scholarly journals Analysis of mass and friction effect of negative stiffness mechanism of rhombic HSLDS vibration isolator

2021 ◽  
Vol 42 (2) ◽  
pp. 207-214
Author(s):  
YUAN Yijie ◽  
◽  
◽  
JI Ming ◽  
ZHANG Weiguo ◽  
...  
Keyword(s):  
Negative Stiffness ◽  
Vibration Isolator ◽  
Friction Effect ◽  
Negative Stiffness Mechanism

scholarly journals An Air Spring Vibration Isolator Based on a Negative-Stiffness Structure for Vehicle Seat

2021 ◽  
Vol 11 (23) ◽  
pp. 11539
Author(s):  
Cong Hung Nguyen ◽  
Cong Minh Ho ◽  
Kyoung Kwan Ahn
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Air Spring ◽  
Nonlinear Force ◽  
Mechanical Spring ◽  
Negative Stiffness Mechanism ◽  
Vehicle Seat

This research introduces an air spring vibration isolator system (ASVIS) based on a negative-stiffness structure (NSS) to improve the vehicle seat’s vibration isolation performance at low excitation frequencies. The main feature of the ASVIS consists of two symmetric bellows-type air springs which were designed on the basis of a negative stiffness mechanism. In addition, a crisscross structure with two straight bars was also used as the supporting legs to provide the nonlinear characteristics with NSS. Moreover, instead of using a vertical mechanical spring, a sleeve-type air spring was employed to provide positive stiffness. As a result, as the weight of the driver varies, the dynamic stiffness of the ASVIS can be easily adjusted and controlled. Next, the effects of the dimension parameters on the nonlinear force and nonlinear stiffness of ASVIS were analyzed. A design process for the ASVIS is provided based on the analytical results in order to achieve high static–low dynamic stiffness. Finally, numerical simulations were performed to evaluate the effectiveness of the ASVIS. The results obtained in this paper show that the values of the seat displacement of the ASVIS with NSS were reduced by 77.16% in comparison with those obtained with the traditional air spring isolator without NSS, which indicates that the design of the ASVIS isolator with NSS allows the effective isolation of vibrations in the low-frequency region.

Design of a Miniaturized Pneumatic Vibration Isolator With High-Static-Low-Dynamic Stiffness

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Yuhu Shan ◽  
Wenjiang Wu ◽  
Xuedong Chen
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Structure Design ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Load Bearing Capacity ◽  
Compact Structure ◽  
Chamber Volume ◽  
Isolation Systems ◽  
Magnetic Rings

In the ultraprecision vibration isolation systems, it is desirable for the isolator to have a larger load bearing capacity and a broader isolation bandwidth simultaneously. Generally, pneumatic spring can bear large load and achieve relatively low natural frequency by enlarging its chamber volume. However, the oversized isolator is inconvenient to use and might cause instability. To reduce the size, a miniaturized pneumatic vibration isolator (MPVI) with high-static-low-dynamic stiffness (HSLDS) is developed in this paper. The volume of proposed isolator is minimized by a compact structure design that combines two magnetic rings in parallel with the pneumatic spring. The two magnetic rings are arranged in the repulsive configuration and can be mounted into the chamber to provide the negative stiffness. Then dynamic model of the developed MPVI is built and the isolation performances are analyzed. Finally, experiments on the isolator with and without the magnetic rings are conducted. The final experimental results are consistent with the dynamical model and verify the effectiveness of the developed vibration isolator.

Development of Vibration Isolator With Controllable Stiffness Using Permanent Magnets and Coils

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Kai Meng ◽  
Yi Sun ◽  
Huayan Pu ◽  
Jun Luo ◽  
Shujin Yuan ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Permanent Magnets ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stealth Technology ◽  
Active Vibration ◽  
Magnetic Rings

In this study, a novel vibration isolator is presented. The presented isolator possesses the controllable stiffness and can be employed in vibration isolation at a low-resonance frequency. The controllable stiffness of the isolator is obtained by manipulating the negative stiffness-based current in a system with a positive and a negative stiffness in parallel. By using an electromagnetic device consisting of permanent magnetic rings and coils, the designed isolator shows that the stiffness can be manipulated as needed and the operational stiffness range is large in vibration isolation. We experimentally demonstrate that the modeling of controllable stiffness and the approximation of the negative stiffness expressions are effective for controlling the resonance frequency and the transmissibility of the vibration isolation system, enhancing applications such as warship stealth technology, vehicles suspension system, and active vibration isolator.

scholarly journals Bidirectional Spiral Pulley Negative Stiffness Mechanism for Passive Energy Balancing

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Jiaying Zhang ◽  
Alexander D. Shaw ◽  
Mohammadreza Amoozgar ◽  
Michael I. Friswell ◽  
Benjamin K. S. Woods
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Energy Conversion Efficiency ◽  
Negative Stiffness ◽  
Energy Balancing ◽  
Morphing Aircraft ◽  
Spring Force ◽  
Morphing Structure ◽  
Negative Stiffness Mechanism ◽  
Analytical Result

The energy balancing concept seeks to reduce actuation requirements for a morphing structure by strategically locating negative stiffness devices to tailor the required deployment forces and moments. One such device is the spiral pulley negative stiffness mechanism. This uses a cable connected with a pre-tension spring to convert the decreasing spring force into the increasing balanced torque. The kinematics of the spiral pulley is first developed for bidirectional actuation, and its geometry is then optimized by employing an energy conversion efficiency function. The performance of the optimized bidirectional spiral pulley is then evaluated through the net torque, the total required energy, and energy conversion efficiency. Then, an additional test rig tests the bidirectional negative stiffness property and compares the characteristics with the corresponding analytical result. Exploiting the negative stiffness mechanism is of significant interest not only in the field of morphing aircraft but also in many other energy and power reduction applications.

scholarly journals A Novel Sensor Prototype with Enhanced and Adaptive Sensitivity Based on Negative Stiffness Mechanism

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4644
Author(s):  
Lijun Liu ◽  
Yongzhong Nie ◽  
Ying Lei
Keyword(s):  
Low Frequency ◽  
High Sensitivity ◽  
Negative Stiffness ◽  
Micro Electro Mechanical Systems ◽  
Enhanced Sensitivity ◽  
Landslide Hazards ◽  
Negative Stiffness Mechanism ◽  
Low Sensitivity ◽  
Electric Filed ◽  
Design And Manufacture

Loess–mudstone/soil-rock interfacial landslide is one of the prominent landslide hazards that occurs in soil rock contacting zones. It is necessary to develop sensors with high sensitivity to weak and low frequency vibrations for the early warning of such interfacial landslides. In this paper, a novel monitoring sensor prototype with enhanced and adaptive sensitivity is developed for this purpose. The novelty of the sensitive sensor is based on the variable capacitances and negative stiffness mechanism due to the electric filed forces on the vibrating plate. Owing to the feedback control of adjustable electrostatic field by an embedded micro controller, the sensor has adaptive amplification characteristics with high sensitivity to weak and low frequency input and low sensitivity to high input. The design and manufacture of the proposed sensor prototype by Micro-Electro-Mechanical Systems (MEMS) with proper packaging are introduced. Post-signal processing is also presented. Some preliminary testing of the prototype and experimental monitoring of sand interfacial slide which mimics soil–rock interfacial landslide were performed to demonstrate the performance of the developed sensor prototype with adaptive amplification and enhanced sensitivity.

scholarly journals Research on a nonlinear quasi-zero stiffness vibration isolator with a vibration absorber

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094089
Author(s):  
Shao-Hua Li ◽  
Nan Liu ◽  
Hu Ding
Keyword(s):  
Frequency Response ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Vibration Absorber ◽  
Vibration Isolator ◽  
Dynamic Vibration Absorber ◽  
Amplitude Frequency Response ◽  
Low Frequency Vibration ◽  
Response Equation ◽  
Negative Stiffness Mechanism

A negative stiffness mechanism consisting of a spring and cylinder is proposed, and a grounded dynamic vibration absorber is designed based on a quasi-zero stiffness vibration isolator to constitute the vibration isolator with a vibration absorber system. The range of parameters for attaining zero stiffness is derived from static analysis. The dynamic analysis of the vibration isolator with a vibration absorber system is carried out by a multiscale method, and the amplitude–frequency response equation of the system is obtained. The influence of different system parameters on the amplitude–frequency response is analyzed. The amplitude–frequency response of the quasi-zero stiffness vibration isolator is compared with that of the vibration isolator with a vibration absorber, and the linear and nonlinear analytical solutions of the vibration isolator with a vibration absorber system are also compared. The results show that the designed vibration isolator with a vibration absorber is an ideal choice for low-frequency vibration isolation, with no large resonance peak throughout the system and significantly improved reliability of the system.

Sign in / Sign up

Export Citation Format

Share Document