Rubber Engine Mount Research Articles

Rice husk silica blended fillers for engine mount application

The functional properties of engine mounts largely depend on the rubber compound formulation. This study proposes the use of rice husk–derived silica (RHS) blended with carbon black (N772) as an effective and environmentally friendly substitute for fillers used in rubber engine mounts (REMs). CV-60 natural rubber was filled with the blended fillers at various ratios, and their compatibility for use as rubber engine mounts (REMs) was assessed. Grey Relational Analysis was utilised to determine the optimal blend loading levels for use in rubber engine mounts, resulting in 40 phr of N772 and 20 phr of RHS cured at 130 °C and 2.5 MPa for 20 min. The developed REMs and conventional REMs had low vibration data variation during the performance assessment. Their resonance transmissibility was 5.03 and 3.74, corresponding to natural frequencies of 24.27 Hz and 26.94 Hz, respectively. The RHS/N772 REMs had excellent damping characteristics and lower transmissibility in the isolation zone of the vibration isolation curve, which is outside of the resonant frequency region. The efficiency curves showed that the blended fillers are a better and more effective material for REMs at all frequencies, balancing static deflection and vibration isolation.

Mechanical characteristics and regression models of rice husk silica reinforced natural rubber composites

Carbon black and silica fillers have been widely used as reinforcing fillers in tyres and engine mounts. However, both fillers are non-renewable and with REACH legislation in Europe, the USA and elsewhere, where some of these fillers are termed hazardous due to the presence of polyaromatic hydrocarbons (PAHs), there is a need to search for sustainable alternative fillers to wholly or partially replace carbon black as a filler. This research studied rice husks-derived silica (RHS) as a filler in natural rubber (NR). The characteristics of RHS at 50 phr to 90 phr filler loading levels were examined to determine its suitability as a substitute for unsustainable carbon black (N772) fillers used in the rubber industry. Bound rubber content, crosslink density, tensile strength, young modulus, tear strength, shore A hardness, compressive set, and elongation at break were measured. Regression models were generated and the correlation of determination (R2) values was obtained. The RHS composites resulted in maximum tensile strength of 13.20 MPa at 90 phr, tear strength of 119 MPa at 90 phr, shore A hardness of 69 at 90 phr, compressive set of 6.72% at 80 and 90 phr, elongation at break of 453.60% at 80 phr, bound rubber content of 92.14% at 50 phr and crosslink density of 3.87×10-2 mol/cm3 at 70 phr. The results obtained were within the range of those obtained for the carbon black filled composites across various loading levels. The R2 value of mechanical characteristics for the RHS and N772 samples respectively were 50.06% and 62.18% (bound rubber content), 97.62% and 99.85% (tensile strength), 98.44% and 63.97% (tear strength), 89.16 and 97.40% (Shore A hardness), 32.90% and 91.80% (compressive set), a d 50.91% and 46.91% (elongation at break). Rice husk-derived Silica filled natural rubber composites showed favourable mechanical properties and can substitute traditional fillers in tyres, rubber engine mounts, bushings, seals and doormats.

Constitutive relation expansion of large load metal rubber engine mount stress bivariate function relationship using the strain and strain rate

Metal rubber materials were first used for vibration cushioning and noise protection applications in aviation equipment. With the recent developments in science and technology, metal rubber materials have been gradually implemented in Vehicle Vibration Suppressing. Metal rubber has significant advantages over ordinary rubber materials, in terms of its vibration damping in extreme environments. Along these lines, the objective of this work was to develop a mechanical model of metal rubber mount for mining vehicles, which can be used to predict the equivalent stress change of large load metal rubber mount in actual operation. Starting from the mechanical model of the mount and then expanding the macroscopic one-dimensional relationship of force and displacement to the binary relationship between the force and displacement and velocity, the microscopic one-dimensional relationship of stress and strain was expanded to the binary relationship between the stress and strain and strain rate. This work focused on the three-dimensional intrinsic structure model of stress, strain, and strain rate for metal rubber mounts. Moreover, the mechanical properties of the metal rubber mounts were explored in conjunction with the Mooney–Rivlin model, while the constitutive relationship of its stress, strain, and strain rate was deduced. The three-dimensional hysteresis curves were plotted by using software simulation analysis of the metal rubber mounts, and the metal rubber mounts hysteresis surface was also fitted. A combination of simulated and experimental data was used to test the accuracy of the proposed mechanical model of the metal rubber mount. From the acquired results, it was demonstrated that the errors of the relevant parameters (c10,c01, and c11) of the mechanical model of the metal rubber mount were about 10%. On top of that, the errors of the simulated stiffness values and the damping ratios of the metal rubber mount and the experimental stiffness values and damping ratios were within 10%. Excluding the interference of the metal rubber mount fabrication error, the proposed mechanical model met the mechanical analysis of the metal rubber mount with a large load and the mechanical model was accurate. The influence of the strain and strain rate on the stiffness and damping of the metal rubber mounts was also clarified, and the expansion method of the constitutive relationship of the metal rubber mount stress and strain was systematically explored. From the analysis of the metal rubber mounts’ mechanical properties, a reference basis for its vibration analysis and for the mechanical analysis of other nonlinear materials was provided.

Reduction of Stresses and Mass of an Engine Rubber Mount Subject to Mechanical Vibrations

A rubber engine mount (EM) is a mechanical coupling between the engine and the chassis, and its main function is to diminish, in the chassis, the amplitude of vibrations caused for the engine operation. Such vibrations cause discomfort for vehicle passengers and reduce the EM lifetime. To increase the comfort of vehicle passengers and the lifetime of the EM, this paper presents an EM optimization by means of reducing three main criteria: the EM mass, the displacements transmitted to the chassis, and the mechanical stress in the EM rubber core. For carrying out the EM optimization, the optimum global determination by linking and interchanging kindred evaluators (GODLIKE), assisted by artificial neural networks (ANN) and finite element method (FEM), was used. Because of the optimization process, a reduction greater than 10 % was achieved in the three criteria in comparison with a baseline design. The frequency responses were compared and showed that although the optimization was carried out for the range of 5 Hz to 30 Hz the trend of reduced responses continues beyond this range. These results increased the comfort of vehicle passengers and the lifetime of the EM; in addition, the reduction of mass diminishes its production costs.

Experimental investigation and material characterization of rubber engine mount for automobile application

The motor mount and body mount are a mind boggling joint get together containing elastic bushings on the top and base of the edge section, a jolt, and retainer. The motor/body mounts are intended to convey the even effect load in an effect and to disengage the clamor, vibration and cruelty (NVH), happening during driving from entering the traveller compartment. The plan of a motor mount is essentially reliant on the limit of the elastic bushing to withstand the heaps coming, the heaps that a motor or body mount is exposed to is pressure during ordinary working of the vehicle and malleable and shear during crash occasions. For a mount to continue these heaps going ahead it, it must have enough quality in the endorsed ways. Consequently here right now will choose three sorts of elastic mount like characteristic elastic, Butyl elastic and silicon elastic to test them for the solidness and damping properties for various excitation powers.

Experimental investigation and comparative analysis of rubber engine mount vibration and noise characteristics

Abstract The importance of vehicle comfort and drivability in a passenger car has attracted importance among the vehicle users and the manufacturers apart from the engine performance, and aesthetic view. Normally the engine mount is the one of primary component that connects the engine and the engine frame, and which isolates the vibration from the engine to the car body. Usually rubber is one of the materials used for the supporting, and damping requirements, and the conventional rubber mounts used in diesel engines are faced with problems like the fatigue failure and brittleness due to the oil spill in which the comfort the passengers is disturbed by the low frequency vibration and noise that is evolving from the engine. Hence, in this work we are going to have an experimental analysis of some blended rubber mount as an evolution of engine mount material and comparisons of their characteristics to that of the existing rubber mount is carried out, and few improvements in their performance has been achieved.

Characterization and modeling of the fatigue behavior of TPU

A comprehensive determination of the material properties is of major importance for the development of an adequate material model for finite element (FE) calculations and further lifetime estimations. As a preparation for the FE simulations, the time-, rate-, temperature- and hysteresis dependency of TPUs is determined and translated into proper hyperelastic material models. The time dependency and the viscoelastic properties were determined with DTMA tests. The methodology of fatigue testing, particularly the determination of local strain bases Wöhler curve (LSWC) for TPUs on Diabolo specimens is covered. As a validation of the whole methodology, the lifetime of a simplified model of a rubber engine mount is calculated.

Numerical methods of multiaxial fatigue life prediction for elastomers under variable amplitude loadings

AbstractIn this paper, numerical methods of fatigue life prediction for elastomers subjected to multidirectional, variable amplitude loadings are presented. Because experiments and numerical methods use different stress measures in large deformation, transformation between nominal stress and the second Piola–Kirchhoff stress is performed before fatigue life calculation. In order to incorporate the Mullins effect, the material properties of elastomers are calculated after an initial transition period. An efficient interpolation scheme using load stress/strain curves under unidirectional loading is proposed based on the fatigue characteristic of elastomers. A rainflow counting method with multi‐stress components is developed for variable amplitude loadings, and the critical plane method is applied to find the plane with the maximum damage parameter. Fatigue life predictions using the proposed numerical method are validated against experimental results. As a practical example, the fatigue life of a rubber engine mount is predicted using the proposed numerical method.

Assessment of vibration and transmissibility behaviour of a rubber engine mount considering vibration tuned modification

Most research and development of internal combustion engine mounting system is to achieve and improve the primary vibration isolator of the engine from the chassis. The purpose of this study is to gain a better knowledge and evaluate the vibration assessment and transmissibility of a rubber engine mount (REM) in vibration suppression of a vehicle engine. The experimental test stand is designed to present the simulation of the actual operating condition which was used on a Lada 2107 vehicle's engine and manual gearbox supported by three types of engine mounting. An improved understanding of the vibration signal is required for early detection of transmissibility. Vibration isolation performances of the engine mount system, such as acceleration and transmitted force, are experimentally evaluated and they are presented in both time and frequency domains. The engine mounting transmission ratios (EMTR) are presented at various engine operating speeds with different mount types. Moreover, the results indicate that root mean square (RMS) of EMTR performance is improved by 14%, 16.5%, 17.9%, 18.6% and 19% at an engine speed of 800 rpm, 1,600 rpm, 2,400 rpm, 3,100 rpm, 4,000 rpm, respectively by using the proposed engine cone and shear mounting system associated with the tuned vibration absorber modification.

INFLUENCE OF FIBER TYPE AND COATING ON THE COMPOSITE PROPERTIES OF EPDM COMPOUNDS REINFORCED WITH SHORT ARAMID FIBERS

ABSTRACT There is a renewed interest in the application of short aramid fibers in elastomers because of the considerable improvement in mechanical and dynamic properties of the corresponding rubber composites. Possible applications of short aramid fiber–reinforced elastomers are tires, dynamically loaded rubber seals, diaphragms, engine mounts, transmission belts, conveyer belts, and hoses. Our studies are related to the investigation of dispersion, length distribution, and the fiber–matrix interaction of two types of short aramid fibers, standard coated and resorcinol formaldehyde latex (RFL) coated, in ethylene–propylene–diene rubber (EPDM). Because the detection of the polymer fiber morphology in rubber compounds is hampered in the presence of carbon black, which is typically used in industrial elastomer compounds, fiber length, fiber length distribution, and dispersion are investigated in corresponding carbon black–free model compounds. Optical methods, scanning electron microscopy, and tensile testing are employed to explore the short aramid fiber–reinforced elastomer composites. The effects of morphology and fiber–matrix interaction on the mechanical properties of composites are discussed. Regarding fiber type, it is shown that co-poly-(paraphenylene/3,4′-oxydiphenylene terephthalamide) (PP/ODPTA) fibers end up with a higher final length than does poly(para-phenylene terephtalamide) (PPTA), which results in considerably higher mechanical properties of corresponding rubber compounds. For each fiber type, the higher final length as a result of RFL coating and the interaction with the rubber matrix are the key factors that overcome even the negative effect of poorer dispersion of RFL-coated fibers. The differences between the short aramid fibers and aramid cords regarding the RFL coating are also discussed.

온도변화를 고려한 고무엔진마운트의 동특성 변동성 해석

Vehicle vibrations arise from engine and road surface excitations. The engine mount system of a passenger car sustains the engine weight and insulates the excitation force from the engine system. The dynamic properties of viscoelastic material used for the vehicle engine mounts have large variation due to environmental factors such as environmental temperature and humidity etc. The present study aims to investigate the variability of dynamic characteristics in rubber engine mounts considering both environmental temperature change and material model errors/uncertainty. The engine mounts for a passenger car were modeled using finite element method. Then, the dynamic stiffness variability of the engine mounts were estimated using Monte Carlo simulation method. In order to estimate the variations in the storage and loss moduli of the viscoelastic materials, the material properties of the synthetic rubber were expressed as a fractional-derivative model. Next, in order to simulate the uncertainty propagation of the dynamic stiffness for the engine mounts due to the storage and loss moduli variations, the Monte Carlo simulation was used. The Monte Carlo simulation results showed large variation of the engine-mount stiffness along frequency axis.

Design Optimization of Rubber Engine-Mount Based on ANSYS

Most domestic automobile factories use test method to design rubber engine-mount, which wasting of time and energy. The design optimization of engine-mount is studied by virtue of ANSYS. In order to satisfying three directions stiffness requires of engine mount, the optimization math model has been established, mount material and geometry parameters have finally been calculated by selecting appropriate arithmetic.

고무-점토 나노복합체 물성 및 피로내구성 평가

실리게이트의 층간에 나노충진제를 삽입하여 합성한 고무-점토 나노복합체에 대해 70?100℃ 의 고온상태에서 정적 및 동적시험을 수행하여 기존 고무소재보다 기계적 물성이 우수함을 확인하였다. 또한, 본 연구에서는 부품의 취약부위에서 발생하는 최대 그린-라그랑지 변형률을 피로손상변수로 하여 설계 초기단계에서도 짧은 기간에 고무부품의 피로수명을 예측할 수 있는 방법을 개발하여 피로내구성을 평가한 결과, 실제 엔진마운트에 대한 피로시험을 통해 얻어진 피로수명과 예측수명이 비교적 정확하게 예측됨을 확인하였다.BR

Design of ANFIS networks using hybrid genetic and SVD methods for modeling and prediction of rubber engine mount stiffness

Genetic Algorithm (GA) and Singular Value Decomposition (SVD) are deployed for optimal design of both the Gaussian membership functions of antecedents and the vector of linear coefficients of consequents, respectively, of ANFIS networks. These networks are used for stiffness modelling and prediction of rubber engine mounts. The aim of such modelling is to show how the stiffness of an engine mount changes with variations in geometric parameters. It is demonstrated that SVD can be optimally used to find the vector of linear coefficients of conclusion parts using ANFIS (Adaptive Neuro-Fuzzy Inference Systems) models. In addition, the Gaussian membership functions in premise parts can be determined using a GA. In this study, the stiffness training data of 36 different bush type engine mounts were obtained using the finite element analysis (FEA).

Degradation and life prediction of a natural rubber engine mount compound

AbstractTo assess and predict the functional life of a natural rubber engine mount compound, the mechanical property changes were determined under accelerated aging conditions. The rubber was aged at temperatures ranging from 70 to 110°C for times ranging from 1 h to 5 weeks. Tensile and fatigue measurements were used to characterize the aging trends and mechanisms of the engine mount compound. With the time–temperature superposition approach, the activation energy was found to be about 98 kJ/mol for the elongation at break, 93 kJ/mol for the tensile strength, and 60 kJ/mol for the fatigue life. The tensile strength after aging for 13 weeks at 50°C was predicted to be 18.73 MPa, which was very close to the experimental value of 19.04 ± 2.25 MPa. With a 50% reduction in the tensile strength used as the failure criterion, it was predicted that the tensile strength of the engine mount compound would take 80 days to decrease by 50% at 70°C. At 23°C, it would last approximately 140 times (31 years) its lifetime at 70°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Fatigue Life Evaluation of Automotive Engine Mount Insulator

Fatigue life of automotive engine mount insulator made of natural rubber was evaluated. In order to develop an appropriate fatigue damage parameter of the rubber material, a series of displacement controlled fatigue tests was conducted using 3-dimensional dumbbell specimens with different levels of mean displacement. It was shown that the maximum Green-Lagrange strain was a proper damage parameter, taking the mean displacement effects into account. Nonlinear finite element analyses of the rubber engine mount insulator and 3D dumbbell specimen were performed based on a hyper-elastic material model determined from the simple and equi-biaxial tension tests. Fatigue life prediction of the engine mount insulator was made by incorporating the maximum Green-Lagrange strain values, which was evaluated from the finite element analysis and fatigue tests, respectively. Predicted fatigue lives of the engine mount insulator showed a fairly good agreement with the experimental fatigue lives.

Experimental evaluation of crucial noise and vibration metrics for engine mount

A multi-objective experimental evaluation method concerning the crucial noise and vibration metrics for engine mounts was developed to provide the trade-off guidelines. We illustrated the noise, vibration, and harshness (NVH) design requirements for rubber engine mounts. Three mount stiffnesses for front mounts were used for development testing according to the results of dynamic analysis. Powertrain rigid body modal validation showed that all three mounts met the powertrain bounce frequency target. The experimental modal results were in a good agreement with the dynamic analysis predictions. The dynamic force validation showed a first promising step toward good design for NVH. Because the single performance of dynamic force was not appropriate for the comprehensive mounts development, we defined a combined NVH performance of an engine mount as the sum of five weighted individual crucial metrics concerning the mount attenuation, idle NVH, interior noise, secondary ride and subjective assessment. The weighting factors were set according to the local driving environment. We proposed the term normalized integration area to efficiently identify the mount performance of isolation and interior noise. Based on the evaluation method developed, we identified the trade-off mount specification for the application case.

Fatigue life estimation of an engine rubber mount

Fatigue life of an engine mount made of natural rubber was estimated, considering the effects of mean load. In order to develop an appropriate fatigue damage parameter of the rubber material, load-controlled fatigue tests were conducted using three-dimensional dumbbell specimens at different levels of mean load. It was shown that the maximum Green–Lagrange strain and the maximum strain energy density were proper damage parameters, taking the mean load effects into account. Nonlinear finite element analyses of the 3D dumbbell specimen and engine mount were performed using Ogden hyperelastic material model determined from the tensile, shear and biaxial tension tests of the natural rubber, and resulted in relationships between load and maximum Green–Lagrange strain for both the dumbbell specimen and engine mount. A fatigue life curve of the natural rubber represented by the maximum Green–Lagrange strain was determined from the finite element analysis and load-controlled fatigue test of the dumbbell specimen. Fatigue life estimation of the rubber engine mount was finally made by using the maximum Green–Lagrange strain of the engine mount and the fatigue life curve equation of the natural rubber material. Predicted fatigue lives of the rubber engine mounts agreed fairly well with the experimental fatigue lives within a factor of four.

High frequency testing of rubber mounts

Abstract Rubber and fluid-filled rubber engine mounts are commonly used in automotive and aerospace applications to provide reduced cabin noise and vibration, and/or motion accommodations. In certain applications, the rubber mount may operate at frequencies as high as 5000 Hz. Therefore, dynamic stiffness of the mount needs to be known in this frequency range. Commercial high frequency test machines are practically nonexistent, and the best high frequency test machine on the market is only capable of frequencies as high as 1000 Hz. In this paper, a high frequency test machine is described that allows test engineers to study the high frequency performance of rubber mounts at frequencies up to 5000 Hz.