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.

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.

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.

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.

Fluidic Composite Tunable Vibration Isolators

2010 ◽  
Author(s):  
Lloyd H. Scarborough ◽  
Christopher D. Rahn ◽  
Edward C. Smith
Keyword(s):  
Material Properties ◽  
Unique Feature ◽  
Vibration Reduction ◽  
Vibration Isolator ◽  
Frequency Range ◽  
Vibration Isolators ◽  
New Class ◽  
Isolation Frequency ◽  
Transmitted Force ◽  
Flexible Matrix Composite

Coupling a Fluidic Flexible Matrix Composite (F2MC) to an air-pressurized fluid port produces a fundamentally new class of tunable vibration isolator. This device provides significant vibration reduction at an isolation frequency that can be tuned over a broad frequency range. The material properties and geometry of the F2MC element, as well as the port inertance, determine the isolation frequency. A unique feature of this device is that the port inertance depends on pressure so the isolation frequency can be adjusted by changing the air pressure. For constant port inertance, the isolation frequency is largely independent of the isolated mass so the device is robust to changes in load. A nonlinear model is developed to predict isolator length and port inertance. The model is linearized and the frequency response calculated. Experiments agree with theory, demonstrating a tunable isolation range from 9 Hz to 36 Hz and minimum transmitted force reductions of 90% at the isolation frequency.

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.

Effect of External Excitation on Dynamic Characteristics of Vibro-Isolating Table

2015 ◽  
Vol 220-221 ◽  
pp. 144-147
Author(s):  
Mindaugas Jurevičius ◽  
Artūras Kilikevičius ◽  
Paulius Ragauskas
Keyword(s):  
Vibrational Excitation ◽  
Vertical Direction ◽  
Vertical Oscillation ◽  
Dynamic Parameters ◽  
Vibration Isolator ◽  
Frequency Range ◽  
External Excitation ◽  
Vibration Isolators ◽  
Optical Table ◽  
Oscillation Characteristics

Performance of optical table with pneumatic vibration isolators is analyzed within 2–50 Hz frequency range. Specific vibrational excitation platform with a vibrator of the frequency range of 1–50 Hz in one of three directions were tested.The following pneumatic vibration isolator dynamic parameters were identified:transmissibility of vertical oscillation characteristics at 50 Hz frequency range;resonant frequency (vertical direction);damping efficiency at 5 Hz to 10 Hz for excitation frequencies.

Vibration control mechanism of the metabarrier under train load via numerical simulation

2019 ◽  
Vol 25 (19-20) ◽  
pp. 2553-2566 ◽  
Author(s):  
Caiyou Zhao ◽  
Liuchong Wang ◽  
Dongya Liu ◽  
Xing Gao ◽  
Xi Sheng ◽  
...  
Keyword(s):  
Phononic Crystal ◽  
Vibration Reduction ◽  
Ambient Vibration ◽  
Vibration Isolator ◽  
Frequency Range ◽  
Control Effect ◽  
Steel Spring ◽  
Vertical Stiffness ◽  
Vibration Isolators ◽  
Reduction Capacity

The problem of ambient vibration caused by rail transit continues to grow, and control effect requirements of different vibration reduction measures are always increasing. A new kind of vibration isolator used for floating slab tracks (FST) has been developed, called a metabarrier. Based on the bandgap properties of phononic crystals, it can realize a better vibration reduction capacity in certain frequency ranges with the same vertical stiffness as the original device. In order to study the vibration reduction characteristics of metabarriers under actual train loading action, two vibration isolators—a steel-spring vibration isolator and a metabarrier—were used to establish a train–FST–substrate dynamic coupling model. This study shows that the reduction capacity influenced by the phononic crystal bandgap is stable under different train speeds. In addition, under train load, the metabarrier can be used not only to isolate vibration by means of the bandgap, but also to absorb vibration dynamically, further expanding the vibration reduction frequency range. With optimized frequency range, metabarriers can reduce the acceleration vibration level by more than 9 dB over steel-spring vibration isolators.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

Sign in / Sign up

Export Citation Format

Share Document