Criteria

Text:
Topic:
Display:

Results

Viewing 1 to 30 of 2193
Event
2015-06-22
This session addresses the strategies and methods for implementing active noise and vibration control in a vehicle. It will cover sensors and transducers, feedback systems, control algorithms, software for active control, noise and vibration cancellation devices, noise and vibration measurement systems, and case studies.
Event
2015-06-22
This session covers noise and vibration sources and paths within a vehicle (automobiles, trucks and recreational vehicles). Example of noise sources included are HVAC system, electric motor powered mechanisms and door closure and example of vibration sources are road and engine. Also included are Whole Body and Hand Arm Vibration experienced by professional drivers as well as acoustical design factors of audio, infotainment, and hands free devices.
Event
2015-06-22
This session is focused on the vehicle body interior noise issues caused by friction and/or impact due to the vibration of interfacing components. The papers in this session will investigate those issues through the best practice of analytical and experimental applications.
Training / Education
2014-10-28
Finite Element Analysis (FEA) has been used by engineers as a design tool in new product development since the early 1990's. Until recently, most FEA applications have been limited to static analysis due to the cost and complexity of advanced types of analyses. Progress in the commercial FEA software and in computing hardware has now made it practical to use advanced types as an everyday design tool of design engineers. In addition, competitive pressures and quality requirements demand a more in-depth understanding of product behavior under real life loading conditions. This course will enable participants to expand the scope of FEA to vibration analysis to simulate product behavior under those conditions. This six-session web seminar introduces vibration analysis performed with Finite Element Analysis (FEA). By considering time-dependent loads and inertial and damping effects, vibration analysis allows for a more in-depth product simulation thus reducing product development cost and time.
Event
2014-10-09
Focus on passive, semi-active and active isolation techniques to reduce the structure’s shock loads and vibration, increase occupants’ ride comfort on constructional, agricultural, commercial and special vehicles; modeling, simulation and testing of passive and controllable isolators, and isolation system. Isolators can be springs, elastomers, fluid mounts, and controllable magnetorheological (MR) and electrorheological (ER) mounts and dampers. The isolated objects include powertrain, driveline, frame, cab, seat, steering wheel, etc.
Event
2014-10-09
Focus on passive, semi-active and active isolation techniques to reduce the structure’s shock loads and vibration, increase occupants’ ride comfort on constructional, agricultural, commercial and special vehicles; modeling, simulation and testing of passive and controllable isolators, and isolation system. Isolators can be springs, elastomers, fluid mounts, and controllable magnetorheological (MR) and electrorheological (ER) mounts and dampers. The isolated objects include powertrain, driveline, frame, cab, seat, steering wheel, etc.
Technical Paper
2014-09-30
Venkatesan C, Mohan Rao
Durability of components plays a major role in the total cost of ownership of a commercial vehicle. The powertrain mount is one such component which is constantly at work in a vehicle and its rubber characteristics play a major role in the NVH and Life of the component. This paper presents the enhanced durability benefits obtained by changing the polymer composition, manufacturing methods and design optimization of a powertrain mount. The methodology involved characterization of the existing mount, arriving a new compound formulation, making of prototypes, experimental validation for durability and repeatability in the laboratory combined with rigorous on field vehicle trials. NVH measurements were also carried out on the improved mounts. The above exhaustive exercise resulted in the development of a comprehensively far better mount than an existing mount with improved durability without compromise on NVH properties. The cost benefit in terms of the total vehicle life was enhanced to a large extent.
Technical Paper
2014-09-30
Masahiro Akei, Takayuki Koizumi, Nobutaka Tsujiuchi, Takayuki Yamauchi
This paper describes the prediction of vibration and transfer path analysis (TPA) using the multi body dynamics (MBD) model of engine and measured frequency response functions (FRF). In agriculture machines, a demand for comfortable work environment is increasing. Reduction of noise and vibration at an operator position is one of these demands. In order to improve the vibration at evaluation position that is operator position, it is important that we take measures against the most contributed transfer path from vibration source to evaluation position. TPA has been used to grasp each contribution of vibration transfer paths. In the TPA, input force from vibration source to passive part should be identified accurately. In the traditional TPA, determination of force is done by mount stiffness method and matrix inversion method. In these traditional methods, the determination of force is done using only experimental result. Therefore, it is difficult to predict beforehand effects of improvement for structure and isolation system.
Technical Paper
2014-09-30
John Stuart, Stefano Cassara, Brendan Chan, Nicholas Augustyniak
This paper will deal with a phenomenon commonly observed in commercial highway vehicles with solid-beam front axles. The phenomenon is typically self-excited and manifests itself as a sustained oscillation about the kingpin in two forms, shimmy and wobble. Wobble is defined as a rotational oscillation about the kingpin while shimmy is wobble accompanied by axle tramp and hop motions. To fully understand the causes of the phenomenon and to develop a corrective action plan, a cross functional team was formed which employed multiple tools and strategies. A tractor that exhibited the phenomenon was selected for physical evaluation and was subsequently baseline tested by measuring the frequency and amplitude of the oscillation at various vehicle speeds. An ADAMS model was developed to simulate the tractor and reproduce the vehicle behavior. A DOE was developed to quantify the impact of a large number of variables and combinations of variables for both physical testing and simulation. Assorted variables were found to have primary, secondary and tertiary impact on the phenomenon.
Technical Paper
2014-09-30
Masahiro Akei, Takayuki Koizumi, Nobutaka Tsujiuchi, Takayuki Yamauchi
 In recent years, the demand for low noise operating agricultural machines is increasing. The engine installed on machines is one of a major sound source. The air-borne noise radiated from the vibration of the engine surface affects the sound quality of the surrounding and at the operator’s point.  For the reduction of noise radiated from the engine, the engine enclosure and the sound absorbing material into the engine room are adopted.  However, the installation of the sound absorbing material leads to the increase in product cost. The structural improvement of the engine room also causes the increase in development period of the product. In order to reduce the noise level effectively at evaluation points, it is necessary to grasp the characteristics of sound source, and predict the improvement effect in advance.  In this study, the sound source model of a diesel engine that is installed on the agricultural machine is identified by inverse-numerical acoustic analysis (INA). INA is a method to identify the surface vibration of sound source from the sound pressure around sound source.
Technical Paper
2014-09-30
John Anderson
This paper describes the development and testing of a Dynamic Vibration Absorber to reduce frame beaming vibration in a highway tractor. Frame beaming is as old as the ladder frame. It occurs when the first vertical bending mode of the frame is excited by road or wheel-end inputs. This is frequently a smooth-road problem that occurs at highway speeds (50 to 60 MPH) when the tire rotational frequency coincides with the frame beaming frequency. Rear drive tire run-out is especially good at exciting the frame. It is primarily a driver comfort problem. Up until now, few options were available to resolve this problem. The paper will review the phenomenon, design factors affecting a vehicle's sensitivity, and the principles of Dynamic Vibration Absorbers (AKA Tuned Mass Dampers). Finally, the paper will describe simulation and testing that led to the development of an effective vibration absorber as a field fix.
Technical Paper
2014-09-30
Rahul Ramola, G Senthilkumar, P kannan, Muralidharan Chennakrishnan
The demand for comfort level in commercial vehicles is steadily increasing. Hence, fine-tuned performance parameters and attributes are required to fulfill the expectations from these vehicles. Refinement of noise and vibration without affecting performances of sub-systems and components has become extremely challenging. This paper presents an approach to identify and reduce the whistling noise that was perceived in the passenger compartment when the vehicle was accelerated above 50 Kmph. Whistling noise is a characteristic of aerodynamic behavior of a component and is produced in the higher RPM and frequency range. Thus Engine Cooling fan, turbocharger, intake unit, exhaust,Alternators and Compressors were suspected. Interior noise measurements revealed that the whistling noise is of specific order. Using NVH techniques like Order tracking and Near field measurements, HVAC alternator was identified as the source of whistling noise. Narrow down approach using noise analysis confirmed the alternator cooling fan as problematic noise radiating component.
Technical Paper
2014-09-30
Anatoliy Dubrovskiy PhD, Sergei Aliukov, Yuriy Rozhdestvenskiy PhD, Olesya Dubrovskaya, Sergei Dubrovskiy
At present, we have developed a fundamentally new design of adaptive suspension systems of vehicles. Their technical characteristics and functional abilities are far better than the existing designs of suspensions. We have developed the following main suspension components of vehicles: a lockable adaptive shock absorber with an ultra-wide range (hyper range) of control performance, implementing "lockout" mode by means of blocking adaptive shock absorber, and an elastic element (spring, torsion, and so on) with progressive non-linear characteristic and automatic optimization of localization of work areas. Our design has no analogues in the practice of modern transport engineering. Our patents confirm the novelty and efficiency of our major design decisions. Advantages of our developments in the vehicle suspensions are the following: Firstly, it should be noted that when the vehicle is in a wide range of speeds in a so-called "comfort zone", we were able, by applying the non-linear elastic element, to reduce significantly the stiffness of the elastic suspension elements in compare with the regular structures - at least in two times!
Technical Paper
2014-09-28
Yannick Desplanques
The ratio of two forces acting respectively perpendicular and normal to a contact surface of two bodies, the so-called "coefficient of friction", is widely used in engineering and science depicting the friction resistance of materials sliding over one another under given conditions. In spite of this dimensionless quantity appears to be convenient for engineering and relatively easy to determine, the use of tabulated friction coefficients becomes somewhat an issue to predict friction behavior of mechanical systems. The system dependence of friction is sometimes ignored, leading to misapplication. Moreover, the fundamental origins of sliding resistance are not as clear and care should be taken when attributing to the friction coefficient a fundamental significance. This paper will review the results obtained on friction by Charles Augustin Coulomb and used for hundred of years [1]. Firstly enunciated in Leonardo da Vinci manuscripts [2], the proportionality of the friction force to the applied load and its independency of the apparent area of contact were noticed from experiences and proposed for generalization by Guillaume Amontons in 1699, known as the two-first friction laws [3].
Technical Paper
2014-06-30
Hiromichi Tsuji, Satoshi Takabayashi, Eiji Takahashi, Hitoshi Murakami, Shinichi Maruyama
A finite element (FE) model of vibro-acoustic coupling analysis, such as a vehicle noise and vibration, is utilized for the improvement of the performance in the vehicle development phase. However, the accuracy of the analysis is not enough for substituting a prototype phase with a digital phase in the product development phases. Therefore, conducting the experiments with the prototype vehicle or the existed production vehicle is still very important for the performance evaluation and the model validation. The vehicle noise transfer function of the road noise performance cannot be evaluated with the existed excitation equipment, such as the 3 or 6 directional electromagnetic shaker. Therefore, this paper proposes new experimental method to measure the road noise vehicle transfer function. This method is based on the reciprocity between the tire contact patch and the driver's ear location. The reaction force sensor of the tire contact patch is newly developed for the reciprocal loud speaker excitation at the passenger ear location.
Technical Paper
2014-06-30
Dirk Mayer, Jonathan Militzer, Thilo Bein
Abstract The automotive industry is aiming at both reducing the weight of the vehicles while improving a high level of comfort. This causes contradicting requirements for the systems used for noise and vibration control. Thus, active systems are investigated which may enhance the performance of passive noise and vibration control in vehicles without adding excessive weight. In this paper, basic principles for the implementations of those systems with a focus on the control systems are reviewed. Examples from implementations in automotive applications are presented, including control of engine vibrations, structure borne noise transmitted from the road into the passenger compartment and low-frequency chassis vibrations. Based on adaptive filter systems already widely used in active noise control adaptation of the control algorithms to the specific application scenarios are discussed. This includes different configurations for feedforward and feedback control, single- and multichannel control systems and the utilization of different actuator concepts like active mounts, inertial mass actuators and active tuned absorbers, as well as different control sensors like accelerometers and microphones.
Technical Paper
2014-06-30
Hiromichi Tsuji, Kimihiko Nakano PhD
This paper presents new technique to estimate the projected operational forces, which is the operational forces with respect to the evaluation location, at the connections of the separated passive substructures with reciprocity. Since the transfer path analysis (TPA) is conducted with respect to the evaluation location, the forces for the substructures are, therefore, also required only to estimate the projected operational forces. In order to estimate the forces, the projected inertance matrix, which is the projection of the inertance matrix onto the subspace with respect to the evaluation location, is estimated without measuring it directly. The acceleration responses at the connections of the passive substructure are measured by the excitation at the evaluation location with the reciprocity. The technique decomposes the acceleration responses into the output and input element vectors on the subspace. With those vectors, the projected inertance matrix is constructed. The projected operational forces at the passive substructure can be estimated by the operational accelerations pre-multiplied by the inverted projected inertance matrix.
Technical Paper
2014-06-30
Farokh Kavarana, Kin Yu, Tyler Robbins, John DeYoung
Abstract The advantages of hydraulic mounts over conventional elastomeric mounts for NVH refinement are well known, particularly in the area of engine and suspension mounts. Recently, hydraulic mounts have been successfully employed as body mounts between the frame and cab, principally to control freeway hop in pickup trucks. Due to their ability to provide increased damping at small displacements, hydraulic body mounts also have good potential to reduce smooth road shake. This paper documents the reduction in smooth road shake performance of a full size pickup truck. Hydraulic body mounts tuned to the frequency of the smooth road shake sensitivity area were added to the rearmost cab mount location. Both tire-wheel balance and uniformity were set to the highest production level specification allowed and the effect of hydraulic cab mount was measured experimentally during smooth road driving at medium to high speeds. Hydraulic body mounts were found to be successful in reducing smooth road floor shake by up to 6 dB, thereby considerably refining the vehicle vibration due to first order tire-wheel input forces.
Technical Paper
2014-06-30
Yuan feng Xia, Jian Pang, Chengtai Hu, Cui Zhou, Cong Wu
Abstract The paper analyzes the characteristics of driveline torsional vibration of a RWD vehicle and provides the control methods of transmission rattle noise caused by the system torsional resonances. A driveline dynamic model of the RWD vehicle is established by multi-body dynamic method. The natural frequencies and modal shapes are calculated for each gear position and torsional vibration responses are predicted by forced vibration analysis. The system sensitivity and DOE are analyzed based on the parameterized stiffness, inertia and damping. The 2nd and 3rd order modal results show that the transmission shaft possesses the maximum amplitudes and its corresponding modal frequencies vary with different gear position. The sensitivity analysis results show that the system torsional vibration is significantly reduced by reducing clutch stiffness, increasing propeller shaft stiffness, raising half shaft stiffness, increasing the input shaft inertia and increasing the clutch damping. The DOE analysis results show that the clutch stiffness, propeller shaft stiffness, and the inertia of axle pinion shaft and transmission input shaft play an important role in reducing torsional vibration of the transmission gear shafts.
Technical Paper
2014-06-30
Albert Albers, Rui Cai, Rainer Spengler, Christian Olfens, Matthias Behrendt
Abstract The driving comfort influences the customer purchase decision; hence it is an important aspect for the vehicle development. To better quantify the comfort level and reduce the experiment costs in the development process, the subjective comfort assessment by test drivers is nowadays more and more replaced by the objective comfort evaluation. Hereby the vibration comfort is described by scalar objective characteristic parameters that correlate with the subjective assessments. The correlation analysis requires the assessments and measurements at different vehicle vibration. To determine the objective parameters regarding the powertrain excitations, most experiments in the previous studies were carried out in several test vehicles with different powertrain units. Due to the different features among test vehicles, the subjective assessments and the objective measurements are influenced by further interfering factors, such as different wheel excitations between vehicles, which lead to an inevitable variance.
Technical Paper
2014-06-30
Gregor Tanner, David J. Chappell, Dominik Löchel, Niels Søndergaard
Abstract Modelling the vibro-acoustic properties of mechanical built-up structures is a challenging task, especially in the mid to high frequency regime, even with the computational resources available today. Standard modelling tools for complex vehicle parts include finite and boundary element methods (FEM and BEM), as well as Multi-Body Simulations (MBS). These methods are, however, robust only in the low frequency regime. In particular, FEM is not scalable to higher frequencies due to the prohibitive increase in model size. We have recently developed a new method called Discrete Flow Mapping (DFM), which extends existing high frequency methods, such as Statistical Energy Analysis or the so-called Dynamical Energy Analysis (DEA), to work on meshed structures. It provides for the first time detailed spatial information about the vibrational energy of a whole built-up structure of arbitrary complexity in this frequency range. The response of small-scale features and coupling coefficients between sub-components are obtained through local FEM models integrated in the global DFM treatment.
Technical Paper
2014-06-30
Ze Zhou, Jonathan Jacqmot, Gai Vo Thi, ChanHee Jeong, Kang-Duck Ih
Abstract The NVH study of trimmed vehicle body is essential in improving the passenger comfort and optimizing the vehicle weight. Efficient modal finite-element approaches are widely used in the automotive industry for investigating the frequency response of large vibro-acoustic systems involving a body structure coupled to an acoustic cavity. In order to accurately account for the localized and frequency-dependant damping mechanism of the trim components, a direct physical approach is however preferred. Thus, a hybrid modal-physical approach combines both efficiency and accuracy for large trimmed body analysis. Dynamic loads and exterior acoustic loads can then be applied on the trimmed body model in order to evaluate the transfer functions between these loads and the acoustic response in the car compartment. The scenario study of installing different trim components into the vehicle provides information on the acoustic absorption and dynamic damping with regard to added vehicle weight by the trim.
Technical Paper
2014-06-30
Giorgio Veronesi, Christopher Albert, Eugène Nijman, Jan Rejlek, Arnaud Bocquillet
Abstract In many application fields, such as automotive and aerospace, the full FE Biot model has been widely applied to vibro-acoustics problems involving poro-elastic materials in order to predict their structural and acoustic performance. The main drawback of this approach is however the large computational burden and the uncertainty of the input data (Biot parameters) that may lead to less accurate prediction. In order to overcome these disadvantages industry is asking for more efficient techniques. The vibro-acoustic behaviour of structures coupled with poroelastic trims and fluid cavities can be predicted by means of the Patch Transfer Function (PTF) approach. The PTF is a sub-structuring procedure that allows for coupling different sub-systems via impedance relations determined at their common interfaces. The coupling surfaces are discretised into elementary areas called patches. Since the patch impedances can be determined in either computational or experimental manner, the PTF approach offers full modularity.
Technical Paper
2014-06-30
Zoran Radmilovic, Josef Zehetner, Daniel Watzenig
Abstract Hybrid electric vehicles (HEVs) with a power-split system offer a variety of possibilities in reduction of CO2 emissions and fuel consumption. Power-split systems use a planetary gear sets to create a strong mechanical coupling between the internal combustion engine, the generator and the electric motor. This concept offers rather low oscillations and therefore passive damping components are not needed. Nevertheless, during acceleration or because of external disturbances, oscillations which are mostly influenced by the ICE, can still occur which leads to a drivability and performance downgrade. This paper proposes a design of an active damping control system which uses the electric motor to suppress those oscillations instead of handling them within the ICE control unit. The control algorithm is implemented as part of an existing hybrid controller without any additional hardware introduced. Because the system is rather slow and acting upon detection of oscillations has no reasonable effect, the controller has to predict the future behavior and the torque distribution in the drive-train.
Technical Paper
2014-06-30
Joël Perret-Liaudet, Alexandre Carbonelli, Emmanuel Rigaud, Brice Nelain, Pascal Bouvet, C. Jacques Vialonga
Abstract The main source of excitation in gearboxes is generated by the meshing process, which generates vibration transmitted to the casings through shafts and bearings. Casing vibration generates leads to acoustic radiation (whining noise). It is usually assumed that the transmission error and variation of the gear mesh stiffness are the dominant excitation mechanisms. These excitations result from tooth deflection and tooth micro-geometries (voluntary profile modifications and manufacturing errors). For real cases, the prediction of noise induced by the Static Transmission Error (STE) remains a difficult problem. In this work, an original calculation procedure is implemented by using a finite element method and taking into account the parametric excitations and their coupling (Spectral Iterative Method, developed by the Ecole Centrale de Lyon). The procedure is based on a modal approach developed in the frequency domain, particularly efficient to analyze systems having many degrees of freedom.
Technical Paper
2014-06-30
Janko Slavic, Martin Cesnik, Miha Boltezar
Abstract Car components are exposed to the random/harmonic/impact excitation which can result in component failure due to vibration fatigue. The stress and strain loads do depend on local stress concentration effects and also on the global structural dynamics properties. Standardized fatigue testing is long-lasting, while the dynamic fatigue testing can be much faster; however, the dynamical changes due to fatigue are usually not taken into account and therefore the identified fatigue and structural parameters can be biased. In detail: damage accumulation results in structural changes (stiffness, damping) which are hard to measure in real time; further, structural changes change the dynamics of the loaded system and without taking this changes into account the fatigue load in the stress concentration zone can change significantly (even if the excitation remains the same). This research presents a new approach for accelerated vibration testing of real structures. The new approach bases on phase locked harmonic excitation and can be used for identification of natural frequencies and damping while the damage due to vibration is being accumulated.
Standard
2014-06-06
Description of Material—The materials classified under this specification are: a. Mastic vibration damping materials used to reduce the sound emanating from metal panels. b. Mastic underbody coatings used to give protection and some vibration damping to motor vehicle underbodies, fenders, and other parts.
WIP Standard
2014-04-30
This SAE Recommended Practice is applicable to all liquid-to-gas, liquid-to-liquid, gas-to-gas, and gas-to-liquid heat exchangers used in vehicle and industrial cooling systems. This document outlines the test to determine durability characteristics of the heat exchanger from vibration-induced loading.
Training / Education
2014-04-24
Pawel M. Kurowski
Finite Element Analysis (FEA) has been used by engineers as a design tool in new product development since the early 1990's. Until recently, most FEA applications have been limited to static analysis due to the cost and complexity of advanced types of analyses. Progress in the commercial FEA software and in computing hardware has now made it practical to use advanced types as an everyday design tool of design engineers. In addition, competitive pressures and quality requirements demand a more in-depth understanding of product behavior under real life loading conditions. This webinar will enable participants to expand the scope of FEA to vibration analysis to simulate product behavior under those conditions. This six-session web seminar introduces vibration analysis performed with Finite Element Analysis (FEA). By considering time-dependent loads and inertial and damping effects, vibration analysis allows for a more in-depth product simulation thus reducing product development cost and time.
Viewing 1 to 30 of 2193

Filter

  • Range:
    to:
  • Year: