Human body inspired vibration isolation: Beneficial nonlinear stiffness, nonlinear damping & nonlinear inertia

2019 ◽  
Vol 117 ◽  
pp. 786-812 ◽  
Author(s):  
Xiao Feng ◽  
Xingjian Jing
Keyword(s):  
Human Body ◽  
Vibration Isolation ◽  
Nonlinear Damping ◽  
Nonlinear Stiffness

scholarly journals Vibration Isolation With Passive Linkage Mechanisms

2021 ◽  
Author(s):  
Xiao Feng ◽  
Xingjian Jing ◽  
Yingqing Guo
Keyword(s):  
Vibration Isolation ◽  
Nonlinear Damping ◽  
Resonant Peak ◽  
Nonlinear Stiffness ◽  
Engineering Systems ◽  
Linkage Mechanism ◽  
Passive Vibration Isolation ◽  
Innovative Solution ◽  
Cost Efficient ◽  
Vibration Isolation Performance

Abstract This study is to present a novel way to achieve superior passive vibration isolation by employing a specially-designed and compact linkage mechanism. The proposed anti-vibration system has beneficial nonlinear inertia, inspired by swinging motion of human arms, and is constructed with an adjustable nonlinear stiffness system inspired by animal or human leg skeleton. It is shown with comprehensive theoretical analysis and consequently validated by a series of well-designed experiments that the nonlinear stiffness, nonlinear damping and nonlinear inertia of the proposed system are very helpful for significantly reducing natural frequency and enhancing damping effect in a beneficial nonlinear way. This results in excellent vibration isolation performance with lower resonant frequency and resonant peak of faster decay rate. This study provides an innovative solution to a cost-efficient vibration control demanded in various engineering systems.

Displacement transmissibility evaluation of vibration isolation system employing nonlinear-damping and nonlinear-stiffness elements

2017 ◽  
Vol 24 (18) ◽  
pp. 4247-4259 ◽  
Author(s):  
S M Mahdi Mofidian ◽  
Hamzeh Bardaweel
Keyword(s):  
Numerical Simulation ◽  
Vibration Isolation ◽  
Harmonic Balance Method ◽  
Nonlinear Damping ◽  
Resonant Peak ◽  
Engineering Practice ◽  
Nonlinear Stiffness ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Isolation Systems

Undesired oscillations commonly encountered in engineering practice can be harmful to structures and machinery. Vibration isolation systems are used to attenuate undesired oscillations. Recently, there has been growing interest in nonlinear approaches towards vibration isolation systems design. This work is focused on investigating the effect of nonlinear cubic viscous damping in a vibration isolation system consisting of a magnetic spring with a positive nonlinear stiffness, and a mechanical oblique spring with geometric nonlinear negative stiffness. Dynamic model of the vibration isolation system is obtained and the harmonic balance method (HBM) is used to solve the governing dynamic equation. Additionally, fourth order Runge–Kutta numerical simulation is used to obtain displacement transmissibility of the system under investigation. Results obtained from numerical simulation are in good agreement with those obtained using HBM. Results show that introducing nonlinear damping improves the performance of the vibration isolation system. Nonlinear damping purposefully introduced into the described vibration isolation system appears to eliminate undesired frequency jump phenomena traditionally encountered in quasi-zero-stiffness vibration isolation systems. Compared to its rival linear vibration isolation system, the described nonlinear system transmits less vibrations around resonant peak. At lower frequencies, both nonlinear and linear isolation systems show comparable transmissibility characteristics.

Primary Resonance of a Vehicle Suspension System With Nonlinear Stiffness and Nonlinear Damping

2006 ◽  
Author(s):  
Shaohua Li ◽  
Shaopu Yang
Keyword(s):  
Primary Resonance ◽  
Singularity Theory ◽  
Nonlinear Damping ◽  
Suspension System ◽  
Vehicle Suspension ◽  
Model Parameters ◽  
Nonlinear Stiffness ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Vehicle Suspension System

In this work, primary resonance of a single-degree-of-freedom (SDOF) vehicle suspension system with nonlinear stiffness and nonlinear damping under multi-frequency excitations is investigated. The primary resonance equation is obtained by average method, and then the system’s bifurcation behaviors are studied by singularity theory. In addition, the effect of changing physical model parameters on the system’s primary resonance is studied.

scholarly journals Reducing Transmitted Vibration Using Delayed Hysteretic Suspension

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Lahcen Mokni ◽  
Mohamed Belhaq
Keyword(s):  
Time Delay ◽  
Perturbation Analysis ◽  
Analytical Study ◽  
Vibration Isolation ◽  
Nonlinear Damping ◽  
Quarter Car Model ◽  
Car Model ◽  
Pneumatic Chamber ◽  
Experimental Works ◽  
Quarter Car

Previous numerical and experimental works show that time delay technique is efficient to reduce transmissibility of vibration in a single pneumatic chamber by controlling the pressure in the chamber. The present work develops an analytical study to demonstrate the effectiveness of such a technique in reducing transmitted vibrations. A quarter-car model is considered and delayed hysteretic suspension is introduced in the system. Analytical predictions based on perturbation analysis show that a delayed hysteretic suspension enhances vibration isolation comparing to the case where the nonlinear damping is delay-independent.

Study on Nonlinear Damping Properties of Hydro-Pneumatic Suspension System for XP302-Pneumatic Tyred Roller

2014 ◽  
Vol 945-949 ◽  
pp. 987-991
Author(s):  
Bang Sheng Xing ◽  
Ning Ning Wang ◽  
Le Xu
Keyword(s):  
Dynamic Performance ◽  
Nonlinear Damping ◽  
Suspension System ◽  
Nonlinear Stiffness ◽  
Damping Properties ◽  
Vehicle Dynamic ◽  
Nonlinear Mathematical Model ◽  
Computer Simulation Program ◽  
Pneumatic Suspension ◽  
Stiffness And Damping

The nonlinear stiffness and damping properties of the hydro-pneumatic suspension system are introduced, and the nonlinear mathematical model of it is established. Using MATLAB 2009b to establish the computer simulation program and draw out the nonlinear stiffness curve and damping properties curve of the hydro-pneumatic suspension system. Then, researching the influences of related parameters' changes on the nonlinear stiffness and damping properties of the hydro-pneumatic suspension system. The simulation of vehicle dynamic performance research's foundation is provided.

Sources and Propagation of Nonlinearity in a Vibration Isolator With Geometrically Nonlinear Damping

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
J. C. Carranza ◽  
M. J. Brennan ◽  
B. Tang
Keyword(s):  
Vibration Isolation ◽  
Nonlinear Behavior ◽  
High Amplitude ◽  
Nonlinear Damping ◽  
Single Frequency ◽  
Geometrically Nonlinear ◽  
Harmonic Force ◽  
Isolation System ◽  
Linear Spring ◽  
Harmonic Components

In this paper, the behavior of a single degree-of-freedom (SDOF) passive vibration isolation system with geometrically nonlinear damping is investigated, and its displacement and force transmissibilities are compared with that of a linear system. The nonlinear system is composed of a linear spring and a linear viscous damper which are connected to a mass so that the damper is perpendicular to the spring. The system is excited by a harmonic force applied to the mass or a displacement of the base in the direction of the spring. The transmissibilities of the nonlinear isolation system are calculated using analytical expressions for small amplitudes of excitation and by using numerical simulations for high amplitude of excitation. When excited with a harmonic force, the forces transmitted through the spring and the damper are analyzed separately by decomposing the forces in terms of their harmonics. This enables the effects of these elements to be studied and to determine how they contribute individually to the nonlinear behavior of the system as a whole. For single frequency excitation, it is shown that the nonlinear damper causes distortion of the velocity of the suspended mass by generating higher harmonic components, and this combines with the time-varying nature of the damping in the system to severely distort the force transmitted though the damper. The distortion of the force transmitted through the spring is much smaller than that through the damper.

scholarly journals A Study on Vibration Characteristics and Stability of the Ambulance Nonlinear Damping System

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Meng Yang ◽  
Xinxi Xu ◽  
Chen Su
Keyword(s):  
Approximate Solution ◽  
Primary Resonance ◽  
Nonlinear Behavior ◽  
Singularity Theory ◽  
Nonlinear Damping ◽  
Nonlinear Stiffness ◽  
First Order ◽  
Damping Effect ◽  
Vibration Model ◽  
The Impact

Considering the impact of the nonlinear stiffness, a 2-DOF vibration model with cubic terms was established according to the structural feature and nonlinear behavior. Ignoring the impact of nonlinear terms, the system was linearly analyzed. In the case of primary resonance and 1 : 1 internal resonance, a multiscale method was used to obtain a first-order approximate solution. Taking the parameters of one tracked ambulance for instance, the approximate solution was corroborated and the influence of the parameters on damping effect was investigated. Finally, motion stability of the damping system was analyzed with singularity theory. The theoretical bases for improving efficiency of the damping system were provided.

On the Performance of a Two-Stage Vibration Isolation System Which has Geometrically Nonlinear Stiffness

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Zeqi Lu ◽  
Tiejun Yang ◽  
Michael J. Brennan ◽  
Xinhui Li ◽  
Zhigang Liu
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Single Stage ◽  
Nonlinear Stiffness ◽  
Two Stage ◽  
Isolation System ◽  
Beneficial Effects ◽  
Isolation Systems ◽  
The Right

Linear single-stage vibration isolation systems have a limitation on their performance, which can be overcome passively by using linear two-stage isolations systems. It has been demonstrated by several researchers that linear single-stage isolation systems can be improved upon by using nonlinear stiffness elements, especially for low-frequency vibrations. In this paper, an investigation is conducted into whether the same improvements can be made to a linear two-stage isolation system using the same methodology for both force and base excitation. The benefits of incorporating geometric stiffness nonlinearity in both upper and lower stages are studied. It is found that there are beneficial effects of using nonlinearity in the stiffness in both stages for both types of excitation. Further, it is found that this nonlinearity causes the transmissibility at the lower resonance frequency to bend to the right, but the transmissibility at the higher resonance frequency is not affected in the same way. Generally, it is found that a nonlinear two-stage system has superior isolation performance compared to that of a linear two-stage isolator.

scholarly journals Nonlinear Torsional Vibration Dynamics Behaviors of Rolling Mill’s Multi-DOF Main Drive System under Parametric Excitation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Dongying Han ◽  
Peiming Shi ◽  
Kewei Xia
Keyword(s):  
Torsional Vibration ◽  
Joint Angle ◽  
Rolling Process ◽  
Nonlinear Damping ◽  
Drive System ◽  
Nonlinear Stiffness ◽  
Coupled Equations ◽  
Principal Coordinates ◽  
Damping Torque ◽  
Main Drive System

Considering the influence caused by joint angle, nonlinear damping, and nonlinear rigidity, the nonlinear torsional vibration dynamical modeling of the multi-DOF rolling mill’s main drive system is established. To analyze the coupled equations by analytic method, the equations are decoupled by transforming them into principal coordinates. The amplitude-frequency characteristic equations are obtained by multiscale method. Furthermore, numerical example based on the 1780 rolling mill’s main drive system of some Steel Co. is given to illustrate the effects of the resonance on the response of the system. The relationship between amplitude and frequency varies according to the parameters changes of nonlinear stiffness, nonlinear friction damping, torque disturbance, and joint angle. During the rolling process, the limited joint angles range is obtained and the variation rules of the joint angle caused by the nonlinear damping, nonlinear stiffness, and the disturbance torque are gained. The results present that the rolling mill can work more stably with the joint angle at a range from 2° to 8° by controlling the value of parameters. The research results provide a theoretical basis and reference for analyzing torsional vibration of rolling mill’s transmission system caused by joint angle.

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