Design and Experimental Analysis of Origami-Inspired Vibration Isolators With Quasi-Zero-Stiffness Characteristic

2016 ◽  
Author(s):  
Sachiko Ishida ◽  
Kohki Suzuki ◽  
Haruo Shimosaka
Keyword(s):  
Experimental Analysis ◽  
Frequency Region ◽  
Vibration Isolator ◽  
Spring Stiffness ◽  
Torsional Buckling ◽  
Harmonic Oscillations ◽  
Vibration Isolators ◽  
Stiffness Characteristic ◽  
Current Specification ◽  
Isolation Performance

We present a prototype vibration isolator whose design is inspired by origami-based foldable cylinders with torsional buckling patterns. The vibration isolator works as a nonlinear spring that has quasi-zero spring stiffness in a given frequency region, where it does not transmit vibration in theory. We evaluate the performance of the prototype vibration isolator through excitation experiments via the use of harmonic oscillations and seismic-wave simulations of the Tohoku-Pacific Ocean and Kobe earthquakes. The results indicate that the isolator with the current specification is able to suppress the transmission of vibrations with frequencies of over 6 Hz. The functionality and constraints of the isolator are also clarified. It has been known that origami-based foldable cylinders with torsional buckling patterns provide bistable folding motions under given conditions. In a previous study, we proposed a vibration isolator utilizing the bistability characteristics and numerically confirmed the device’s validity as a vibration isolator. Here, we attempt prototyping the isolator with the use of versatile metallic components and experimentally evaluate the isolation performance.

Design and Experimental Analysis of Origami-Inspired Vibration Isolator With Quasi-Zero-Stiffness Characteristic

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Sachiko Ishida ◽  
Kohki Suzuki ◽  
Haruo Shimosaka
Keyword(s):  
Pacific Ocean ◽  
Experimental Analysis ◽  
Frequency Region ◽  
Vibration Isolator ◽  
Spring Stiffness ◽  
Torsional Buckling ◽  
Harmonic Oscillations ◽  
Stiffness Characteristic ◽  
Current Specification ◽  
Isolation Performance

We present a prototype vibration isolator whose design is inspired by origami-based foldable cylinders with torsional buckling patterns. The vibration isolator works as a nonlinear spring that has quasi-zero spring stiffness in a given frequency region, where it does not transmit vibration in theory. We evaluate the performance of the prototype vibration isolator through excitation experiments via the use of harmonic oscillations and seismic-wave simulations of the Tohoku-Pacific Ocean and Kobe earthquakes. The results indicate that the isolator with the current specification is able to suppress the transmission of vibrations with frequencies of over 6 Hz. The functionality and constraints of the isolator are also clarified. It has been known that origami-based foldable cylinders with torsional buckling patterns provide bistable folding motions under given conditions. In a previous study, we proposed a vibration isolator utilizing the bistability characteristics and numerically confirmed the device's validity as a vibration isolator. Here, we attempt prototyping the isolator with the use of versatile metallic components and experimentally evaluate the isolation performance.

Improved Feasible Load Range and Its Effect on the Frequency Response of Origami-Inspired Vibration Isolators With Quasi-Zero-Stiffness Characteristics1

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Kazuya Inamoto ◽  
Sachiko Ishida
Keyword(s):  
Numerical Analysis ◽  
Vibration Isolator ◽  
Spring Stiffness ◽  
Frequency Range ◽  
Torsional Buckling ◽  
Load Range ◽  
Nonlinear Characteristics ◽  
Vibration Isolators ◽  
Initial Load ◽  
Linear Spring

We describe herein a method for extending the load range of a vibration isolator using a foldable cylinder consisting of a torsional buckling pattern and evaluate the vibration isolating performance through excitation experiments. A previous study determined that the foldable cylinder is bistable and acts as a vibration isolator with nonlinear characteristics in a displacement region, where the spring stiffness is zero. Its spring characteristics and vibration isolating performance were clarified by numerical analysis and excitation experiments. The findings indicated that the vibration in a certain frequency range is reduced where the spring stiffness is zero. However, this vibration isolator has a disadvantage in that it can only support an initial load that transfers to the zero-spring-stiffness region. Therefore, in this research, we improve the position of the linear spring attached to the isolator. As a result, the initial load range is extended by two to four times that of the conventional vibration isolator. Furthermore, the isolating performance is maintained even when the initial load is changed within a given load range.

Design Concepts and Prototypes of Vibration Isolators Using Bi-Stable Foldable Structures

2015 ◽  
Author(s):  
Sachiko Ishida ◽  
Hiroshi Uchida ◽  
Haruo Shimosaka ◽  
Ichiro Hagiwara
Keyword(s):  
Structural Vibration ◽  
Vibration Isolator ◽  
Spring Stiffness ◽  
Torsional Buckling ◽  
Vibration Isolators ◽  
Design Concepts ◽  
Minimum Value ◽  
Relative Minimum ◽  
Foldable Structures ◽  
The Given

In this paper, a new vibration isolator using origami-based foldable structures is proposed and the performance of the isolator is numerically evaluated to prevent structural vibration. Next, the prototype of the isolator is introduced. It has been known that the origami-based foldable structures based on torsional buckling pattern provide the bistable folding motions under the given conditions. We propose to apply additional linear springs to this structure. It is numerically confirmed that the structure with additional linear springs can work as a vibration isolator around the region that the total spring stiffness of the whole structure reaches the relative minimum value that is close to zero. The prototype of the isolator consists of metallic components. The structure is adequately simplified from the above-mentioned conceptual foldable structure, still maintaining the bi-stability.

Design and Numerical Analysis of Vibration Isolators With Quasi-Zero-Stiffness Characteristics Using Bistable Foldable Structures

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Sachiko Ishida ◽  
Hiroshi Uchida ◽  
Haruo Shimosaka ◽  
Ichiro Hagiwara
Keyword(s):  
Structural Vibration ◽  
Vibration Isolator ◽  
Spring Stiffness ◽  
Torsional Buckling ◽  
High Frequencies ◽  
Vibration Isolators ◽  
Foldable Structures ◽  
Combined Structure ◽  
Rigid Frames ◽  
Stiffness Characteristics

In this paper, a novel vibration isolator based on a foldable cylinder with a torsional buckling pattern, which is also called Kresling's pattern, is proposed, and the performance of the proposed isolator in terms of preventing structural vibration is numerically evaluated. It is known that foldable cylinders with a torsional buckling pattern provide bistable folding motions under specific conditions. For simplification, a foldable cylinder with a torsional buckling pattern is modeled using horizontal, longitudinal, and diagonal truss elements connected by rotational joints and enforced by rigid frames, which are also called Rahmen, while maintaining the bistability of the structure. Additional linear springs are incorporated into the structure in order to obtain a nonlinear spring with quasi-zero-stiffness characteristics. It is numerically established that: (i) the resonance of the combined structure is effectively suppressed and (ii) the structure decreases the vibration response even at high frequencies when it is used around the equilibrium position at which the spring stiffness is quasi-zero.

Shock isolation characteristics of a bistable vibration isolator with tunable magnetic controlled stiffness

2021 ◽  
pp. 1-28
Author(s):  
Bo Yan ◽  
Peng Ling ◽  
Yanlin Zhou ◽  
Chuan-yu Wu ◽  
Wen-Ming Zhang
Keyword(s):  
Damping Ratio ◽  
Excitation Amplitude ◽  
Relative Displacement ◽  
Vibration Isolator ◽  
Maximum Acceleration ◽  
Vibration Isolators ◽  
Displacement Ratio ◽  
Shock Isolation ◽  
Maximum Relative Displacement ◽  
Isolation Performance

Abstract This paper investigates the shock isolation characteristics of an electromagnetic bistable vibration isolator (BVI) with tunable magnetic controlled stiffness. The theoretical model of the BVI is established. The maximum acceleration ratio (MAR), maximum absolute displacement ratio (MADR) and maximum relative displacement ratio (MRDR) are introduced to evaluate the shock isolation performance of the BVI. The kinetic and potential energy are observed to further explore the performance of the BVI. The effects of the potential barrier, shape of potential well, damping ratio on the BVI are discussed compared to the linear vibration isolators (LVI). The results demonstrate that the intrawell oscillations and snap-through oscillations are determined by the excitation amplitude and duration time of main pulse. MADR and MRDR of the BVI are smaller than those of the LVI. The maximum acceleration peak amplitude of the BVI is far below that of the LVI, especially when the snap-through oscillation occurs. In brief, the proposed BVI has a better shock isolation performance than the LVI and has the potential to suppress the shock of space structures during the launch and on-orbit deploying process.

scholarly journals A Novel Ring Spring Vibration Isolator for Metro Superstructure

2021 ◽  
Vol 11 (18) ◽  
pp. 8422
Author(s):  
Yuhong Ling ◽  
Shan Wu ◽  
Jingxin Gu ◽  
Hongtao Lai
Keyword(s):  
Vibration Isolation ◽  
Common Knowledge ◽  
Displacement Curve ◽  
Vibration Isolator ◽  
Spring Stiffness ◽  
Dynamic Simulations ◽  
Theoretical Derivation ◽  
Vibration Isolators ◽  
Good Energy ◽  
Compression Springs

Due to the serious impact of metro vibration on people’s lives, it is important to design vibration isolators. In this study, the dynamic characteristics of a thick-walled ring spring are studied first. Through theoretical derivation, a new formula suitable for thick-walled ring springs is proposed. Finite element numerical analysis was performed to study the load–displacement curve and stress of the ring spring and verified the correctness of the formula. According to the studied mechanic characteristics, a novel ring spring isolator is proposed for vibration isolation of the metro superstructure. With the help of a ring spring, the proposed isolator has good energy absorption and self-reset function. The dynamic simulations were conducted in a multi-story building with the ring spring isolator as the isolator to study the vibration performance. It is common knowledge that the vertical natural frequency of the superstructure that is isolated by compression springs is given by the mass of the superstructure and the spring stiffness. In order to obtain vibration attenuation and control the vertical deformation, the spring stiffness needs to be 500–1000 kN/mm. Hence, it is clear that the vibration isolator does reduce the vertical eigenfrequency. By comparing the isolated structure with the non-isolated structure, it is proved that the new isolator can effectively improve a building’s serviceability.

The design of negative stiffness spring for precision vibration isolation using axially magnetized permanent magnet rings

2019 ◽  
Vol 25 (19-20) ◽  
pp. 2667-2677 ◽  
Author(s):  
Zhenhua Zhou ◽  
Shuhan Chen ◽  
Dun Xia ◽  
Jianjun He ◽  
Peng Zhang
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Design Procedure ◽  
Air Gap ◽  
Negative Stiffness ◽  
Linear Component ◽  
Vibration Isolator ◽  
Stiffness Characteristic ◽  
Isolation Performance

A negative stiffness element is always employed to generate high-static–low-dynamic stiffness characteristic of the vibration isolator, reduce the resonance frequency of the isolator, and improve the vibration isolation performance under low and ultra-low frequency excitation. In this paper, a new compact negative stiffness permanent magnetic spring (NSPMS) that is composed of two axial-magnetized permanent magnetic rings is proposed. An analytical expression of magnetic negative stiffness of the NSPMS is deduced by using the Coulombian model. After analyzing the effect of air-gap width, air-gap position, height difference between the inner ring and outer ring on the negative stiffness characteristic, a design procedure is proposed to realize the negative stiffness characteristic with a global minimum linear component and uniformity stiffness near the equilibrium position. Finally, an experimental prototype is developed to validate the effectiveness of the NSPMS. The experimental results show that combining a vibration isolator with the NSPMS in parallel can lower the natural frequency and improve the isolation performance of the isolator.

Improved Feasible Load Range and its Effect on the Frequency Response of Origami-Inspired Vibration Isolators With Quasi-Zero-Stiffness Characteristics

2018 ◽  
Author(s):  
Kazuya Inamoto ◽  
Sachiko Ishida
Keyword(s):  
Vibration Isolator ◽  
Spring Stiffness ◽  
Frequency Range ◽  
Load Range ◽  
Nonlinear Characteristics ◽  
Vibration Isolators ◽  
Design Variables ◽  
Initial Load ◽  
Linear Spring ◽  
Stiffness Characteristics

We describe a method for extending the load range of a vibration isolator using a foldable cylinder consisting of a twist buckling pattern (Kresling’s Pattern), and evaluate the vibration isolating performance through excitation experiments. In a previous study, it was determined that the foldable cylinder is bistable and acts as a vibration isolator with nonlinear characteristics in a displacement region where the spring stiffness is zero. Its spring characteristics and vibration isolating performance were clarified by numerical analysis and excitation experiments, and indicated that vibration in a certain frequency range is reduced where the spring stiffness is zero. However, this vibration isolator has a disadvantage in that it can only support an initial load that transfers to the zero-spring-stiffness region. Therefore, in this research, we improve the design variables of the isolator and the position of the linear spring attached to the isolator. As a result, the initial load range is extended by two to three times that of the conventional vibration isolator. Furthermore, the isolating performance is maintained even when the initial load is changed within a given load range.

scholarly journals The Transmissibility of Vibration Isolators With a Nonlinear Antisymmetric Damping Characteristic

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Z. K. Peng ◽  
Z. Q. Lang ◽  
X. J. Jing ◽  
S. A. Billings ◽  
G. R. Tomlinson ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Frequency Region ◽  
Simulation Studies ◽  
Vibration Isolator ◽  
Linear Vibration ◽  
Output Frequency ◽  
Single Degree Of Freedom ◽  
Vibration Isolators ◽  
Single Degree ◽  
Force Transmissibility

In the present study, the concept of the output frequency response function, recently proposed by the authors, is applied to theoretically investigate the force transmissibility of single degree of freedom (SDOF) passive vibration isolators with a nonlinear antisymmetric damping characteristic. The results reveal that a nonlinear antisymmetric damping characteristic has almost no effect on the transmissibility of SDOF vibration isolators over the ranges of frequencies, which are much lower or higher than the isolator’s resonance frequency. On the other hand, the introduction of a nonlinear antisymmetric damping can significantly reduce the transmissibility of the vibration isolator over the resonance frequency region. The results indicate that nonlinear vibration isolators with an antisymmetric damping characteristic have great potential to overcome the dilemma encountered in the design of passive linear vibration isolators, that is, increasing the level of damping to reduce the transmissibility at the resonance could increase the transmissibility over the range of higher frequencies. These important theoretical conclusions are then verified by simulation studies.

Analysis and Comparison of the Dynamic Performance of One-Stage Inerter-Based and Linear Vibration Isolators

2018 ◽  
Vol 10 (01) ◽  
pp. 1850005 ◽  
Author(s):  
Yong Wang ◽  
Ruo-Chen Wang ◽  
Hao-Dong Meng
Keyword(s):  
Vibration Isolation ◽  
Fixed Point Theory ◽  
Structural Parameters ◽  
Vibration Isolator ◽  
Linear Vibration ◽  
Isolation System ◽  
Vibration Isolators ◽  
One Stage ◽  
Performance Indexes ◽  
Isolation Performance

Inerter, which is defined as a two-terminal mechanical element, has the characteristic that the force generated at its two terminals is proportional to the relative acceleration between its two ends. Here, the inerter is used in the vibration isolation system; eight kinds of one-stage inerter-based vibration isolators are presented in this paper. Dynamic equations of eight kinds of one-stage inerter-based vibration isolators are established, the natural frequency is considered, and the dynamic response and transmissibility are obtained using the time domain analysis method or the Laplace-transformed method. Four performance indexes are defined to evaluate their isolation performance and compared with the linear vibration isolator (LVI). The best structural parameters of these one-stage inerter-based vibration isolators are determined using the H[Formula: see text] optimization method based on the fixed-point theory, which aims to minimize the maximum transmissibility. The results show that compared with the LVI, some kinds of one-stage inerter-based vibration isolators can offer a better isolation performance according to the four performance indexes. Furthermore, the best vibration isolator among these vibration isolators is determined by the four performance indexes.

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