scholarly journals INCREASED VIBRATION ON REFRIGERATOR SHIPS OF B437/11 PROJECT AND TECHNICAL PROPOSALS ON ITS REDUCTION

2018 ◽  
pp. 58-69
Author(s):  
Minas Armenakovich Minasyan ◽  
Aung Myo Thant ◽  
Armen Minasovich Minasyan
Keyword(s):  
Service Life ◽  
Vibration Isolation ◽  
Steel Wire ◽  
Modern Technology ◽  
Wire Rope ◽  
Diesel Generator ◽  
Vibration Isolators ◽  
Wide Range ◽  
Isolation Systems ◽  
The Impact

The paper considers the causes of increased vibration of four auxiliary diesel-generator sets of "Sulzer" 5АL25 type on board nine refrigerated vessels of B437 / 11 project after 15 years of operation. The proposed wide range of possible applications to address the problem of high vibration of diesel generators and motor vessels there were generally implemented upgraded turbocharger brackets, engine sub-frame and supporting spiral-rope vibration isolators in the shock absorption system of the diesel-generator. Four original patented technical solutions have been presented, among which one solution is implemented in 5AL25 diesel generator and 2H 8.5/11 diesel damping systems. There has been offered wide application both wire rope vibration isolators and combined isolators, in which elastic elements are made of nonflammable materials. Wire rope vibration isolators combine high bearing capacity (static loads within 1 N - 50 kN) with high elasticity under dynamic effects; their natural frequencies can drop to 2.5 Hz. Under the worst conditions 75% of the free moving weakens the impact to values that ensure the necessary safety of the object. Experience in designing vibration isolation systems allows to set the maximum range of loads within 15 - 25 g. The vibration isolators made of steel wire rope are practically not affected by the environment, they are made of stainless steel. They effectively operate at temperatures -200°C - +370°C in the presence of oil, dirt, sand, salt fog, etc. They usually have a service life comparable with the service life of the insulated object. Wire rope vibration isolators and combined vibration isolators can be used in all fields of modern technology: shipbuilding, power engineering, automotive, aviation and space industries, etc.

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.

Rolling/Sliding Wear Behavior of High Carbon Steel Wire Rod (HSWR) of Traction Machine

2008 ◽  
Author(s):  
Beom-Taek Jang ◽  
Seock-Sam Kim
Keyword(s):  
Wear Behavior ◽  
Steel Wire ◽  
High Carbon Steel ◽  
Wire Rope ◽  
Wear Volume ◽  
Steel Wires ◽  
Volume Curve ◽  
Wide Range ◽  
Lubrication Condition ◽  
Worn Surface

Steel wires are critical load-bearing components in a wide range of applications such as elevator, cranes, mine haulage etc. The traction machine of elevator which transmits power to wire rope causes micro-slip between wire rope and sheave during reciprocating action. The lubrication condition of wire rope is also changed due to the lack of grease. This study focuses on the wear behavior of steel wire and effect of both dry and grease conditions by using the rolling/sliding contact wear tester done under various slip ratios and rolling speeds. The experimental results of the wear volume curve against the number of revolutions under the grease condition are compared with the results under dry condition. The worn surface of steel wire and the size of wear particles were observed by SEM. In order to quantify the wear amount of steel wire we established an equation and finally obtained the wear coefficient.

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 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 Dynamically variable negative stiffness structures

2016 ◽  
Vol 2 (2) ◽  
pp. e1500778 ◽  
Author(s):  
Christopher B. Churchill ◽  
David W. Shahan ◽  
Sloan P. Smith ◽  
Andrew C. Keefe ◽  
Geoffrey P. McKnight
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Variable Stiffness ◽  
Negative Stiffness ◽  
Load Bearing ◽  
Vibration Isolators ◽  
Wide Range ◽  
Engineered Systems ◽  
Tunable Stiffness

Variable stiffness structures that enable a wide range of efficient load-bearing and dexterous activity are ubiquitous in mammalian musculoskeletal systems but are rare in engineered systems because of their complexity, power, and cost. We present a new negative stiffness–based load-bearing structure with dynamically tunable stiffness. Negative stiffness, traditionally used to achieve novel response from passive structures, is a powerful tool to achieve dynamic stiffness changes when configured with an active component. Using relatively simple hardware and low-power, low-frequency actuation, we show an assembly capable of fast (<10 ms) and useful (>100×) dynamic stiffness control. This approach mitigates limitations of conventional tunable stiffness structures that exhibit either small (<30%) stiffness change, high friction, poor load/torque transmission at low stiffness, or high power active control at the frequencies of interest. We experimentally demonstrate actively tunable vibration isolation and stiffness tuning independent of supported loads, enhancing applications such as humanoid robotic limbs and lightweight adaptive vibration isolators.

scholarly journals Vibration Isolation Critical to Measuring Neuronal Patterns in the Brain

2009 ◽  
Vol 17 (3) ◽  
pp. 12-15
Author(s):  
David L. Platus
Keyword(s):  
Neuronal Activity ◽  
Vibration Isolation ◽  
Medical Center ◽  
Low Frequency ◽  
Vibration Isolators ◽  
Low Frequency Vibration ◽  
Conducting Research ◽  
Neuronal Patterns ◽  
Isolation Systems ◽  
The Brain

Researchers at Georgetown University's Department of Physiology and Biophysics use negative-stiffness vibration isolators to help measure micron-level patterns of neuronal activity in the mammalian neocortex. The research is shedding new light into brain sensory and motor processing functions relating to cardiac fibrillation and epilepsy.Isolating a laboratory's sensitive microscopy equipment against low-frequency vibration has become increasingly more vital to maintaining imaging quality and data integrity for neurobiology researches. Ever more frequently, laboratory researchers are discovering that conventional air tables and the more recent active (electronic) vibration isolation systems are not able to adequately cancel out the lower frequency perturbations derived from air conditioning systems, outside vehicular movements and ambulatory personnel. Such was the case with the Department of Physiology and Biophysics at Georgetown University Medical Center, where Professor Jian-Young Wu has been conducting research on waves of neuronal activity in the neocortex of the brain.

The Structural Design and Experimental Research of Multi-Level Cushioning Packaging Storage Box

2013 ◽  
Vol 655-657 ◽  
pp. 207-210
Author(s):  
Ming Xi Hu ◽  
Sheng Jun Liu ◽  
Yan Jun Zhang ◽  
Zhen Jie Du ◽  
Feng Tian ◽  
...  
Keyword(s):  
Experimental Research ◽  
Structural Design ◽  
Impact Force ◽  
Steel Wire ◽  
Wire Rope ◽  
Hydraulic Damper ◽  
Emergency Rescue ◽  
Multi Level ◽  
The Moment ◽  
The Impact

Aiming at the damage of package caused by emergency rescue and other severe transportation environment, a multi-level cushioning packaging storage box is proposed in this paper, the precise instrument is fixed in the box, which achieves the box-instrument integration. At the moment when air-dropped box touches the ground, the impact force is absorbed and cushioned through plastic cork base, rubber absorber, box body, steel wire rope spring, hydraulic damper for five times, which could provide effective cushion protection for the precise instrument which fragility value is not less than 15G. Simulation airdrop tests are performed to the storage box with different cushion levels, and the test shows that the result of five-level cushion method proposed in the paper is the best, and overload values are all within 12G, which could provide enough cushion space for precise instrument to avoid touchdown damage.

Resonance Characteristics of Unidirectional Viscous and Coulomb-Damped Vibration Isolation Systems

1967 ◽  
Vol 89 (4) ◽  
pp. 729-740 ◽  
Author(s):  
Jerome E. Ruzicka
Keyword(s):  
Resonant Frequency ◽  
Vibration Isolation ◽  
Elementary Theory ◽  
Rate Of Change ◽  
Design Data ◽  
Isolation System ◽  
Extensive Evaluation ◽  
Wide Range ◽  
Isolation Systems ◽  
Damped Systems

Elementary vibration theory based on transfer response analyses of single-degree-of-freedom systems indicates that an increase in isolation system damping causes a decrease in resonant transmissibility. This theory further specifies that, for viscous-damped systems, an increase in damping decreases the resonant frequency whereas, for Coulomb-damped systems, an increase in damping increases the resonant frequency. It is frequently found in practice that an increase in damping may increase the resonant transmissibility and cause a change in resonant frequency opposite to that predicted by elementary theory. This paper presents a more extensive evaluation of the resonance characteristics of unidirectional vibration isolation systems, including the effects of directly coupled and elastically coupled damping elements. Mathematical models and absolute transmissibility characteristics of viscous and Coulomb-damped vibration isolation systems are discussed and resonance characteristics are analyzed in terms of the resonant frequency ratio, the resonant transmissibility, and the rate of change of these parameters with damping. Design data are presented graphically for parametric variations of stiffness and damping which are sufficiently broad to encompass a wide range of practical engineering problems.

STUDY OF THE VIBRATION ISOLATION SYSTEM OF MARINE POWER PLANTS WITH A 5AL 25/30 DIESEL DRIVE

Akustika ◽  
2021 ◽  
pp. 112
Author(s):  
Minas Minasyan ◽  
Armen Minasyan ◽  
Kyaw Thet Naing
Keyword(s):  
Experimental Study ◽  
Diesel Engine ◽  
Power Plants ◽  
Vibration Isolation ◽  
Field Studies ◽  
Absorption System ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
The Impact

The article is devoted to the study of the support and side stop vibration isolation system of two marine power plants DGA- 500 with a 5AL 25/30 drive diesel engine, in which a hypothesis is put forward about the imperfection of the shock absorption system. The purpose of the research is to substantiate the imperfection of the support and side stop vibration isolation system of marine power plants with a 5 AL 25/30 drive diesel engine. The confirmation of this hypothesis and the achievement of this goal is justified on the basis of presentation of the results of field studies on the project’s courts B437/11 and the personal presence during the preparation of DGA-500 to repair at the shipyard. For the use of unbalanced engines as a drive for ship power plants, the authors, on the basis of a full-scale experimental study and analysis of known works, recommend initially assessing the possibility and purpose of depreciation of the unit according to the Katz unbalance criterion [1]. The objective of fixing the unit with diesel 5AL 25/30 on the criterion of imbalance Katz is soundproof, and the calculation of depreciation should be based on the impact of side stop vibration isolators. A significant improvement is recommended to the support 36-40 and side stop 41-52 vibration isolation system, elastic pipe fittings 8, support frame 2 and turbocharger bracket 4 (Fig. 1).

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