Anti-vibration Mount Research Articles

Deflection Prediction of an Anti-vibration Mount by Finite Element Analysis

Deflection Prediction of an Anti-vibration Mount by Finite Element Analysis

Optimization for anti-vibration mount performance analysis

Optimization for anti-vibration mount performance analysis

Effects of Sand Bed Anti-Vibration Mount on Transmitted Noise from Portable On-Site Electricity Generator

This study investigated the effect of different particle sizes of sand bed anti-vibration mount on transmitted noise from a portable on-site electricity generator. Ten sand bed anti-vibration mounts, 650mm x 650mm in cross section and 75mm thickness were prepared with particle sizes ranging from 0.09 to 2.30mm. Noise measurements were taken in the four cardinal directions using Extech HD600 digital sound level meter. The results of the study showed that the ability of the sand particles to dampen vibration noise from the portable electricity generator reduces with increase in particle size. The sand bed anti-vibration mounts reduced noise levels by 0.11 to 2.78 dB(A). However, fine sand bed of particle size 0.09mm and 0.15mm exhibited superiority in noise reduction over all other sand beds. In order to achieve appreciable noise reduction, the use of ISO 14688-1:2002 fine sand category is recommended as anti-vibration mount in combination with other damping methods.
 Keywords: Electricity generator, noise, sand, particle size and attenuation

The Influence of the Number of Polyurethane Anti-Vibration Mount on the Vibration Damping Efficiency of Steel Structure

Abstract The publication presents the results of research on the statistically significant impact of the number of layers on vibration damping properties of vibroacoustic mats. The research was carried out on the author’s research stand. The research was carried out on sandwich systems made of polyurethane foam. The impact force of the analyzed variables was determined on the basis of constructed multiple regression models, the so-called multifactor models and determination of the standardized value β. The research was carried out using the PQStat software. In the models being built, the significance level was p < 0.05. Three statistically significant linear multivariate models for one-third frequencies were constructed: • 0-20000 Hz – a model for the entire frequency spectrum analysed during the tests, • 0-400 Hz – a model for frequencies generating construction vibrations that may affect the worker as general vibrations, • 50-20000 Hz – a model for frequencies that generate construction vibrations that can cause auditory sensations (noise). It was found: positive correlation of the number of layers in vibration damping systems with a third octave frequency of up to 400 Hz; negative correlation of the number of layers in vibration damping systems with a third octave frequency of 50 to 20000 Hz.

Research on Design and Method to Predict Fatigue Life of an Anti-Vibration Mount

In Industry almost all the machinery are subjected to noise, shocks and vibrations when machines are working. These vibrations leads to more frequent repairs and replacements of machine parts also reduce their life span. Antivibration mount is used as a Vibration Control Solutions for machineries. This work is more focused on the importance of anti-vibration mount, which can be used for various mechanical system. This study includes the design of mounts for various functional requirements and fatigue life prediction methods. There are several approaches to predict the fatigue life of mount. Initially, different types of failures in anti-vibration mounts are discussed in detail. Analytical method, Finite Element Method and Experimental approach to predict the fatigue life are analyzed. The strain life approach is considered, incorporate with material properties of mount and another approaches were discussed that are harmonic response, crack nucleation and crack growth mechanics. It is conclude with, the strain life approach is convenient method to predict the fatigue life of antivibration mount, because it give highly non-linear effect to find the critical region of mount

Dynamics of anti-vibration mount with quazi-zero stiffness

The paper considers the dynamics of the anti-vabration mount of a new design with the quasi-zero stiffness effect, in which the mounting element is an elastic rubber-cord casing of type I-09, and a load adding element (corrector) is a toroid-shape rubber-cord shell. A mathematical model is developed and motion graphs of vibro-isolated object in the range of 1-10 Hz are built.

Naval-vessel on board equipment base to minimize structure-borne noise

In order to reduce the structure-borne noise of naval-vessel onboard equipment to meet imposed standards, the equipment exciting force should be restricted and additional anti-vibration devices such as resilient mounts and bellows should be applied. Since the structure-borne noise is dependent on the design of the equipment base, the realization of a low-vibration base design is important. In this study, a typical pump base is optimized using Design of experiment (DOE) and Computer-aided engineering (CAE) techniques, in order to minimize the vibration transferred from the equipment base to the floor. In addition, a sandwich panel consisting of a steel plate and rubber material is applied to the pump base between an anti-vibration mount and the base, so as to reduce the vibration transferred from the pump using the double-mounting-system principle. Consequently, the structure-borne noise reduction achieved by applying the proposed base design is verified via experiment.

D evelopment and Testing of a Closed Loop Feedback Controlled Magnetorheological Fluid Anti-vibration Mount for Onboard Naval Applications

An intelligent semi-active anti-vibration mount using a magnetorheological (MR) fluid is designed and developed for onboard applications. The mount consists of a load bearing elastomer, MR fluid chamber; MEMS based vibration sensor and a controller for closed loop feedback mechanism. The controller regulates the solenoid current in the MR fluid chamber, which in turn regulates the flow of MR fluid through the valve. Comparison of the performance of MR mount with a passive resilient rubber mount shows that the former provides 7 dB extra damping at resonance compared to the later and the isolation of MR mount starts at 10 Hz compared to 50 Hz by rubber mount. This mount can operate in real time, passive and active modes by using a closed loop feedback control mechanism. The efficacy of the mount for outdoor applications is evaluated by characterizing the mechanical, environmental, electrical and electromagnetic properties as per MIL-17185, JSS-55555 and IEC 61000 standards and found to be superior compared to passive mounts. The mount is being evaluated for onboard applications in INS Ranvijay.

Impact simulation and experiment on rubber anti-vibration systems

There is very limited literature regarding impact analysis on solid rubber anti-vibration systems as the true damping characteristics of rubber materials are very complex and difficult to define. Viscoelastic approach is a usual method and has only achieved limited success. In this article, an integrated quasi-static and impact analysis with validation on an anti-vibration mount is presented. The Rayleigh damping has been introduced for rubber hysteresis. The impact responses from both simulation and experiment have been compared and have shown very good agreement in real time domain. In addition, it has been revealed that real geometry and elasticity of an impact object have to be included in simulation in order to obtain an accurate response. It has been shown that the proposed approach is reliable and can be used for an appropriate design stage to evaluate an impact/dynamic response of rubber anti-vibration systems. The key points to use this approach are also provided.

Design, Development and Testing of a Real Time Anti-Vibration Mount Using a Shear Thickening Nanofluid

Design, Development and Testing of a Real Time Anti-Vibration Mount Using a Shear Thickening Nanofluid

Design and Development of a Closed Loop Feedback Controlled Magnetorheological Fluid Anti-Vibration Mount

Design and Development of a Closed Loop Feedback Controlled Magnetorheological Fluid Anti-Vibration Mount

A nonlinear spring mechanism incorporating a bistable composite plate for vibration isolation

The High Static Low Dynamic Stiffness (HSLDS) concept is a design strategy for a nonlinear anti-vibration mount that seeks to increase isolation by lowering the natural frequency of the mount whilst maintaining the same static load bearing capacity. It has previously been proposed that an HSLDS mount could be implemented by connecting linear springs in parallel with the transverse flexure of a composite bistable plate — a plate that has two stable shapes between which it may snap. Using a bistable plate in this way will lead to lightweight and efficient designs of HSLDS mounts. This paper experimentally demonstrates the feasibility of this idea. Firstly, the quasi-static force–displacement curve of a mounted bistable plate is determined experimentally. Then the dynamic response of a nonlinear mass–spring system incorporating this plate is measured. Excellent agreement is obtained when compared to theoretical predictions based on the measured force–displacement curve, and the system shows a greater isolation region and a lower peak response to base excitation than the equivalent linear system.

Dynamic analysis of high static low dynamic stiffness vibration isolation mounts

The high static low dynamic stiffness (HSLDS) concept is a design strategy for an anti-vibration mount that seeks to increase isolation by lowering the natural frequency of the mount, whilst maintaining the same static load bearing capacity. Previous studies have successfully analysed many features of the response by modelling the concept as a Duffing oscillator. This study extends the previous findings by characterising the HSLDS model in terms of two simple parameters. A fifth-order polynomial model allows us to explore the effects of these parameters. We analyse the steady-state response, showing that simple changes to the shape of the force displacement curve can have large effects on the amplitude and frequency of peak response, and can even lead to unbounded response at certain levels of excitation. Harmonics of the fundamental response are also analysed, and it is shown that they are unlikely to pose significant design limitations. Predictions compare well to simulation results.

수치해석을 위한 방진 마운트의 동적 특성 결정 및 검증

고무재료의 비선형적인 특성으로 인해 고무재질 방진 마운트의 탄성계수와 감쇠계수는 주파수에 따라 달라진다. 따라서 고무재질의 방진 마운트 설계 시 마운트의 동적 특성을 반드시 고려해야만 한다. 특히, 수치해석을 수행하는데 있어 해석결과는 마운트의 동적 강성 고려 여부에 따라 크게 달라진다. 본 논문에서는 한국 해군에서 승인되어 사용되고 있는 특정 표준 마운트에 대해 실험적으로 동적 특성을 정의하였으며, 이러한 동적 특성을 적용한 경우와 적용하지 않은 경우에 대해 수행한 수치해석 결과와 실험 결과를 비교하였다. Because the non-linear property of the rubber, the elastic modulus and damping factor of the rubber mount are dependent on the frequency. Therefore, the dynamic properties of the rubber mount should be considered when the anti-vibration mount is designed. Especially, when the numerical analysis is performed, the results can have much errors not considering the dynamic characteristics of the rubber mount. In this paper, the dynamic properties of typical standard rubber mount approved by ROK navy are defined experimentally and the results from the numerical analysis and experiment are compared for considering and non-considering the dynamic properties of the rubber mount respectively.

수치해석을 이용한 함정용 장비 받침대의 기계적 임피던스 및 전달 진동 분석

Reduction of the structure-borne noise of the naval vessel is very important in order to reduce the underwater radiated noise of it. One of the important factors to reduce the structure-borne noise of the installed machine in a ship is the design of the foundation having sufficiently high mechanical impedance. In this paper, the mechanical impedance of the foundation for the fan-coil unit in a naval vessel is evaluated numerically according to variation of the thickness of the foundation. And also, the forced vibration analysis is conducted considering the dynamic property of the anti-vibration mount. Through the analysis results, it can be known that the dynamic property of the anti-vibration mount should be considered when the minimum level of the mechanical impedance of the foundation is set.

방진 마운트의 동적 강성을 고려한 선체 바닥 및 받침대의 강성과 임피던스 규제에 대한 고찰

The mechanical impedance and stiffness of the foundation of shipboard equipments and hulls supported by anti-vibration mount are very important so that the anti-vibration mount can accomplish its performance effectively. But, it is frequently argued how much stiffness and mechanical impedance are necessary for those foundations and hulls. In this research, it is discussed by evaluating the dynamic stiffness of the commercial anti-vibration mounts used in a naval vessel. Consequently, in this research, the minimum level of the mechanical impedance and stiffness of the foundation of shipboard equipments and hulls are suggested considering the dynamic stiffness of the mount which varies as frequency.

Rheological‐dynamical Analogy: Frequency Dependence of the System Parameters of Internally Damped Bars

An analytical rheological‐dynamical visco‐elastic solution of one‐dimensional longitudinal continuous vibration of bars has been developed and used to evaluate the validity of the classical analytical elastic solutions. As it is well known, the resonance occurs only in the continuous or singledegree‐of‐freedom ideal elastic system when the excitation frequency ωP is equal to the one of the natural frequency of the bar. However, owing to the visco‐elastic nature of materials and frequency dependence of the damping factor it is useful to consider separately the situations arising when the is positive (system is stable) and when it is negative. Negative damping factor means that the complementary solution of the response would not die away (system is unstable because of the factor e). Rheologic behavior of the bar can be characterized by one parameter, i.e. dynamic time of retardation TK D=1/ω, like in a single‐degree‐of‐freedom spring mass system. RDA model has the same phase angle as a simple single‐degree‐of‐freedom spring mass system with damping in the steady state vibration and from that the damping factor is obtained. This paper provides description of the dynamic magnification factor and the transmissibility of several metallic materials using RDA similitude and could be concluded that an ideally effective antivibration mount material should satisfy at least two requirements: first, it should posses a relatively large damping factor; and second, it should possess a damping factor that either remains constant or decreases only slowly with frequency.

Method of damping vibration, active hydraulic anti-vibration mount and vehicle including such a mount

Active hydraulic anti-vibration mount comprising two support elements connected by an elastomer body partially delimiting a working chamber filled with liquid, this working chamber communicating by a throttled passage with a compensation chamber separated from said working chamber by a rigid partition. The rigid partition is penetrated by a first regulating nozzle closed by a movable exciting device, and a second regulating nozzle closed by a valve the movements of which are limited to correspond to an amplitude of variation in the volume of the working chamber which is less than 20% of the amplitude of the variations in volume generated by the exciting device.

Pointing, acquisition and tracking for optical space communications

Free-space links between satellites provide a means of introducing increased connectivity into a satellite system. This can result in enhanced traffic capacity and extended coverage for telecommunication systems and real-time relay of instrument data to the ground for Earth observation missions. Optical links offer the potential advantages over microwave links of lower mass and power and reduced size so that they can be accommodated more easily on the satellite. However the narrow optical beamwidths involved result in stringent pointing, acquisition and tracking (PAT) requirements. This paper describes a concept for a compact PAT system which employs a passive antivibration mount to filter out high-frequency disturbances from the satellite. This is under development as part of the ESA-funded Small Optical User Terminal (SOUT) programme. The system concept, hardware implementation, and results of breadboarding critical items are presented.

The SOUT optical intersatellite communication terminal

Optical communications links between satellites promise to become an important element of future space infrastructure and are the subject of considerable development in Europe. Major advantages over conventional microwave links are low mass and power and smaller size leading to easier accommodation on the satellite. The Small Optical User Terminal (SOUT) is an optical communications package for interconnecting a low earth orbiting satellite to future optical data relay terminals and is the subject of an ESA development programme led by MMS (UK). The baseline terminal has a data rate of 2 Mbps over the return interorbit link and a mass of around 25 kg. The terminal configuration uses a unique combination of a periscopic coarse pointing assembly, refractive telescope, passive antivibration mount, combined acquisition and tracking sensor, and fibre coupled lasers and receivers. The paper discusses the design aspects for an asymmetric optical link based on the SOUT, covering link budgets, pointing, acquisition, and tracking and communications performance. Key SOUT subsystems are described and the structural and thermal configuration which allows these features to be combined in a compact unit is reported.