Criteria

Display:

Results

Viewing 91 to 120 of 7819
2017-06-05
Technical Paper
2017-01-1855
Ramakanta Routaray
Abstract 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 [2] 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 (guide lines) while designing 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
2017-01-1884
Ruimeng Wu, David W. Herrin
Abstract 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.
2017-06-05
Technical Paper
2017-01-1883
Arnaud Duval, Guillaume Crignon, Mickael Goret, Maxime Roux
Abstract The lightweighting research on noise treatments since years tends to prove the efficiency of the combination of good insulation with steep insulation slopes with broadband absorption, even in the context of bad passthroughs management implying strong leakages. The real issue lies more in the industrial capacity to adapt the barrier mass per unit area to the acoustic target from low to high segment or from low petrol to high diesel sources, while remaining easy to manipulate. The hybrid stiff insulator family can realize this easily with hard felts barriers backfoamed weighting from 800 g/m2 to 2000 g/m2 typically with compressions below 10 mm. Above these equivalent barrier weights and traditional compressions of 7 mm for example, the high density of the felts begins to destroy the open porosity and thus the absorption properties (insulation works anyway here, whenever vibration modes do not appear due to too high stiffness…).
2017-06-05
Technical Paper
2017-01-1878
Kevin Verdiere, Raymond Panneton, Noureddine Atalla, Saïd Elkoun
Abstract A poroelastic characterization of open-cell porous materials using an impedance tube is proposed in this paper. Commonly, porous materials are modeled using Biot’s theory. However, this theory requires several parameters which can be difficult to obtain by different methods (direct, indirect or inverse measurements). The proposed method retrieves all the Biot’s parameters with one absorption measurement in an impedance tube for isotropic poroelastic materials following the Johnson-Champoux-Allard’s model (for the fluid phase). The sample is a cylinder bonded to the rigid termination of the tube with a diameter smaller than the tube’s one. In that case, a lateral air gap is voluntary induced to prevent lateral clamping. Using this setup, the absorption curve exhibits a characteristic elastic resonance (quarter wavelength resonance) and the repeatability is ensured by controlling boundary and mounting conditions.
2017-06-05
Technical Paper
2017-01-1875
Martino Pigozzi, Flavio Faccioli, Carlo Ubertino, Davide Allegro, Daniel Zeni
Abstract Within recent years, passenger comfort has become a main focus of the automotive industry. The topic is directly connected with acoustics, since sounds and noises have a major impact on the well-being of vehicle occupants. 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 Diesel Exhaust Fluid (DEF) in the tank. Until now, no procedure for measuring sloshing noise in SCR tanks has been defined, and neither a specific acoustic target which the SCR tanks need to fulfil.
2017-06-05
Technical Paper
2017-01-1874
Tongyang Shi, Yangfan Liu, J Stuart Bolton, Frank Eberhardt, Warner Frazer
Abstract Wideband Acoustical Holography (WBH), which is a monopole-based, equivalent source procedure (J. Hald, “Wideband Acoustical Holography,” INTER-NOISE 2014), has proven to offer accurate noise source visualization results in experiments with a simple noise source: e.g., a loudspeaker (T. Shi, Y. Liu, J.S. 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 much smaller 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-five channel combo-array placed in front of the engine.
2017-06-05
Technical Paper
2017-01-1872
Masao Nagamatsu
Abstract The almost current sound localization methods do not have enough resolution in low frequency sound localization. To overcome this disadvantage, I am now developing the 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 the sound source is explained. Some experimental results with changing measurement distance are shown in this paper.
2017-06-05
Technical Paper
2017-01-1871
Nobutaka Tsujiuchi, Masahiro Akei, Akihito Ito, Daisuke Kubota, Koichi Osamura
Abstract This paper describes new method for selecting optimal field points in Inverse-Numerical Acoustic analysis (INA), and its application to construction of a sound source model for diesel engines. INA identifies the surface vibration of a sound source by using acoustic transfer functions and actual sound pressures measured at field points located near the sound source. When measuring sound pressures with INA, it is necessary to determine the field point arrangement. Increased field points leads to longer test and analysis time. Therefore, guidelines for selecting the field point arrangement are needed to conduct INA efficiently. The authors focused on the standard deviations of distance between sound source elements and field points and proposed a new guideline for optimal field point selection in our past study. In that study, we verified the effectiveness of this guideline using a simple plate model.
2017-06-05
Technical Paper
2017-01-1869
Glenn Pietila, Gang Yin, Branton Dennis IV
Abstract During the development of an automotive acoustic package, valuable information can be gained by visualizing the acoustic energy flow through the Front-of-Dash (FOD) when a sound source is placed in the engine compartment. Two of the commonly used methods for generating the visual map of the acoustic field include Sound Intensity measurements and array technologies. An alternative method is to use a tracked 3-dimensional acoustic probe to scan and visualize the FOD in real-time when the sound source is injecting noise into the engine compartment. The scan is used to focus the development of the FOD acoustic package on the weakest areas by identifying acoustic leaks and locations with low Transmission Loss. This paper provides a brief discussion of the capabilities of the tracked 3-D acoustic probe, and presents examples of the implementation of the probe during the development of the FOD acoustic package for two mid-sized sedans.
2017-06-05
Technical Paper
2017-01-1868
Rod Morris-Kirby, Evan Harry
Abstract The authors previously presented at SAE 2015, the use of acoustic diagnostic network algorithms (Acoustic DNA) for the measurement and analysis of noise paths in motor vehicles. To further the understanding of the huge amount of data created in this method, especially by the end user or customer, a secure web based application platform has been engineered. The current paper presents operating aspects of the web based approach, including cyber security, multi device accessibility and intuitive user interface together with an innovative optimization toolbox from which both noise sources and vehicle body systems can be modified to be target compliant.
2017-06-05
Technical Paper
2017-01-1829
Guillaume Loussert
Abstract The new fuel efficiency and emission standards have forced OEMs to put emphasis on different strategies such as engine downsizing, cylinder deactivation… Unfortunately these new technologies may lead to increased powertrain vibrations generated by the engine and transmitted to the chassis and the car cabin, such that their reduction or elimination has become a key topic for the automotive industry. The use of active engine mounts, acting directly on the fluid of an hydromount, or active vibration dampers, acting as an inertial mass-spring system, are very effective solutions, particularly when using electromagnetic based actuators. Nevertheless, all electromagnetic actuators technologies are not equals and the choice of such actuators must be considered carefully by taking into account the full performances and the overall cost of the solutions.
2017-06-05
Technical Paper
2017-01-1831
Longchen Li, Wei Huang, Hailin Ruan, Xiujie Tian, Keda Zhu, Melvyn Care, Richard Wentzel, Xiaojun Chen, Changwei Zheng
Abstract The control strategy design of vehicle active noise control (ANC) relies too much on experiment experience, which costs a lot to gather mass data and the experimental results lack representation. To solve these problems, a new control strategy optimization method based on the genetic algorithm is proposed. First, a vehicle cabin sound field simulation model is built by sound transfer function. Based on the filtered-X Least Mean Squares (FX-LMS) algorithm and the vehicle cabin sound field simulation model, a vehicle ANC simulation model is proposed and verified by a vehicle field test. Furthermore, the genetic algorithm is used as a strategy optimization tool to optimize an ANC control strategy parameter set based on the vehicle ANC simulation model. The optimized results provide a reference for the ANC control strategy design of the vehicle.
2017-06-05
Technical Paper
2017-01-1832
Giovanni Rinaldi, Jason Edgington, Brian Thom
Abstract Typical approaches to regulating sound performance of vehicles and products rely upon A-weighted sound pressure level or sound power level. It is well known that these parameters do not provide a complete picture of the customer’s perception of the product and may mislead engineering efforts for product improvement. A leading manufacturer of agricultural equipment set out to implement a process to include sound quality targets in its product engineering cycle. First, meaningful vehicle level targets were set for a tractor by conducting extensive jury evaluation testing and by using objective metrics that represent the customer’s subjective preference for sound. Sensitivity studies (“what-if” games) were then conducted, using the predicted sound quality (SQ) index as validation metric, to define the impact on the SQ performance of different noise components (frequency ranges, tones, transients).
2017-06-05
Technical Paper
2017-01-1826
Sagar Deshmukh, Sandip Hazra
Abstract Engine mounting system maintains the position of powertrain in the vehicle with respect to chassis and other accessories during inertia, torque reaction loads and roadway disturbances. The mounting system also plays a role in terms of isolation of the rest of the vehicle and its occupants from powertrain and helps in maintaining vehicle ride and handling condition. This paper investigates the performance comparison between hydromount and switchable hydromount during idle and ride performance. The optimization scheme aims to improve the performance of the mounting system in order to achieve overall powertrain performance and NVH attribute balancing through switchable mount technology.
2017-06-05
Technical Paper
2017-01-1827
Michael J. Santora, Cyril Gbenga Ige, Jeff Otto, David Egolf
Abstract A muffler attached to an engine attenuates sound over a dedicated frequency range. This research involves the development of an active muffler that is keyed to the revolutions per minute (rpm) of the engine and suppresses the fundamental frequency being exhausted through the tailpipe. The active muffler consists of a tracking side-branch resonator terminated with a composite piezoelectric transducer. The use of an exponential horn as a resonating cavity and terminated with a composite piezoelectric transducer is presented. This would create Electromechanical Active Helmholtz Resonator (EMAHR) creates a notch that can be moved between 200-1000 Hz. The use of acoustical-to-mechanical, mechanical-to-electrical, and analog-to-digital transformations to develop a system model for the active muffler are presented. These transforms will be presented as two-port network parameters. The use of two-port networks to model the electroacoustic system are a defining factor in the analysis.
2017-06-05
Technical Paper
2017-01-1828
Jonathan Christian, Dylan Stafford
Abstract The use of active noise control (ANC) systems in automotive applications has been common practice for well over a decade. Many of these systems utilize at least one error microphone that is placed inside the vehicle cabin and provides feedback to the algorithm in order to assess the effectiveness of the anti-noise signal as it attempts to cancel primary noise. Prior work pertaining to optimal error microphone placement has not provided any objective metrics that correlate to the noise reduction experienced inside the vehicle cabin. The goal of this paper is to establish empirically-based metrics which can be used to quantitatively describe why one microphone position in the vehicle is superior or less favorable when compared to another. These metrics are used when considering concurrent multiple-input multiple-output (MIMO) ANC systems that utilize the same error microphones but are trying to attenuate both broadband and narrowband noise.
2017-06-05
Technical Paper
2017-01-1822
Kopal Agarwal, Sandip Hazra
Abstract In this study we will be discussing two issues related to vibrations which effect car owners. The first one, called lateral shake, can be described as a lateral vibration felt by customer in low speed of around 1200rpm, when vehicle shakes severely in Y-direction. The vibration is significantly felt at the thighs of passengers. A 16DOF rigid body model is established to simulate the power train & body system. The second vibration issue, called drive away shudder (also known as clutch judder/chatter/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 common solution of shudder is to optimize clutch friction & engagement, in this study solution has been provided by optimizing the power train mounting system. Clutch shudder is observed on a medium sized car when driven in the range of 10-20 Km/h.
2017-06-05
Technical Paper
2017-01-1823
Dennis J. Kinchen
Abstract Powertrain mounting systems design and development involves creating and optimizing a solution using specific mount rates and evaluation over multiple operating conditions. These mount rates become the recommended “nominal” rates in the specifications. The powertrain mounts typically contain natural materials. These properties have variation, resulting in a tolerance around the nominal specification and lead to differences in noise and vibration performance. A powertrain mounting system that is robust to this variation is desired. The design and development process requires evaluation of these mounts, within tolerance, to ensure that the noise and vibration performance is consistently met. During the hardware development of the powertrain mounting system, a library of mounts that include the range of production variation is studied. However, this is time consuming.
2017-06-05
Technical Paper
2017-01-1824
Reza Kashani, Karthik S. Jayakumar, Neville Bugli, Jeff Lapp
Abstract Passive, tuned acoustic absorbers, such as Helmholtz resonators (HR) and quarter-wave tubes, are commonly used solutions for abating the low-frequency tonal noise in air induction systems. Since absorption at multiple frequencies is required, multiple absorbers tuned to different frequencies are commonly used. Typically, the large size and multiple numbers of these devices under the hood is a packaging challenge. Also, the lack of acoustic damping narrows their effective bandwidth and creates undesirable side lobes. Active noise control could address all of the above-mentioned issues. Most active noise control systems use feedforward adaptive algorithms as their controllers. These complex algorithms need fast, powerful digital signal processors to run. To ensure the convergence of the adaptation algorithm, the rate of adaptation should be made slow.
2017-06-05
Technical Paper
2017-01-1817
Steven M. Gasworth, Vasudev Nilajkar, Matteo Terragni
Abstract Polycarbonate (PC) glazing as a one-for-one glass replacement offers a 50% weight reduction, but exhibits several dB lower sound transmission loss (STL) in the low frequency range where tire and engine noise are dominant. In the high frequency range where wind noise is dominant, PC glazing offers an STL at least comparable to its glass counterpart, and an STL exceeding glass when this frequency range encompasses the glass coincidence frequency. However, a key value proposition of PC glazing is the opportunity for feature integration afforded by the injection molding process generally used for forming such glazing. Two-component (2K) molding fuses a second shot of plastic material behind, and along the perimeter of, the transparent PC first shot. This second shot can incorporate features and implement functions that require additional components attached or peripheral to a glass version.
2017-06-05
Technical Paper
2017-01-1848
Richard DeJong
Abstract From 1983 to 1995, Richard H. Lyon published several papers on Statistical Phase Analysis, showing that the average phase of the transfer functions in complex systems grows with frequency in proportion to the modal density of the system. In one dimensional systems this phase growth is the same as that of freely propagating waves. However, in two and three dimensional systems this phase growth is much larger than the corresponding freely propagating wave. Recent work has shown that these phase growth functions can be used as mode shape functions in discrete system models to obtain results consistent with Statistical Energy Analysis. This paper reviews these results and proposes naming the statistical mode shape functions in honor of Lyon.
2017-06-05
Technical Paper
2017-01-1847
Asif Basha Shaik Mohammad, Ravindran Vijayakumar, Nageshwar rao.P
Abstract Tractor operators prefer to drive more comfortable tractors in the recent years. The high noise and vibration levels, to which drivers of agricultural tractor are often exposed for long periods of time, have a significant part in the driver’s fatigue and may lead to substantial hearing impairment and health problems. Therefore, it is essential for an optimal cabin design to have time and cost effective analysis tools for the assessment of the noise and vibration characteristics of various design alternatives at both the early design stages and the prototype testing phase. Airborne excitation and Structure Borne excitation are two types of dynamic cabin excitations mainly cause the interior noise in a driver’s cabin. Structure-borne excitation is studied in this paper and it consists of dynamic forces, which are directly transmitted to the cabin through the cabin suspension. These transmitted forces introduce cabin vibrations, which in turn generate interior noise.
2017-06-05
Technical Paper
2017-01-1850
Samaneh Arabi, Glen Steyer, Zhaohui Sun, Jeffrey Nyquist
Abstract The Environmental Protection Agency (EPA) requirement for 54.5mpg by 2025 to reduce greenhouse gases has pushed the industry to look for alternative fuels to run vehicles. Electricity is of those green energies that can help auto industry to achieve those strict requirements. However, the electric or hybrid-electric vehicles brought new challenges into science and engineering world including the Noise and Vibration issues which are usually tied up with both airborne and structural noises. The electromagnetic force plays a significant role in acoustic noise radiation in the electric motor which is an air-gap radial Maxwell force. This paper describes an innovative approach to model the physics of noise radiated by the electric motor.
2017-06-05
Technical Paper
2017-01-1849
Laurent Gagliardini, Romain Leneveu, Aurélien Cloix, Alexandre Durr
Abstract 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 trim 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
2017-01-1844
Jiawei Liu, Yangfan Liu, J. Stuart Bolton
Abstract In modern engine design, downsizing and reducing weight while still providing an increased amount of power has been a general trend in recent decades. Traditionally, an engine design with superior NVH performance usually comes with a heavier, thus sturdier structure. Therefore, modern engine design requires that NVH be considered in the very early design stage to avoid modifications of engine structure at the last minute, when very few changes can be made. NVH design optimization of engine components has become more practical due to the development of computer software and hardware. However, there is still a need for smarter algorithms to draw a direct relationship between the design and the radiated sound power. At the moment, techniques based on modal acoustic transfer vectors (MATVs) have gained popularity in design optimization for their good performance in sound pressure prediction.
2017-06-05
Technical Paper
2017-01-1843
Taejin Shin, Jaemin Jin, Sang Kwon Lee, Insoo Jung
Abstract This paper presents the influence of radiated noise from engine surface according to assembly condition between the engine block and oil pan. At the first, the force exciting the main bearing of cylinder block is calculated by using a multi-body dynamics model of the engine crankshaft. Secondly, the modal analysis is processed to obtain the mode contribution and modal participation factors for the FEM of a virtual cylinder block. Thirdly, the radiated noise from a structure is calculated by acoustic-FEM analysis. This structure is assembled by the virtual oil pan with a rigid connection method and a soft connection method. The sandwich panel connection model is used for the soft connection method. The sound radiated from this assemble structure is calculated according to two different connection properties respectively. The sound matrices for two results are compared using an objective method.
2017-06-05
Technical Paper
2017-01-1839
Edward T. Lee
Abstract It is common for automotive manufacturers and off-highway machinery manufacturers to gain insight into the system’s structural dynamics by evaluating the system inertance functions near the mount locations. The acoustic response of the operator’s ears is a function of the vibro-acoustic characteristics of the system structural dynamics interacting with the cavity, with the actual load applied at the mount locations. The overall vibro-acoustic characteristics can be influenced by a change in local stiffness. To analyze the response of a system, it is necessary to go beyond analyzing its transfer functions. The actual load needs to be understood and applied to the transfer function set. Finite element (FE) based analysis provides a good foundation for deterministic solutions. However the finite element method decreases in accuracy as frequency increases.
2017-06-05
Technical Paper
2017-01-1842
Akin Oktav, Cetin Yilmaz, Gunay Anlas
Abstract To prevent trunk lid slam noise, reactive openings are used in the trunk cavities of passenger vehicles. In sedans, the trunk cavity and the cabin cavity are coupled acoustically through the discontinuities on the parcel shelf and/or the rear seat. In such a case, these openings behave as necks of a Helmholtz resonator, which in turn change the acoustic response of the system. In this study, the Helmholtz resonator effect of the trunk cavity is discussed analytically through a simplified cavity model. A case study, where the acoustic response of a sedan is analyzed through a computational model considering the resonator effect is also given. Sound pressure levels show that instant pressure drops and damping effects observed in the acoustic response can be explained with the resonator effect. Results obtained from the computational model of the sedan are verified with the track test measurements.
2017-06-05
Technical Paper
2017-01-1840
Thierry Bourdon, Rainer Weber, Johann Massinger
Abstract Virtual NVH Engineering is going to be reviewed in this paper for the development of FIE (fuel injection equipment) components. Some examples based on high pressure pumps and SCR air cooling injectors will illustrate the explanation. The use of a 3D FEM vibro-acoustic model is essential to support virtual NVH Engineering. Therefore, a review of techniques to study components is done first. Model correlation is also an important topic which will be discussed and which makes any NVH engineer confident in using a model instead of real HW. It is quite challenging to establish these models, as they must mimic the entire physical phenomenon of real structure borne hardware sound in the whole audible frequency range. Limitations of models are also identified and allow answering one true question: Should we stay considering only each component separately or as an assembly of parts of a larger system in the development process?
2017-06-05
Technical Paper
2017-01-1834
Dirk von Werne, Prasanna Chaduvula, Patrick Stahl, Michael Jordan, Jamison Huber, Korcan Kucukcoskun, Mircea Niculescu
Abstract Fan noise can form a significant part of the vehicle noise signature and needs hence to be optimized in view of exterior noise and operator exposure. Putting together unsteady CFD simulation with acoustic FEM modeling, tonal and broadband fan noise can be accurately predicted, accounting for the sound propagation through engine compartment and vehicle frame structure. This paper focuses on method development and validation in view of the practical vehicle design process. In a step by-step approach, the model has been validated against a dedicated test-set-up, so that good accuracy of operational fan noise prediction could be achieved. Main focus was on the acoustic transfer through the engine compartment. The equivalent acoustic transfer through radiators/heat exchangers is modeled based on separate detailed acoustic models. The updating process revealed the sensitivity of various components in the engine compartment.
Viewing 91 to 120 of 7819

Filter