A Detailed Mechanical Model of a Double Pumper Fluid Mount

1998 ◽  
Vol 120 (2) ◽  
pp. 361-370 ◽  
Author(s):  
N. Vahdati
Keyword(s):  
Mechanical Model ◽  
Vibration Isolation ◽  
Detailed Model ◽  
Noise And Vibration ◽  
Vibration Isolators ◽  
The Past

Conventional passive elastomenc mounts have been used as noise and vibration isolators in the automotive and aircraft industries for many years. For even better noise and vibration isolation, passive fluid mounts have been replacing elastomeric mounts in both the automotive and aerospace industries during the past few years. With more increase in the popularity of fluid mounts, it is important to characterize the dynamics of the fluid mounts more accurately. Many papers have been published on the modeling of these devices, but mostly on single pumper fluid mounts. In this paper, we focus on double pumper fluid mounts. The intent of this paper is to develop a very detailed model of a double pumper fluid mount including all dampings.

Acoustic decoupling for structural elements by affixed supports - inherent contradiction or perfect complement? Restrained vibration isolation supports - a critical review

2021 ◽  
Vol 263 (4) ◽  
pp. 2801-2811
Author(s):  
Adam Wells ◽  
Patrick Carels
Keyword(s):  
Analytical Model ◽  
Critical Review ◽  
Laboratory Testing ◽  
Vibration Isolation ◽  
Mechanical Vibration ◽  
Structural Elements ◽  
Noise And Vibration ◽  
Vibration Isolators ◽  
Models Comparison ◽  
Isolation Performance

Restrained vibration isolation supports balance efficient isolation performance and stability for the supporting body under present loads. Necessary and beneficially for noise and vibration isolation applications with stringent stability requirements, such as full building isolation with potential uplift, interior partition sway bracing, curtain walls, elevator rail isolation, and mechanical vibration isolation, the performance of restrained vibration isolators are often misunderstood or oversimplified. This paper investigates the general vibration isolation theory used to create the analytical model for restrained isolation supports, intricacies of vibration isolation materials which may cause reality to diverge from well-known models, comparison of theory to laboratory testing, and a review of common uses/applications for these types of vibration isolation solutions, and recommendation to avoid undesired results from common pitfalls associated with restrained isolation supports implementation and installations.

scholarly journals A Novel Approach to the Analysis of Under Sleeper Pads (USP) Applied in the Ballasted Track Structures

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2438 ◽  
Author(s):  
Artur Zbiciak ◽  
Cezary Kraśkiewicz ◽  
Anna Al Sabouni-Zawadzka ◽  
Jan Pełczyński ◽  
Sławomir Dudziak
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Mechanical Model ◽  
Rheological Model ◽  
Laboratory Tests ◽  
Vibration Isolation ◽  
Special Focus ◽  
Vibration Isolators ◽  
Novel Approach ◽  
Ballasted Track

The present paper is dedicated to the analysis of under sleeper pads (USP), which are resilient elements used in ballasted track systems as vibration isolators. Four types of USP are considered. The authors present the results of laboratory tests, which are then used as input values for the finite element (FE) and mechanical model of the structure. A special focus is put on the description of an original four-degree-of-freedom (4DoF) mechanical model of the system that includes a fractional rheological model of USP. Using the proposed approaches, the dynamic characteristics of under sleeper pads are determined, and conclusions on vibration isolation effectiveness are drawn.

A Variable Stiffness Vibration Isolation System Based on Magneto-Rheological Elastomer

2012 ◽  
Vol 452-453 ◽  
pp. 659-662
Author(s):  
Wei Wang ◽  
Yi Min Deng
Keyword(s):  
Shear Modulus ◽  
Vibration Isolation ◽  
Variable Stiffness ◽  
Control Area ◽  
Frequency Range ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
Magneto Rheological ◽  
Conventional Type

Vibration isolation is a most widely used vibration protection method.The stiffness of vibration isolators in existing conventional type of vibration isolation system is usually of fixed value. This limits the system in exhibiting its vibration isolation effect in that, it has poor results for lower frequency vibration, especially for resonance frequency. Magneto-rheological elastomer is a new branch of Magneto-rheological materials. It’s an intelligent materials in that it’s shear modulus can be controlled by a magnetic field. It has wide application prospects in the vibration control area. This paper proposes using adjustable stiffness of magneto-rheological elastomer vibration isolation in vibration isolation system. By changing the current of vibration isolators coil to control the shear modulus of magneto-rheological elastomer, it can adjust the stiffness of the isolation system, making the system obtain wider vibration isolation frequency range. By exploying SimuLink software to analyze the vibration isolation system, it is found that such a design is effective and applicable.

scholarly journals Laboratory Tests and Analyses of the Level of Vibration Suppression of Prototype under Ballast Mats (UBM) in the Ballasted Track Systems

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 313
Author(s):  
Cezary Kraśkiewicz ◽  
Artur Zbiciak ◽  
Kacper Wasilewski ◽  
Anna Al Sabouni-Zawadzka
Keyword(s):  
Mechanical Model ◽  
Laboratory Tests ◽  
Vibration Suppression ◽  
Track Structure ◽  
European Standard ◽  
Static And Dynamic Characteristics ◽  
Vibration Isolators ◽  
Testing Procedures ◽  
Ballasted Track ◽  
German Standard

The present paper is aimed at the analysis of under ballast mats (UBM) which are used in ballasted track structures as vibration isolators and to protect the ballast layer against fast degradation. The mats were tested in the laboratory and afterwards a novel 4-DoF mechanical model of the track structure with UBM was developed. The novelty of this study consists in the comparison of two testing procedures: a procedure based on the popular German standard DIN 45673-5 and a new European standard EN 17282, released in October 2020. Major discrepancies were demonstrated in the determined values of the static and dynamic characteristics using both approaches—especially in reference to the mats with higher stiffness.

Energy flow and performance evaluation of inerter-based vibration isolators mounted on finite and infinite flexible foundation structures

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110704
Author(s):  
Zhuang Dong ◽  
Jian Yang ◽  
Chendi Zhu ◽  
Dimitrios Chronopoulos ◽  
Tianyun Li
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Flow Behavior ◽  
Flexible Beam ◽  
Vibration Isolators ◽  
Force Transmissibility ◽  
And Performance ◽  
Flexible Foundation ◽  
Isolation Performance

This study investigates the vibration power flow behavior and performance of inerter-based vibration isolators mounted on finite and infinite flexible beam structures. Two configurations of vibration isolators with spring, damper, and inerter as well as different rigidities of finite and infinite foundation structures are considered. Both the time-averaged power flow transmission and the force transmissibility are studied and used as indices to evaluate the isolation performance. Comparisons are made between the two proposed configurations of inerter-based isolators and the conventional spring-damper isolators to show potential performance benefits of including inerter for effective vibration isolation. It is shown that by configuring the inerter, spring, and damper in parallel in the isolator, anti-peaks are introduced in the time-averaged transmitted power and force transmissibility at specific frequencies such that the vibration transmission to the foundation can be greatly suppressed. When the inerter is connected in series with a spring-damper unit and then in-parallel with a spring, considerable improvement in vibration isolation can be achieved near the original peak frequency while maintaining good high-frequency isolation performance. The study provides better understanding of the effects of adding inerters to vibration isolators mounted on a flexible foundation, and benefits enhanced designs of inerter-based vibration suppression systems.

Influence of Fractional Damping and Time Delay on Maxwell-Voigt Model for Vibration Isolation

2016 ◽  
Author(s):  
Sudhir Kaul
Keyword(s):  
Time Delay ◽  
Dynamic Characteristics ◽  
Vibration Isolation ◽  
Model Parameters ◽  
Fractional Damping ◽  
Vibration Isolators ◽  
Multiple Parameters ◽  
Realistic Representation ◽  
Voigt Model ◽  
Isolation Systems

Models of vibration isolators are very commonly used for the design and analysis of isolation systems. Accurate isolator modeling is critical for a successful prediction of the dynamic characteristics of isolated systems. Isolators exhibit a complex behavior that depends on multiple parameters such as frequency, displacement amplitude, temperature and loading conditions. Therefore, it is important to choose a model that is accurate while adequately representing the relationships with relevant parameters. Recent literature has indicated some inherent advantages of fractional derivatives that can be exploited in the modeling of elastomeric isolators. Furthermore, time delay of damping is also seen to provide a realistic representation of damping. This paper examines the Maxwell-Voigt model with fractional damping and a time delay. This model is compared with the conventional Maxwell-Voigt model (without time delay or fractional damping) and the Voigt model in order to comprehend the influence of fractional damping and time delay on dynamic characteristics. Multiple simulations are performed after identifying model parameters from the data collected for a passive elastomeric isolator. The analysis results are compared and it is observed that the Voigt model is highly sensitive to fractional damping as well as time delay.

scholarly journals Experimental investigation of torsional vibration isolation using Magneto Rheological Elastomer

2018 ◽  
Vol 144 ◽  
pp. 01007
Author(s):  
K Praveen Shenoy ◽  
Abhishek Kumar Singh ◽  
K Sai Aditya Raman ◽  
K. V. Gangadharan
Keyword(s):  
Magnetic Field ◽  
Vibration Isolation ◽  
Dynamic Performance ◽  
Torsional Vibrations ◽  
Loading Conditions ◽  
Vibration Isolators ◽  
Rotating Systems ◽  
Modes Of Vibration ◽  
Magneto Rheological ◽  
Average Size

Rotating systems suffer from lateral and torsional vibrations which have detrimental effect on the roto-dynamic performance. Many available technologies such as vibration isolators and vibration absorbers deal with the torsional vibrations to a certain extent, however passive isolators and absorbers find less application when the input conditions are dynamic. The present work discusses use of a smart material called as Magneto Rheological Elastomer (MRE), whose properties can be changed based on magnetic field input, as a potential isolator for torsional vibrations under dynamic loading conditions. Carbonyl Iron Particles (CIP) of average size 5 μm were mixed with RTV Silicone rubber to form the MRE. The effect of magnetic field on the system parameters was comprehended under impulse loading conditions using a custom built in-house system. Series arrangement of accelerometers were used to differentiate between the torsional and the bending modes of vibration of the system. Impact hammer tests were carried out on the torsional system to study its response, in the presence and absence of magnetic field. The tests revealed a shift in torsional frequency in the presence of magnetic field which elucidates the ability of MRE to work as a potential vibration isolator for torsional systems.

scholarly journals The trend of the oxidants in boreal forest over 2007–2018: comprehensive modelling study with long-term measurements at SMEAR II, Finland

2020 ◽  
Author(s):  
Dean Chen ◽  
Putian Zhou ◽  
Tuomo Nieminen ◽  
Pontus Roldin ◽  
Ximeng Qi ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Size Range ◽  
Chemical Components ◽  
Detailed Model ◽  
One Dimensional ◽  
The Past ◽  
Main Driver ◽  
The One ◽  
Long Term Trend

Abstract. Major atmospheric oxidants (OH, O3 and NO3) dominate the atmospheric oxidation capacity, while H2SO4 is considered as a main driver for new particle formation events. Although numerous studies have investigated the long-term trend of ozone in Europe, the trend of OH, NO3 and H2SO4 at specific sites are to a large extent unknown. In this study, we investigated how the trends in major atmospheric oxidants (OH, O3 and NO3) and H2SO4 changed in southern Finland during the past 12 years and discuss how these trends relate to decreasing emissions of regulated air pollutants in Europe. The one-dimensional model SOSAA has been applied in several studies at the SMEAR II station, and has been validated by measurements in several projects. Here, we ran the SOSAA model for the years 2007–2018 to simulate the atmospheric chemical components, especially the atmospheric oxidants and H2SO4 at SMEAR II. The simulations were evaluated with observations at SMEAR II for several shorter and longer campaigns. Our results show that OH increased by +1.56 (−0.8; +3.17) % yr−1 during daytime and NO3 decreased by −3.92 (−6.49; −1.79) % yr−1 during nighttime, indicating different trends of the oxidants during day and night. Sulphuric acid decreased during daytime by −5.12 (−11.39; −0.52) % yr−1, which correlated with the observed decreasing concentration of newly formed particles in the size range 3–25 nm by 1.4 % yr−1 at SMEAR II during the years 1997–2012 (Nieminen et al., 2014). Additionally we compared our simulated OH, NO3 and H2SO4 concentrations with proxies, which are commonly applied in case limited amount of parameters are measured and no detailed model simulations are available.

scholarly journals Influence of the use of spring vibration isolators in the construction of track pavement for damping vibrations from the track

2018 ◽  
Vol 2018 (5) ◽  
pp. 1-9
Author(s):  
Ewelina Kwiatkowska ◽  
Wiesław Fiebig
Keyword(s):  
Noise Reduction ◽  
Vibration Isolation ◽  
New Technology ◽  
Track Structure ◽  
Vibration Isolators ◽  
Isolation Systems ◽  
Tuning Frequency ◽  
Mass Spring ◽  
Lower Frequencies

The paper presents tuned track bed vibration isolation systems used for the railway and tramway lines. The presented solution based on mass spring systems and is effective especially at lower frequencies. The tuning frequency of such systems is mostly in the range 5 to 8 Hz. With measures based on spring elements elaborated by GERB company the significant vibration and noise reduction coming from the railways and tramways can be achieved. This new technology in Poland can be used during the track structure modernization as well as in the new projects, in which the track bed vibration isolation is required.

scholarly journals STUDY OF THE EFFECTIVENESS OF VIBRATION ISOLATION OF UNCONVENTIONAL TOROIDAL ROPE VIBRATION ISOLATORS IN DIESEL UNITS VIBRATION ISOLATION SYSTEM

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 110-114
Author(s):  
Minas Minasyan ◽  
Armen Minasyan ◽  
Aung Thant
Keyword(s):  
Power Plants ◽  
Vibration Isolation ◽  
Steel Wire ◽  
Experimental Studies ◽  
Wire Rope ◽  
Diesel Generator ◽  
Isolation System ◽  
Vibration Isolators ◽  
Before And After ◽  
Materials Used

The paper notes that the structure of the wire rope is one of the most suitable materials used as a fire-resistant elastic element of vibration-insulating structures and fasteners (vibration isolators). To solve the problems of vibration isolation of marine diesel power plants in the framework of development and improvement of the shock absorption system, the original patented elastic supports with elastic elements made of steel wire rope in the form of a torus are presented. When commercially available vibration isolators do not meet the relevant requirements of vibration protection of a particular object, the solution to the existing problem can be achieved by using the proposed wire rope vibration isolators. The technical results of the original patented inventions are: - equal stiffness in the horizontal plane - ensuring the reliability and high vibration efficiency of protection against impacts and shocks. The proposed designs of vibration isolators are easy (technological in manufacturing) to manufacture and assemble, reliable and durable - the service life is 10 years or more. Vibration efficiency is confirmed by the vibration acceleration spectra before and after the vibration isolator of the damping system of the ship diesel-generator DGA-500 and the diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame. The three-year trial life of the DGA-500 and experimental studies on a diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame confirms their efficiency and effectiveness.

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