Integrated negative stiffness friction damping device and application thereof

Abstract

This invention relates to an integrated negative stiffness friction damping device and its application, belonging to the field of vibration control technology. It includes an external frame comprising a horizontal top frame, a bottom frame, and four vertical support rods at the corners. A vertical fixed track is installed at the center line of the top connecting plate, with one end of a sliding track embedded in the fixed track and the other end fixed to the bottom connecting plate. The two ends of the horizontal support rods are connected to the fixed track and the top frame, respectively. An L-shaped connector is connected at one end to the sliding friction plate and at the other end to the bottom connecting plate. A friction assembly is symmetrically arranged around the fixed track. The two ends of each friction assembly are bolted to the top and bottom frames, respectively. Double-ear connectors are provided on the inner side of the friction assembly and the outer side of the fixed track for hinged connection with nitrogen springs. This invention employs a parallel design and integration principle, providing significant negative stiffness while improving energy dissipation capacity and significantly reducing structural displacement, acceleration, and internal force response.

Description

Technical Field

[0001] This invention relates to an integrated negative stiffness friction damping device and its application, belonging to the field of vibration control technology. Background Technology

[0002] my country experiences widespread earthquake activity, with a high frequency of occurrence, numerous strong earthquakes, and shallow focal depths. Historically, many strong earthquakes have proven their immense destructive power as a primary cause of building collapses and casualties. When using traditional metal dampers, friction dampers, and viscoelastic dampers for vibration control, a significant stiffness is typically added to the structure, thereby enhancing the dynamic response of the upper layers and reducing the damping effect of the damping device.

[0003] Traditional damping devices have a relatively simple structure and limited energy dissipation efficiency. To improve energy dissipation capacity, multiple damping devices are usually arranged in parallel to meet the expected seismic resistance targets. However, this approach not only places greater demands on the space available for device placement but also increases equipment procurement and subsequent maintenance costs. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention proposes an integrated negative stiffness friction damping device and its application, which solves the problems of low dynamic response and energy dissipation efficiency of the upper structure due to the increased additional stiffness provided by traditional damping devices.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An integrated negative stiffness friction damping device includes an external frame, a fixed track, a sliding track, and a friction assembly. The external frame includes a horizontal top frame, a horizontal bottom frame, and support rods that are vertically connected at the four corners between the two. The two ends of the support rods are respectively bolted to the top frame and the bottom frame. One end of the horizontal support rod is connected to the inside of the top frame, and the other end of the horizontal support rod is connected to the side of the fixed track. The top end of the fixed track is concentrically welded to the top connecting plate, and a sliding track is embedded inside it. The bottom end of the sliding track is concentrically welded to the bottom connecting plate. A set of friction components is symmetrically arranged around the fixed track, and the two ends of the friction components are respectively connected to the top frame and the bottom frame by bolts. Each friction assembly includes a fixed friction plate, a sliding friction plate, a first double-ear connector, a second double-ear connector, and a nitrogen spring; the two ends of the nitrogen spring are respectively hinged to the first double-ear connector and the second double-ear connector; the first double-ear connector is fixed on the sliding friction plate, and the second double-ear connector is fixed on the fixed track; the fixed friction plate is disposed between the top frame and the bottom frame, and is clamped in the middle of the sliding friction plate.

[0007] Furthermore, each set of friction components specifically includes a fixed friction plate, two sliding friction plates, two brake pads, two first double-ear connectors, two second double-ear connectors, and two nitrogen springs.

[0008] Furthermore, each friction assembly also includes two brake pads. A rectangular groove is formed on both the inner and outer surfaces of the fixed friction plate for placing the brake pads. The two sliding friction plates are clamped in the middle by bolts, so that the brake pads are in close contact with the sliding friction plates. Different normal pressures can be applied to the friction surface by adjusting the torque of the preload bolts.

[0009] Furthermore, each of the four corners of the bottom connecting plate is bolted with two L-shaped connectors, and the other end of each L-shaped connector is bolted to the corresponding sliding friction plate.

[0010] Furthermore, the fixed track and the sliding track are coaxial, and the inner wall of the fixed track is in contact with the outer wall of the sliding track.

[0011] Furthermore, both the top connecting plate and the bottom connecting plate are provided with threaded holes for easy installation.

[0012] Furthermore, the integrated negative stiffness friction damping device consists of four sets of friction components connected in parallel, and the negative stiffness characteristic is provided by an integrated nitrogen spring.

[0013] Furthermore, each set of friction components is arranged in parallel with a fixed track as the axis of symmetry, which can better achieve work coordination and prevent skewing during reciprocating motion.

[0014] Furthermore, the nitrogen spring is hinged to the first double-ear connector and the second double-ear connector by means of a pin, and the nitrogen spring is guaranteed to rotate freely about the pin as the axis, and its maximum compression should be less than 90% of the maximum stroke of the nitrogen spring.

[0015] The above-mentioned integrated negative stiffness friction damping device is used as a whole in the vibration reduction structure.

[0016] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art: (1) The negative stiffness characteristics of the device are mainly provided by the stable nitrogen spring, which can provide a large pressure with a small loss of compression displacement and requires little installation space. The integrated negative stiffness friction damping device composed of it has a compact structure and significant negative stiffness characteristics.

[0017] (2) The damping part of the device is mainly generated by four friction components. It adopts a symmetrical layout and parallel design. While ensuring the coordination and stability of the operation, the energy consumption capacity is multiplied by integrating four friction damping units.

[0018] (3) The device mostly uses bolt connections, which facilitates assembly and disassembly and also makes it easier to replace damaged components. Its mechanical properties can be adjusted by adjusting the friction slip distance, the torque of the pre-tightening bolts, the parameters and number of nitrogen springs, and the friction coefficient of the brake pads. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the integrated negative stiffness friction damping device described in this invention; Figure 2 This is a front view of the integrated negative stiffness friction damping device described in this invention; Figure 3 This is a structural diagram of the top frame described in this invention; Figure 4 This is a structural diagram of the bottom frame described in this invention; Figure 5 This is a structural diagram of the vertical support rod described in this invention; Figure 6 This is a structural diagram of the top connecting plate described in this invention; Figure 7 This is a structural diagram of the bottom connecting plate described in this invention; Figure 8 This is a structural diagram of the horizontal support rod described in this invention; Figure 9 This is a structural diagram of the sliding friction plate described in this invention; Figure 10 This is a structural diagram of the fixed friction plate described in this invention; Figure 11 This is a structural diagram of the brake pad described in this invention; Figure 12 This is a structural diagram of the fixed track described in this invention; Figure 13 This is a structural diagram of the sliding track described in this invention; Figure 14 This is a structural diagram of the double-ear connector described in this invention; Figure 15 This is a structural diagram of the L-shaped connector described in this invention; Figure 16 This is a structural diagram of the nitrogen spring described in this invention; Figure 17 These are the hysteresis curves of the integrated negative stiffness friction damping device described in this invention under different pre-applied torques.

[0020] Figure 18These are the hysteresis curves of the integrated negative stiffness friction damping device described in this invention under different displacement amplitudes.

[0021] Figure 19 These are the hysteresis curves of the integrated negative stiffness friction damping device described in this invention under different loading frequencies. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-19 The present invention will be further described in detail below to facilitate a clear understanding of the invention, but these descriptions do not constitute a limitation thereof.

[0023] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", 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 limiting this invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example 1 like Figure 1 and Figure 2 As shown, an integrated negative stiffness friction damping device according to this embodiment includes an outer frame, a fixed track 10, a sliding track 11, and a friction assembly, specifically, as follows: Figure 1-2 As shown, it includes a top connecting plate 1, a top frame 2, a horizontal support rod 3, a fixed friction plate 4, a brake pad 5, a sliding friction plate 6, a first double-ear connector 7, an L-shaped connector 8, a nitrogen spring 9, a fixed track 10, a sliding track 11, a bottom frame 12, a vertical support rod 13, a bottom connecting plate 14, and a second double-ear connector 15.

[0026] In this embodiment, the external frame consists of a horizontal top frame 2, a horizontal bottom frame 12, and four support rods 13 that are vertically connected at the four corners of the two. The two ends of the support rods 13 are respectively connected to the top frame and the bottom frame by bolts.

[0027] In this embodiment, four horizontal support rods 3 are provided between the top frame 2 and the fixed track 10 to further enhance the stability of the device. One end of the horizontal support rod 3 is connected to the inner side of the top frame 2, and the other end of the horizontal support rod 3 is connected to the side of the fixed track 10.

[0028] The fixed track 10 and the sliding track 11 are coaxial. The top of the fixed track 10 is concentrically welded to the top connecting plate 1, and the bottom is embedded in the sliding track 11. The bottom of the sliding track 11 is concentrically welded to the bottom connecting plate 14, and its top is free and can move vertically within the fixed track 10. A set of friction components is symmetrically arranged around the fixed track 10. The friction components consist of a fixed friction plate 4, two sliding friction plates 6, two brake pads 5, two first double-ear connectors 7, two second double-ear connectors 15, and two nitrogen springs 9. Two L-shaped connectors 8 are bolted to the four corners of the bottom connecting plate 14, and the other end of the L-shaped connectors 8 is bolted to the inner sliding friction plate, thus forming a linkage mechanism.

[0029] like Figure 9 , 12 As shown in Figures 14 and 16, the first double-ear connector 7 and the second double-ear connector 15 are respectively connected to the inner sliding friction plate 6 and the fixed track 10 by bolts. The nitrogen spring 9 is hinged to the first double-ear connector 7 and the second double-ear connector 15 by pins, thereby forming a mechanism that provides negative stiffness.

[0030] like Figure 3 , 4 As shown in Figure 10, rectangular through slots, 10mm wide and 150mm long, are cut at the center of each of the four sides of the top frame 2 and the bottom frame 12. The two ends of the fixed friction plate 4 are inserted into the slots of the top frame 2 and the bottom frame 12 respectively, and are connected by bolts to constrain the movement of the fixed friction plate 4. In addition, the connection and constraint of the top frame 2 and the bottom frame 12 enable the four friction components to be arranged in parallel.

[0031] like Figure 9 , 10 As shown in Figure 11, the sliding friction plates 6 on the inner and outer sides are connected by bolts to clamp the fixed friction plate 4 in the middle and make close contact with the brake pad 5 in the groove, thus forming the main damping part of the friction assembly. The normal pressure applied to the friction surface can be changed by adjusting the bolt torque, thereby adjusting the damping force.

[0032] like Figure 6 , 7 As shown, threaded holes are provided on the top connecting plate 1 and the bottom connecting plate 14 to facilitate connection with the embedded parts in the structure.

[0033] like Figure 12 ,13 As shown, the outer wall of the sliding track 11 is in contact with the inner wall of the fixed track 10, and the two together form the central axis of symmetry of the integrated negative stiffness friction damping device. Other components are strictly symmetrical about the plane containing the center line of this axis, which can ensure that the device has good coordination and stability.

[0034] In this embodiment, the integrated negative stiffness friction damping device consists of four sets of friction components connected in parallel, and the negative stiffness is provided by an integrated nitrogen spring 9. Each set of friction components is arranged in parallel with a fixed track as the axis of symmetry, which can better achieve work coordination and prevent deflection during reciprocating motion.

[0035] The maximum compression of the nitrogen spring 9 in the horizontal state shall not exceed 90% of the specification. When it rotates up and down with the sliding friction plate 6, its working length shall not exceed its natural length when uncompressed, so as to avoid the nitrogen spring 9 being over-compressed or stretched and thus prevent damage.

[0036] The mechanical properties of the integrated negative stiffness friction damping device, including damping force and negative stiffness, can be adjusted by changing the friction coefficient of the brake pad 5, the parameters and number of nitrogen springs 9, the stroke of the sliding friction plate 6, and the torque of the bolts.

[0037] The damping force generated by the integrated negative stiffness friction damping device of this invention is provided by the friction force corresponding to the vector sum of the normal pressure applied to the friction surface by the preloaded bolt and the normal component of the nitrogen spring. In the initial equilibrium state, the nitrogen spring 9 is perpendicular to the surface of the sliding friction plate 6, at which point the spring compression is at its maximum. As the device enters the working state under external load, the sliding friction plate 6 slides up and down along the fixed friction plate 4. At this time, a certain angle is generated between the nitrogen spring 9 and the sliding friction plate 6. The component of the nitrogen spring 9 along the direction of motion causes the device to move away from the initial equilibrium position, exhibiting a negative stiffness force. The component of the nitrogen spring 9 parallel to the normal of the sliding friction plate 6 provides a positive pressure, which decreases as the angle increases, i.e., the generated damping force decreases. Under the coupled action of the negative stiffness force and the damping force, the hysteresis curve generated by the device will exhibit obvious negative stiffness characteristics. The friction coefficient of the brake pads used is approximately 0.43, the initial load of the nitrogen springs is 1000N, and a total of 8 nitrogen springs are used, i.e., 2 are arranged in parallel on each side. The integrated negative stiffness friction damping device described in this embodiment, with the loading frequency and stroke remaining constant and only the pre-applied torque changed, yielded the following hysteresis loading test results: Figure 17 As shown. The hysteresis loading test results when the loading frequency and pre-applied torque remain constant, and only the stroke is changed are as follows. Figure 18 As shown. The hysteresis loading test results when the pre-torque and stroke remain constant, and only the loading frequency is changed are as follows. Figure 19 As shown. By Figure 17It can be seen that as the preload torque increases, the damping force and hysteresis area increase, and the hysteresis curve exhibits a clear negative stiffness characteristic. From Figure 18 It can be seen that as the stroke increases, the damping force and hysteresis area increase, and the hysteresis curve exhibits obvious negative stiffness characteristics, indicating that the mechanical performance of the integrated negative stiffness friction damping device has a significant displacement correlation. Figure 19 It can be seen that as the loading frequency increases, the damping force and hysteresis area change very little, indicating that the mechanical performance of the integrated negative stiffness friction damping device is basically independent of the loading frequency.

[0038] Example 2 This embodiment is an application of the integrated negative stiffness friction damping device of Embodiment 1. In this embodiment, the integrated negative stiffness friction damping device is applied as a whole in a vibration reduction structure or other engineering structure.

[0039] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the structure of the present invention. The arrangement and quantity of the present invention are not limited to this example and can be optimized according to actual engineering conditions. Any modifications, equivalent changes, and decorations made to the above embodiments based on the technical principles of the present invention, without departing from the scope of the present invention, are still within the scope of the present invention.

Claims

1. An integrated negative stiffness friction damping device, characterized in that: It includes an external frame, a fixed track (10), a sliding track (11), and a friction assembly; The external frame includes a horizontal top frame (2), a horizontal bottom frame (12), and support rods (13) that are vertically connected at the four corners between the two. The two ends of the support rods (13) are respectively bolted to the top frame and the bottom frame. One end of a horizontal support rod (3) is connected to the inside of the top frame (2), and the other end of the horizontal support rod (3) is connected to the side of the fixed track (10). The top end of the fixed track (10) is concentrically welded to the top connecting plate (1), and a sliding track (11) is embedded inside it. The bottom end of the sliding track (11) is concentrically welded to the bottom connecting plate (14). A set of friction components is symmetrically arranged around the fixed track (10), and the two ends of the friction components are respectively connected to the top frame (2) and the bottom frame (12) by bolts; Each friction assembly includes a fixed friction plate (4), a sliding friction plate (6), a first double-ear connector (7), a second double-ear connector (15), and a nitrogen spring (9); the two ends of the nitrogen spring (9) are respectively hinged to the first double-ear connector (7) and the second double-ear connector (15); the first double-ear connector (7) is fixed on the sliding friction plate (6), and the second double-ear connector (15) is fixed on the fixed track (10); the fixed friction plate (4) is set between the top frame (2) and the bottom frame (12) and is clamped in the middle of the sliding friction plate (6).

2. The integrated negative stiffness friction damping device according to claim 1, characterized in that: Each set of friction components specifically includes a fixed friction plate (4), two sliding friction plates (6), two brake pads (5), two first double-ear connectors (7), two second double-ear connectors (15), and two nitrogen springs (9).

3. The integrated negative stiffness friction damping device according to claim 2, characterized in that: Each friction assembly also includes two brake pads (5). The inner and outer surfaces of the fixed friction plate (4) are provided with a rectangular groove for placing the brake pads (5). The two sliding friction plates (6) are clamped in the middle of the fixed friction plate (4) by bolts, so that the brake pads (5) and the sliding friction plates (6) are in close contact. Different normal pressures can be applied to the friction surface by adjusting the torque of the pre-tightening bolts.

4. The integrated negative stiffness friction damping device according to claim 1, characterized in that: The bottom connecting plate (14) has two L-shaped connectors (8) at each of its four corners, and the other end of the L-shaped connector (8) is connected to the corresponding sliding friction plate (6) by bolts.

5. The integrated negative stiffness friction damping device according to claim 1, characterized in that: The fixed track (10) is coaxial with the sliding track (11), and the inner wall of the fixed track (10) is in contact with the outer wall of the sliding track (11).

6. The integrated negative stiffness friction damping device according to claim 1, characterized in that: Both the top connecting plate (1) and the bottom connecting plate (14) are provided with threaded holes for easy installation.

7. An integrated negative stiffness friction damping device according to any one of claims 1-6, characterized in that: The integrated negative stiffness friction damping device consists of four sets of friction components connected in parallel, and the negative stiffness is provided by an integrated nitrogen spring (9).

8. The integrated negative stiffness friction damping device according to claim 7, characterized in that: Each set of friction components is arranged in parallel with a fixed track as the axis of symmetry, which can better achieve work coordination and prevent skewing during reciprocating motion.

9. An integrated negative stiffness friction damping device according to any one of claims 1-6, characterized in that: The nitrogen spring (9) is hinged to the first double-ear connector and the second double-ear connector by means of a pin, and the nitrogen spring (9) is guaranteed to rotate freely around the pin, and its maximum compression should be less than 90% of the maximum stroke of the nitrogen spring (9).

10. An application of an integrated negative stiffness friction damping device according to any one of claims 1-9, characterized in that: The integrated negative stiffness friction damping device is used as a whole in the vibration reduction structure.

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