Two-Dimensional Linear Friction Damper Consisting of Concave Cone and Cylindrical Member (Investigation of Performance by Numerical Simulation and Experiment)

2015 ◽  
Author(s):  
Hideya Yamaguchi ◽  
Hidehisa Yoshida
Keyword(s):  
Numerical Simulations ◽  
Friction Force ◽  
Vibration Isolation ◽  
Two Dimensions ◽  
Resonant Peak ◽  
Friction Damper ◽  
Isolation System ◽  
Friction Forces ◽  
Vibration Isolation System ◽  
Linear Friction

A passive vibration isolation system consisting of a constant friction force has performance limitations; the isolation performance declines and the residual displacement becomes large in the case of the large friction force, while the resonant peak becomes large in the case of the small friction force. It is known that above drawbacks are avoidable when the friction force varies in proportion to the relative displacement. Recently, authors have proposed a simple linear friction damper mechanism that consists of a cylindrical block and a tilt lever supported with a pivot or a leaf spring. Performance of the vibration isolation system equipped with the proposed damper is investigated, and its effectiveness is confirmed by numerical simulations and the experiments. However, the motion of the mechanism is limited to one-dimension. This paper proposes an extended mechanism that can be applied to motion moving in two dimensions by combining the concave cone and the cylindrical member. The concave cone is supported with a universal joint on the apex side and its tilting motion is constrained by the restoring spring. The rounded edge of the cylindrical member is set up to contact the inside flank of the concave cone. When the cylindrical member moves in an arbitrary direction on the planar floor and pushes the concave cone, the normal and friction forces at the contact point vary depending on the displacement of the cylindrical member. The fundamental property and the performance of the proposed mechanism are investigated by numerical simulations and experiments.

Linear Friction Damper Consisted of Cylindrical Block and Inclined Lever (Improvement to Avoid Sprag-Slip Problem and Analytical Model to Verify Cause)

2011 ◽  
Author(s):  
Hideya Yamaguchi ◽  
Hidehisa Yoshida
Keyword(s):  
Analytical Model ◽  
Friction Force ◽  
Friction Damper ◽  
Friction Forces ◽  
Constant Friction ◽  
Linear Friction ◽  
New Type ◽  
Passive Isolation ◽  
Isolation Systems ◽  
Cylindrical Block

For the passive isolation systems, the ordinary friction damper of constant friction force has performance limitations. This is, because the isolation characteristic declines and the displacement remains apart from the equilibrium position after the disturbance disappears, when the friction force is large. It is known that the above drawbacks are improved when the friction force varies depending on the displacement. The authors have proposed a new type of friction damper in our previous paper. This friction damper uses an inclined lever, which contacts the cylindrical block by means of a rotational spring. The angle of inclination of the lever varies together with the displacement of the cylindrical block. Then, the normal and friction forces on the contact surface vary depending on the displacement. However, “Sprag-slip” vibration occurred in some cases in the experiments. This paper investigates the cause of the vibration and a design to prevent it. Then, an analytical model is proposed to simulate the problem and to estimate the effect of improvement.

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.

Investigation of Damping Nonlinearity in Duffing-Type Vibration Isolation System With Geometric and Magnetic Stiffness Nonlinearities

2017 ◽  
Author(s):  
S. M. Mahdi Mofidian ◽  
Hamzeh Bardaweel
Keyword(s):  
Resonant Frequency ◽  
Dynamic Behavior ◽  
Vibration Isolation ◽  
Harmonic Balance Method ◽  
Nonlinear Damping ◽  
Resonant Peak ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Magnetic Stiffness ◽  
Sinusoidal Input

In this work, the effect of nonlinear damping in presence of geometric nonlinearities and magnetic stiffness nonlinearities in vibration isolation system is investigated. The dynamic behavior of the isolation system design is modeled. Harmonic Balance Method (HBM) is used to investigate the dynamic behavior of the vibration isolation system in response to sinusoidal input waveform. Results obtained using the HBM are compared to the results from numerical simulation attained using Runge-kutta method. Results show that introducing nonlinear viscous damping into the vibration isolation system suppresses frequency jump phenomena observed in Duffing-type vibration isolation systems. Additionally, results show that nonlinear damping can suppress transmissibility around resonant peak. For frequencies lower than resonant frequency the effect of nonlinear damping is minimum compared to a linear isolation system. Beyond resonant frequency higher nonlinear damping may slightly alter transmissibility of the isolation system.

Principle and Application of Free Resonance Vibration Isolation Based on Dry Friction Damper

2011 ◽  
Vol 141 ◽  
pp. 59-63
Author(s):  
Hui Jie Yu ◽  
Xiao Long Yan
Keyword(s):  
Dry Friction ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Resonance Vibration ◽  
Transmission Ratio ◽  
Friction Damper ◽  
Frequency Range ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Classical Vibration

This paper deals with the analysis of a single degree of freedom vibration isolation system with dry friction damper. Based on the analysis of classical vibration isolation transmission ratio, the conditions of free resonance are found. Regard to the character of vibration isolation system on critical frequency of vibration isolation and resonance, the transmission ratio formula of vibration isolation with friction force under full frequency range is educed which provided the rounded theory principle for free resonance vibration isolation. The vibration isolation system is designed which can realize the non-amplification in low frequency range and better vibration isolation effect in high frequency. Lately, the correctness of the principle is verified by the actual experiment.

Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

2021 ◽  
pp. 107754632110005
Author(s):  
Yonglei Zhang ◽  
Guo Wei ◽  
Hao Wen ◽  
Dongping Jin ◽  
Haiyan Hu
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stiffness Characteristic ◽  
Negative Stiffness Mechanism ◽  
Isolation Systems ◽  
Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

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