Low-frequency quasi-zero stiffness vibration isolator with curved euler beam structure

Abstract

The application discloses a low-frequency quasi-zero stiffness isolator of a curved Euler beam structure and belongs to the technical field of low-frequency quasi-zero stiffness isolation. In order to solve the problems of instability and poor space utilization of the existing Euler beam isolation system, the isolator comprises a support plate, a load-bearing platform unit and two curved Euler beam isolation units. The load-bearing platform unit is arranged at the center of the upper surface of the support plate, the bottom of the load-bearing platform unit is fixedly connected with the upper surface of the support plate, the two curved Euler beam isolation units are symmetrically arranged at the two sides of the load-bearing platform unit along the center line of the width direction of the support plate, the bottom of each curved Euler beam isolation unit is fixedly connected with the upper surface of the support plate, and each side of the load-bearing platform unit is detachably connected with the adjacent curved Euler beam isolation unit. The application is mainly used for the device for isolating the load-carrying platform.

Description

Technical Field

[0001] This invention belongs to the field of low-frequency quasi-zero stiffness vibration isolation technology, specifically relating to a low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure. Background Technology

[0002] Passive vibration control technology has advantages such as low cost, simple structure, and easy maintenance, and is therefore widely used in practical engineering. However, traditional vibration isolators present a contradiction between low isolation frequency and high load-bearing capacity, which necessitates more advanced vibration isolation methods. Low-frequency quasi-zero stiffness vibration isolators, due to the high static and low dynamic stiffness of the overall structure, can achieve high load-bearing capacity by utilizing the large stiffness range, while exhibiting excellent vibration isolation performance in the low stiffness range (quasi-zero stiffness range). This effectively resolves the contradiction, significantly improving the low-frequency vibration isolation performance of the system while maintaining structural stability and load-bearing capacity.

[0003] Euler beams have been widely used by scholars as negative stiffness elements in quasi-zero stiffness vibration isolators due to their simple structure and high substitutability. However, Euler beams exhibit bistable characteristics under compression, leading to instability and poor space utilization. Furthermore, research on Euler beam structures under transverse compression is scarce. Therefore, developing a low-frequency quasi-zero stiffness vibration isolator using a curved Euler beam structure to apply Euler beams to the field of low-frequency quasi-zero stiffness vibration isolation is highly practical. Summary of the Invention

[0004] To address the instability and poor space utilization of existing Euler beam vibration isolation systems, this invention provides a low-frequency quasi-zero stiffness vibration isolator for curved Euler beam structures.

[0005] A low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure is disclosed. The isolator includes a support plate, a load-bearing platform unit, and two curved Euler beam vibration isolation units. The load-bearing platform unit is located at the center of the upper surface of the support plate, and the bottom of the load-bearing platform unit is fixedly connected to the upper surface of the support plate. The two curved Euler beam vibration isolation units are symmetrically arranged on both sides of the load-bearing platform unit along the centerline of the width direction of the support plate, and the bottom of each curved Euler beam vibration isolation unit is fixedly connected to the upper surface of the support plate. Each side of the load-bearing platform unit is detachably connected to an adjacent curved Euler beam vibration isolation unit.

[0006] Furthermore, the load-bearing platform unit includes a load-bearing platform, two No. 1 connecting cylindrical rods, and four support guide components. The load-bearing platform is positioned above the support plate and is parallel to the support plate. The two No. 1 connecting cylindrical rods are symmetrically arranged on both sides of the load-bearing platform along the center line of the support plate's width direction. One end of each No. 1 connecting cylindrical rod is fixedly connected to the center of one side of the load-bearing platform. Each No. 1 connecting cylindrical rod is correspondingly positioned above a curved Euler beam vibration isolation unit. The load-bearing platform is detachably connected to a curved Euler beam vibration isolation unit through a No. 1 connecting cylindrical rod. A support guide component is provided at each of the four corners of the lower surface of the load-bearing platform. Each support guide component is vertically positioned between the load-bearing platform and the support plate. The top of each support guide component is fixedly connected to the lower surface of the load-bearing platform, and the bottom of each support guide component is fixedly connected to the upper surface of the support plate.

[0007] Furthermore, the support and guide assembly includes a guide sleeve, a linear bearing, a spring, and an optical shaft. The guide sleeve is vertically disposed on the upper surface of the support plate. A linear bearing is embedded in the inner wall of the top opening of the sleeve. The bottom end of the optical shaft is inserted into the linear bearing and is slidably connected to the guide sleeve through the linear bearing. The top end of the optical shaft is fixedly connected to the lower surface of the load-bearing platform. The spring is disposed inside the sleeve and between the linear bearing and the support plate. The bottom end of the spring is fixedly connected to the upper surface of the support plate, and the top end of the spring is fixedly connected to the bottom end of the optical shaft.

[0008] Furthermore, the height of the guide sleeve is less than the length of the optical axis;

[0009] Furthermore, the curved Euler beam vibration isolation unit includes a curved Euler beam and two fixed adjustment components. The curved Euler beam is located directly below a first connecting cylindrical rod, and the first connecting cylindrical rod is detachably connected to the outer arc top of the curved Euler beam. Both ends of the curved Euler beam are located on the upper surface of the support plate, and each end of the curved Euler beam is detachably connected to the support plate. The two fixed adjustment components are symmetrically fitted on the outer arc surface of the curved Euler beam along the centerline of the length direction of the curved Euler beam. The bottom of each longitudinal adjustment component is fixedly connected to the upper surface of the support plate, and the upper part of each longitudinal adjustment component is detachably connected to the outer arc surface of the curved Euler beam.

[0010] Furthermore, two guide thread grooves are machined on the upper surface of the support plate. The two guide thread grooves are arranged parallel to each other along the center line of the width direction of the support plate, and each guide thread groove is correspondingly located below a curved Euler beam. A horizontal connecting plate is provided at each end of the curved Euler beam, and the two horizontal connecting plates are integrally formed with the curved Euler beam. A limiting through hole is machined on the upper surface of each horizontal connecting plate, and a fastening bolt is provided in each limiting through hole. The threaded section of each fastening bolt passes through a limiting through hole and is located in the corresponding guide thread groove, and the threaded section of each fastening bolt is threadedly connected to the corresponding guide thread groove.

[0011] Furthermore, the fixed adjustment assembly includes a second connecting cylindrical rod and two guide rails. The two guide rails are arranged parallel to each other along the center line of the width extension direction of the curved Euler beam. Each guide rail is arranged vertically on the upper surface of the support plate. The bottom of each guide rail is fixedly connected to the upper surface of the support plate. The second connecting cylindrical rod is arranged between the two guide rails, and each end of the second connecting cylindrical rod is correspondingly arranged in one guide rail. The second connecting cylindrical rod is slidably connected to the two guide rails. A connecting through hole is machined on the outer circular surface of the second connecting cylindrical rod. A locking bolt is provided in each connecting through hole. A connecting threaded hole is machined on the outer arc surface of the curved Euler beam at the corresponding position of each second connecting cylindrical rod. The threaded section of each locking bolt passes through a connecting through hole and is correspondingly arranged in a connecting threaded hole. The threaded section of each locking bolt is threadedly fastened to the curved Euler beam.

[0012] Furthermore, a fixed through hole is machined on the outer circular surface of the first connecting cylindrical rod, and a fixed bolt is provided in the fixed through hole. A fixed threaded hole is machined at the outer arc apex of the curved Euler beam. The threaded segment of each fixed bolt passes through a fixed through hole and is set in a fixed threaded hole, and the threaded segment of each fixed bolt is threadedly fastened to the curved Euler beam.

[0013] The beneficial effects of this application compared to the prior art are:

[0014] 1. The low-frequency quasi-zero stiffness vibration isolator of the curved Euler beam structure proposed in this application is a quasi-zero stiffness vibration isolator composed of a curved Euler beam, a compression spring, a load-bearing platform, a support base and a vertical limiter assembly. The transversely arranged curved Euler beam and the vertical spring are the main load-bearing components, eliminating the bistable jump phenomenon existing in the curved Euler beam, so that it can achieve a smooth transition of bistable state during the working process, thereby improving stability and space utilization, increasing load-bearing capacity and widening the quasi-zero stiffness range of the structure.

[0015] 2. The low-frequency quasi-zero stiffness vibration isolator proposed in this application for a curved Euler beam structure changes the force distribution mode of the curved Euler beam compared with the existing Euler beam structure. It innovatively makes it transversely compressed, which is easier to eliminate the bistable jump phenomenon and achieve a smooth transition between bistable states compared with the existing Euler beam vibration isolators that are vertically compressed. At the same time, it changes the size and position of the quasi-zero stiffness range of the structure.

[0016] 3. The low-frequency quasi-zero stiffness vibration isolator for a curved Euler beam structure proposed in this application is a nonlinear quasi-zero stiffness vibration isolator that uses a positive stiffness spring as a stiffness compensation mechanism. While ensuring that the nonlinear characteristics of the Euler beam structure are fully utilized, the positive stiffness spring increases the stiffness of the isolator's load-bearing range, widens the quasi-zero stiffness range, and increases the working range and optimal isolation range of the isolator. The low-frequency isolation range is located in the first half of the entire working range, accounting for 1 / 3 of the entire working range, so that the space of the structure is fully utilized and the beneficial effect of reducing the vibration response amplitude is obtained.

[0017] 4. The low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure proposed in this application uses compression springs, which are evenly distributed in the sleeve of the support base to ensure the stress stability of the bearing platform and make it easier to apply in practice. The deformation mode of the transverse curved Euler beam is changed by using the vertical fixed adjustment unit component, so that the curved Euler beam enters the bistable transition section earlier. By this measure, the position of the quasi-zero stiffness range of the vibration isolator is changed, and the control of the quasi-zero stiffness range is achieved.

[0018] 5. The low-frequency quasi-zero stiffness vibration isolator for a curved Euler beam structure proposed in this application can adjust the quasi-zero stiffness range and load-bearing capacity of the vibration isolator by changing the span, span height, thickness, spring stiffness, and installation position of the vertical limiter assembly of the curved Euler beam. It can flexibly control the static performance and vibration isolation performance of the structure from multiple aspects, ensuring that it can adapt to the vibration isolation requirements of different masses and locations.

[0019] 6. The low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure proposed in this application is inexpensive, simple in structure, high in space utilization, highly practical and adjustable, and economically feasible. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the shaft side of the vibration isolator described in this application;

[0021] Figure 2 This is a front view schematic diagram of the vibration isolator described in this application;

[0022] Figure 3 This is a partial cross-sectional schematic diagram of the vibration isolator described in this application;

[0023] Figure 4This is a top view of the vibration isolator described in this application;

[0024] Figure 5 This is a side view of the vibration isolator described in this application;

[0025] Figure 6 This is a schematic diagram of the deformation of a single bending Euler beam composite structure in the vibration isolator described in this application before and after deformation;

[0026] Figure 7 This is a force-displacement curve of the vibration isolator described in this application during operation;

[0027] Figure 8 This is a stiffness-displacement curve of the vibration isolator described in this application during operation;

[0028] Figure 9 This is a displacement transmissivity curve of the vibration isolator described in this application during operation;

[0029] The figure shows: 1. Support plate, 2. Guide sleeve, 3. Bending Euler beam, 4. Linear bearing, 5. Spring, 6. Guide rail, 7. Optical axis, 8. Bearing platform, 9. No. 1 connecting cylindrical rod, 10. No. 2 connecting cylindrical rod, and 11. Guide thread groove. Detailed Implementation

[0030] Specific implementation method one: Combining Figures 1 to 8 This embodiment describes a low-frequency quasi-zero stiffness vibration isolator for a curved Euler beam structure. The isolator includes a support plate 1, a load-bearing platform unit, and two curved Euler beam vibration isolation units. The load-bearing platform unit is located at the center of the upper surface of the support plate 1, and its bottom is fixedly connected to the upper surface of the support plate 1. The two curved Euler beam vibration isolation units are symmetrically arranged on both sides of the load-bearing platform unit along the centerline of the width direction of the support plate 1, and the bottom of each curved Euler beam vibration isolation unit is fixedly connected to the upper surface of the support plate 1. Each side of the load-bearing platform unit is detachably connected to an adjacent curved Euler beam vibration isolation unit.

[0031] Specific Implementation Method Two: Combining Figures 1 to 8This embodiment differs from Specific Embodiment 1 in that the load-bearing platform unit includes a load-bearing platform 8, two No. 1 connecting cylindrical rods 9, and four support guide assemblies. The load-bearing platform 8 is positioned above the support plate 1 and is parallel to the support plate 1. The two No. 1 connecting cylindrical rods 9 are symmetrically arranged on both sides of the load-bearing platform 8 along the centerline of the width direction of the support plate 1, and one end of each No. 1 connecting cylindrical rod 9 is fixedly connected to the center of one side of the load-bearing platform 8. Each No. 1 connecting cylindrical rod 9 is correspondingly positioned above a curved Euler beam vibration isolation unit, and the load-bearing platform 8 is detachably connected to a curved Euler beam vibration isolation unit through a No. 1 connecting cylindrical rod 9. A support guide assembly is provided at each of the four corners of the lower surface of the load-bearing platform 8. Each support guide assembly is vertically positioned between the load-bearing platform 8 and the support plate 1, and the top of each support guide assembly is fixedly connected to the lower surface of the load-bearing platform 8, and the bottom of each support guide assembly is fixedly connected to the upper surface of the support plate 1. Other components and connection methods are the same as in Specific Embodiment 1.

[0032] In this embodiment, the load-bearing platform 8 is connected to the bending Euler beam vibration isolation unit via a first connecting cylindrical rod 9, ensuring the connection stability between the load-bearing platform 8 and the bending Euler beam vibration isolation unit. Simultaneously, the load-bearing platform 8 relies on four support and guide components as the main support and motion units, effectively ensuring the accuracy of the load-bearing platform 8's vertical movement. Furthermore, to ensure the accuracy of vibration isolation, the axis of the load-bearing platform 8 is arranged collinearly with the axis of the support plate 1. To improve the versatility of the device, the shapes of the load-bearing platform 8 and the support plate 1 can be different, such as triangles, circles, or regular polygons. It is worth noting that when the shape of the load-bearing platform 8 changes, the number of support and guide components will also change accordingly, corresponding to the number of angles in a regular polygon. If the load-bearing platform 8 is circular, an even number of support and guide components of four or more can be selected, and they can be arranged equidistantly along the circumference according to actual conditions.

[0033] Specific implementation method three: Combining Figures 1 to 8 This embodiment differs from Specific Embodiment Two in that the support and guiding assembly includes a guide sleeve 2, a linear bearing 4, a spring 5, and an optical shaft 7. The guide sleeve 2 is vertically disposed on the upper surface of the support plate 1. A linear bearing 4 is embedded in the inner wall of the top opening of the sleeve 2. The bottom end of the optical shaft 7 is inserted into the linear bearing 4, and the optical shaft 7 is slidably connected to the guide sleeve 2 through the linear bearing 4. The top end of the optical shaft 7 is fixedly connected to the lower surface of the load-bearing platform 8. The spring 5 is disposed inside the sleeve 2, between the linear bearing 4 and the support plate 1. The bottom end of the spring 5 is fixedly connected to the upper surface of the support plate 1, and the top end of the spring 5 is fixedly connected to the bottom end of the optical shaft 7. Other components and connection methods are the same as in Specific Embodiment Two.

[0034] In this embodiment, the spring 5 used in the support guide assembly is a compression spring, which is evenly distributed in the sleeve of the support seat to ensure the stress stability of the bearing platform and make it easier to apply in practice. By using the spring 5 in conjunction with the bending Euler beam vibration isolation unit as the main bearing body, the bistable jump phenomenon of the bending Euler beam is effectively eliminated, so that it can achieve a smooth transition of bistable state during the working process, thereby improving stability and space utilization, increasing load-bearing capacity and widening the quasi-zero stiffness range of the structure.

[0035] Specific implementation method four: Combination Figures 1 to 8 This embodiment differs from Specific Embodiment Three in that the height of the guide sleeve 2 is less than the length of the optical axis 7. Other components and connection methods are the same as in Specific Embodiment Three.

[0036] Specific Implementation Method Five: Combining Figures 1 to 8 This embodiment differs from Specific Embodiment Four in that the curved Euler beam vibration isolation unit includes a curved Euler beam 3 and two fixed adjustment components. The curved Euler beam 3 is positioned directly below a first connecting cylindrical rod 9, and the first connecting cylindrical rod 9 is detachably connected to the outer arc top of the curved Euler beam 3. Both ends of the curved Euler beam 3 are positioned on the upper surface of the support plate 1, and each end of the curved Euler beam 3 is detachably connected to the support plate 1. The two fixed adjustment components are symmetrically fitted onto the outer arc surface of the curved Euler beam 3 along the centerline of the length direction of the curved Euler beam 3. The bottom of each longitudinal adjustment component is fixedly connected to the upper surface of the support plate 1, and the upper part of each longitudinal adjustment component is detachably connected to the outer arc surface of the curved Euler beam 3. Other components and connection methods are the same as in Specific Embodiment Four.

[0037] In this embodiment, the stress distribution of the curved Euler beam is changed, and it is innovatively subjected to lateral compression. Compared with the Euler beam vibration isolators subjected to vertical compression in the prior art, it is easier to eliminate the bistable transition phenomenon and achieve a smooth transition between bistable states. At the same time, the size and position of the quasi-zero stiffness range of the structure are changed. On this basis, the stiffness of the vibration isolator's load-bearing range is increased by spring 5, the quasi-zero stiffness range is widened, and the working range and optimal vibration isolation range of the vibration isolator are increased. The low-frequency vibration isolation range is located in the first half of the entire working range, accounting for 1 / 3 of the entire working range, so that the space of the structure is fully utilized and the beneficial effect of reducing the vibration response amplitude is obtained.

[0038] Specific Implementation Method Six: Combination Figures 1 to 8This embodiment differs from specific embodiment five in that two guide thread grooves 11 are machined on the upper surface of the support plate 1. These two guide thread grooves 11 are parallel to each other along the centerline of the support plate 1's width direction, and each guide thread groove 11 is positioned below a curved Euler beam 3. A horizontal connecting plate is provided at each end of the curved Euler beam 3, and the two horizontal connecting plates are integrally formed with the curved Euler beam 3. A limiting through hole is machined on the upper surface of each horizontal connecting plate, and a fastening bolt is provided in each limiting through hole. The threaded segment of each fastening bolt passes through a limiting through hole and is positioned in the corresponding guide thread groove 11, and the threaded segment of each fastening bolt is threadedly connected to the corresponding guide thread groove 11. Other components and connection methods are the same as in specific embodiment five.

[0039] This setup facilitates the adjustment of the initial arrangement position of the curved Euler beam 3, as well as the bending state and curvature of the Euler beam. It can be adjusted according to the load on the load-bearing platform to achieve the best vibration isolation state.

[0040] Specific implementation method seven: Combination Figures 1 to 8 This embodiment differs from specific embodiment six in that the fixing and adjusting assembly includes a second connecting cylindrical rod 10 and two guide rails 6. The two guide rails 6 are arranged parallel to each other along the centerline of the width extension direction of the curved Euler beam 3. Each guide rail 6 is vertically arranged on the upper surface of the support plate 1, and the bottom of each guide rail 6 is fixedly connected to the upper surface of the support plate 1. The second connecting cylindrical rod 10 is arranged between the two guide rails 6, and each end of the second connecting cylindrical rod 10 is correspondingly arranged in one guide rail 6. The second connecting cylindrical rod 10 is slidably connected to the two guide rails 6. A connecting through hole is machined on the outer circular surface of the second connecting cylindrical rod 10, and a locking bolt is provided in each connecting through hole. A connecting threaded hole is machined on the outer arc surface of the curved Euler beam 3 at the corresponding position of each second connecting cylindrical rod 10. The threaded segment of each locking bolt passes through a connecting through hole and is correspondingly arranged in a connecting threaded hole. The threaded segment of each locking bolt is threadedly fastened to the curved Euler beam 3. Other components and connection methods are the same as in specific embodiment six.

[0041] In this embodiment, the fixed adjustment component is a limiting component that changes the deformation mode of the transversely bent Euler beam, allowing the bent Euler beam to enter the bistable transition section earlier. This measure alters the position of the quasi-zero stiffness range of the vibration isolator, achieving control over the quasi-zero stiffness range. The position of the second connecting cylindrical rod 10 can be adjusted according to the initial shape of the bent Euler beam 3. It engages with the bent Euler beam 3 by sliding up and down along the guide rail 6. During operation, the end of the second connecting cylindrical rod 10 is locked to the guide rail with bolts, thereby ensuring the stability of the second connecting cylindrical rod. The position of the column rod 10 does not change during operation. Normally, the bolt is set on the rear side wall of the guide rail. A through groove is machined along the length of the rear side wall of the guide rail. A threaded hole is machined at the end of the second connecting cylindrical rod 10. The threaded section of the bolt passes through the through groove and is set in the threaded hole at the end of the second connecting cylindrical rod 10. The bolt is locked to the second connecting cylindrical rod. A washer is provided between the bolt head and the rear side wall of the guide rail. The second connecting cylindrical rod 10 is clamped and fixed to the guide rail by the helical clamping force of the bolt, thereby ensuring the stability during operation.

[0042] Specific implementation method eight: Combination Figures 1 to 8 This embodiment differs from specific embodiment seven in that a fixed through hole is machined on the outer circumference of the first connecting cylindrical rod 9, and a fixing bolt is installed in the fixed through hole. A fixing threaded hole is machined at the outer arc apex of the curved Euler beam 3. The threaded segment of each fixing bolt passes through a fixed through hole and is installed in a fixing threaded hole, and the threaded segment of each fixing bolt is threadedly fastened to the curved Euler beam 3 to which it is located. Other components and connection methods are the same as in specific embodiment seven.

[0043] The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed structure and technical content to create equivalent embodiments without departing from the scope of the present invention. However, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

[0044] Working principle

[0045] This invention relates to a novel low-frequency quasi-zero stiffness vibration isolator composed of a transversely curved Euler beam structure and a compression spring. Specifically, it describes a low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure, combined with... Figure 1As shown, a transversely curved Euler beam structure and a compression spring are used as the load-bearing elements of the structure. The high stiffness range in the first half of the structure's working range is mainly provided by the curved Euler beam structure, with the compression spring as an auxiliary element. The spring is embedded in the sleeve of the support base and provides reaction force through compression via the optical axis. The bearings and springs need to be selected according to the sleeve size. The optical axis 7 is fixed on the bottom surface of the bearing platform 8, and the guide sleeve 2 is fixed on the upper surface of the support plate 1. The fixing and adjusting components can be flexibly installed in different positions, requiring them to be symmetrically installed on both sides about the axis of the curved Euler beam.

[0046] The distance L between the guide rails 6 installed side by side along the longitudinal direction of the curved Euler beam (i.e. Figure 6 The distance between midpoint A and point B and the distance S between the two curved Euler beams should be greater than the side length of the bearing platform 8 to avoid collisions between structures during vibration. The edge of the guide rail 6 should coincide with the edge of the support plate 1. The distance between each group of No. 2 connecting cylindrical rods 10 is L. The stiffness of the spring is k. The initial length of the spring should be equal to or slightly less than the sleeve height h1. The height h2 of the optical axis 7 should be greater than the height h1 of the guide sleeve 2 to maximize the vibration working displacement of the vibration isolator. At the connection position between the curved Euler beam and the auxiliary cylindrical rod, one or more bolt holes should be pre-drilled as needed, and the two should be tightly fitted by bolts.

[0047] As attached Figure 7-8 The figure shows the force-displacement curve and stiffness-displacement curve of the vibration isolator. The shaded area represents the quasi-zero stiffness range of the invention. It can be seen that the optimal vibration isolation range of the invention is approximately 12mm-29mm. Figure 7 It can be concluded that the spring stiffness of this quasi-zero stiffness isolator is greater than 400 N / m within the 0-10 mm range, with a maximum stiffness of approximately 4700 N / m, providing good load-bearing capacity. Within the 35-40 mm working range, the overall structural stiffness increases further. The working range of this isolator is approximately half the span of a curved Euler beam, improving the overall load-bearing capacity and stability of the structure, and offering a larger quasi-zero stiffness isolation range.

[0048] As attached Figure 9The force transmissibility curve of the vibration isolator is shown, with the peak coordinates at (2.88Hz, 36.11). The initial isolation frequency is approximately 4Hz, indicating that the isolator produces a vibration isolation effect when the external excitation is greater than 4Hz. Furthermore, due to its relatively high quasi-zero stiffness, the structure still maintains good vibration isolation performance even with large external excitations, whereas the bistable bending Euler beam will experience instability and even structural failure. Calculating the force transmissibility curve of the isolator allows for a more accurate assessment of its vibration isolation performance, providing better guidance for practical applications and more precise isolator design to achieve the expected working requirements. It is evident that this invention can isolate vibrations at lower frequencies and over a wider frequency range, a beneficial effect obtained by altering the deformation mode and stress distribution of the bending Euler beam.

[0049] A low-frequency quasi-zero stiffness vibration isolator for a curved Euler beam structure, designed based on the above method, was obtained through simulation calculations, yielding its force-displacement and stiffness-displacement curves, as shown in the attached figure. Figure 6 and attached Figure 7 As shown, the quasi-zero stiffness isolator obtained by this design has a wider quasi-zero stiffness range and better load-bearing capacity. When the external load is too large, the overall stiffness of the isolator will not have a negative stiffness region, resulting in better structural stability and expanding the entire working range and quasi-zero stiffness range.

Claims

1. A low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure, characterized in that: The vibration isolator includes a support plate (1), a load-bearing platform unit and two curved Euler beam vibration isolation units. The load-bearing platform unit is located at the center of the upper surface of the support plate (1), and the bottom of the load-bearing platform unit is fixedly connected to the upper surface of the support plate (1). The two curved Euler beam vibration isolation units are symmetrically arranged on both sides of the load-bearing platform unit along the center line of the width direction of the support plate (1), and the bottom of each curved Euler beam vibration isolation unit is fixedly connected to the upper surface of the support plate (1). Each side of the load-bearing platform unit is detachably connected to an adjacent curved Euler beam vibration isolation unit. The load-bearing platform unit includes a load-bearing platform (8), two No. 1 connecting cylindrical rods (9), and four support and guide components. The load-bearing platform (8) is positioned above the support plate (1) and is parallel to the support plate (1). The two No. 1 connecting cylindrical rods (9) are symmetrically arranged on both sides of the load-bearing platform (8) along the center line of the width direction of the support plate (1), and one end of each No. 1 connecting cylindrical rod (9) is fixedly connected to the center of one side of the load-bearing platform (8). Each No. 1 connecting cylindrical rod (9) is fixed to the center of one side of the load-bearing platform (8). It should be set above a curved Euler beam vibration isolation unit, and the load-bearing platform (8) is detachably connected to a curved Euler beam vibration isolation unit through a No. 1 connecting cylindrical rod (9). A support guide component is provided at each of the four corners of the lower surface of the load-bearing platform (8). Each support guide component is set vertically between the load-bearing platform (8) and the support plate (1). The top of each support guide component is fixedly connected to the lower surface of the load-bearing platform (8), and the bottom of each support guide component is fixedly connected to the upper surface of the support plate (1). The bending Euler beam vibration isolation unit includes a bending Euler beam (3) and two fixed adjustment components. The bending Euler beam (3) is located directly below a first connecting cylindrical rod (9), and the first connecting cylindrical rod (9) is detachably connected to the outer arc top of the bending Euler beam (3). Both ends of the bending Euler beam (3) are located on the upper surface of the support plate (1), and each end of the bending Euler beam (3) is detachably connected to the support plate (1). The two fixed adjustment components are symmetrically sleeved on the outer arc surface of the bending Euler beam (3) along the center line of the length direction of the bending Euler beam (3), and the bottom of each longitudinal adjustment component is fixedly connected to the upper surface of the support plate (1), and the upper part of each longitudinal adjustment component is detachably connected to the outer arc surface of the bending Euler beam (3).

2. The low-frequency quasi-zero stiffness vibration isolator of a curved Euler beam structure according to claim 1, characterized in that: The support and guide assembly includes a guide sleeve (2), a linear bearing (4), a spring (5), and an optical axis (7). The guide sleeve (2) is vertically disposed on the upper surface of the support plate (1). A linear bearing (4) is embedded in the inner wall of the top opening of the sleeve (2). The bottom end of the optical axis (7) is inserted into the linear bearing (4), and the optical axis (7) is slidably connected to the guide sleeve (2) through the linear bearing (4). The top end of the optical axis (7) is fixedly connected to the lower surface of the load-bearing platform (8). The spring (5) is disposed inside the sleeve (2) and between the linear bearing (4) and the support plate (1). The bottom end of the spring (5) is fixedly connected to the upper surface of the support plate (1), and the top end of the spring (5) is fixedly connected to the bottom end of the optical axis (7).

3. The low-frequency quasi-zero stiffness vibration isolator of a curved Euler beam structure according to claim 2, characterized in that: The height of the guide sleeve (2) is less than the length of the optical axis (7).

4. A low-frequency quasi-zero stiffness vibration isolator for a curved Euler beam structure according to claim 3, characterized in that: The upper surface of the support plate (1) is machined with two guide thread grooves (11). The two guide thread grooves (11) are arranged parallel to each other along the center line of the width direction of the support plate (1). Each guide thread groove (11) is arranged below a curved Euler beam (3). A horizontal connecting plate is provided at each end of the curved Euler beam (3). The two horizontal connecting plates are integrally formed with the curved Euler beam (3). A limiting through hole is machined on the upper surface of each horizontal connecting plate. A fastening bolt is provided in each limiting through hole. The threaded section of each fastening bolt passes through a limiting through hole and is set in the corresponding guide thread groove (11). The threaded section of each fastening bolt is threadedly connected to the corresponding guide thread groove (11).

5. A low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure according to claim 4, characterized in that: The fixed adjustment assembly includes a second connecting cylindrical rod (10) and two guide rails (6). The two guide rails (6) are arranged parallel to each other along the center line of the width extension direction of the curved Euler beam (3). Each guide rail (6) is arranged vertically on the upper surface of the support plate (1). The bottom of each guide rail (6) is fixedly connected to the upper surface of the support plate (1). The second connecting cylindrical rod (10) is arranged between the two guide rails (6), and each end of the second connecting cylindrical rod (10) is correspondingly arranged in one guide rail (6). Furthermore, the second connecting cylindrical rod (10) is slidably connected to the two guide rails (6). The outer circular surface of the second connecting cylindrical rod (10) is machined with a connecting through hole. Each connecting through hole is provided with a locking bolt. A connecting threaded hole is machined on the outer arc surface of the curved Euler beam (3) at the corresponding position of each second connecting cylindrical rod (10). The threaded section of each locking bolt passes through a connecting through hole and is correspondingly set in a connecting threaded hole. The threaded section of each locking bolt is threadedly fastened to the curved Euler beam (3) where it is located.

6. A low-frequency quasi-zero stiffness vibration isolator with a curved Euler beam structure according to claim 5, characterized in that: A fixed through hole is machined on the outer circular surface of the first connecting cylindrical rod (9), and a fixed bolt is provided in the fixed through hole. A fixed threaded hole is machined at the outer arc top of the curved Euler beam (3). The threaded section of each fixed bolt passes through a fixed through hole and is set in a fixed threaded hole, and the threaded section of each fixed bolt is threadedly fastened to the curved Euler beam (3) where it is located.

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