Series single-sided impact bistable non-linear energy sink

Abstract

The application relates to the technical field of vibration reduction, and particularly discloses a series type single-side collision bistable non-linear energy sink. In view of the technical problem that the vibration reduction effect of an existing non-linear energy sink is easily affected by an excitation energy level and the robustness is poor, the application integrates a bistable non-linear mechanism and a single-side collision mechanism in the same non-linear energy sink system, and adopts a series type auxiliary structure form to guide the hierarchical transfer and dissipation of the vibration energy of a main structure, so that the stability and the robustness of the vibration reduction performance are improved, the sensitivity of the system to the excitation energy level is reduced, and the application has better engineering vibration reduction applicability.

Description

Technical Field

[0001] This invention relates to the field of vibration reduction technology, specifically to a series-connected single-sided collision bistable nonlinear energy trap. Background Technology

[0002] Under earthquakes, shocks, and strong transient excitations, engineering structures often experience large-amplitude vibrations. Traditional linear tuned mass dampers (TMDs) rely on precise tuning, and their vibration reduction performance is highly sensitive to parameter mismatch, making it difficult to maintain stability under broadband excitation conditions. Nonlinear energy traps (NES), by introducing inherently nonlinear restoring forces, can achieve unidirectional energy transfer from the main structure to auxiliary systems without precise tuning, and are considered a promising passive vibration reduction solution. In existing research, bistable nonlinear energy traps (BNES) enhance energy trapping capabilities through a bistable energy trap structure, while single-sided collision-type nonlinear energy traps (SSVI NES) rely on collision processes to achieve instantaneous energy dissipation. However, existing BNES and SSVINES are usually directly attached to the main structure, and their vibration reduction effect is highly sensitive to the input energy level, easily failing under weak excitations or outside specific energy ranges, and their stability and robustness remain limited. To address these issues, existing research has attempted to introduce multiple nonlinear mechanisms into the same nonlinear energy trap unit to enhance its energy trapping and dissipation capabilities.

[0003] However, existing nonlinear energy traps have the following drawbacks: (1) their vibration reduction performance is sensitive to the excitation energy level and can only play a good role in a specific energy range; (2) their vibration reduction effect is unstable under wide frequency excitation conditions and is prone to performance degradation; (3) their vibration reduction effect is sensitive to changes in the main structural parameters and is not robust enough under parameter deviation conditions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a novel series-connected single-sided collision bistable nonlinear energy trap, thereby improving the stability and robustness of vibration reduction performance and reducing the system's sensitivity to excitation energy levels.

[0005] To achieve the above objectives, the present invention provides a series-connected single-sided collision bistable nonlinear energy trap, comprising a main structure and a nonlinear energy trap system connected to the main structure; The nonlinear energy trap system consists of a first auxiliary oscillator and a second auxiliary oscillator, which are connected in series via a linear restoring force element K3 and a damping element C3. The first auxiliary oscillator is connected to the main structure through symmetrically arranged linear restoring force elements K2, and a rigid stop constraint structure is provided on one side of the motion path of the first auxiliary oscillator, so that the first auxiliary oscillator has both bistable mechanical characteristics and unilateral collision characteristics. Both the first and second auxiliary oscillators are mounted on the guide rod and can reciprocate linearly along the guide rod. The vibration energy of the main structure is transmitted sequentially through the first and second auxiliary oscillators, and the energy is dissipated in stages through unilateral collision and damping. The main structure, the first auxiliary oscillator, and the second auxiliary oscillator have collinear axes of motion and vibrate linearly only along the extension and contraction directions of the linear restoring force elements K2 and K3.

[0006] Furthermore, the linear restoring force element K2 includes two symmetrically arranged springs, which are symmetrically arranged along the motion axis of the first auxiliary oscillator. One end of each spring is fixedly connected to the main structure, and the other end is connected to the first auxiliary oscillator. The extension and contraction direction of the spring is consistent with the motion direction of the first auxiliary oscillator.

[0007] Furthermore, the rigid stop is fixed on the mounting base that is fixed to the main structure. The collision surface of the rigid stop is parallel to and opposite to the collision end of the first auxiliary oscillator, and the collision surface is perpendicular to the motion axis of the first auxiliary oscillator.

[0008] Furthermore, one end of the linear restoring force element K3 is fixedly connected to the center node of the side wall of the first auxiliary oscillator away from the main structure, and the other end is fixedly connected to the center node of the side wall of the second auxiliary oscillator. The extension and retraction direction of K3 is consistent with the movement direction of the first auxiliary oscillator. The damping elements C3 and K3 are arranged in parallel to achieve the series connection of the first and second auxiliary oscillators and the transfer and dissipation of energy.

[0009] Furthermore, a damping element C2 is provided between the first auxiliary oscillator and the main structure. The damping element C2 is arranged between two symmetrical linear restoring force elements K2. One end of the damping element C2 is fixedly connected to the main structure, and the other end is fixedly connected to the center position of the first auxiliary oscillator. Both the damping element C2 and the damping element C3 are arranged along the motion axis.

[0010] Compared with other existing technologies, the present invention has the following advantages: This invention combines a bistable structure, unilateral collision energy dissipation, and a dual-oscillator series configuration, which broadens the vibration reduction frequency band, improves energy dissipation efficiency, reduces the sensitivity of vibration reduction performance to excitation energy levels, maintains a more stable vibration suppression effect under different excitation conditions, improves system robustness, and features a simple overall structure, reliable motion, and superior engineering applicability. Attached Figure Description

[0011] Figure 1 A schematic diagram of the overall structure of a series-connected single-sided collision bistable nonlinear energy trap system; Figure 2 A physical model diagram of a series-connected single-sided collision bistable nonlinear energy trap system; Figure 3 This is a schematic diagram of energy dissipation under pulse excitation. Figure 4 This is a schematic diagram of the vibration response of the main structure under seismic wave excitation. Figure 5 This is a schematic diagram illustrating the stability of the system's vibration reduction effect under different excitation energy levels or parameters.

[0012] Among them, 1. main structure, 2. first auxiliary oscillator, 3. second auxiliary oscillator, 4. restoring force element K2, 5. linear restoring force element K3, 6. damping element C2, 7. damping element C3, 8. rigid stop, 9. guide rod. Detailed Implementation

[0013] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the following embodiments are given for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0014] like Figure 1 and Figure 2 As shown, the series-connected single-sided collision nonlinear energy trap system provided by the present invention includes a main structure. m 1. A nonlinear energy trap device connected to the main structure. The nonlinear energy trap device consists of a first auxiliary oscillator. m 2 and second auxiliary oscillator m 3. Through linear restoring force element ( K 3) Series connection. Among them, the first auxiliary oscillator... m 2. Symmetrically passing through linear restoring force elements on both sides of its motion path ( K 2) Connected to the main structure, it forms an equivalent bistable nonlinear restoring force in the direction of motion. Simultaneously, a rigid stop is placed on one side of the motion path of the first auxiliary oscillator, thus forming a unilateral collision structure. Based on the above structural relationship, according to Newton's second law, a dynamic equation describing the coupled motion of the main structure, the first auxiliary oscillator, and the second auxiliary oscillator can be established to characterize the system's motion response and vibration energy transfer and dissipation process under external excitation. ; in When the motion displacement of the second auxiliary oscillator satisfies the preset collision condition At that time, the second auxiliary oscillator undergoes an inelastic collision with the rigid stop. This collision process causes a transient change in the velocity of the series-connected single-sided collision bistable nonlinear energy trap system and the main structure within a very short time, and after the collision ends and the oscillator separates from the stop, the system enters a new state of motion. Here, the "point" in the above symbols represents the time variable... t The derivative of .

[0015] ; The superscripts "(-)" and "(+)" represent the physical states of the objects immediately before and after the collision, respectively, including but not limited to displacement and velocity. Coefficient of Restitution r c It is used to characterize the inelasticity of the collision process, and its value is determined by the material properties and surface characteristics of the contacting parts that collide.

[0016] The natural angular frequency of the main structure is defined as: And the following dimensionless parameters are introduced: ; After dimensionless processing of equation (1), its dimensionless form can be expressed as follows: ; in Equation (2) can be further expressed as: ; In the above symbols, "point" represents the time variable. The derivative of . The initial conditions of the coupled system are set as follows: .

[0017] To verify the vibration reduction performance of the series-connected single-sided collision bistable nonlinear energy trap (SSSVI-BNES) under pulse excitation conditions, low-energy pulse excitations (initial velocity (…)) were applied to the main structure under selected system parameters. v 0 =0.8) and high-energy pulse excitation (initial velocity) v 0 =8), and compare the system vibration response with that of a bistable nonlinear energy trap (BNES) and a single-sided collision-type nonlinear energy trap (SSVI-NES), such as Figure 3 As shown. (Parameters are:) Subgraphs (a) and (c) show the ratio of the remaining energy of the main structure under low-pulse and high-pulse excitation. ξ PSThe evolution process is shown in subgraphs (b) and (d), which illustrate the energy dissipation rate of the system under the corresponding conditions. μ sys The changes in energy dissipation rate are as follows: the remaining energy ratio characterizes the vibrational energy in the system that has not yet been dissipated, and the smaller the value, the higher the degree of energy dissipation; the energy dissipation rate characterizes the ability of vibrational energy to dissipate per unit time, and the larger the value, the higher the energy dissipation efficiency.

[0018] Depend on Figure 3 It is evident that, under both low-pulse and high-pulse excitation conditions, when employing the series-connected single-sided collision nonlinear energy trap described in this invention, the residual energy ratio of the main structure can be rapidly reduced within a short time, while the energy dissipation rate rapidly increases after excitation and remains at a high level. Compared with bistable nonlinear energy traps (BNES) and single-sided collision-type nonlinear energy traps (SSVI-NES), the overall vibration reduction performance of this invention is superior to existing nonlinear energy trap structures.

[0019] To verify the vibration reduction performance of the series-connected single-sided collision bistable nonlinear energy trap described in this invention under seismic wave excitation conditions, an actual main structure was selected as the research object, and its structural parameters are as follows: Under the condition that the parameters of the additional nonlinear energy trap device are optimized and determined (specific parameters are shown in Table 1), different seismic wave excitations are applied to the main structure, and the displacement of the main structure is compared and analyzed with the other two existing nonlinear energy trap schemes under Section 2.

[0020] like Figure 4 As shown, after adopting the series-connected single-sided collision nonlinear energy trap described in this invention, the displacement response of the main structure remains at a low level throughout the entire seismic excitation process, and the vibration amplitude is effectively suppressed. This indicates that the present invention has a good vibration reduction effect under broadband, non-stationary excitation conditions such as seismic waves.

[0021] Table 1 parameter <![CDATA[ m 2(kg)]]> <![CDATA[ K 2(N / m)]]> <![CDATA[ K 3(N / m)]]> <![CDATA[ L 0(m)]]> <![CDATA[ C 2(Ns / m)]]> <![CDATA[ C 3(Ns / m)]]> SSSVI-BNES 0.038 176.4 151.2 0.923 0.47 0.75 BNES 0.100 97.7 - 0.820 0.71 - SSVI-NES 0.100 39.2 - 0.817 0.39 - ; To verify the ability of the series-connected single-sided collision bistable nonlinear energy trap described in this invention to suppress the vibration of the main structure under parameter variation conditions, the root mean square displacement attenuation ratio was used as the basis for evaluation. As an evaluation index (the larger the value, the better the vibration reduction effect), when selecting and... Figure 4 Under the same seismic wave excitation conditions, the stiffness of the main structure is varied by ±20% from its nominal value, where the rate of stiffness variation is defined as... Meanwhile, the energy level of the seismic excitation was changed, and the vibration response of the system was compared and analyzed.

[0022] like Figure 5As shown, compared with bistable nonlinear energy traps (BNES) and single-sided collision-type nonlinear energy traps (SSVI-NES), the series-connected single-sided collision-type bistable nonlinear energy trap described in this invention can maintain the maximum root-mean-square displacement attenuation ratio under different seismic excitation intensities and main structural stiffness values. Its overall vibration response amplitude is lower than that of the comparative structures, and no obvious performance degradation is observed. Therefore, this invention exhibits good vibration reduction stability and robustness under broadband, non-stationary excitation conditions such as seismic waves.

[0023] This invention uses specific experimental data to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of the invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the invention.

Claims

1. A series-connected single-sided collisional bistable nonlinear energy trap, characterized in that, It includes a main structure (1) and a nonlinear energy trap system connected to the main structure (1); The nonlinear energy trap system consists of a first auxiliary oscillator (2) and a second auxiliary oscillator (3), and the first auxiliary oscillator (2) and the second auxiliary oscillator (3) are connected in series through a linear restoring force element K3 (5) and a damping element C3 (7); The first auxiliary oscillator (2) is connected to the main structure (1) through symmetrically arranged linear restoring force elements K2 (4), and a rigid stop block (8) constraint structure is provided on one side of the motion path of the first auxiliary oscillator (2), so that the first auxiliary oscillator (2) has both bistable mechanical characteristics and unilateral collision characteristics. The first auxiliary oscillator (2) and the second auxiliary oscillator (3) are both mounted on the guide rod (9) and can reciprocate in a straight line along the guide rod (9); The vibration energy of the main structure (1) is transmitted sequentially through the first auxiliary oscillator (2) and the second auxiliary oscillator (3), and the energy is dissipated in stages through unilateral collision and damping. The main structure (1), the first auxiliary oscillator (2), and the second auxiliary oscillator (3) have collinear axes of motion and vibrate linearly only along the extension and contraction directions of the linear restoring force elements K2 (4) and K3 (5).

2. The series-connected single-sided collision bistable nonlinear energy trap according to claim 1, characterized in that, The linear restoring force element K2 (4) includes two symmetrically arranged springs, which are arranged symmetrically along the motion axis of the first auxiliary oscillator (2). One end of each spring is fixedly connected to the main structure (1), and the other end is connected to the first auxiliary oscillator (2). The extension and contraction direction of the spring is consistent with the motion direction of the first auxiliary oscillator (2).

3. The series-connected single-sided collision bistable nonlinear energy trap according to claim 1, characterized in that, The rigid stop (8) is fixed on the mounting base that is fixed to the main structure (1). The collision surface of the rigid stop (8) is parallel to the collision end of the first auxiliary vibrator (2), and the collision surface is perpendicular to the motion axis of the first auxiliary vibrator (2).

4. The series-connected single-sided collision bistable nonlinear energy trap according to claim 1, characterized in that, One end of the linear restoring force element K3 (5) is fixedly connected to the center node of the side wall of the first auxiliary oscillator (2) away from the main structure (1), and the other end is fixedly connected to the center node of the side wall of the second auxiliary oscillator (3). The extension and retraction direction of K3 (5) is consistent with the movement direction of the first auxiliary oscillator (2). The damping elements C3 (7) and K3 (5) are arranged in parallel to achieve the series connection of the first auxiliary oscillator (2) and the second auxiliary oscillator (3) and the energy transfer and dissipation.

5. The series-connected single-sided collision bistable nonlinear energy trap according to claim 1, characterized in that, A damping element C2 (6) is provided between the first auxiliary oscillator (2) and the main structure (1). The damping element C2 (6) is arranged between two symmetrical linear restoring force elements K2 (4). One end of the damping element C2 (6) is fixedly connected to the main structure (1), and the other end is fixedly connected to the center position of the first auxiliary oscillator (2). The damping element C2 (6) and the damping element C3 (7) are both arranged along the motion axis.

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