Rubber Mounts Research Articles

역류방지 글로브 밸브를 이용한 소화 주관계의 진동개선

Main source of URN(underwater radiated noise) which is related to the ship's survivability is divided into two groups. Cavitation is the main source of URN when the speed of ship is upper than CIS(cavitation inception speed). But when the speed of ship is lower than CIS, the main source of URN is the structure-borne noise on the hull which is originated from propulsion system, pump system and trnasmitted vibration of the pipe system. In this paper, to reduce the vibration of discharge pipe and valve system, back flow prevent globe valve and new rubber mount are applied to the ship. As the result of applying new valve and mount, the vibration is reduced drastically.

선박의 해수 이송 배관용 고무 마운트의 진동 전달률에 대한 파라미터 연구

Pipe system widely used in a ship is usually attached to the hull of a ship, and its vibration lead to structure-borne noise. Rubber mount is usually used as a vibration isolator of a pipe in a ship. In this paper, the effects of several factors, besides the stiffness and damping of the rubber mount, on vibration-isolating performance are taken into consideration. The parameters considered in this paper are hardness of the rubber material, painting on the rubber and deformation from clamping. Through the results of parametric study, the effective specifications of rubber mount are suggested to improve vibrationisolating performance. The performance under fluid flowing condition is calculated numerically and verified experimentally.

ALE based Finite Element Method for Characteristic Simulation of Hydraulically Damped Rubber Mount

ALE based Finite Element Method for Characteristic Simulation of Hydraulically Damped Rubber Mount

Fatigue life prediction of a rubber mount based on test of material properties and finite element analysis

Failure analysis and fatigue life prediction are very important in the design procedure to assure the safety and reliability of rubber components. The fatigue life of a rubber mount was predicted by combining test of material properties and finite element analysis (FEA). The natural rubber material material’s fatigue life equation was acquired based on uniaxial tensile test and fatigue life tests of the natural rubber. The strain distribution contours and the maximum total principal strains of the rubber mount at different loads in the x and y directions were obtained using finite element analysis method. The critical region cracks prone to arise were obtained and analyzed. Then the maximum total principal strain was used as the fatigue parameter, which was substituted into the natural rubber’s fatigue life equation, to predict the fatigue life of the rubber mount. Finally, fatigue lives of the rubber mount at different loads were measured on a fatigue test rig to validate the accuracy of the fatigue life prediction method. The test results imply that the fatigue lives predicted agree well with the test results.

Investigation into the fluid—structure interaction of a hydraulically damped rubber mount on the basis of finite element analysis

This paper investigates the working process simulation of a hydraulically damped rubber mount (HDM) based on finite element (FE) analysis of the fluid—structure interaction (FSI). The direct computing method of coupled FSI formulation in arbitrary Lagrangian—Eulerian coordinates and the mixed displacement—pressure FE formulation for the incompressible medium, rubber, are adopted. The constitutive law of rubber is determined by FE analysis of incompressible material. A proportion mesh control algorithm helps to overcome fluid mesh distortion. Comparison of the predicted and experimental static elasticities verifies the effectiveness of the presented modelling approach of an HDM. Analysis of fluid pressure—velocity fields and deformation—stress fields of rubber components under typical working conditions clarifies the working process of the HDM, which can help to evaluate the carrying capacity, to identify the chamber volumetric characteristics, and to determine the fluid field distribution and stress distribution of rubber parts for the structural design of the HDM.

Modelling of rubber mounts and applications for time response analysis of dynamic systems including elastomerics

The dynamic characteristics of a Rubber Mount (RM) are dependent on preload, excitation amplitude and excitation frequency. In this paper, a nonlinear model for modelling the dynamic performances of a RM is proposed based on the assumption that the force of a RM sustained is a superposition of elastic force, friction force and viscoelastic force. The methods for estimating the model parameters are presented in detail. The time response for a single-degree-of-freedom system using the proposed model and the parameter identification method are estimated, and the calculated displacement vs. time relation for the mass agree well with the experiment data, which validates the model and the parameter identification method.

Viscoelastic models for rubber mounts: influence on the dynamic behaviour of an elastomeric isolated system

The influence of the viscoelastic model employed to represent the stiffness of rubber mounts on the dynamic response of an elastomeric isolated system is investigated. A steel block supported on four rubber mounts is analysed. Each mount is characterised by its axial stiffness and two shear stiffness. Three viscoelastic models are proposed to fit the experimental stiffness of the mounts over a frequency range from 0 Hz to 50 Hz, defined by two, three and five parameters respectively. Simulations in IDEAS® are compared to dynamic measurements performed on the supporting system, showing that the Generalised-2 Maxwell model provides the best agreement.

DESIGN OF VIBRATION-DAMPERS FOR STEEL CHIMNEYS WITH LATEST FEATURES

In the past there have been attempts to control wind response of chimneys using strakes, perforated screens, rubber mountings, hanging chain dampers and tuned mass dampers. However, a systematic and detailed study on latest designed vibrationdampers at chimney top is not seen in literature. In the present paper, principle of the damping system is discussed. Mass and stiffness of the damper are calculated. Amplitude of the top of chimney during vortex shedding is calculated. Results thus obtained have been discussed. Some latest damping systems have also been presented for authenticity.

Subframe structure and vibration damper for the same

A subframe structure for an automotive vehicle wherein a subframe is attached through a rubber mount to a vehicle body, suspension components are assembled onto the subframe so that the suspension components are held connected to the vehicle body through the subframe, and a detecting assembly capable of providing an output signal according to a load that acts between a subframe and a vehicle body is provided. A rubber mount for use in this subframe structure is also disclosed.

Engine mounts and powertrain mounting systems: a review

The developments, performances and applications of mounts that from conventional rubber mount to active mount are reviewed and discussed. In the design of a Powertrain Mounting System (PMS), the layouts for a powertrain and the mounts should meet some generally used layouts that are discussed in this paper. Also the natural optimisation method, motion control strategies and calculation methods for vibration control and isolation in design a PMS are reviewed and discussed. It is concluded that the optimisation technology in determining the stiffness in nonlinear section and tuning points in the force vs. displacement curve of a mount should be developed and the application of Trans Path Analysis (TPA) and theory of power flow should be enhanced. The bracket of a mount has great influenance on the isolation effects of a PMS, and should be designed carefully.

Parameter Optimization of Rubber Mounts Based on Finite Element Analysis and Genetic Neural Network

The structures of vehicle rubber mounts cannot be optimized with conventional optimization methods due to their complex structures and irregular sections. A parameter optimization methodology for a rubber mount based on Finite Element Analysis (FEA) and Genetic Neural Network models is proposed in this study. A FEA model of the rubber mount was developed and analyzed using the software MSC.MARC, and the primary stiffness of rubber mounts with different geometric parameters in three principle directions were obtained by this FEA method. Then the FEA results were used as samples to train the neural network (NN) model which defines the non-linear global mapping relationship between the rubber mount's geometric parameters and its primary stiffness in three principle directions. The fitness values of the population in the genetic algorithm (GA) were calculated by the trained NN model and the optimal solution was acquired with the mutation of population. Finally, experiments were made to validate the reliability of the optimal solution. The proposed optimization method can shorten the product design cycle and decrease the design and trial-product cost considerably.

마운트 형상에 따른 선박용 해수 이송 배관의 진동 전달률 감소

The reduction of the structure-borne noise is very important in order to reduce the noise of a ship. The noise at the high frequency range usually comes from the fluid flowing. The noise from the sea-water conveying pipe is one of the main source on these high frequency range. Therefore, the transmissibility variations are evaluated according to the shape of the rubber mount. The evaluations are performed with the frequency response function numerically and experimentally.

선체로 전달되는 해수 이송 배관의 진동 저감 분석

URN(underwater radiated noise) is one of the important performances of the battle ship related to the stealth. The main source of the URN is the structure-borne noise on the hull. And the pipe vibration transmitted to the hull is the main source of the structure-borne noise when the speed of the ship is lower than CIS(cavitation inception speed). In this paper, the vibration isolator(rubber mount) for the pipe system is described in order to reduce the structure-borne noise transmitted to the hull. The vibrations on the sea-water conveying pipes and their supports are measured in order to know how much vibration occurs on those positions. Based on these test results, the improved design of the rubber mount is suggested by the parametric study and is verified numerically with the pipe and hull model.

Finite Element Analysis and Structure Optimization for Improving the Fatigue Life of Rubber Mounts

The fatigue crack problem of a rubber mount on the crankshaft of a wheel in an automobile was investigated by theoretical calculation and experimental analysis. A finite element analysis (FEA) model of the rubber mount was developed and analyzed using the software MSC.MARC. FEA results imply that stress concentration may arise on the interfaces of the rubber layer and metal layer. Modifications were made to the structure parameters and rubber material of the rubber mount based on the analysis of FEA results. The stress concentration of the rubber mount at the rubber and metal interfaces was improved and the fatigue life of the improved rubber mount was increased. Finally, experiments were made to validate the accuracy of the FEA process and the reliability of the improved method. The proposed FEA and improved method can shorten the product design cycle, decrease the design and trial‐product cost and remarkably improve the product quality.

Finite Element Analysis and Structure Optimization for Improving the Fatigue Life of Rubber Mounts

The fatigue crack problem of a rubber mount on the crankshaft of a wheel in an automobile was investigated by theoretical calculation and experimental analysis. A finite element analysis (FEA) model of the rubber mount was developed and analyzed using the software MSC.MARC. FEA results imply that stress concentration may arise on the interfaces of the rubber layer and metal layer. Modifications were made to the structure parameters and rubber material of the rubber mount based on the analysis of FEA results. The stress concentration of the rubber mount at the rubber and metal interfaces was improved and the fatigue life of the improved rubber mount was increased. Finally, experiments were made to validate the accuracy of the FEA process and the reliability of the improved method. The proposed FEA and improved method can shorten the product design cycle, decrease the design and trial‐product cost and remarkably improve the product quality.

Modelling of dynamic performances for Hydraulic Engine Mounts using fractional derivative and optimisation of Powertrain Mounting Systems

A Hydraulic Engine Mount (HEM) is an advanced passive vibration isolator, and is now widely used in automotive Powertrain Mounting System (PMS). A version of fractional derivative model characterised by five parameters is presented to describe the dynamic properties of an HEM. A model for a PMS is established, and formulae for estimating the dynamic displacement of the powertrain Centre of Gravity (CG) and the reaction forces of a mount under different loads are presented. An optimisation procedure is developed for reducing resonance peaks of a powertrain CG and the reaction forces at mounts. A generic PMS with two rubber mounts and two HEMs is used to validate the optimisation method.

Dynamic characteristic simulation of hydraulically damped rubber mount based on finite element parameter estimation for vehicle powertrain

Performance analysis of the dynamic characteristics of hydraulically damped rubber mounts (HDM) faces challenges owing to the fluid-structure interaction between rubber springs and fluid in chambers, non-linear material properties of rubber parts and turbulent flow in chambers and fluid track linking chambers. In this article, finite element-based parameter estimation and lumped-parameter modelling of HDM are developed for numerical simulation of dynamic characteristic of HDM. Dynamic characteristics of a typical HDM with fixed decoupler are predicted and compared with experimental results, which verify the effectiveness of the proposed approach. The presented approach provides design guidelines for HDM to meet vibration isolation requirements of a powertrain mount system through parameter adjustment.

Finite element-based parameter estimations for a characteristic simulation model of a hydraulically damped rubber mount for vehicle engines

The hydraulically damped rubber mount (HDM) is widely used for vibration isolation in automotive powertrains and other dynamic systems. In predictions of its dynamic characteristics, some key parameters or parametric characteristics in the lumped-parameter dynamic analysis model of an HDM, such as the volumetric elastic characteristics of fluid chambers and the equivalent piston cross-sectional area of the upper chamber, must be especially determined, because they are difficult to measure by experiment owing to fluid-structure interactions (FSIs). In this paper, a numerical simulation approach of volumetric elastic characteristics is developed on the basis of finite element analysis methods relating to rubber material hyperelasticity and hydrostatic FSI using ABAQUS software. Volumetric elastic characteristics of the upper fluid chamber, including the main rubber spring and/or uncoupling rubber membrane, and that of the lower fluid chamber are identified; volumetric stiffness and equivalent piston cross-sectional area are also calculated for further dynamic characteristic simulations of HDM. The contributions of different rubber parts to the volumetric elastic characteristics of the upper chamber are revealed. Predications of dynamic characteristics and frequency response analysis of a typical HDM with fixed decoupler verify the effectiveness of the proposed parameter identification method. The proposed simulation methods of volumetric elastic characteristics can be applied to other FSI systems.

An Engine Mount Stacked with Auto-Tuning Anti-resonance Dynamic Absorber Consisting of Conical Springs and Vibration Isolation Control Method

An engine mount is developed which is consisting of a fluid filled rubber mount stacked with a variable spring constant absorber. In engine mounts, the transmissibility due to mass vibrations should be small, and high frequency vibration causing noise should be isolated. In the mount developed by the authors, the high frequency vibrations are isolated with a fluid filled rubber mount. It is difficult to suppress both mass vibrations and its transmissibility to the base simultaneously. For suppressing both, the authors applied an anti-resonance control system. In order to achieve the anti-resonance condition, a new type tunable absorber using conical helical spring is developed, and its control method is presented. Using our mount, both the mass vibration and transmissibility can be suppressed, and the amplitude ratio and the transmissibility can be controlled to be less than one which will be difficult to be achieved in the previous mounts. The present mount has other advantages on its compact size, small control energy and simple control system.

Simulation of Engine Vibration on Nonlinear Hydraulic Engine Mounts

In this paper, vibration behavior of engine on the nonlinear hydraulic engine mount, including inertia track and decoupler, is studied. In this regard, after introducing the nonlinear factors of this mount (i.e., inertia and decoupler resistances in turbulent region), the vibration governing equations of engine on one hydraulic engine mount are solved and the effect of nonlinearity is investigated. In order to have a comparison between the rubber and the hydraulic engine mounts, a six-degree-of-freedom four-cylinder V-shaped engine under shaking and balancing mass forces and torques is considered. By solving the time domain nonlinear equations of motion of the engine on three inclined mounts, translational and rotational motions of an engine body are obtained for different engine speeds. Transmitted base forces are also determined for both types of engine mount. Comparison of rubber and hydraulic mounts indicates the efficiency of a hydraulic one in the low-frequency region.