10) adopts a bilaterally symmetrical cam design, and its thickness is smaller than the inner groove of the roller (9) to ensure non-interference relative movement between the roller (9) and the cam structure (10), thereby ensuring the movement accuracy and stability of the mechanism.

7. The adjustable negative stiffness damping vibration reduction device according to claim 6, characterized in that: When the cam structure (10) moves from the equilibrium position, the inner annular magnet (13) moves along the movable shaft (4) toward the center line of the cam structure (10), and the two magnets generate relative axial displacement. Their same-direction magnetization characteristics induce repulsive force, and the repulsive force-displacement has a nonlinear relationship. The repulsive force is converted into pressure applied to the cam structure (10) through the movable shaft (4) and the roller (9), further promoting the movement of the cam structure (10), thereby generating a significant negative stiffness characteristic.

8. The adjustable negative stiffness damping vibration reduction device according to claim 5, characterized in that: Except for the outer annular magnet (12) and the inner annular magnet (13) in the adjustable negative stiffness component (1), and the viscous liquid and the sealing ring in the viscous damper component (2), the remaining structural components are all made of stainless steel. To ensure smooth movement, reduce friction and facilitate installation, clearance fit is adopted between the small diameter end of the movable shaft (4) and the opening on the connecting plate (3), the inner annular magnet (13) and the first variable cross-section of the movable shaft (4), and the outer annular magnet (12) and the inside of the sleeve (7), and the fitting surfaces are precisely machined to ensure surface smoothness.

9. The adjustable negative stiffness damping vibration reduction device according to claim 1, characterized in that: The connecting plate (3) and the sleeve (7) are fixedly connected by high-strength bolts; the fixing rod (5) and the fixing plate (6) are fixedly connected to the upper and lower ends of the connecting plate (3) respectively by high-strength bolts; the movable platform (11) is fixedly connected to the two side surfaces of the cam structure (10) by L-shaped angle brackets and high-strength bolts; the movable shaft (4) is fixedly connected to the connecting member (8) by high-strength bolts, and the roller (9) is fixedly connected to the connecting member (8) by high-strength bolts; the movable platform (11) is rigidly connected to the main body of the engineering structure by high-strength bolts; the fixing plate (6) is fixedly connected to the supporting structure by high-strength bolts; wherein the connection parts of the movable platform (11) and the fixing plate (6) include but are not limited to: key connection parts such as the connection nodes between adjacent layers of the building structure, the joint between the bridge body and the auxiliary structure, and the interface transition zone of the building external protective structure bearing system or the multi-stage shock absorption system.

10. A method for installing an adjustable negative stiffness damping vibration reduction device according to any one of claims 1 to 8, characterized in that: The installation method includes the following steps: S1: Fix the inner ring magnet (13) on the moving shaft (4), and reserve axial space for installing the precision gasket (14) and the shaft retaining ring (15); S2: Pass the small diameter end of the movable shaft (4) through the circular hole on the connecting plate (3), and install a shaft sleeve on the small diameter end of the movable shaft (4) passing through the back of the connecting plate (3), and fasten the end with a nut; S3: Fix the outer ring magnet (12) in the sleeve (7), then pass the sleeve (7) through the large diameter end of the movable shaft (4), and finally connect and fix it with the connecting plate (3) through high-strength bolts; S4: Fix the movable shaft (4) and the connecting member (8) with high-strength bolts, and then complete the assembly of the connecting member (8) and the roller (9); S5: Use high-strength bolts to connect and fix the connecting plate (3) and the fixing plate (6); S6: Use high-strength bolts to connect and fix the fixing rod (5) and the connecting plate (3); S7: Assemble the cam structure (10) and the movable platen (11) by using L-shaped angle brackets and high-strength bolts, and finally embed the cam part into the inner groove of the roller (9). Adjust the position of the cam structure (10) so that its widest part contacts the roller (9), and complete the assembly of the adjustable negative stiffness component (1); S8: Assemble the viscous damper component (2) and the adjustable negative stiffness component (1), wherein the cam structure (10) and the front earring (16) are connected and fixed by high-strength bolts, and the fixing plate (6) and the two sides of the rear earring (18) are connected and fixed by L-shaped angle brackets and high-strength bolts.

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