A quasi-zero stiffness vibration isolation device with double gradient double material compression-torsion coupling characteristics

Abstract

This invention discloses a quasi-zero stiffness vibration isolation device with dual-gradient, dual-material compression-torsional coupling characteristics, belonging to the field of metamaterial structure vibration isolation technology. The invention includes an upper quasi-zero stiffness compression-torsional structure, a lower quasi-zero stiffness compression-torsional structure, and a middle quasi-zero stiffness cell disposed between the upper and lower quasi-zero stiffness compression-torsional structures; the upper, lower, and middle quasi-zero stiffness cells are arranged in series along the vertical compression direction. By combining the upper and lower quasi-zero stiffness compression-torsional structures with the middle quasi-zero stiffness cell in series, this invention enables the structure to exhibit a quasi-zero stiffness response with two response stages during compression-torsional coupling deformation and compression deformation, thereby improving the structure's stiffness control capability and load-bearing stability.

Description

Technical Field

[0001] This invention relates to the field of metamaterial structure vibration isolation technology, specifically to a quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics. Background Technology

[0002] With the development of aerospace, precision instruments, and high-end equipment, higher requirements are being placed on the low-frequency vibration isolation performance and structural load-bearing capacity of equipment. Traditional linear vibration isolation devices typically achieve lower natural frequencies by reducing structural stiffness, but low stiffness leads to decreased load-bearing capacity and increased static deformation, making it difficult to simultaneously meet the requirements of low-frequency vibration isolation and high load-bearing capacity. Therefore, quasi-zero stiffness vibration isolation structures with low dynamic stiffness and high static load-bearing capacity have gradually become a research hotspot.

[0003] Existing quasi-zero stiffness vibration isolation structures primarily achieve quasi-zero stiffness characteristics through the coupling of positive and negative stiffness elements. For example, the coupling effect of a curved beam and its supporting structure can be utilized to induce nonlinear buckling deformation in the curved beam under load, thereby generating a negative stiffness effect and forming stiffness compensation with the positive stiffness elastic structure. Some structures broaden the quasi-zero stiffness operating range and improve vibration isolation performance through multi-stage buckling, multi-stable-state structures, and arrayed designs. However, most existing structures rely on a single bending, buckling, or axial compression deformation mode, resulting in relatively simple stiffness control methods.

[0004] In recent years, the development of flexible metamaterials and additive manufacturing technologies has provided new approaches for the design of quasi-zero stiffness structures. By combining flexible materials with rigid support structures, it is possible to control the mechanical properties under complex deformation modes. However, existing dual-material quasi-zero stiffness structures mainly focus on material stiffness matching and structural load-bearing optimization. Therefore, existing technologies still require a quasi-zero stiffness vibration isolation device that can combine different deformation modes and achieve multi-stage quasi-zero stiffness response. Summary of the Invention

[0005] This invention provides a quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsion coupling characteristics, in order to solve the problem that existing quasi-zero stiffness vibration isolation structures mainly rely on single bending, buckling or compression deformation to achieve stiffness control, resulting in a single deformation mode and a single quasi-zero stiffness response stage.

[0006] The technical solution of this invention is:

[0007] A quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsion coupling characteristics includes an upper quasi-zero stiffness compression-torsion structure, a lower quasi-zero stiffness compression-torsion structure, and a middle quasi-zero stiffness cell disposed between the upper and lower quasi-zero stiffness compression-torsion structures; the upper, lower, and middle quasi-zero stiffness cells are arranged in series along the vertical compression direction.

[0008] The upper quasi-zero stiffness compression-torsion structure includes an upper contact support frustum 11, an upper flexible unit 12, and an upper cylindrical support rod 13. The upper contact support frustum 11 is provided with an upper cylindrical support rod 13 and multiple upper flexible units 12 on the side near the lower quasi-zero stiffness compression-torsion structure. The upper cylindrical support rod 13 is coaxially arranged with the upper contact support frustum 11, and the multiple upper flexible units 12 are evenly distributed around the upper cylindrical support rod 13 with the upper cylindrical support rod 13 as the center.

[0009] The lower quasi-zero stiffness compression-torsion structure includes a lower flexible unit 31, a lower contact support frustum 32, and a lower cylindrical support rod 33. The lower contact support frustum 32 is provided with a lower cylindrical support rod 33 and multiple lower flexible units 31 on the side near the upper quasi-zero stiffness compression-torsion structure. The lower cylindrical support rod 33 and the lower contact support frustum 32 are arranged coaxially. The multiple lower flexible units 31 are evenly arrayed around the lower cylindrical support rod 33 in the circumferential direction with the lower cylindrical support rod 33 as the center.

[0010] Furthermore, one end of the upper flexible unit 12 is integrally connected to the upper contact support frustum 11, and the other end of the upper flexible unit 12 is integrally connected to the top support structure 22 in the middle quasi-zero stiffness cell; one end of the lower flexible unit 31 is integrally connected to the lower contact support frustum 32, and the other end of the lower flexible unit 31 is integrally connected to the bottom support structure 24 in the middle quasi-zero stiffness cell; one end of the upper cylindrical support rod 13 is integrally connected to the upper contact support frustum 11, and the other end of the upper cylindrical support rod 13 is spaced apart from the top support structure 22 in the vertical direction; one end of the lower cylindrical support rod 33 is integrally connected to the lower contact support frustum 32, and the other end of the lower cylindrical support rod 33 is spaced apart from the bottom support structure 24 in the vertical direction.

[0011] Furthermore, the upper flexible unit 12 and the lower flexible unit 31 are constructed in the same way. The upper flexible unit 12 is described below. It is obtained by cutting a Möbius strip structure and is arranged in a uniform array of M units along the circumference, centered on the upper cylindrical support rod 13. Specifically, it is constructed as follows: using an ellipse as the spatial path and a rectangle as the scanning section, a 360° torsional scan is performed along the elliptical path, and a single Möbius strip structure is formed by uniformly torturing it 180° around the major axis of the ellipse; the single Möbius strip structure is then rotated along the major axis of the ellipse... Cut off a predetermined length from the top and bottom towards the center to obtain inner flexible units and outer flexible units. Translate the major axis of the elliptical space path inward along the minor axis of the ellipse to be coaxial with the central axis of the upper cylindrical support rod 13, and use the translated major axis as the rotation axis. With the rotation axis as the center, arrange the outer flexible units in an equal-angle circular array so that M outer flexible units are evenly distributed along the circumferential direction, thereby forming M evenly arranged upper flexible units 12. The M evenly arranged upper flexible units 12 constitute the upper flexible structure.

[0012] Furthermore, the central quasi-zero stiffness cell includes a positive stiffness curved beam 21 connected tangentially by three circular arcs, a top support structure 22, a double-layer negative stiffness curved beam 23, a bottom support structure 24, a first support column 25, and a second support column 26; the top support structure 22 and the bottom support structure 24, which are arranged vertically at intervals, adopt a centrally symmetrical regular polygonal structure on their adjacent sides, and the ends of corresponding sides of the top support structure 22 and the bottom support structure 24 are integrally connected by the positive stiffness curved beam 21 connected tangentially by three circular arcs; the top support structure 22 is located near the middle of the bottom support structure 24. The unit is provided with an integrally formed first support column 25 extending vertically, and there is a vertical gap between the end of the first support column 25 away from the top support structure 22 and the bottom support structure 24; the bottom support structure 24 is provided with a second support column 26 extending vertically at the middle of each side of the side closer to the top support structure 22, and there is a vertical gap between the end of the second support column 26 away from the bottom support structure 24 and the top support structure 22; the first support column 25 and the second support column 26 are integrally connected by a double-layer negative stiffness curved beam 23.

[0013] Furthermore, the positive stiffness curved beam 21 with three circular arcs tangentially connected is formed by a first inclined straight bar, a three-segment circular arc curved bar, and a second inclined straight bar being connected tangentially in sequence; the three-segment circular arc curved bar is composed of a first concave circular arc curved bar, an convex circular arc curved bar, and a second concave circular arc curved bar connected in sequence.

[0014] Furthermore, the first concave arc rod and the second concave arc rod have the same dimensions, and the outer arc radii corresponding to the first concave arc rod and the convex arc rod are respectively... and The inner arc radii corresponding to the first concave circular arc rod and the outer convex circular arc rod are respectively and The inner arc of the three-section circular arc rod is formed by the corresponding outer arc at equal intervals along the radial direction.

[0015] Furthermore, the double-layer negative stiffness curved beam 23 adopts a double-layer structure. Each layer consists of four cosine-shaped curved beams arranged in a cross shape based on the first support column 25. The two layers of cosine-shaped curved beams are arranged in parallel. One end of each cosine-shaped curved beam in each layer is integrally connected to the first support column 25, and the other end of each cosine-shaped curved beam in each layer is integrally connected to the second support column 26 on the corresponding side.

[0016] Furthermore, the cosine-shaped curved beam is formed at equal intervals inward and outward from its center curve, and the center curve takes the following form: ;

[0017] in, The coordinate variable for the horizontal projection direction of the cosine curved beam, with a value range of [value missing]. ; For the maximum arc height, The horizontal projection length of the cosine-shaped curved beam; For the coordinate variables of the vertical projection direction of the cosine curved beam.

[0018] The beneficial effects of this invention are:

[0019] This invention improves the structure's stiffness control capability and load-bearing stability by combining an upper quasi-zero stiffness compression-torsion structure, a lower quasi-zero stiffness compression-torsion structure, and a central quasi-zero stiffness cell in series. This allows the structure to undergo compression-torsion coupled deformation and compression deformation with two response stages of quasi-zero stiffness, thus enhancing its stiffness control capability and load-bearing stability. Firstly, the invention cleverly employs flexible outer units cut from a Möbius strip to construct the upper and lower quasi-zero stiffness compression-torsion structures, transforming the traditional single-axial deformation into compression-torsion coupled deformation. It utilizes hyperelastic materials to generate nonlinear restoring forces, achieving a new quasi-zero stiffness control method. Secondly, the central quasi-zero stiffness cell employs a collaborative design of a positive stiffness curved beam connected by three tangential arcs and a cosine-type double-layer negative stiffness curved beam. This mutual compensation of positive and negative stiffness reduces the overall equivalent stiffness while maintaining good load-bearing stability. Furthermore, this invention employs a multi-material additive manufacturing method, wherein the upper and lower flexible units cut from the Möbius strip are made of TPU material, and the remaining support structures in the upper quasi-zero stiffness compression-torsion structure and the lower quasi-zero stiffness compression-torsion structure, as well as the middle quasi-zero stiffness cell, are made of PLA material. A reliable connection between the flexible deformation region and the load-bearing support region is achieved through a multi-material integrated molding method. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsion coupling characteristics of the present invention.

[0021] Figure 2 This is a schematic diagram of the upper quasi-zero stiffness compression-torsion structure of the present invention;

[0022] Figure 3 This is a schematic diagram of the quasi-zero stiffness cell in the middle of the present invention;

[0023] Figure 4 This is a schematic diagram of the upper flexible unit model of the present invention;

[0024] Figure 5 This is a schematic diagram of a two-dimensional curved beam with positive stiffness, formed by three tangentially connected circular arcs.

[0025] Figure 6 This is a schematic diagram of the inner flexible structure vibration isolation device;

[0026] Figure 7 This is a schematic diagram of a spiral beam vibration isolation device;

[0027] Figure 8 This is a schematic diagram of a helical beam model;

[0028] Figure 9 This is a schematic diagram of a vibration isolation device without cylindrical support rods;

[0029] Figure 10 This is a schematic diagram of a spiral beam vibration isolation device without cylindrical support rods;

[0030] Figure 11 This is the force-displacement curve of the upper quasi-zero stiffness compression-torsion structure;

[0031] Figure 12 This is the force-displacement curve of the quasi-zero stiffness cell in the middle.

[0032] Figure 13 It is a comparison chart of force-displacement curves corresponding to the upper quasi-zero stiffness compression-torsion structure that has been translated inward by different distances;

[0033] Figure 14 This is a comparison diagram of the force-displacement curves of comparative test 1 of the present invention;

[0034] Figure 15 This is a comparison diagram of the force-displacement curves of comparative test 2 of the present invention;

[0035] Figure 16 This is a comparison diagram of the force-displacement curves of comparative test 3 of the present invention;

[0036] Figure 17 This is a comparison diagram of the force-displacement curves from comparative test 4 of this invention;

[0037] Figure 18 This is a comparison of the acceleration response curves of the upper quasi-zero stiffness compression-torsion structure under different excitation accelerations;

[0038] Figure 19 This is a comparison of the acceleration response curves of the quasi-zero stiffness cell in the middle under different excitation accelerations;

[0039] Figure 20 This is a comparison of the acceleration response curves of the vibration isolation device of the present invention under different excitation accelerations;

[0040] The labels in the figure are as follows: 11—Upper contact support frustum, 12—Upper flexible unit, 13—Upper cylindrical support rod, 21—Three circular arcs tangentially connected positive stiffness curved beam, 22—Top support structure, 23—Double-layer negative stiffness curved beam, 24—Bottom support structure, 25—First support column, 26—Second support column, 31—Lower flexible unit, 32—Lower contact support frustum, 33—Lower cylindrical support rod. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0042] Example 1: As Figures 1-5 As shown, a quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsion coupling characteristics includes: an upper quasi-zero stiffness compression-torsion structure, a lower quasi-zero stiffness compression-torsion structure with identical structures, and a middle quasi-zero stiffness cell disposed between the upper and lower quasi-zero stiffness compression-torsion structures arranged symmetrically in the vertical direction; the upper quasi-zero stiffness compression-torsion structure, the lower quasi-zero stiffness compression-torsion structure, and the middle quasi-zero stiffness cell are arranged in series along the vertical compression direction, and the dual-gradient quasi-zero stiffness characteristics are achieved through deformation response at different stages;

[0043] The upper quasi-zero stiffness compression-torsion structure includes an upper contact support frustum 11, an upper flexible unit 12, and an upper cylindrical support rod 13. The upper contact support frustum 11 is provided with an upper cylindrical support rod 13 and multiple upper flexible units 12 on the side near the lower quasi-zero stiffness compression-torsion structure. The upper cylindrical support rod 13 is coaxially arranged with the upper contact support frustum 11, and the multiple upper flexible units 12 are evenly distributed around the upper cylindrical support rod 13 with the upper cylindrical support rod 13 as the center.

[0044] The lower quasi-zero stiffness compression-torsion structure includes a lower flexible unit 31, a lower contact support frustum 32, and a lower cylindrical support rod 33. The lower contact support frustum 32 is provided with a lower cylindrical support rod 33 and multiple lower flexible units 31 on the side near the upper quasi-zero stiffness compression-torsion structure. The lower cylindrical support rod 33 and the lower contact support frustum 32 are arranged coaxially. The multiple lower flexible units 31 are evenly arrayed around the lower cylindrical support rod 33 in the circumferential direction with the lower cylindrical support rod 33 as the center.

[0045] Furthermore, one end of the upper flexible unit 12 is integrally connected to the upper contact support frustum 11, and the other end of the upper flexible unit 12 is integrally connected to the top support structure 22 in the middle quasi-zero stiffness cell; one end of the lower flexible unit 31 is integrally connected to the lower contact support frustum 32, and the other end of the lower flexible unit 31 is integrally connected to the bottom support structure 24 in the middle quasi-zero stiffness cell; one end of the upper cylindrical support rod 13 is integrally connected to the upper contact support frustum 11, and the other end of the upper cylindrical support rod 13 is spaced apart from the top support structure 22 in the vertical direction; one end of the lower cylindrical support rod 33 is integrally connected to the lower contact support frustum 32, and the other end of the lower cylindrical support rod 33 is spaced apart from the bottom support structure 24 in the vertical direction. For example, the vertical height of the upper flexible unit 12 and the lower flexible unit 31 along the vertical direction is 18mm, and the vertical height of the upper contact support frustum 11 and the lower contact support frustum 32 along the vertical direction is 8.5mm.

[0046] The quasi-zero stiffness vibration isolation device of this invention achieves dual-gradient quasi-zero stiffness characteristics through compression-torsional coupling deformation and positive and negative stiffness coupling: when a vertical load is applied, the upper flexible unit 12 and the lower flexible unit 31 first undergo compression-torsional coupling deformation, achieving the first stage of quasi-zero stiffness response; as the compression displacement increases, the upper cylindrical support rod 13 and the lower cylindrical support rod 33 transfer the load to the middle quasi-zero stiffness cell, causing the positive stiffness curved beam 21 and the double-layer negative stiffness curved beam 23, which are tangentially connected by three circular arcs in the middle quasi-zero stiffness cell, to deform synergistically, achieving the second stage of quasi-zero stiffness response through positive and negative stiffness coupling; the two types of quasi-zero stiffness structures are connected in series and synergistically along the loading direction to achieve dual-gradient compression-torsional coupling quasi-zero stiffness control.

[0047] Furthermore, the upper flexible unit 12 is obtained by cutting a Möbius strip structure, and M units are evenly arrayed along the circumference with the upper cylindrical support rod 13 as the center. The specific construction method is as follows: using an ellipse as the spatial path and a rectangle as the scanning section, a 360° torsional scan is performed along the elliptical path, and a single Möbius strip structure is formed by uniformly torturing 180° around the major axis of the ellipse; a preset length is cut off from the top and bottom towards the center along the major axis of the ellipse to obtain the inner flexible unit and the outer flexible unit; the major axis of the elliptical spatial path is translated inward along the minor axis of the ellipse to be coaxial with the central axis of the upper cylindrical support rod 13, and the translated major axis is used as the rotation axis; with the rotation axis as the center, the outer flexible units are arrayed in a uniform circumferential pattern, so that the M outer flexible units are evenly distributed along the circumference, thereby forming M evenly arranged upper flexible units 12, and the M evenly arranged upper flexible units 12 constitute the upper flexible structure; where M is a positive integer greater than 2. The modeling process is as follows Figure 4 As shown. The lower flexible unit 31 is constructed in the same way, with M uniformly arranged lower flexible units 31 forming the lower flexible structure.

[0048] For example, an ellipse with a major axis of 20 mm and a minor axis of 10 mm is used as the spatial path, and a rectangle with a length of 4 mm and a width of 1 mm is used as the scanning section. A single Möbius strip structure is formed by performing a 360° torsional scan along the elliptical path and uniformly torturing it 180° around the major axis of the ellipse. The single Möbius strip structure is cut 2 mm from the top and bottom towards the center along the major axis of the ellipse to obtain the inner flexible unit and the outer flexible unit. The major axis of the elliptical spatial path is translated inward along the minor axis of the ellipse to be coaxial with the central axis of the upper cylindrical support rod 13 (in this embodiment of the invention, the inward translation distance R is 14 mm), and the translated major axis is used as the rotation axis. The outer flexible units are arranged in an equal-angle circular array with the rotation axis as the center, so that the four outer flexible units are evenly distributed along the circumferential direction, thereby forming four uniformly arranged upper flexible units 12.

[0049] Furthermore, the central quasi-zero stiffness cell includes a positive stiffness curved beam 21 connected tangentially by three circular arcs, a top support structure 22, a double-layer negative stiffness curved beam 23, a bottom support structure 24, a first support column 25, and a second support column 26; the top support structure 22 and the bottom support structure 24, which are arranged vertically at intervals, adopt a centrally symmetrical regular polygonal structure on their adjacent sides, and the ends of corresponding sides of the top support structure 22 and the bottom support structure 24 are integrally connected by the positive stiffness curved beam 21 connected tangentially by three circular arcs; the top support structure 22 is located near the middle of the bottom support structure 24. The unit is provided with an integrally formed first support column 25 extending vertically, and there is a vertical gap between the end of the first support column 25 away from the top support structure 22 and the bottom support structure 24; the bottom support structure 24 is provided with a second support column 26 extending vertically at the middle of each side of the side closer to the top support structure 22, and there is a vertical gap between the end of the second support column 26 away from the bottom support structure 24 and the top support structure 22; the first support column 25 and the second support column 26 are integrally connected by a double-layer negative stiffness curved beam 23.

[0050] For example, such as Figure 3 As shown, the top support structure 22 and the bottom support structure 24, which are arranged at intervals, adopt a centrally symmetrical regular quadrilateral structure on the side closest to each other. The ends of each side of the top support structure 22 and the bottom support structure 24 are provided with extensions, and there is a gap between the corresponding extensions. The ends of the corresponding sides of the top support structure 22 and the bottom support structure 24 are integrally connected by a positive stiffness curved beam 21 that is tangent to each other by three circular arcs through the extensions. The extensions, the first support column 25, and the second support column 26 adopt a cuboid structure. The first support column 25 and the second support column 26 are integrally connected by a double-layer negative stiffness curved beam 23. The outer end faces of the positive stiffness curved beam 21 and the second support column 26, which are tangent to each other by three circular arcs on the corresponding sides of the top support structure 22 and the bottom support structure 24, are on the same plane as the end faces of the corresponding sides.

[0051] Furthermore, the positive stiffness curved beam 21 with three circular arcs tangentially connected is formed by a first inclined straight bar, a three-segment circular arc curved bar, and a second inclined straight bar being connected tangentially in sequence; the three-segment circular arc curved bar is composed of a first concave circular arc curved bar, an convex circular arc curved bar, and a second concave circular arc curved bar connected in sequence.

[0052] Furthermore, the first concave arc rod and the second concave arc rod have the same dimensions, and the outer arc radii corresponding to the first concave arc rod and the convex arc rod are respectively... and The inner arc radii corresponding to the first concave circular arc rod and the outer convex circular arc rod are respectively and The inner arc of the three-section circular arc rod is formed by the corresponding outer arc at equal intervals along the radial direction.

[0053] For example, such as Figure 5 As shown, in the positive stiffness curved beam 21 with three circular arcs tangentially connected, It is 1.5mm. It is 5.64mm. and Each by and Obtained at equal intervals of 1.6mm radially inward. The first and second inclined straight bars form an angle of 60° with the vertical direction, in the positive stiffness curved beam 21 where the three circular arcs are tangentially connected. The vertical distance between the center distance and the inner end face of the extension of the positive stiffness curved beam 21 connected by the current three circular arcs is 9mm. In the current positive stiffness curved beam 21 connected by the three circular arcs... The vertical distance between the center of the corresponding circle and the inner end face of the extension of the positive stiffness curved beam 21 connected to the current three circular arcs is 10mm.

[0054] Furthermore, the double-layer negative stiffness curved beam 23 adopts a double-layer structure. Each layer consists of four cosine-shaped curved beams arranged in a cross shape based on the first support column 25. The two layers of cosine-shaped curved beams are arranged in parallel. One end of each cosine-shaped curved beam in each layer is integrally connected to the first support column 25, and the other end of each cosine-shaped curved beam in each layer is integrally connected to the second support column 26 on the corresponding side.

[0055] Furthermore, the cosine-shaped curved beam is formed with equidistant 1mm intervals from the center curve inwards and outwards, and its center curve takes the following form:

[0056] ;

[0057] in, The coordinate variable for the horizontal projection direction of the cosine curved beam, with a value range of [value missing]. ; For the maximum arc height, The horizontal projection length of the cosine-shaped curved beam; For the coordinate variables of the vertical projection direction of the cosine curved beam.

[0058] For example, the horizontal projection length of the cosine curved beam is 36mm, the maximum arc height is 4mm, and the wall thickness of the cosine curved beam is 1mm.

[0059] In this invention, the positive stiffness curved beam 21, which is tangentially connected by three circular arcs, forms a continuous and smooth curved beam structure through the above-mentioned geometric parameters. When subjected to axial compressive load, it generates a positive stiffness response through the bending deformation of the curved beam. The upper and lower ends of the double-layer negative stiffness curved beam 23 in this invention are connected to the first support rod 25 and the second support rod 26, respectively, to generate a negative stiffness effect. The positive stiffness curved beam 21 and the double-layer negative stiffness curved beam 23, which are tangentially connected by three circular arcs, coordinate deformation during loading to form a quasi-zero stiffness characteristic.

[0060] Furthermore, the quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics provided by the present invention is fabricated using a multi-material additive manufacturing method. The upper flexible unit 12 and the lower flexible unit 31 are made of thermoplastic polyurethane (TPU) material with superelastic characteristics, while the remaining upper contact support frustum 11, lower contact support frustum 32, upper cylindrical support rod 13, lower cylindrical support rod 33, and the central quasi-zero stiffness cell are all made of polylactic acid (PLA) material. The multi-material additive manufacturing process achieves integrated molding of different material regions. Because TPU material has a large elastic deformation capacity, it can generate large recoverable deformation under external loads and provide nonlinear restoring force through its superelastic properties, enabling the upper flexible unit 12 and the lower flexible unit 31 to generate stable compression-torsional coupling deformation during compression.

[0061] Furthermore, to verify the quasi-zero stiffness characteristics of the structure of this invention, numerical simulation analysis was performed on the designed structure using the finite element analysis software Abaqus. The supporting structure of this invention (upper contact support frustum 11, upper cylindrical support rod 13, top support structure 22, bottom support structure 24, first support rod 25, second support rod 26, lower contact support frustum 32, and lower cylindrical support rod 33) was set as a rigid body for ease of calculation and analysis. Since TPU material has approximately incompressible properties, hybrid elements (C3D8RH) were used in the finite element analysis to improve the calculation accuracy of the structural response under large deformation conditions.

[0062] like Figure 11 As shown, for Figure 2Quasi-static compression simulation analysis was performed on the upper quasi-zero stiffness compression-torsion structure shown, and the same was done on the lower quasi-zero stiffness compression-torsion structure. During the simulation, a compressive displacement was applied vertically to the upper quasi-zero stiffness compression-torsion structure, and a rotational constraint about the vertical direction was applied to the center position of the bottom of the upper quasi-zero stiffness compression-torsion structure. The compressive displacement was set to 9.5 mm. By extracting the structural reaction force, the force-displacement response curve of the upper quasi-zero stiffness compression-torsion structure was obtained. During loading, the upper flexible element 12 generates spatial torsional deformation, coupling the axial compressive deformation with the torsional deformation. Based on the nonlinear mechanical properties of the TPU hyperelastic material, a restoring force is generated, thus causing the compression-torsion structure to exhibit a compression-torsion coupled quasi-zero stiffness mechanical response. Figure 11 As shown, the upper quasi-zero stiffness compression-torsion structure forms a quasi-zero stiffness response platform within a displacement range of approximately 3mm to 9.5mm, with a platform bearing capacity of approximately 20.6N. Figure 12 As shown, for Figure 3 Quasi-static compression simulation analysis was performed on the central quasi-zero stiffness cell shown. During the simulation, a compressive displacement was applied to the central quasi-zero stiffness cell along the vertical direction, and a completely fixed constraint was applied to the bottom of the cell. The compressive displacement was set to 8 mm. By extracting the structural reaction force, the force-displacement response curve of the central quasi-zero stiffness cell was obtained. During loading, the positive stiffness curved beam 21 and the double-layer negative stiffness curved beam 23, connected tangentially by three circular arcs, underwent coordinated deformation. The positive stiffness curved beam 21 provided restoring force during deformation, while the double-layer negative stiffness curved beam 23 generated a negative stiffness effect through nonlinear bending deformation. The two interacted, causing the central quasi-zero stiffness cell to exhibit low stiffness response characteristics within a certain displacement range. Figure 12 As shown, the quasi-zero stiffness cell in the middle forms a quasi-zero stiffness response platform within a displacement range of approximately 1.5 mm to 5 mm, and the platform bearing capacity is approximately 52.6 N.

[0063] To further analyze the influence of the geometric parameters of the upper flexible element 12 on the mechanical properties of the upper quasi-zero stiffness compression-torsion structure, while keeping other structural parameters constant, only the inward translation distance R in the design of the upper flexible element 12 was changed. Finite element analysis was performed using three values: 10mm, 14mm, and 18mm. The results are as follows: Figure 13 As shown, when R is 10mm, the structure exhibits a negative stiffness response within a displacement range of approximately 3mm to 8mm; when R is 14mm, the structure exhibits a quasi-zero stiffness response within the same displacement range; and when R is 18mm, the structure exhibits a positive stiffness response. Therefore, it can be seen that by adjusting the inward translation distance parameter of the upper flexible element 12, the stiffness characteristics of the upper quasi-zero stiffness compression-torsion structure can be controlled. The same applies to the lower flexible element 31.

[0064] To verify the quasi-zero stiffness characteristics of the vibration isolation device of the present invention, multiple sets of comparative tests were set up to compare and analyze the mechanical response of the vibration isolation device under different structural forms.

[0065] Comparative Experiment 1: A quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics provided by this invention (e.g., Figure 1 As shown, (hereinafter referred to as "the vibration isolation device of the present invention") and the vibration isolation device formed by replacing the upper flexible unit 12 and the lower flexible unit 31 with the inner flexible unit (e.g.) Figure 6 As shown, the "inner flexible structure vibration isolation device" (hereinafter referred to as "inner flexible structure vibration isolation device") is subjected to quasi-static compression simulation analysis to compare the differences in mechanical response between the two under quasi-static compression conditions. The modeling method of the inner flexible structure vibration isolation device is basically the same as that of the vibration isolation device of this invention, except that the outer flexible units in the upper flexible unit 12 and the lower flexible unit 31 are replaced with inner flexible units, while the remaining structural parameters remain unchanged.

[0066] To ensure the validity and consistency of the comparison results, the two vibration isolation devices in Comparative Experiment 1 used the same material parameters, mesh size, contact settings, and simulation boundary conditions. During the simulation, a compressive displacement load was applied to the vibration isolation device in the vertical direction, and a completely fixed constraint was applied to its bottom, with the compressive displacement set to 27 mm. By extracting the structural reaction force in the loading direction, the force-displacement response curves of the two vibration isolation devices were obtained, as shown below. Figure 14 As shown.

[0067] In the initial loading stage, because the central quasi-zero stiffness cell is made of PLA material with high stiffness, its initial deformation is small. The overall deformation of the vibration isolation device is mainly concentrated in the upper and lower quasi-zero stiffness compression-torsion structures. As the compression displacement further increases, the upper cylindrical support rod 13 gradually comes into contact with the top support structure 22 of the central quasi-zero stiffness cell, and the lower cylindrical support rod 33 gradually comes into contact with the bottom support structure 24 of the central quasi-zero stiffness cell, so that the load is further transferred to the central quasi-zero stiffness cell, and the positive stiffness curved beam 21 and the double-layer negative stiffness curved beam 23 connected by three circular arcs undergo coordinated deformation.

[0068] like Figure 14As shown, the vibration isolation device of the present invention forms two distinct quasi-zero stiffness response platforms during compression. The first quasi-zero stiffness response platform corresponds to a compression displacement range of approximately 5mm to 18mm, with a platform bearing capacity of approximately 20.6N; the second quasi-zero stiffness response platform corresponds to a compression displacement range of approximately 22mm to 24mm, with a platform bearing capacity of approximately 50.6N. In contrast, the inner flexible structure vibration isolation device exhibits a generally positive stiffness response within the displacement range corresponding to the first quasi-zero stiffness response platform, without forming a distinct first quasi-zero stiffness response platform; in the second quasi-zero stiffness response stage, its mechanical response is essentially consistent with that of the vibration isolation device of the present invention. From the above comparison results, it can be seen that using the outer flexible unit enables the vibration isolation device of the present invention to form a first quasi-zero stiffness response platform within a larger compression displacement range, which, in conjunction with the second quasi-zero stiffness response platform formed by the central quasi-zero stiffness cell, allows the vibration isolation device of the present invention to possess dual-gradient quasi-zero stiffness mechanical response characteristics through a dual deformation mode.

[0069] Comparative Experiment 2: A quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics provided by this invention (e.g., Figure 1 As shown, (hereinafter referred to as "the vibration isolation device of the present invention") and the vibration isolation device formed by replacing both the upper and lower flexible structures of the vibration isolation device of the present invention with a helical beam structure (e.g.) Figure 7 As shown, a quasi-static compression simulation analysis was performed on the spiral beam vibration isolation device (hereinafter referred to as the "spiral beam vibration isolation device") to compare the differences in mechanical response between the two devices under quasi-static compression conditions. The difference between the spiral beam vibration isolation device and the vibration isolation device of this invention is that the upper and lower flexible structures are replaced with a spiral beam structure, while the remaining structural parameters remain unchanged. Figure 8 As shown, the modeling process of the helical beam structure is as follows: Four parallelogram beams arranged horizontally are wrapped around the side of a cylinder with radius R3 and height h, and the four parallelogram beams are evenly distributed along the circumference of the cylinder; the central axis of the wrapping of the parallelogram beams coincides with the central axis of the cylinder; the bottom edges of the four parallelogram beams are located in the same horizontal plane, the parallelogram beams adopt a rectangular cross section with a width of a=4mm and a thickness of t=1mm; the angle between the side of the parallelogram beam and the horizontal direction is θ=65°; the height is set to h=18mm, and the remaining structural parameters are consistent with the upper quasi-zero stiffness compression-torsion structure and the lower quasi-zero stiffness compression-torsion structure in this invention.

[0070] To ensure the validity and consistency of the comparison results, the two vibration isolation devices in Comparative Experiment 2 used the same material parameters, mesh size, contact settings, and simulation boundary conditions. During the simulation, a compressive displacement load was applied to the vibration isolation device in the vertical direction, and a completely fixed constraint was applied to its bottom, with the compressive displacement set to 27 mm. By extracting the structural reaction force in the loading direction, the force-displacement response curves of the two vibration isolation devices were obtained, as shown below. Figure 15 As shown.

[0071] During the loading process, the deformation process of the two devices in Comparative Test 2 is basically the same as that in Comparative Test 1. That is, the upper quasi-zero stiffness compression-torsion structure and the lower quasi-zero stiffness compression-torsion structure first undergo compression-torsion coupling deformation, forming the first stage quasi-zero stiffness response. As the compression displacement further increases, the positive stiffness curved beam 21 and the double-layer negative stiffness curved beam 23 connected by three circular arcs in the middle quasi-zero stiffness cell undergo coordinated deformation, forming the second stage quasi-zero stiffness response through the coupling effect of positive and negative stiffness effects.

[0072] like Figure 15 As shown, the vibration isolation device of the present invention forms two distinct quasi-zero stiffness response platforms during compression, and its response characteristics are consistent with those of Comparative Test 1. In contrast, the helical beam vibration isolation device exhibits a positive stiffness response overall within the displacement range corresponding to the first quasi-zero stiffness response platform, without forming a distinct first quasi-zero stiffness response platform; in the second quasi-zero stiffness response stage, its mechanical response is basically consistent with that of the vibration isolation device of the present invention. Therefore, it can be seen that the upper quasi-zero stiffness compression-torsion structure constructed by the upper flexible unit 12 and the lower quasi-zero stiffness compression-torsion structure constructed by the lower flexible unit 31 proposed in this invention are beneficial for forming the first quasi-zero stiffness response platform during compression, which, in conjunction with the second quasi-zero stiffness response formed by the middle quasi-zero stiffness cell, enables the vibration isolation device of the present invention to exhibit dual-gradient quasi-zero stiffness mechanical response characteristics.

[0073] Comparative Test 3: A quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics provided by this invention (e.g., Figure 1 As shown, hereinafter referred to as "the vibration isolation device of the present invention") and the vibration isolation device formed after removing the upper cylindrical support rod 13 and the lower cylindrical support rod 33 from the vibration isolation device of the present invention (e.g. Figure 9 As shown, the "vibration isolation device without cylindrical support rod" (hereinafter referred to as "vibration isolation device") was subjected to quasi-static compression simulation analysis to compare the differences in mechanical response between the two under quasi-static compression conditions. The difference between the vibration isolation device without cylindrical support rod and the vibration isolation device of this invention is that the upper cylindrical support rod 13 and the lower cylindrical support rod 33 are removed, while the remaining structural parameters remain unchanged.

[0074] To ensure the validity and consistency of the comparison results, the material parameters, mesh size, contact settings, and simulation boundary conditions of the two vibration isolation devices in Comparative Experiment 3 were kept consistent with those in Comparative Experiment 1. Specifically, to fully characterize the mechanical response of the vibration isolation device without cylindrical support rods under large compressive displacement, its compressive displacement was set to 35 mm. By extracting the structural reaction force in the loading direction, the force-displacement response curves of the two vibration isolation devices were obtained, as shown below. Figure 16 As shown.

[0075] During loading, both vibration isolation devices initially undergo compression-torsional coupling deformation primarily through the upper flexible unit 12 and the lower flexible unit 31. For the vibration isolation device of this invention, as the compression displacement increases, the upper cylindrical support rod 13 and the lower cylindrical support rod 33 contact the top support structure 22 and the bottom support structure 24 of the middle quasi-zero stiffness cell, respectively, transferring the load to the middle quasi-zero stiffness cell and allowing it to further participate in deformation. However, the vibration isolation device without cylindrical support rods lacks a corresponding load transfer path and requires further compression of the upper flexible unit 12 and the lower flexible unit 31 to transfer the load to the middle quasi-zero stiffness cell.

[0076] like Figure 16 As shown, the vibration isolation device of the present invention forms two distinct quasi-zero stiffness response platforms during compression, and its response characteristics are consistent with those of Comparative Test 1. In contrast, the vibration isolation device without cylindrical support rods forms a first quasi-zero stiffness response platform within a compression displacement range of approximately 5mm to 20mm, with a platform bearing capacity of approximately 20.6N. As the compression displacement further increases, due to the lack of effective load transfer and structural deformation guidance by the cylindrical support rods, local contact easily occurs between the upper flexible unit 12 and the lower flexible unit 31, resulting in uneven distribution of stress and deformation in the structure, and thus no distinct second quasi-zero stiffness response platform is formed. From the above comparison results, it can be seen that the upper cylindrical support rod 13 and the lower cylindrical support rod 33 can establish load transfer paths between the upper quasi-zero stiffness compression-torsion structure, the lower quasi-zero stiffness compression-torsion structure, and the middle quasi-zero stiffness cell during loading, which is beneficial to improving the stress and deformation coordination of the structure, enabling the middle quasi-zero stiffness cell to effectively participate in deformation during the predetermined compression stage, thereby facilitating the formation of a dual-gradient quasi-zero stiffness response characteristic in the vibration isolation device of the present invention.

[0077] Comparative Test 4: This test was conducted on a quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics (e.g., ...). Figure 1 As shown, hereinafter referred to as "the vibration isolation device of the present invention") and the vibration isolation device formed by replacing the upper flexible unit 12 and the lower flexible unit 31 in the vibration isolation device of the present invention with a helical beam structure and removing the upper cylindrical support rod 13 and the lower cylindrical support rod 33 (e.g. Figure 10As shown, a quasi-static compression simulation analysis was performed on the helical beam vibration isolation device (hereinafter referred to as "the device without cylindrical support rod") to compare the differences in mechanical response between the two devices under quasi-static compression conditions. The difference between the helical beam vibration isolation device without cylindrical support rod and the vibration isolation device of this invention is that the upper flexible unit 12 and the lower flexible unit 31 are replaced with a helical beam structure, and the upper cylindrical support rod 13 and the lower cylindrical support rod 33 are removed, while the remaining structural parameters remain unchanged.

[0078] To ensure the validity and consistency of the comparison results, the material parameters, mesh size, contact settings, and simulation boundary conditions used for the two vibration isolation devices in Comparative Experiment 4 were consistent with those in Comparative Experiment 1. Specifically, to fully characterize the mechanical response of the helical beam vibration isolation device without cylindrical support rods within a large compressive displacement range, its compressive displacement was set to 36 mm. By extracting the structural reaction force in the loading direction, the force-displacement response curves of the two vibration isolation devices were obtained, as shown below. Figure 17 As shown.

[0079] During loading, the vibration isolation device of this invention initially undergoes compression-torsional coupling deformation primarily through the upper flexible unit 12 and the lower flexible unit 31. As the compression displacement increases, the upper cylindrical support rod 13 and the lower cylindrical support rod 33 come into contact with the top support structure 22 and the bottom support structure 24 of the middle quasi-zero stiffness cell, respectively, and transfer the load to the middle quasi-zero stiffness cell, causing the positive stiffness curved beam 21 and the double-layer negative stiffness curved beam 23, which are tangentially connected by three circular arcs, to participate in coordinated deformation. In contrast, the helical beam vibration isolation device without cylindrical support rods, due to its helical beam structure and lack of a load transfer path formed by cylindrical support rods, requires further compression deformation of the upper and lower helical beams before transferring the load to the middle quasi-zero stiffness cell.

[0080] like Figure 17As shown, the vibration isolation device of the present invention forms two distinct quasi-zero stiffness response platforms during compression, and its response characteristics are consistent with those of Comparative Test 1. In contrast, the helical beam vibration isolation device without cylindrical support rods exhibits a positive stiffness response overall within a compression displacement range of approximately 6mm to 27mm, and does not form a distinct first quasi-zero stiffness response platform. As the compression displacement further increases, due to the lack of effective load transfer and structural deformation guidance by the cylindrical support rods, local contact easily occurs between the upper and lower helical beams, resulting in uneven distribution of stress and deformation in the structure, and therefore, a distinct second quasi-zero stiffness response platform is also not formed. As can be seen from the above comparison results, the present invention uses the upper flexible unit 12 in conjunction with the upper cylindrical support rod 13, and the lower flexible unit 31 in conjunction with the lower cylindrical support rod 33. On the one hand, the compression-torsional coupling deformation of the upper flexible unit 12 and the lower flexible unit 31 can form a first-stage quasi-zero stiffness response. On the other hand, the upper cylindrical support rod 13 and the lower cylindrical support rod 33 can establish a load transfer path between the upper quasi-zero stiffness compression-torsional structure, the lower quasi-zero stiffness compression-torsional structure and the middle quasi-zero stiffness cell, so that the middle quasi-zero stiffness cell participates in deformation in the predetermined compression stage and forms a second-stage quasi-zero stiffness response. Thus, the vibration isolation device of the present invention exhibits dual-gradient quasi-zero stiffness mechanical response characteristics.

[0081] To verify the dynamic vibration isolation performance of the vibration isolation structure of the present invention, the Abaqus implicit dynamic analysis method was used to perform acceleration response analysis on the upper quasi-zero stiffness compression-torsion structure, the middle quasi-zero stiffness cell, and the vibration isolation device of the present invention.

[0082] like Figure 18 As shown, for Figure 2 Acceleration response analysis was performed on the quasi-zero stiffness compression-torsion structure shown. A concentrated mass point of 0.6 kg was placed at the center of the lower end face of the structure. A vertically downward half-sine acceleration excitation with a period of 0.006 s was applied to the upper end face of the structure, and the acceleration response at the concentrated mass point was extracted. The excitation acceleration was set to 100 m / s². 2 200m / s 2 and 300m / s 2 The dynamic response characteristics of the upper quasi-zero stiffness compression-torsion structure under different excitation intensities were analyzed. The lower quasi-zero stiffness compression-torsion structure is symmetrically arranged with respect to the horizontal plane as the upper quasi-zero stiffness compression-torsion structure, and the two have the same dynamic response characteristics.

[0083] The results show that as the excitation acceleration increases, the upper quasi-zero stiffness compression-torsion structure gradually enters the quasi-zero stiffness working range and exhibits a clear response acceleration plateau characteristic. When the excitation acceleration is 200 m / s², the structure... 2 At that time, the quasi-zero stiffness region of the structure was fully activated, and the response acceleration plateau was quite obvious, with a plateau response acceleration of approximately 32 m / s². 2The corresponding acceleration transmissibility is approximately 16%, indicating that the upper quasi-zero stiffness compression-torsion structure can effectively reduce the acceleration response. During this process, due to the combined effects of the rotational inertia and elastic restoring force of the upper flexible unit 12, the response curve exhibits a certain degree of local fluctuation. When the excitation acceleration increases to 300 m / s², the response curve shows a certain degree of local fluctuation. 2 At that time, the upper cylindrical support rod 13 comes into contact with the top support structure 22 of the middle quasi-zero stiffness cell, causing a change in the local stiffness of the structure, thereby causing a local abrupt change in the response acceleration.

[0084] like Figure 19 As shown, for Figure 3 Acceleration response analysis was performed on the central quasi-zero stiffness cell shown. A concentrated mass point of 0.66 kg was placed at the center of the lower end face of the central quasi-zero stiffness cell; a vertically downward half-sine acceleration excitation with a period of 0.006 s was applied to its upper end face, and the acceleration response at the concentrated mass point was extracted. The excitation acceleration was set to 100 m / s². 2 250m / s 2 and 300m / s 2 Acceleration response curves of the quasi-zero stiffness cell in the middle were obtained under different excitation intensities.

[0085] The results show that as the excitation acceleration increases, the quasi-zero stiffness cell in the middle gradually enters the quasi-zero stiffness working range and exhibits response acceleration plateau characteristics. When the excitation acceleration is 250 m / s², the cell gradually reaches this plateau. 2 At that time, the quasi-zero stiffness region of the central quasi-zero stiffness cell was fully activated, and its response acceleration plateau was quite obvious, with a plateau response acceleration of approximately 80 m / s². 2 The corresponding acceleration transmissibility is about 32%, indicating that the quasi-zero stiffness cell in the middle can produce a significant buffering and vibration isolation effect on external acceleration excitation.

[0086] like Figure 20 As shown, for Figure 1 The vibration isolation device of the present invention is subjected to acceleration response analysis. A concentrated mass point of 0.66 kg is set at the center of the lower end face of the vibration isolation device; a vertically downward half-sine acceleration excitation with a period of 0.006 s is applied to the upper end face of the vibration isolation device, and the acceleration response at the concentrated mass point is extracted. The excitation acceleration is set to 200 m / s². 2 and 300m / s 2 The dynamic vibration isolation response characteristics of the vibration isolation device of the present invention under different excitation intensities were analyzed.

[0087] When the excitation acceleration is 200 m / s 2At this time, the vibration isolation device of the present invention mainly undergoes compression-torsional coupling deformation of the upper flexible unit 12 and the lower flexible unit 31, which fully activates the quasi-zero stiffness working areas of the upper and lower quasi-zero stiffness compression-torsional structures, forming a first response acceleration platform with a platform response acceleration of approximately 32 m / s². 2 The corresponding acceleration transmissibility is approximately 16%. During this stage, the deformation of the quasi-zero stiffness cell in the middle is relatively small. The vibration isolation device mainly achieves buffering and isolation of the acceleration excitation through the upper and lower quasi-zero stiffness compression-torsion structures. When the excitation acceleration increases to 300 m / s²... 2 At that time, the upper flexible unit 12 and the lower flexible unit 31 first undergo compression-torsional coupling deformation and form a first response acceleration plateau, the response acceleration of which is approximately 32 m / s². 2 As the structural deformation further increases, the upper cylindrical support rod 13 and the lower cylindrical support rod 33 come into contact with the top support structure 22 and the bottom support structure 24 of the middle quasi-zero stiffness cell, respectively, and transfer the load to the middle quasi-zero stiffness cell. This causes the positive stiffness curved beam 21 and the double-layer negative stiffness curved beam 23, which are connected tangentially by three circular arcs, to participate in coordinated deformation. The middle quasi-zero stiffness cell is then activated, thus forming a second response acceleration platform with a platform response acceleration of approximately 80 m / s². 2 The corresponding acceleration transmissibility is approximately 26.67%.

[0088] As shown in the above results, the vibration isolation device of the present invention can sequentially activate the upper quasi-zero stiffness compression-torsion structure, the lower quasi-zero stiffness compression-torsion structure, and the middle quasi-zero stiffness cell according to the change in external excitation intensity. Under lower excitation intensity, the first stage of quasi-zero stiffness vibration isolation response is mainly formed through the upper and lower quasi-zero stiffness compression-torsion structures. Under higher excitation intensity, the middle quasi-zero stiffness cell is further activated through the load transfer effect of the upper cylindrical support rod 13 and the lower cylindrical support rod 33, forming the second stage of quasi-zero stiffness vibration isolation response. Therefore, the vibration isolation device of the present invention has dual-gradient quasi-zero stiffness dynamic response characteristics, which can adapt to the vibration isolation and buffering requirements under different excitation intensities.

[0089] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics, characterized in that, It includes an upper quasi-zero stiffness compression-torsion structure, a lower quasi-zero stiffness compression-torsion structure, and a middle quasi-zero stiffness cell set between the upper and lower quasi-zero stiffness compression-torsion structures; the upper quasi-zero stiffness compression-torsion structure, the lower quasi-zero stiffness compression-torsion structure, and the middle quasi-zero stiffness cell are arranged in series along the vertical compression direction. The upper quasi-zero stiffness compression-torsion structure includes an upper contact support frustum (11), an upper flexible unit (12), and an upper cylindrical support rod (13). The upper contact support frustum (11) is provided with an upper cylindrical support rod (13) and multiple upper flexible units (12) on the side near the lower quasi-zero stiffness compression-torsion structure. The upper cylindrical support rod (13) is coaxially arranged with the upper contact support frustum (11), and multiple upper flexible units (12) are evenly distributed around the upper cylindrical support rod (13) with the upper cylindrical support rod (13) as the center. The lower end quasi-zero stiffness compression-torsion structure includes a lower end flexible unit (31), a lower end contact support frustum (32), and a lower end cylindrical support rod (33). The lower end contact support frustum (32) is provided with a lower end cylindrical support rod (33) and multiple lower end flexible units (31) on the side near the upper end quasi-zero stiffness compression-torsion structure. The lower end cylindrical support rod (33) and the lower end contact support frustum (32) are arranged coaxially. Multiple lower end flexible units (31) are evenly arrayed around the lower end cylindrical support rod (33) in the circumferential direction with the lower end cylindrical support rod (33) as the center.

2. The quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics according to claim 1, characterized in that, One end of the upper flexible unit (12) is integrally connected to the upper contact support frustum (11), and the other end of the upper flexible unit (12) is integrally connected to the top support structure (22) in the middle quasi-zero stiffness cell; one end of the lower flexible unit (31) is integrally connected to the lower contact support frustum (32), and the other end of the lower flexible unit (31) is integrally connected to the bottom support structure (24) in the middle quasi-zero stiffness cell; One end of the upper cylindrical support rod (13) is integrally connected to the upper contact support frustum (11), and the other end of the upper cylindrical support rod (13) is spaced apart from the top support structure (22) in the vertical direction; one end of the lower cylindrical support rod (33) is integrally connected to the lower contact support frustum (32), and the other end of the lower cylindrical support rod (33) is spaced apart from the bottom support structure (24) in the vertical direction.

3. The quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics according to claim 1, characterized in that, The upper flexible unit (12) and the lower flexible unit (31) are constructed in the same way. The upper flexible unit (12) is described in this way. The upper flexible unit (12) is obtained by cutting a Möbius strip structure and M units are evenly arrayed along the circumference with the upper cylindrical support rod (13) as the center. The specific construction method is as follows: using an ellipse as the spatial path and a rectangle as the scanning section, a 360° torsional scan is performed along the elliptical path, and a single Möbius strip structure is formed by uniformly torturing 180° around the major axis of the ellipse; the single Möbius strip structure is then subjected to a 360° torsional scan along the major axis of the ellipse. Cut off a preset length from the top and bottom towards the center to obtain inner flexible unit and outer flexible unit respectively; translate the long axis of the elliptical space path inward along the short axis of the ellipse to be coaxial with the central axis of the upper cylindrical support rod (13), and take the translated long axis as the rotation axis; with the rotation axis as the center, perform an equal-angle circular array of the outer flexible unit, so that M outer flexible units are evenly distributed along the circumferential direction, thereby forming M evenly arranged upper flexible units (12), and the M evenly arranged upper flexible units (12) constitute the upper flexible structure.

4. The quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics according to claim 1, characterized in that, The central quasi-zero stiffness cell includes a positive stiffness curved beam (21) connected by three circular arcs, a top support structure (22), a double-layer negative stiffness curved beam (23), a bottom support structure (24), a first support rod (25), and a second support rod (26). The top support structure (22) and the bottom support structure (24) arranged at intervals are arranged in a centrally symmetrical regular polygonal structure on the side closest to each other. The ends of the corresponding sides of the top support structure (22) and the bottom support structure (24) are integrally connected by the positive stiffness curved beam (21) connected by three circular arcs. The top support structure (22) is provided with an integrally formed first support rod (25) extending vertically in the middle near the bottom support structure (24), and there is a vertical gap between the end of the first support rod (25) away from the top support structure (22) and the bottom support structure (24). The bottom support structure (24) has a second support pole (26) extending vertically at the middle of each side near the top support structure (22), and there is a vertical gap between the end of the second support pole (26) away from the bottom support structure (24) and the top support structure (22). The first support pole (25) and the second support pole (26) are integrally connected by a double-layer negative stiffness curved beam (23).

5. The quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics according to claim 4, characterized in that, The positive stiffness curved beam (21) with three circular arcs connected in a tangential manner is formed by the first inclined straight bar, the three-section circular arc curved bar and the second inclined straight bar being connected in a tangential manner in sequence; the three-section circular arc curved bar is composed of the first concave circular arc curved bar, the convex circular arc curved bar and the second concave circular arc curved bar connected in sequence.

6. The quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics according to claim 5, characterized in that, The first concave arc rod and the second concave arc rod have the same dimensions. The outer arc radii of the first concave arc rod and the outer convex arc rod are respectively... and The inner arc radii corresponding to the first concave circular arc rod and the outer convex circular arc rod are respectively and The inner arc of the three-section circular arc rod is formed by the corresponding outer arc at equal intervals along the radial direction.

7. The quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics according to claim 4, characterized in that, The double-layer negative stiffness curved beam (23) adopts a double-layer structure. Each layer consists of four cosine curved beams arranged in a cross shape based on the first support column (25). The two layers of cosine curved beams are arranged in parallel. One end of each cosine curved beam in each layer is integrally connected to the first support column (25), and the other end of each cosine curved beam in each layer is integrally connected to the second support column (26) on the corresponding side.

8. The quasi-zero stiffness vibration isolation device with dual-gradient dual-material compression-torsional coupling characteristics according to claim 7, characterized in that, The cosine-shaped curved beam is formed at equal intervals inward and outward from its center curve, and its center curve takes the following form: ； in, The coordinate variable for the horizontal projection direction of the cosine curved beam, with a value range of [value missing]. ; For the maximum arc height, The horizontal projection length of the cosine-shaped curved beam; For the coordinate variables of the vertical projection direction of the cosine curved beam.

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