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Viewing 91 to 120 of 109901
2017-06-05
Technical Paper
2017-01-1872
Masao Nagamatsu
The almost current sound localization methods do not have enough resolution in low frequency sound localization. To overcome this disadvantage, I am now developing a new sound localization method, Double Nearfield Acoustic Holography (DNAH) method. This method is a converted method of conventional Nearfield Acoustic Holography (NAH) method. In this proposing method, the resolution of low frequency sound localization is improved by using sound propagation information on doubled measurement planes. To prove the performance of proposing method, the basic experiments with variable conditions are conducted. In these experiments, the small speakers are used as sound sources. In this paper, to discuss the ability to apply to actual industry, the effect of measurement distance from sound source is explained. Some experimental results with changing measurement distance are shown in this paper.
2017-06-05
Technical Paper
2017-01-1874
Tongyang Shi, Yangfan Liu, J Stuart Bolton, Frank Eberhardt, Warner Frazer
Wideband Acoustical Holography, which is a monopole-based equivalent source procedure (J. Hald, “Wideband Acoustical Holography”, INTER-NOISE 2014), have been proven to offer an accurate noise source holography result in experiments with a simple noise source: e..g., a loudspeaker (T. Shi, Y. Liu, J. Bolton, ”The Use of Wideband Holography for Noise Source Visualization”, NOISE-CON 2016). From a previous study, it was found that the advantage of this procedure is the ability to optimize the solution in the case of an under-determined system: i.e., when the number of measurements is less than the number of parameters that must be estimated in the model. In the present work, a diesel engine noise source was measured by using one set of measurements from a thirty six channel irregular array placed in front of the diesel engine.
2017-06-05
Technical Paper
2017-01-1895
Troy Bouman, Andrew Barnard, Joshua Alexander
Compared to moving coil loudspeakers, carbon nanotube (CNT) loudspeakers are extremely lightweight and are capable of creating sound over a broad frequency range (1 Hz to 100 kHz). The thermoacoustic effect that allows for this non-vibrating sound source is naturally inefficient and nonlinear. Signal processing techniques are one option that may help counteract these concerns. Previous studies have evaluated a hybrid efficiency metric, the ratio of the sound pressure level at a single point to the input electrical power. True efficiency is the ratio of output acoustic power to the input electrical power. True efficiency data are presented for two new drive signal processing techniques borrowed from the hearing aid industry. Spectral envelope decimation of an AC Signal operates in the frequency domain (FCAC) and dynamic linear frequency compression of an AC signal operates in the time domain (TCAC). Each type of processing affects the true efficiency differently.
2017-06-05
Technical Paper
2017-01-1890
Xingyu Zhang, Bo Yang, Manchuang Zhang, Sanbao Hu
H-Bahn ("hanging railway") refers to the suspended, unmanned urban railway transportation system. Through the reasonable platform layout, H-Bahn can be easily integrated into the existing urban transit system. With the development of urban roads, the associated rail facilities can be conveniently disassembled, moved and expanded. The track beam, circuits, communication equipment, and sound insulation screen are all installed in a box-type track beam so that the system can achieve a high level of integration and intelligence. The carriage of the modern H-banh vehicle is connected with the bogies by two hanging devices. The vehicle is always running in the box-type track beam; therefore there are less possibilities of derailment. Consequently, the key work focuses on the running stability evaluation and curve negotiation performance analysis.
2017-06-05
Technical Paper
2017-01-1888
Rasheed Khan, Mahdi Ali, Eric C. Frank
Vehicle voice recognition systems have become an essential tool for hands free communication. As such, it has become more and more important to have reliable, consistent voice recognition in a vehicle. Vehicle voice recognition system performance is based on a variety of factors, including the speakers' gender & background noise. Male and female voice characteristics are inherently different, and some of these variations are investigated in this work. In this work, three vehicles have been tested during five different steady state road conditions (70 mph, 45 mph, Idle HVAC off, Idle HVAC on, vehicle off). Twelve speakers (six male and six female) were recorded announcing twenty mono- and multi-syllable call commands. Each speaker was recorded three times for repeatability, along with the vehicle voice recognition system response. Based on the resulting success rates, the least-recognized commands were synthesized to resemble the best detected commands from the different genders.
2017-06-05
Technical Paper
2017-01-1886
Siwen Zhang, Jian Pang, Jun Zhang, Zhuangzhuang Ma, Xiaoxuan Zhang, Congguang Liu, Lihui Deng
In this paper, the subjective evaluation method for the air-borne sound insulation performance of vehicle body in reverberation room is developed and investigated. To improve the credibility of the traditional subjective evaluation methods for the air-borne sound insulation, the test vehicles are placed in the reverberation room and exposed in the homogeneous reverberation sound field. The stationary vehicle's interior noise is recorded by using a digital artificial head. The noise testing method in reverberation room demonstrates more credible than the traditional methods based on the standard deviation analysis of vehicle external fields. With paired comparison scoring method, the recorded interior noises of six different vehicles are replayed and evaluated subjectively by 22 appraisers in the sound quality room. Kendall's correlation coefficient and circular error rates are introduced to check the consistency and correctness of the appraisers' evaluation scores.
2017-06-05
Technical Paper
2017-01-1752
Kapil Gupta, Arun Choudhary, Rakesh Bidre
At present, a Dual Mass Flywheel (DMF) system is widely known to provide benefits on driveline induced noise, vibration and drivability over a Single Mass Flywheel (SMF). A well-tuned DMF provides nice isolation of torsional vibrations generated in periodic combustion process of automobile IC engines. Similarly, a torsional vibration damper mounted on driveline component reduces the torsional excitation and results a lower torsional vibration at driveline components. Noise and vibration issues like boom noise and high vibrations at low engine rpm range drive are often resulted due to high engine firing order torsional excitation input to the driveline. More often, this becomes one of the most objectionable noise and vibration issues in vehicle and should be eliminated or reduced for better NVH performance. A 4 cylinder, 4 stroke small diesel engine equipped with SMF is found to have high engine firing order torsional excitation.
2017-06-05
Technical Paper
2017-01-1793
William Seldon, Amer Shoeb, Daniel Schimmel, Jared Cromas
As regulations become increasing stringent and customer expectations of vehicle refinement increase the accurate control and prediction of the air induction system (AIS) and exhaust system airborne acoustics are a critical factor in creating a vehicle that wins in the marketplace. The team selected two projects to highlight for SAE. This paper will explore the details of an exhaust focused correlation project that was performed on a naturally aspirated eight cylinder engine. While the other SAE paper (XX-XX-XX) focus on correlation of an induction system on a turbocharged four cylinder.
2017-06-05
Technical Paper
2017-01-1794
William Seldon, Jamie Hamilton, Jared Cromas, Daniel Schimmel
Abstract As regulations become increasing stringent and customer expectations of vehicle refinement increase the accurate control and prediction of the air induction system (AIS) and exhaust system airborne acoustics are a critical factor in creating a vehicle that wins in the marketplace. The team selected two projects to highlight for SAE. This paper will explore the details of an induction focused correlation project that was performed on a turbocharged four cylinder engine. The other SAE paper (XX-XX-XX) will focus on the correlation of an exhaust system on a naturally aspirated eight cylinder.
2017-06-05
Technical Paper
2017-01-1779
Xianwu Yang, Jian Pang, Lanjun Wang, Xiong Tian, Yu Tang
With the development of automobile industry, the higher NVH performance is required for customers, and with drastically reduction of engine noise, the gear rattle noise generated by the impact between neutral gears inside transmission can be much easily perceived. It is well known that the torsional mode of powertrain system has a direct relationship with transmission gear rattle noise, the higher torsional vibration leads to more serious gear rattle noise. This paper establishes a torsional model of a front wheel drive automotive drivetrain, including clutch system, transmission box and equivalent load of a full vehicle in AMESim software. The experimental engine speed fluctuations at different gears are used to excite the torsional model.
2017-06-05
Technical Paper
2017-01-1790
Vinayak H. Patil, Ravi Kumar Sara, T. R. Milind, Rodney C. Glover
Vehicle noise emission regulations are becoming more stringent each passing year (e.g. pass-by noise requirement for passenger vehicles is now 74 dB(A) in some parts of the world). The common focus areas for noise treatment in the vehicle are primarily on three sub-systems i.e., engine compartment, exhaust systems and power train systems. Down- sizing and down- speeding of engines without compromising on power output has meant use of boosting technologies that have produced challenges to design low-noise intake systems minimizing losses and meeting today’s vehicle emission regulations. There are multiple sources of noise in an intake system. Thus an understanding of the sources of noise in the intake system is needed. One such boosting system consists of Turbo-Super configuration with elements like air box filter, outlet manifold and intercooler.
2017-06-05
Technical Paper
2017-01-1811
Jouji Kimura, Tatsuya Tanaka, Kenjiro Hakomoto, Kousuke Kawase, Shinichiro Kobayashi
This paper describes based on the mechanism of whirl resonance about the characteristic of serious bending stress which occurred in the crankshaft rear. The following steps to prove that the bending stress is caused by whirl resonance of the crankshaft rear end. At first, the authors showed that the resonance frequency of bending stress for forward whirl which takes place in the same direction as crankshaft rotation increases with the increasing engine speed, and the resonance frequency of bending stress for reverse whirl which takes place in the reverse direction as crankshaft rotation decreases with the increasing engine speed. Secondly, it was found out that there are two groups, the correlation between the resonance frequency and the resonance engine speed of the measured bending stresses in the crankshaft rear. One is the group that the resonance frequency increases with the increasing engine speed.
2017-06-05
Technical Paper
2017-01-1819
Cyril Nerubenko, George Nerubenko
The results of dynamical study of new patented Torsional Vibration Dampers mounted on a crankshaft in V8 engines are presented. Design and structure of Torsional Vibration Damper is based on author’s US Patent 7,438,165 having the control system with instantaneous frequencies tuner for all frequencies of running engine. Analysis and disadvantages of conventional rubber and viscous Crank Dampers are shown. The focus of the study is on Torsional Vibration Damper having the mechanical self-tuning structure applicable for V8 engines. Mathematical model based on the system of ordinary differential equations describing the rotation and vibration of mechanical components has been used for the analysis of the dynamic behavior of V8 engine crankshaft system having proposed Torsional Vibration Damper. Attention is paid to composition and selection of optimal parameters of a proposed device for solving the problems of effective mitigation of crankshaft torsional vibrations in V6 engines.
2017-06-05
Technical Paper
2017-01-1852
Satyajeet P. Deshpande, Pranab Saha, Kerry Cone
Most of NVH related issues start from the vibration of structures where often the vibrations at resonance radiates the energy in terms of sound. This phenomenon is more pragmatic at low frequencies. This paper discusses a case study where different viscoelastic materials were evaluated on a bench study and then carried on to system level evaluation. A steel panel with a glazing system was used to study both airborne and structureborne noise radiation. System level studies were carried out using experimental modal analysis to shift and tune the mode shapes of the structure using visco-elastic materials with appropriate damping properties to increase the sound transmission loss. The paper discusses the findings of the study where the mode shapes of the panel were shifted and resulted in an increase in sound transmission loss and eventually resulted in reduced sound level in the cabin interior.
2017-06-05
Technical Paper
2017-01-1855
Ramakanta Routaray
The basic function of a motorcycle frame is somewhat similar to that of the skeleton in the human body, i.e. to hold together the different parts in one rigid structure. One of the major benefits (for a motorcycle enthusiast) of using an advanced frame design lies in the sporty handling characteristics of the bike. A well designed frame can add to the joy of riding a motorcycle as the bike would feel more stable, effortless, and confident around corners, in straight lines and while braking. A well approved modeling techniques or adequate guide line principles have to be followed while designing the body and chassis in order to achieve the vibration within control. This paper depicts a methodological right approach to model the body and chassis of a two wheeler in order to control noise and vibration of the body and chassis.
2017-06-05
Technical Paper
2017-01-1861
Ismail Benhayoun, Frédéric Bonin, Antoine Milliet de Faverges, Julien Masson
NVH (Noise Vibration & Harshness) is one of the main focus areas during the development of products such as passenger cars or trucks. Physical test methods have traditionally been used to assess NVH, but the necessity for reducing cost and creating a robust solution early on in the design process has driven the increased usage of simulation tools. Development of well-defined methods and tools for NVH analysis allows today's OEMs to have a Virtual Engineering based Development Cycle from Concept to Test. However, not all NVH problems have been focused on, including the issue of Squeak and Rattle (S&R). In a vehicle, S&R is a recurring problem for interior plastic parts such as an Instrument Panel or Door Trim. Since 2012, Altair has been developing S&R Director (SnRD), which is a solution that identifies and combats S&R issues by embedding E-Line methodology [1] [2]. This methodology is based on Industry Best Practices, as described in the paper SAE 2012-01-1553.
2017-06-05
Technical Paper
2017-01-1900
Leiaixin Yang, Yinong Li, Peiran Ding, Parsa Zamankhan, John G. Cherng
The numerical modeling of brake squeal performance must consider the influence of temperature under different operating conditions. Temperature changes due to frictional heat generation causes axial and radial deformations of the rotor along with pad expansion. The change in shape affects the contact between the rotor and pad surface area and thus will influence the load distribution at the friction interface. A systematic approach was applied to investigate the automotive vehicle brake squeal with the consideration of thermal stress induced during the braking. A typical brake assembly model was developed using both FLUENT and Mechanical modules of ANSYS software. The thermal load induced stress was then transferred to the mechanical model for dynamic characteristics and stability analyses. Three different analysis methods were investigated including, linear, partial non-linear and full non-linear.
2017-06-05
Technical Paper
2017-01-1884
Ruimeng Wu, David W. Herrin
Sound absorbing materials are commonly compressed when installed in passenger compartments or underhood applications altering the sound absorption performance of the material. However, most prior work has focused on uncompressed materials and only a few models based on poroelastic properties are available for compressed materials. Empirical models based on flow resistivity are commonly used to characterize the complex wavenumber and characteristic impedance of uncompressed sound absorbing materials from which the sound absorption can be determined. In this work, the sound absorption is measured for both uncompressed and compressed samples of fiber and foam, and the flow resistivity is curve fit using an appropriate empirical model. Following this, the flow resistivity of the material is determined as a function of the compression ratio. The procedure outlined in the paper is a simple approach for characterizing compressed materials that only.
2017-06-05
Technical Paper
2017-01-1908
Rong Guo, Jun Gao, Xiao-kang Wei, Zhao-ming Wu, Shao-kang Zhang
This work aims to provide theoretical basis for improving engine shake performance based on full vehicle model by optimizing the design parameters of hydraulic engine mounts (HEMs). The definition of the engine shake problem is presented through comparing the quarter vehicle models with the rigid-connected and flexible-connected powertrain which is supported by a rubber mount. Then the model is extended by replacing the rubber mount as a HEM with regard to the inertia and resistance of the fluid within the inertia track. Based on these, a full vehicle model with 14 degree of freedoms (DOFs) is proposed to calculate the engine shake, which consists of 6 of the powertrain, 1 of the fluid within the inertia track of the HEM, 3 of the car body and 4 of the unsprung mass. Parameter study is performed to determine the most effective parameters of the HEM influencing engine shake and then the HEM is optimized through the genetic algorithm (GA).
2017-06-05
Technical Paper
2017-01-1907
Yang Wang, Yong Xu, Xiao Tan
OPTIMIZATION OF THE POWERTRAIN MOUNTING SYSTEM VIA DOE METHOD Authors: Wang Yang*, Wang Hui*, Xu Yong* * NVH Section, Brilliance-Auto Engineering Research Institute, Shenyang, China, 110141 Key Words: NVH; DOE; Powertrain Mounting System; Analysis of Variance Research and/or Engineering Questions/Objective The vibration isolation performance of vehicle powertrain mounting system is mostly determined by the three-directional stiffnesses of each mount block. Because of the manufacturing tolerance and the coupling effect, the stiffnesses of mounts cannot be maintained stable. The purpose of this study was to find out the way to optimize the stiffnesses of mounts via the design of experiments (DOE). Methodology According to the DOE process, a full factorial design was implemented. The z-direction stiffnesses of three mount blocks in the mounting system were selected as the three analysis factors.
2017-06-05
Technical Paper
2017-01-1875
Martino Pigozzi, Flavio Faccioli, Carlo Ubertino, Davide Allegro, Daniel Zeni
Within recent years, passenger comfort has become a main focus for the automotive industry. The topic is directly connected to acoustics, since sounds and noises have a major impact on the well-being of vehicle occupants. The so-called “noise control” focuses on directly optimizing acoustic comfort by implementing innovative materials or geometries for automotive components and systems. One possibility to optimize the acoustics within a vehicle is connected to the phenomenon of sloshing in selective catalytic reduction (SCR) tanks. Sloshing is a noise which is generated during normal driving situations by the motion of the liquid in the tank. Until now, no valid procedure for measuring the sloshing noise in SCR tanks, or a specific acoustic target which the SCR tanks need to fulfill has been defined. For this reason, It's been developed a reproducible laboratory-based methodology to measure the sound generated by the tank to compare it with a defined sound pressure level target.
2017-06-05
Technical Paper
2017-01-1783
Chris Todter, Olivier Robin, Paul Bremner, Christophe Marchetto, Alain Berry
Fluctuating surface pressure measurements using microphone arrays are still challenging, especially in an automotive context with cruising speeds around Mach 0.1. The separated turbulent boundary layer excitation and the side mirror wake flow generate both acoustic and aerodynamic components, which have wavenumbers that differ by a factor of approximately 10. This calls for high spatial resolution measurements to fully resolve the wavenumber-frequency spectrum. In SAE paper 2015-01-2325, the authors reported a micro-electro-mechanical (MEMS) surface microphone array that successfully used wavenumber analysis to quantify acoustic versus turbulence loading. It was shown that the measured surface pressure at each microphone could be strongly influenced by self noise induced by the microphone ”packaging”, which can be attenuated with a suitable windscreen.
2017-06-05
Technical Paper
2017-01-1843
Taejin Shin, Jaemin Jin, Sang Kwon Lee, Insoo Jung
This paper presents the influence of radiated noise from engine surface depending on assembly condition between engine block and oil pan. At the first, force at the crank bearing is obtained from multi-body dynamics model. Secondly, modal analysis is operated to define mode contribution and modal participation factors at the Structure – FEM model for virtual cylinder block. Thirdly, the radiated noise is calculated by Acoustic-FEM. Above procedure is applied at rigid connection model and sandwich panel connection model. Connection properties are applied between engine block and oil pan. Finally, the sound quality of the radiated noise at each condition are compared.
2017-06-05
Technical Paper
2017-01-1822
Kopal Agarwal, Sandip Hazra
Vehicle Drive away shudder is a vibration felt by customers at the time of marching off. The vibration is significantly felt at the time of Clutch Engagement as a shiver in vehicle. While the known reason of Shudder is clutch friction & engagement, in this study we have provided a solution to reduce the shudder by optimizing the power train mounting system. The shake occurs at approximately 10-20kmph in a medium sized car. The design of powertrain mounting system has been modified to achieve the reduction in shake. The pros & cons of the said change in mounting system on the overall NVH performance is also discussed.
2017-06-05
Technical Paper
2017-01-1835
Nader Dolatabadi, Ramin Rahmani, Stephanos Theodossiades, Homer Rahnejat, Guy Blundell, Guillaume Bernard
Clutches are commonly utilised in passenger type and off-road heavy-duty vehicles to disconnect the engine from the driveline and other parasitic loads. In off-road heavy-duty vehicles, fuel efficiency and start-up functionality at extended ambient conditions, such as cold start-up and low intake absolute pressure are crucial. Off-road vehicle manufacturers usually overcome the parasitic loads in these conditions by oversizing the engine. Caterpillar Inc. as the pioneer in the off-road technology has developed a novel clutch design to allow for engine downsizing while vehicle’s performance is not affected. The tribology behaviour of clutch will be crucial to start engagement in time and reach the maximum clutch capacity in the shortest possible time and the safest method in terms of dynamics. A multi-body dynamics model of the clutch system is developed in MSC ADAMS. Flywheel carries the same speed and torque as engine and represents the engine input to the clutch.
2017-06-05
Technical Paper
2017-01-1903
Masami Matsubara, Nobutaka Tsujiuchi, Tomohiko Ise, Shozo Kawamura
The tire is one of the most important parts, which influence the noise, vibration, and harshness of the passenger cars. It is well known that effect of rotation influences tire vibration characteristics, and earlier studies presented formulas of tire vibration behavior. However, there is no studies of tire vibration including lateral vibration on effect of rotation. In this paper, we present new formulas of tire vibration on effect of rotation using a three-dimensional flexible ring model. The model consists of the cylindrical ring represents the tread and the springs represent the sidewall stiffness. The equation of motion of lateral, longitudinal, and radial vibration on the tread are derived based on the assumption of inextensional deformation. Many of the associated numerical parameters are identified from experimental tests.
2017-06-05
Technical Paper
2017-01-1849
Laurent Gagliardini, Romain Leneveu, Aurélien Cloix, Alexandre Durr
The door response to audio excitation contributes to the overall performance of the audio system on several items. First, acting as a cabinet, it influences the loudspeaker response. Second, due to the door inner panel radiation, the radiated power is disturbed. A third effect is the regular occurrence of squeak and rattle, that will not be considered at this stage. Design issues regarding these attributes are numerous, from the loudspeaker design to door structure and trim definition. Modeling then appears as an unavoidable tool to handle the acoustic response of the loudspeaker in its actual surrounding.
2017-06-05
Technical Paper
2017-01-1905
Kiran Patil, Javad Baqersad, Jennifer Bastiaan
Tires are one of the major sources of noise and vibrations in vehicles. The vibration characteristic of a tire depends on its resonant frequencies and mode shapes. Hence, it is desirable to study how different parameters affect the characteristics of tires. In the current paper, experimental modal tests are performed on a tire in free-free and fixed conditions. To obtain the mode shapes and the natural frequencies, the tire is excited using a mechanical shaker and the response is measured using three roving tri-axial accelerometers. The mode shapes and resonant frequencies of the tire are extracted using LMS POLYMAX modal analysis. The extracted mode shapes in the two configurations are compared using Modal Assurance Criterion (MAC) to show how mode shapes of tires change when the tire is moved from a free-free configuration to a fixed configuration.
2017-06-05
Technical Paper
2017-01-1818
Ramya Teja, T. R. Milind, Rodney C. Glover, Sunil Sonawane
Helical gears are used more commonly than spur gears due to their higher load carrying capacity, efficiency and lower noise. Helical gear pairs consist of base and axial planes in the plane of action. Transmission Error (TE) is considered as a dominant source of gear whine noise so gears pairs are analyzed and designed for lower TE. In process of designing helical gears for lower TE, the shuttling moment can be a significant excitation source. A shuttling moment is caused by the shifting of the centroid of the tooth normal force back and forth across the lead. Shuttling force is produced by a combination of design parameters, misalignment and manufacturing errors. Limited details are available on this excitation and its effect on overall noise radiated from the gear box or transmission at is gear mesh frequency and harmonics. LDP provides shuttling force as a bearing force in the base plane direction at one edge of the face width only.
2017-06-05
Journal Article
2017-01-1767
Zhenghong Shi, Teik Lim
Nonlinear interaction between time-varying hypoid gear mesh and bearing support is investigated in this study. Mesh parameters are time-varying due to complex tooth profile of hypoid gear. Bearing stiffness is formulated based on real geometry and instantaneous orbital position of rolling elements. Linear model is firstly analyzed to study the modal frequency and mode shape variations under different stiffness ratio between gear mesh and bearing support. Then, nonlinear analysis is conducted to compare the differences between linear and nonlinear dynamic response based on specific nonlinear conditions of geared rotor system. It is found that the coupling between hypoid gear mesh and bearing support can be either strong or weak depending on the ratio between mesh stiffness along line-of-action (LOA) and bearing stiffness in radial direction. Parametric studies indicate that dynamic mesh force is sensitive to bearing clearance for certain stiffness ratio.
Viewing 91 to 120 of 109901