Compounding an Ethylene Propylene Terpolmer Elastomer for Dynamic Applications

1965 ◽  
Vol 38 (4) ◽  
pp. 967-978
Author(s):  
G. A. Baseden
Keyword(s):  
Low Temperatures ◽  
Vibration Isolation ◽  
Dynamic Properties ◽  
Ethylene Propylene ◽  
Vibration Isolators

Abstract Dynamic properties of vibration isolators made with EPT vulcanizates may be controlled, within limits, by choice of compounding ingredients in the vulcanizate. The choice of compounding ingredients will also affect efficiency of the isolator in preventing transmission of vibrations at low temperatures. Efficiency of vibration isolation may be calculated by measuring dynamic spring rates at the temperatures of operation.

Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

2020 ◽  
pp. 66-73
Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Molecular Mobility ◽  
Fe3o4 Nanoparticles ◽  
Low Temperatures ◽  
Frost Resistance ◽  
Relaxation Processes ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

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.

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 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.

On the Effects of Mistuning a Force-Excited System Containing a Quasi-Zero-Stiffness Vibration Isolator

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Ali Abolfathi ◽  
M. J. Brennan ◽  
T. P. Waters ◽  
B. Tang
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Vibration Isolator ◽  
Linear Vibration ◽  
Vibration Isolators ◽  
Zero Dynamic ◽  
Low Frequency Vibration ◽  
Excited System ◽  
Better Than

Nonlinear isolators with high-static-low-dynamic-stiffness have received considerable attention in the recent literature due to their performance benefits compared to linear vibration isolators. A quasi-zero-stiffness (QZS) isolator is a particular case of this type of isolator, which has a zero dynamic stiffness at the static equilibrium position. These types of isolators can be used to achieve very low frequency vibration isolation, but a drawback is that they have purely hardening stiffness behavior. If something occurs to destroy the symmetry of the system, for example, by an additional static load being applied to the isolator during operation, or by the incorrect mass being suspended on the isolator, then the isolator behavior will change dramatically. The question is whether this will be detrimental to the performance of the isolator and this is addressed in this paper. The analysis in this paper shows that although the asymmetry will degrade the performance of the isolator compared to the perfectly tuned case, it will still perform better than the corresponding linear isolator provided that the amplitude of excitation is not too large.

scholarly journals Reconstruction of Input Excitation Acting on Vibration Isolation System

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Pan Zhou ◽  
Wen L. Li ◽  
Wanyou Li ◽  
Zhijun Shuai
Keyword(s):  
Vibration Isolation ◽  
Mechanical Design ◽  
Spectral Density Function ◽  
Dynamic Responses ◽  
Accurate Estimation ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
Supporting Structure ◽  
Vibration Prediction

Vibration isolation systems are widely employed in automotive, marine, aerospace, and other engineering fields. Accurate input forces are of great significance for mechanical design, vibration prediction, and structure modification and optimization. One-stage vibration isolation system including engine, vibration isolators, and flexible supporting structure is modeled theoretically in this paper. Input excitation acting on the vibration isolation system is reconstructed using dynamic responses measured on engine and supporting structure under in-suit condition. The reconstructed forces reveal that dynamic responses on rigid body are likely to provide more accurate estimation results. Moreover, in order to improve the accuracy of excitation reconstructed by dynamic responses on flexible supporting structure, auto/cross-power spectral density function is utilized to reduce measurement noise.

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