Simple and easy-to-realize multi-section beam type quasi-zero stiffness structure device

Abstract

The invention discloses a multi-section beam type quasi-zero stiffness structure device, and belongs to the technical field of low-frequency vibration isolation. The structure comprises an integrated circular platform and four flexible supporting beams, the supporting beams are arranged below the platform in a cross-shaped mirror symmetry mode, and the far ends of the supporting beams are fixed to a base. All the sections of beams form a mirror symmetry structure, and the quasi-zero stiffness characteristic of the whole structure is achieved through the geometric nonlinear effect generated by the inclined beams under vertical pressure. The structure is integrally formed through 3D printing, the manufacturing precision is high, and assembling is easy and convenient. Under a vertical loading load, the flexible beams generate nonlinear coupling bending, so that the platform shows quasi-zero stiffness response within a certain displacement range, and the vibration isolation platform is suitable for low-frequency vibration isolation. Structural parameters are subjected to optimization design through finite element simulation in combination with a Kriging agent model and a genetic algorithm, so that a wider quasi-zero stiffness platform and better mechanical properties are obtained. The structure is suitable for vibration isolation systems of equipment sensitive to low-frequency vibration, such as precise instruments, MEMS devices and spaceflight assemblies.

Description

Technical Field

[0001] The present invention relates to the field of vibration isolation technology, and in particular to a quasi-zero stiffness vibration isolation structure suitable for low-frequency vibration control, specifically a multi-segment beam-type quasi-zero stiffness structure with a simplified structure, adjustable platform width, and suitable for additive manufacturing. Background Art

[0002] Quasi-zero stiffness structures are nonlinear structures whose equivalent stiffness approaches zero within a specific range of structural deformation. They exhibit excellent low-frequency vibration isolation properties and are widely used in vibration control for high-precision instruments, micro- and nano-test platforms, inertial navigation systems, and spacecraft equipment. The key principle is to introduce a mechanical coupling relationship between positive and negative stiffness to create a nearly "flat" force-displacement curve near the equilibrium position, thereby reducing the structure's dynamic response under low-frequency excitation. Currently, various methods have been developed to achieve quasi-zero stiffness, including exploiting the geometric nonlinear deformation of curved or arched beams, compensating for negative stiffness using magnetic or force-levitation systems, and employing bistable mechanisms. Although these structures can achieve near-zero stiffness response under certain conditions, they generally have the following problems: For example, magnetic levitation-type quasi-zero stiffness systems require additional electromagnets, permanent magnets, or external power supply control systems, resulting in large systems, difficult debugging, and high structural complexity; in addition, some structures rely on the fine adjustment of spring constants or external loads, and their performance is sensitive to parameter fluctuations, making it difficult to maintain the optimal ideal state; arch beams and curved beam structures often require precision machining and assembly, which are limited by materials and manufacturing processes; and some structures only exhibit quasi-zero stiffness within a very small displacement range, or have strong negative stiffness that can easily lead to structural instability. In addition, the design of traditional quasi-zero stiffness structures mostly relies on empirical methods or finite parameter sweep tests, lacking a systematic modeling and optimization process, making it difficult to achieve compact size and efficient material utilization while ensuring stable performance.

[0003] Therefore, there is an urgent need for a quasi-zero stiffness structure with a simple structure, machine-friendly design, adjustable performance, and optimized design capabilities to meet engineering needs. Summary of the Invention

[0004] The present invention aims to provide a quasi-zero stiffness structural unit with a simple structure, adjustable performance and convenient manufacturing. On the basis of ensuring overall symmetry, the structure is first connected to the intermediate platform through double inclined beams to form mirror symmetry. Secondly, a cross-shaped structure is formed by replication and rotation, realizing a negative stiffness effect under pre-compression conditions, thereby generating quasi-zero stiffness characteristics within a certain displacement range and effectively isolating vibrations.

[0005] A new type of multi-segment beam-type quasi-zero stiffness structure uses a multi-segment structure formed by two symmetrically arranged inclined straight beams and a middle straight beam. By optimizing the model, it achieves a wide platform and low stiffness characteristics while maintaining the overall stability of the structure, making it suitable for low-frequency vibration isolation scenarios.

[0006] The present invention provides a multi-segment beam-type quasi-zero stiffness structure, characterized in that:

[0007] The structure consists of: a central circular platform for bearing vertical loads;

[0008] Four flexible support beams are evenly distributed at the bottom of the platform and arranged radiating in a cross shape around the center;

[0009] The support beam in turn comprises a broken line structure formed by connecting two inclined sections, with the distal end fixed to the bottom base;

[0010] The platform and the support beam are integrally formed, made of nylon and prepared by 3D printing;

[0011] The flexible beam bends nonlinearly under the action of vertical compressive load, so that the platform exhibits a mechanical response of approximately zero stiffness within a certain displacement range;

[0012] The inclined straight beams are connected continuously with the straight beams, and the whole is mirror-symmetrical about the center;

[0013] Two mirror-symmetrically arranged inclined beams jointly support the central mass block. When it is compressed in the vertical direction, the structure produces nonlinear deformation, thus achieving quasi-zero stiffness.

[0014] By controlling the beam length and inclination angle, the width and force range of the quasi-zero stiffness platform can be adjusted.

[0015] Compared with the prior art, the present invention has the following significant advantages:

[0016] 1. Simple structural design and strong symmetry: The mirror-symmetrical multi-segment beam configuration is adopted, which is convenient for analysis and parameter adjustment and has excellent mechanical stability;

[0017] 2. Excellent low-frequency vibration isolation performance: exhibits wide platform quasi-zero stiffness behavior under specific pre-compression conditions;

[0018] 3. Adjustable stiffness platform range: Different platform widths and stiffness characteristics can be designed through structural parameter optimization;

[0019] 4. Friendly manufacturing process: The structure can be 3D printed as a whole, without the need for post-assembly. The manufacturing process is simple and suitable for rapid batch production.

[0020] 5. Lightweight structure and low cost: No external magnets or extra elastic parts are required, the material is versatile, and it is suitable for space-limited or cost-sensitive scenarios;

[0021] 6. Reasonable modeling and optimization methods: Combining agent modeling and evolutionary algorithms for structural optimization to improve design efficiency and reliability.

[0022] 7. Strong scalability: It can be integrated into modular vibration isolation devices and is widely applicable to spacecraft, precision equipment, and MEMS systems. In summary, the present invention provides an engineering-implementable quasi-zero stiffness structural unit with broad application prospects in high-performance passive vibration isolation, micro-vibration control, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a geometric modeling design drawing of the present invention.

[0024] Figure 2 This is a diagram of a vertical downward load applied to the center of the double-end clamped support of the present invention.

[0025] Figure 3 This is a schematic diagram of the final three-dimensional structure of the multi-segment beam-type quasi-zero stiffness structure of the present invention. DETAILED DESCRIPTION

[0026] The quasi-zero stiffness structure of the present invention is composed of bilaterally symmetrical inclined beams (numbered AB and BC) and an intermediate platform section (CD). Under pre-compression loading conditions, the structure produces a nonlinear response of bending-tension coupling, and the overall stiffness approaches zero within a specific displacement range, forming a quasi-zero stiffness platform. In order to obtain better quasi-zero stiffness performance and structural stability, a multi-parameter optimization method based on the Kriging agent model and the genetic algorithm (GA) is adopted. The optimization objects include the key structural parameters of beam length and angle, so that the structure exhibits excellent low-frequency vibration isolation performance in this range.

[0027] This structure is suitable for flexible manufacturing methods such as 3D printing. The selected material is nylon, and it is formed in one step through SLS selective laser sintering to ensure structural symmetry and geometric accuracy.

Claims

1. A simple and easy to implement multi-segment beam type quasi-zero stiffness structure device, characterized in that: include: A central circular platform for carrying vertical downward loads; Four flexible support beams are arranged radiating from the lower surface of the platform in a horizontal direction and symmetrically distributed in a cross shape around the center; Each flexible support beam comprises a first section of inclined beam and a second section of inclined beam connected in sequence to form a broken line structure, and is fixedly connected to the bottom base at the far end; The platform and the support beam are integrally formed by 3D printing; The support beams undergo coupled bending under vertical loading, so that the overall stiffness of the platform approaches zero within a certain displacement range, achieving a quasi-zero stiffness response. Two sections of a single beam are a first inclined beam and a second inclined beam arranged in mirror symmetry; Two symmetrically arranged first inclined beams (1) and second inclined beams (2), one end of which is connected to the fixed end and the other end of which is inclined toward the middle of the structure; a central platform (3) connecting the free ends of the first inclined beam and the second inclined beam; The load is set in the middle of the central connecting platform and is directed vertically downward; The inclined beams and the central connecting beam are configured as "double inclined beams-platform-double inclined beams", and are arranged in a mirror-symmetrical manner as a whole; the structure is integrally formed and manufactured by additive manufacturing, and each beam segment is an elastic element that can produce bending deformation under vertical compression loading.

2. The quasi-zero stiffness structure according to claim 1, characterized in that: The first tilt angle is 0 to 30°, preferably 0 to 7°.

3. The quasi-zero stiffness structure according to claim 1 or 2, characterized in that: The length of the first section of the inclined beam is 5 mm to 45 mm, preferably 25 mm to 35 mm.

4. The quasi-zero stiffness structure according to any one of claims 1 to 3, characterized in that: The load is a vertical downward pre-compression force.

5. The quasi-zero stiffness structure according to claim 1, characterized in that: The inclined beam and the central platform generate equivalent negative stiffness characteristics during the compression deformation process, and the overall stiffness of the structure approaches zero within a specific displacement range, forming a quasi-zero stiffness platform.

6. The quasi-zero stiffness structure according to claim 5, characterized in that: The force range of the quasi-zero stiffness platform is 50 to 90 N, and the displacement range is 4 mm to 7 mm.

7. The quasi-zero stiffness structure according to claim 1, characterized in that: The structure is made of nylon material and is 3D printed by selective laser sintering (SLS).

8. The quasi-zero stiffness structure according to claim 1, characterized in that: The structure is suitable for a low-frequency vibration isolation system, and the quasi-zero stiffness platform characteristics can be controlled by adjusting the beam length and angle parameters.

9. The structure according to claim 1, characterized in that: The structural parameters are obtained by joint optimization of the Kriging proxy model and the genetic algorithm to maximize the platform width.

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