Quasi-zero stiffness device based on buckling beam structure and six-degree-of-freedom quasi-zero stiffness device

Abstract

The application provides a quasi-zero stiffness device based on a buckling beam structure and a six-degree-of-freedom quasi-zero stiffness device, wherein the quasi-zero stiffness device comprises a frame and a diagonal support beam; the frame comprises an upper plate, a lower plate and a plurality of beams fixedly connected between the upper plate and the lower plate; the first end of the diagonal support beam is fixedly connected with the upper plate of the frame, and the second end of the diagonal support beam is connected with the lower plate of the frame on the same base body. The diagonal support beam provides negative stiffness, the beam provides positive stiffness, and quasi-zero stiffness is achieved. The integrated quasi-zero stiffness device based on the buckling beam structure and the six-degree-of-freedom quasi-zero stiffness device provided by the application require smaller displacement when high static load is achieved, the dynamic displacement range is larger near the quasi-zero stiffness position, and the application is beneficial. The friction existing at the hinge when the hinge is used is avoided to affect the vibration isolation effect, and the situation that the gap at the hinge has poor vibration isolation effect is also avoided.

Description

Quasi-zero stiffness device based on buckling beam structure and six-degree-of-freedom quasi-zero stiffness device Technical Field

[0001] This invention belongs to the technical field of vibration damping devices, and in particular relates to a quasi-zero stiffness device based on a buckling beam structure and a six-degree-of-freedom quasi-zero stiffness device. Background Technology

[0002] Quasi-zero stiffness vibration isolators connect negative stiffness elements in parallel with positive stiffness elements to achieve zero stiffness characteristics at the static equilibrium position. Compared with traditional linear vibration isolators, the quasi-zero stiffness vibration isolator achieves high static stiffness and low dynamic stiffness, with greater load-bearing capacity, small structural deformation, and a wider vibration isolation frequency band.

[0003] Existing quasi-zero stiffness systems have poor isolation effects against micro-vibrations, are structurally unstable, and are not conducive to practical applications. Furthermore, the displacement range of the equilibrium position of existing quasi-zero stiffness designs at zero stiffness is small, making adjustment inconvenient.

[0004] Existing quasi-zero stiffness systems often employ mechanically hinged helical springs for their negative stiffness structures. However, friction and clearance result in poor isolation of micro-vibrations, and helical springs are prone to lateral instability under compression. Furthermore, existing quasi-zero stiffness designs have a limited displacement range at the equilibrium position, making adjustment inconvenient. Summary of the Invention

[0005] This application provides an integrated quasi-zero stiffness device based on a buckling beam structure, which exhibits good vibration isolation performance for micro-vibration disturbances. The structure remains in a stable zero-stiffness state over a wide range and is adjustable for different load masses. This application also provides an integrated six-degree-of-freedom quasi-zero stiffness device based on a buckling beam structure, which also exhibits good vibration isolation performance for micro-vibration disturbances. It can achieve quasi-zero stiffness in six directions within a relatively small height design, and the structure remains in a stable zero-stiffness state over a wide range, with adjustable stiffness for different load masses.

[0006] The invention aims to achieve its objective through the following technical solutions.

[0007] A quasi-zero stiffness device based on a buckling beam structure, comprising a frame and inclined beams;

[0008] The frame includes an upper plate, a lower plate, and several beams fixedly connected between the upper plate and the lower plate;

[0009] The inclined beam includes a first end and a second end, with the first end of the inclined beam being higher than the second end of the inclined beam; the first end of the inclined beam is fixedly connected to the upper plate of the frame, and the second end of the inclined beam is connected to the lower plate of the frame in the same base.

[0010] In this context, "oblique" in the oblique support beam refers to a beam that is neither parallel nor perpendicular to the longitudinal centerline of the frame. "Upper" and "lower" in the upper and lower plates refer to the direction above and below the longitudinal centerline of the frame, respectively. "Higher" in "the first end of the oblique support beam is higher than the second end of the oblique support beam" refers to the height of the beam along the longitudinal centerline of the frame.

[0011] The fixed connection can be made by bolts, screws, or other means, or by riveting, welding, etc.

[0012] The second end of the inclined beam is connected to the lower plate of the frame in the same base. This can be because both the second end of the inclined beam and the lower plate of the frame are connected to the frame, or the second end of the inclined beam is connected to the lower plate of the frame through other structures.

[0013] In a preferred embodiment, the upper plate and the lower plate are polygonal plates of the same size and the upper plate and the lower plate are not deflected.

[0014] In a preferred embodiment, the frame includes an upper plate and a lower plate, which are regular polygons with the same number of sides and equal side lengths, and there is no offset between the upper and lower plates of each polygon.

[0015] For example, both the upper plate and the lower plate are regular hexagons, equilateral triangles, squares, or regular octagons, and the side lengths of the upper plate and the lower plate are the same, and each corner of the upper plate and the lower plate is aligned, i.e., there is no deflection.

[0016] In a preferred embodiment, both the beam and the inclined support beam are symmetrically arranged with respect to the longitudinal centerline of the frame;

[0017] Both the beam and the inclined support beam are slender.

[0018] The number of beams and the number of inclined support beams can be the same or different.

[0019] The term "slender" refers to the cross-sectional area of ​​the beam and the inclined support beam being much smaller than their length.

[0020] In a preferred embodiment, the thickness of the inclined support beam is greater than the thickness of the beam.

[0021] In a preferred embodiment, it further includes a plurality of legs extending outward from the lower plate;

[0022] The second end of the inclined support beam is connected to the support leg;

[0023] The length and height of the support leg are adjustable, making the position of the second end of the inclined support beam relative to the first end of the inclined support beam adjustable.

[0024] In a preferred embodiment, the outrigger comprises:

[0025] A transverse support leg includes a transverse segment and a longitudinal segment, the transverse segment and the longitudinal segment of the transverse support leg being vertically connected; a radial transverse track is provided on the lower plate of the frame, the transverse segment of the transverse support leg can slide or lock within the transverse track; a longitudinal track is provided on the longitudinal segment of the transverse support leg.

[0026] Longitudinal support leg, which can slide or lock within the longitudinal track;

[0027] The second end of the inclined support beam is fixedly connected to the longitudinal support leg.

[0028] This application also provides a six-degree-of-freedom quasi-zero stiffness device based on a buckling beam structure, comprising several frames and inclined beams;

[0029] The frame includes an upper plate, a lower plate, and several beams fixedly connected between the upper plate and the lower plate; the outermost frame is fitted over the innermost frame, and the lower plate of the innermost frame is suspended from the upper plate of the outermost frame by inner and outer connectors; the inner and outer connectors are fixedly connected to the lower plate of the innermost frame and to the upper plate of the outermost frame.

[0030] The inclined beam includes a first end and a second end, with the first end of the inclined beam being higher than the second end of the inclined beam; the first end of the inclined beam is fixedly connected to the upper plate of the outermost frame, and the second end of the inclined beam extends outward from the frame and is connected to the lower plate of the outermost frame in the same base.

[0031] In this context, "oblique" in the term "oblique support beam" refers to a beam that is neither parallel nor perpendicular to the longitudinal centerline of the frame. "Upper" and "lower" in "upper plate" and "lower plate" refer to the direction above and below the longitudinal centerline of the frame, respectively. "Inner layer" and "outer layer" refer to layers closer and farther from the longitudinal centerline of the frame, respectively. "Higher" in "the first end of the oblique support beam is higher than the second end of the oblique support beam" refers to the height of the beam along the longitudinal centerline of the frame.

[0032] The fixed connection can be made by bolts, screws, or other means, or by riveting, welding, etc.

[0033] The six-degree-of-freedom quasi-zero stiffness device based on a buckling beam structure may include a two-layer frame; the outer frame is fitted over the inner frame, and the lower plate of the inner frame is suspended from the upper plate of the outer frame via internal and external connectors. The beams in the inner and outer frames may be arranged in the same orientation or staggered in different orientations.

[0034] In other embodiments, the included frame may also have three or more layers, and the beams in each layer of the frame may be arranged in the same orientation or staggered in different orientations.

[0035] The second end of the inclined beam is connected to the lower plate of the outermost frame in the same base. This can be because both the second end of the inclined beam and the lower plate of the outermost frame are connected to the frame, or the second end of the inclined beam is connected to the lower plate of the frame through other structures.

[0036] In this context, "outer side" in "outer side of the frame" refers to the side farther from the longitudinal centerline of the frame.

[0037] In a preferred embodiment, the upper plate and the lower plate contained in the same frame are polygonal plates of the same size and the upper plate and the lower plate are not deflected.

[0038] In a preferred embodiment, the frame of the six-degree-of-freedom quasi-zero stiffness device contains upper and lower plates that are regular polygons with the same number of sides, and there is no deflection between the upper and lower plates of each polygon.

[0039] For example, the upper and lower plates of the same frame are both regular hexagons, equilateral triangles, squares or regular octagons, and the side lengths of the upper and lower plates are the same, and each corner of the upper and lower plates of the frame is aligned, i.e. there is no deflection.

[0040] In a preferred embodiment, the beam, the inclined support beam, and the inner and outer connecting members are all symmetrically arranged with respect to the longitudinal centerline of the frame;

[0041] Both the beam and the inclined support beam are slender.

[0042] The number of beams, inclined support beams, and inner and outer connecting parts may be the same or different.

[0043] The term "slender" refers to a beam whose cross-sectional area is much smaller than its length.

[0044] In a preferred embodiment, the thickness of the inclined support beam is greater than the thickness of the beam.

[0045] In a preferred embodiment, the inner and outer connectors are elongated, and the stiffness of the inner and outer connectors is less than the stiffness of the beam.

[0046] In a preferred embodiment, it further includes a plurality of legs extending outward from the lower plate of the outermost frame;

[0047] The second end of the inclined support beam is connected to the support leg;

[0048] The length and height of the support leg are adjustable, making the position of the second end of the inclined support beam relative to the first end of the inclined support beam adjustable.

[0049] In a preferred embodiment, the outrigger comprises:

[0050] A transverse support leg includes a transverse segment and a longitudinal segment, the transverse segment and the longitudinal segment of the transverse support leg being vertically connected; a radial transverse track is provided on the lower plate of the outermost frame, the transverse segment of the transverse support leg can slide or lock within the transverse track; a longitudinal track is provided on the longitudinal segment of the transverse support leg.

[0051] Longitudinal support leg, which can slide or lock within the longitudinal track;

[0052] The second end of the inclined support beam is fixedly connected to the longitudinal support leg.

[0053] Compared with the prior art, the technical advantages of the six-degree-of-freedom quasi-zero stiffness device based on buckling beam structure provided in this application are as follows:

[0054] The quasi-zero stiffness device based on a buckling beam structure includes a frame and inclined beams. The frame includes an upper plate, a lower plate, and several beams fixedly connected between the upper and lower plates. Each inclined beam has a first end and a second end, with the first end higher than the second end. The first end of the inclined beam is fixedly connected to the upper plate of the frame, and the second end is connected to the lower plate of the frame within the same base. The inclined beams provide negative stiffness. The beams provide positive stiffness; when bending occurs, the beams provide extremely high positive stiffness, while the stiffness becomes minimal as the beams bend to a certain extent. This characteristic allows the device to achieve a large load-bearing capacity with very small displacements, while simultaneously matching the negative stiffness provided by the inclined beams at the point of minimum stiffness, thus achieving quasi-zero stiffness.

[0055] The inventors studied the negative stiffness structure of existing quasi-zero stiffness systems. One reason why the negative stiffness structure of existing quasi-zero stiffness systems often uses mechanically hinged helical springs with poor isolation effects is that the friction and gaps at the mechanical hinges provide poor isolation for micro-vibrations, and the helical springs are prone to lateral instability under compression. In contrast, the frame solution provided in this application uses fixed connections between the beams and the lower plate, and between the beams and the upper plate. This avoids the friction at the hinges that affects the vibration isolation effect, and also avoids the poor isolation effect of gaps at the hinges for micro-vibrations. Simultaneously, it also avoids the lateral instability that easily occurs when the helical springs are compressed.

[0056] Compared to traditional quasi-zero stiffness systems where positive stiffness is provided by linear springs, the quasi-zero stiffness device provided in this application requires less displacement to achieve high static loads and can provide vibration isolation in the vertical direction and the rotational direction around the horizontal axis, which is beneficial for practical applications.

[0057] Furthermore, this application discloses a six-degree-of-freedom quasi-zero stiffness device based on a buckling beam structure, comprising several frames and inclined beams. Each frame includes an upper plate, a lower plate, and several beams fixedly connected between the upper and lower plates. The outermost frame is fitted over the innermost frame, and the lower plate of the innermost frame is suspended from the upper plate of the outermost frame via internal and external connectors. Each inclined beam includes a first end and a second end, with the first end higher than the second end. The first end of the inclined beam is fixedly connected to the upper plate of the outermost frame, and the second end of the inclined beam is connected to the lower plate of the outermost frame in the same base. The inclined beams provide negative stiffness. The beams provide positive stiffness; when bending occurs, the beams provide extremely high positive stiffness, while when the beams bend to a certain extent, the stiffness becomes extremely low. This characteristic allows the device to achieve a large load-bearing capacity with very small displacement, while simultaneously matching the negative stiffness provided by the inclined beams in the section with extremely low stiffness, achieving quasi-zero stiffness.

[0058] The inventors studied the negative stiffness structure of existing quasi-zero stiffness systems. One reason why the negative stiffness structure of existing quasi-zero stiffness systems often uses mechanically hinged helical springs with poor isolation effects is that the friction and gaps at the mechanical hinges provide poor isolation for micro-vibrations, and the helical springs are prone to lateral instability under compression. In the technical solution provided in this application, the inner and outer connecting parts are fixedly connected to the lower plate of the innermost frame, and the inner and outer connecting parts are fixedly connected to the upper plate of the outermost frame. This avoids the friction at the hinge points affecting the vibration isolation effect, and also avoids the poor isolation effect of gaps at the hinge points on micro-vibrations. Simultaneously, it also avoids the lateral instability that easily occurs when the helical springs are compressed.

[0059] Compared to traditional quasi-zero stiffness systems that use linear springs to provide positive stiffness, the quasi-zero stiffness device provided in this application requires less displacement to achieve high static loads, which is beneficial for practical applications. The outer frame provides quasi-zero stiffness in vertical translation and horizontal axial bending, while the inner and outer connecting parts provide vibration isolation in torsional and horizontal translational directions, thereby achieving six degrees of freedom quasi-zero stiffness.

[0060] Existing structures employ multi-layer stacking to achieve multi-degree-of-freedom vibration isolation, resulting in structural instability. The six-degree-of-freedom quasi-zero stiffness device based on a buckling beam structure provided in this application uses a suspension method, with the inner and outer layers at similar heights. This lowers the system's center of gravity, further improving structural stability while reducing the space occupied by the structure. Attached Figure Description

[0061] Figure 1 is a schematic diagram of the quasi-zero stiffness device based on a buckling beam structure provided in Embodiment 1 of this application;

[0062] Figure 2 is a schematic diagram of the quasi-zero stiffness device based on a buckling beam structure provided in Embodiment 2 of this application;

[0063] Figure 3 is a structural schematic diagram of a six-degree-of-freedom quasi-zero stiffness device provided according to Embodiment 3 of this application;

[0064] Figure 4 shows the force-displacement curves obtained after static testing of the outer beam in Embodiment 3 of this application;

[0065] Figure 5 shows the force-displacement curve obtained after static testing of the inclined beam in Embodiment 3 of this application. Detailed Implementation

[0066] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The principles and features of the present invention are described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0067] Example 1

[0068] This embodiment provides a quasi-zero stiffness device based on a buckling beam structure, as shown in Figure 1, which includes a frame and an inclined support beam 400;

[0069] The frame includes a regular hexagonal upper plate 100, a regular hexagonal lower plate 200, and 12 beams 300 fixedly connected between the upper plate 100 and the lower plate 200; the beams 300 are divided into 6 groups of beams symmetrical about the longitudinal centerline of the frame, with 2 beams in each group symmetrically distributed on both sides of the corner.

[0070] The inclined beam 400 includes a first end and a second end, with the first end of the inclined beam 400 being higher than the second end. The first end of the inclined beam 400 is fixedly connected to the upper plate 100, and the second end of the inclined beam 400 extends outward from the frame and connects to the lower plate 200. In this embodiment, six inclined beams 400 are included. The connection positions of the first ends of the inclined beams 400 to the upper plate 100 are located at the centerline of each side of the upper plate 100, and each connection position is symmetrically distributed with respect to the longitudinal centerline of the frame.

[0071] In this embodiment, the upper plate 100 and the lower plate 200 are regular hexagons of the same size, and the upper plate 100 and the lower plate 200 are not deflected.

[0072] In this embodiment, both beam 300 and inclined support beam 400 are slender, and the thickness of inclined support beam 400 is greater than the thickness of beam 300.

[0073] In this embodiment, the quasi-zero stiffness device further includes 6 legs extending outward from the lower plate 200;

[0074] The second end of the inclined support beam 400 is connected to the support leg;

[0075] The length and height of the support leg are adjustable, so that the position of the second end of the inclined support beam 400 relative to the first end of the inclined support beam is adjustable.

[0076] In this embodiment, all component connections utilize fixed connections, resolving the impact of hinge friction on vibration reduction in traditional quasi-zero systems. Furthermore, the absence of gaps between structures effectively isolates micro-vibrations. Through the nonlinear variation of beam 300's stiffness, the stiffness gradually decreases from a maximum as displacement increases. Therefore, greater load-bearing capacity can be achieved under relatively small displacement conditions, while simultaneously achieving quasi-zero vibration in combination with the negative stiffness provided by the inclined support beam 400. Moreover, the tilt angle of the inclined support beam 400, which provides negative stiffness, is adjustable, allowing for adjustment of the device's load-bearing capacity within a certain range without altering the magnitude of the negative stiffness.

[0077] In this embodiment, the support leg includes:

[0078] The transverse support leg 501 includes a transverse segment and a longitudinal segment, which are vertically connected. A radial transverse track is provided on the lower plate 200 of the frame, and the transverse segment of the transverse support leg 501 slides or locks within the transverse track. A longitudinal track is provided on the longitudinal segment of the transverse support leg 501.

[0079] Longitudinal support leg 502, which can slide or lock within the longitudinal track;

[0080] The second end of the inclined support beam 400 is fixedly connected to the longitudinal support leg 502.

[0081] In the quasi-zero stiffness device, positive stiffness is provided by beam 300. The material of beam 300 can be spring steel, etc. Static experiments were conducted on beam 300 to obtain force-displacement curves. The force-displacement curves show that beam 300 provides extremely high positive stiffness when it just begins to bend, but its stiffness becomes extremely low when it bends to a certain extent. This characteristic allows the quasi-zero stiffness device to achieve a large load-bearing capacity with very small displacements, while the section with the lowest stiffness can match the negative stiffness system to achieve quasi-zero stiffness. Negative stiffness is provided by inclined beam 400, which is also made of spring steel, but is thicker than the slender beam 300 used for positive stiffness. Force-displacement curves were obtained from mechanical experiments on inclined beam 400 with different inclination angles. These curves show that changing the inclination angle of inclined beam 400 has little effect on the magnitude of negative stiffness. Therefore, after the small positive stiffness value provided by the bending of the beam 300 to a certain extent matches the negative stiffness value provided by the inclined beam 400, the load-bearing capacity of the inclined beam 400 can be changed by adjusting the position of the second end of the inclined beam 400 relative to the first end of the inclined beam 400, so as to adapt to loads of different weights.

[0082] The quasi-zero stiffness device provided in this application has stable stiffness coefficients for the beam providing positive stiffness and the inclined support beam providing negative stiffness over a large displacement range. Therefore, the quasi-zero stiffness device has a large quasi-zero stiffness vibration isolation range and is widely applicable in practical applications.

[0083] This embodiment also provides the application of the quasi-zero stiffness device in a vibration isolation system. The equipment to be isolated is placed on the upper plate 100 of the quasi-zero stiffness structure, and the position of the first end of the inclined support beam 400 relative to the second end is adjusted according to the weight of the equipment. In this embodiment, the position of the first end of the inclined support beam 3 relative to the second end is adjusted by adjusting the position of the transverse segment of the transverse support leg 501 within the transverse track and the position of the longitudinal support leg 502 within the longitudinal track.

[0084] Example 2

[0085] Referring to Figure 2, the difference between this embodiment and Embodiment 1 is that the inclined support beam 400 includes a first end and a second end, the first end of the inclined support beam 400 is higher than the second end of the inclined support beam 400; the first end of the inclined support beam 400 is fixedly connected to the upper plate 100, and the second end of the inclined support beam 400 extends into the frame and is connected to the lower plate 200.

[0086] In Examples 1 and 2, the instruments and equipment to be isolated from vibration can be placed on the upper plate 100 or the lower plate 200.

[0087] Example 3

[0088] Referring to Figure 3, this embodiment provides a six-degree-of-freedom quasi-zero stiffness device based on a buckling beam structure, comprising an outer frame, an inner frame, and an inclined support beam 3;

[0089] The outer frame includes a regular hexagonal upper outer plate 11, a regular hexagonal lower outer plate 12, and 12 outer beams 13 fixedly connected between the upper outer plate 11 and the lower outer plate 12. The outer beams 13 are divided into 6 groups that are symmetrical about the longitudinal centerline of the outer frame, with 2 beams in each group, symmetrically distributed on both sides of the corner.

[0090] The inner frame includes a regular hexagonal upper inner plate 21, a regular hexagonal lower inner plate 22, and six inner beams 23 fixedly connected between the upper inner plate 21 and the lower inner plate 22; the inner beams 23 are symmetrically distributed at the centerline of each side with respect to the longitudinal centerline of the outer frame.

[0091] The outer frame is fitted over the inner frame, and the inner lower plate 22 is suspended from the outer upper plate 11 by inner and outer connectors 4. The inner and outer connectors 4 are fixedly connected to the inner lower plate 22 and to the outer upper plate 11. The connection points between the inner and outer connectors 4 and the outer upper plate 11 are located at the centerline of each side of the outer upper plate 11, and each connection point is symmetrically distributed with respect to the longitudinal centerline of the outer frame. The connection points between the inner and outer connectors 4 and the inner lower plate 22 are located at the centerline of each side of the inner lower plate 22, and each connection point is symmetrically distributed with respect to the longitudinal centerline of the inner frame.

[0092] The inclined beam 3 includes a first end and a second end, with the first end of the inclined beam 3 being higher than the second end. The first end of the inclined beam 3 is fixedly connected to the outer upper plate 11, and the second end of the inclined beam 3 is connected to the outer lower plate 12. In this embodiment, there are 6 inclined beams 3. The connection positions of the first ends of the inclined beams 3 to the outer upper plate 11 are located at the centerline of each side of the outer upper plate 11, and each connection position is symmetrically distributed with respect to the longitudinal centerline of the outer frame.

[0093] In this embodiment, the outer upper plate 11 and outer lower plate 12 contained in the outer frame are regular hexagons of the same size, and the outer upper plate 11 and outer lower plate 12 are not deflected.

[0094] In this embodiment, the inner upper plate 21 and inner lower plate 22 contained in the inner frame are regular hexagons of the same size, and the inner upper plate 21 and inner lower plate 22 are not deflected.

[0095] Furthermore, the outer upper plate 11 and the inner upper plate 21 are not deflected.

[0096] In this embodiment, the outer beam 13 and the inner beam 23 are slender.

[0097] In this embodiment, the six-degree-of-freedom quasi-zero stiffness device also includes six legs extending outward from the outer lower plate 12.

[0098] The second end of the inclined support beam 3 is connected to the support leg;

[0099] The adjustable length and height of the support leg allow the position of the second end of the inclined support beam 3 relative to the first end of the inclined support beam to be adjustable, i.e., the tilt angle of the inclined support beam 3 is adjustable.

[0100] In this embodiment, all component connections are fixed, solving the problem of friction at hinges affecting vibration reduction in traditional quasi-zero systems. Furthermore, the absence of gaps between structures isolates micro-vibrations. Through the non-linear stiffness variation of the outer beam 13 and inner beam 23, the stiffness gradually decreases from a maximum as displacement increases. Therefore, greater load-bearing capacity can be achieved under relatively small displacement conditions, while simultaneously achieving quasi-zero vibration in combination with the negative stiffness provided by the inclined support beam 3. Moreover, the tilt angle of the inclined support beam 3, which provides negative stiffness, is adjustable, allowing for adjustment of the device's load-bearing capacity within a certain range without altering the magnitude of the negative stiffness.

[0101] The outer frame provides quasi-zero stiffness in vertical translation and horizontal axial bending, while the inner and outer connectors 4 provide vibration isolation in torsional and horizontal translational directions, thereby achieving quasi-zero stiffness in six degrees of freedom.

[0102] Furthermore, compared to the typical parallel structure where the inner structure is on the upper layer, the technical solution provided in this embodiment uses a suspension method to design the inner and outer layers at approximately the same height, which lowers the system's center of gravity, improves structural stability, and reduces the space occupied by the structure.

[0103] In this embodiment, the support leg includes:

[0104] The transverse support leg 51 includes a transverse section and a longitudinal section, which are vertically connected; a radial transverse track is provided on the outer lower plate 12, and the transverse section of the transverse support leg 51 can slide or lock within the transverse track; a longitudinal track is provided on the longitudinal section of the transverse support leg 51.

[0105] Longitudinal support leg 52, which can slide or lock within the longitudinal track;

[0106] The second end of the inclined support beam 3 is fixedly connected to the top surface of the longitudinal support leg 52.

[0107] In this embodiment, the inclined support beam 3 is slender, and the thickness of the inclined support beam 3 is greater than the thickness of the outer beam 13 and the inner beam 23.

[0108] In this embodiment, the inner and outer connecting parts 4 are elongated, and the stiffness of the inner and outer connecting parts 4 is less than that of the outer beam 13 and the inner beam 23.

[0109] In this embodiment, the outer beam 13, the inner beam 23, and the inner and outer connecting parts 4 are made of the same material, and the inner and outer connecting parts 4 are thinner than the outer beam 13 and the inner beam 23.

[0110] In the six-degree-of-freedom quasi-zero stiffness device, positive stiffness is provided by the outer beam 13 and the inner beam 23. The outer beam 13 and the inner beam 23 are made of spring steel. Static experiments were conducted on the outer beam 13, yielding the force-displacement curve shown in Figure 3. As shown in Figure 4, the force-displacement curve reveals that the outer beam 13 provides extremely high positive stiffness when it just begins to bend, but its stiffness becomes minimal when it bends to a certain extent. Similarly, the inner beam 23 provides extremely high positive stiffness when it just begins to bend, but its stiffness becomes minimal when it bends to a certain extent. This characteristic allows the six-degree-of-freedom quasi-zero stiffness device to achieve a large load-bearing capacity with very small displacements, while the segment with minimal stiffness can match the negative stiffness system, achieving quasi-zero stiffness. Negative stiffness is provided by the inclined support beam 3, which is also made of spring steel, but its thickness is greater than that of the slender beams used for positive stiffness. The force-displacement curves obtained from mechanical experiments on the inclined beam 3 with different inclination angles are shown in Figure 5, where β is the angle between the inclined beam 3 and the inner upper plate 21. That is, changing the inclination angle of the inclined beam 3 has little effect on the magnitude of the negative stiffness. Therefore, after the small positive stiffness value provided by the outer beam 13 bending to a certain extent matches the negative stiffness value provided by the inclined beam 3, the load-bearing capacity of the inclined beam 3 can be changed by adjusting the position of the second end of the inclined beam 3 relative to the first end of the inclined beam 3, thus adapting to loads of different weights.

[0111] This embodiment also provides the application of the six-degree-of-freedom quasi-zero stiffness device in a vibration isolation system. The equipment to be isolated is placed on the inner upper plate 21 of the six-degree-of-freedom quasi-zero stiffness structure, and the position of the first end of the inclined support beam 3 relative to the second end is adjusted according to the weight of the equipment. In this embodiment, the position of the first end of the inclined support beam 3 relative to the second end is adjusted by adjusting the position of the transverse segment of the transverse support leg 51 within the transverse track and the position of the longitudinal support leg 52 within the longitudinal track.

[0112] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0113] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A six-degree-of-freedom quasi-zero stiffness device based on a buckling beam structure, characterized in that, The system comprises several frames and inclined beams; each frame includes an upper plate, a lower plate, and several beams fixedly connected between the upper and lower plates; the outermost frame is fitted over the innermost frame, and the lower plate of the innermost frame is suspended from the upper plate of the outermost frame by internal and external connectors; the internal and external connectors are fixedly connected to the lower plate of the innermost frame and to the upper plate of the outermost frame, and the upper and lower plates contained within the same frame are polygonal plates of the same size with no deflection; each inclined beam includes a first end and a second end, the first end of which is higher than the upper and lower plates. The second end of the inclined beam; the first end of the inclined beam is fixedly connected to the upper plate of the outermost frame, and the second end of the inclined beam extends outward from the frame and is connected to the lower plate of the outermost frame in the same base; the six-degree-of-freedom quasi-zero stiffness device also includes a leg extending outward from the outer lower plate, the second end of the inclined beam is connected to the leg, and the length and height of the leg are adjustable so that the position of the second end of the inclined beam relative to the first end of the inclined beam is adjustable; the leg includes a transverse leg and a longitudinal leg, and the second end of the inclined beam is fixedly connected to the top surface of the longitudinal leg; the thickness of the inclined beam is greater than the thickness of the beam.

2. The six-degree-of-freedom quasi-zero stiffness device according to claim 1, characterized in that, The beams, the inclined support beams, and the inner and outer connecting members are all symmetrically arranged with respect to the longitudinal centerline of the frame; the beams and the inclined support beams are all slender.

3. The six-degree-of-freedom quasi-zero stiffness device according to claim 2, characterized in that, The inner and outer connecting parts are elongated, and their stiffness is less than that of the beam.

4. The six-degree-of-freedom quasi-zero stiffness device according to claim 1, characterized in that, The transverse support leg includes a transverse segment and a longitudinal segment, which are perpendicularly connected. A radial transverse track is provided on the lower plate of the outermost frame, and the transverse segment of the transverse support leg can slide or lock within the transverse track. A longitudinal track is provided on the longitudinal segment of the transverse support leg, and the longitudinal support leg can slide or lock within the longitudinal track. The second end of the inclined support beam is fixedly connected to the longitudinal support leg.

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