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2015-06-15
Technical Paper
2015-01-2081
Hossein Habibi, Graham Edwards, Liang Cheng, Haitao Zheng, Adam Marks, Vassilios Kappatos, Cem Selcuk, Tat-Hean Gan
Wind turbines mounted on cold climate sites are subject to icing which could significantly influence the performance of turbine blades for harvesting wind energy. To alleviate this problem, a number of techniques have been developed and tested. The currently used methods are surface coating, antifreeze chemicals, electrical resistance heating, hot air circulation, pulse electrothermal de-icing, manual chip-off, etc. Almost all thermal de-ice methods demand a high level of power to operate. Also, the high temperature induced to the blade by the thermal techniques may pose a risk for the integrity of composite blades. A relatively new strategy used for ice protection systems is ultrasonic guided waves (vibrations of very short length wave) on which a few research projects have been recently accomplished. This method is well known for non-destructive testing applications in which the waves typically propagate between 20 kHz and 100 kHz for long-range ultrasonic testing.
2015-06-15
Technical Paper
2015-01-2216
Dong Chul Park, Eun Soo Jo, Seokgwan Hong, Michael Csakan
An important trend among vehicle NVH engineers is to produce the attractive engine sounds matching with a vehicle concept and engine performance. Recently customers have much more interests in their personal preferences and enjoying tuning their cars. The PESS(Personalized Engine Sound System) has been developed for making a unique and individual concept of a vehicle. The system helps customers make variety of engine sound in a single vehicle using active sound design technology. In this system, three different concept of engine sound has been defined-Dynamic, Sporty, and Extreme. Each of the engine sounds can be adjusted with a parameter that determines the timbre such as main orders, half orders, and high orders. In addition, the extent to the drivers stepping on the accelerator pedal has been used as a parameter to differ the sound response. An AVN application has been implemented that allows users to easily design those functions.
2015-06-15
Technical Paper
2015-01-2215
Thomas L. Lago
How to decrease noise and vibration exposure has been of interest for many years. Empirical data have verified that too high dose values can create multiple problems to a human body - often severe. Some years back, the European Machinery Directive has increased the responsibility for manufacturers and employers to make sure limits are complying with legislation. Classical technology often consists of passive solutions aiming at trying to cut back on noise and vibration levels. For low frequency, these methods are often lacking the needed performance especially if weight should be considered at the same time. A smart combination of passive and active techniques can make a real difference. Today, with possibilities for low cost and embedded electronics and the rapid development of new actuators, a vast range of applications are possible for this combined combat approach, with a financial advantage as well.
2015-06-15
Technical Paper
2015-01-2213
John Van Baren
The accumulated damage that a product experiences in the field due to the variety of vibration stresses placed upon it will eventually cause failures in the product. The failure modes resulting from these dynamic stresses can be replicated in the laboratory and correlated to end use environment to validate target reliability requirements. This presentation will discuss which random profile is needed to simulate end use environment, how to combine multiple vibration environments into one, and how to use FDS to accelerate the test.
2015-06-15
Technical Paper
2015-01-2218
Shuguang Zuo, Jun Zhang, xudong wu, jiajie HU, Guo Long
Title: Study on Active Noise Control of Blower in Fuel Cell Vehicle under Transient Conditions Authors: Zuo Shuguang, Zhang Jun, Wu Xudong, Hu Jiajie, Long Guo Abstract: Blower is one of the main noise sources of fuel cell vehicle. In this paper, a narrowband active noise control (ANC) model is established based on adaptive notch filter (ANF) to control the medium-high frequency noise produced by the blower. In actual application, the frequency of reference signal differs from the frequency of the noise signal inevitably. This difference is referred to as frequency mismatch (FM) which greatly degenerates the performance of the narrowband ANC algorithm. Under transient conditions, in order to reduce the FM of ANC for blower, a new Frequency Mismatch Filtered-Error Least Mean Square algorithm (FM-FELMS) is proposed to attenuate blower noise.
2015-06-15
Technical Paper
2015-01-2222
Nikos Zafeiropoulos, Marco Ballatore PhD, Andy Moorhouse PhD, Andy Mackay
Road noise forces can excite different structural resonances of the vehicle hence a high number of sensors required for observing and separating all the vibrations that are coherent with the cabin noise. Current reference sensor selection methods for feedforward road noise control result to high number of sensors. Therefore there is a necessity for reducing the number of sensors without degrading the performance of an ANC system. In the past coherence function analysis has been found to be useful for optimising the sensor location. Thus, in this case coherence function mapping was performed between an array of vibration sensors and a microphone in order to identify the locations on the structure with highly correlated with road bands in the compartment. A vehicle with an advanced suspension system was used for applying the method and defining some locations as reference signals for feedforward active road noise control.
2015-06-15
Technical Paper
2015-01-2223
Rolf Schirmacher
Active Noise Control (ANC) and Active Sound Design (ASD) have long been seen as emerging technologies. During recent years, however, they became quite mainstream for new vehicle and infotainment platforms within a broad range of OEMs. This paper presents the current state-of-the-art of production ANC and ASD systems, including the lessons learned during the last years of bringing the technology from the lab into vehicles. Based on this current status, critical elements for an even broader application of the technologies are identified and developments to overcome them are discussed. In addition, as the integration of these technologies with other in-vehicle systems is crucial for a commercially viable application, trends of future IVI systems are discussed and integration scenarios for next generation IVI systems are shown.
2015-06-15
Technical Paper
2015-01-2230
Chatter vibrations are causing large monetary losses daily in industry. New materials have increased the challenges with harmful vibration levels. Since the vibrations, when observed as a final result, are chaotic and the vibration process nonlinear, it is a challenging task to deal with it. It is also a common “understanding” in the cutting industry that chatter is RPM (the rotational speed) dependent, since the behavior changes with RPM. Many attempts have been done over many years to mitigate and understand the vibrations. In our vast research on these topics, we have found that it is rewarding to classify the vibrations into categories, enabling a better understanding of its underlying physics and “source of vibrations,” and thus also the formulation of a possible remedy. An analysis approach has been developed where vibrations are analyzed and categorized and a GO/NOGO indicator is telling if the machine has the “right type of vibrations.”
2015-06-15
Technical Paper
2015-01-2242
Ling Zheng, Zhanpeng Fang
The design optimization of interior noise in vehicle is addressed to reduce interior noise and improve customer satisfaction in this paper. The structural-acoustic model is established and the response of sound pressure in frequency domain is predicted by using finite element method. The minimization of sound pressure inside cabins depends on body structure and the thickness for each panel. The panel participation analysis is carried out to find out the key panels as design variables and improve the efficiency of optimization computation. Response Surface Method (RSM) is proposed and utilized to optimize the vibro-acoustic properties of body structure instead of complex structural-acoustic coupling finite element model. The accuracy of the proposed RSM is evaluated and discussed. Structural-acoustic problem is approximated by a series of quadratic polynomial using RSM. Geometric optimization problem of panels is described and solved to minimize the interior noise in vehicle.
2015-06-15
Technical Paper
2015-01-2244
Ulhas Dilipraj Mohite, Niket Bhatia, Prashant Bhavsar
Noise radiated from motorcycle engine is gaining significance not only to meet regulations but also to fulfil customer demands of quiet products. In IC engines, combustion pressure is one of the major excitations which is transmitted through powertrain to the casings and radiate noise. Early identification and correction of the casing critical areas contributing to noise will lead to substantial cost and development time reduction. In this paper the approach to predict engine noise under combustion forces is presented. This Methodology is divided into three stages: 1. Multi body dynamic (MBD) Simulation to determine excitation forces 2. Vibration analysis of engine under combustion load 3. Acoustic analysis of engine to predict Sound Pressure Level (SPL). Important parts of motorcycle engine with single cylinder are considered as flexible bodies for MBD simulation.
2015-06-15
Technical Paper
2015-01-2240
Gong Cheng, David W. Herrin
The theory of patch (or panel) contribution analysis is first reviewed and then applied to a motorcycle engine on a test stand. The approach is used to predict the sound pressure in the far field and the contribution from different engine components to the sound pressure at a point. First, the engine is divided into a number of patches. The transfer function between the sound pressure in the field and the volume velocity of a patch is determined by taking advantage of vibro-acoustic reciprocity. An inexpensive monopole source is placed at the receiver point and the sound pressure is measured at the center of each patch. With the engine idling, a P-U probe was used to measure particle velocity and sound intensity simultaneously on each patch. The contribution from each patch to the target point is the multiplication of the transfer function and the volume velocity, which can be calculated from particle velocity or sound intensity. There were two target points considered.
2015-06-15
Technical Paper
2015-01-2283
Andrew Smith
iOS devices, including iPhones and iPads, are being used increasingly for professional and scientific applications. Using an iOS device for noise & vibration measurements is an application with many advantages, given its small size, availability, cost, and ease of operation. We have created a system for measuring noise level, logging noise over time, doing FFT frequency analysis of sound, and measuring speech intelligibility using iPhones and iPads as the host device. This provides a portable, cost-effective, and easy to deploy test and measurement system. The main area of concern for the performance of the system is the transducer, which in the case of the microphone was designed for the speech applications, rather than wide-band acoustical analysis, and for the gyroscope, for recognizing gross movement.
2015-06-15
Technical Paper
2015-01-2277
Vishal Vaidya, Pravin Hujare
Recently quietness has become an important quality parameter for automotive vehicles and as a result various improvements have been brought to reduce noise at system and vehicle level. Due to stringent noise emission norms on automotive vehicles and increasing desire of quieter in-cab performance by users, reduction of air intake noise tends to be an area of explanation. Air intake noise, which was relatively considered as a minor source of noise in the past, is now gaining importance. This paper emphasizes the sound pressure level reduction through the increase in transmission loss at an air intake system. The intake noise of an automobile induced by firing of an engine accompanies acoustic resonance of ducts of an intake system. Conventionally, the adoption of an integrated type resonator was one of possible ways to eliminate the booming noise due to acoustic resonances of air ducts.
2015-06-15
Technical Paper
2015-01-2331
Alexander Schell, Vincent Cotoni
Aero-vibro-acoustic prediction of interior noise associated with exterior flow requires accurate predictions of both fluctuating surface pressures across the exterior of a vehicle and efficient models of the vibro-acoustic transmission of these surfaces pressures to the interior of a vehicle. The frequency range of interest varies depending on the region and source of interest. For noise transmitted through a sideglass the frequency range of interest is typically from 1-5kHz. The vibro-acoustic methods used to describe noise and vibration transmission also depend on the frequency range of interest. At higher frequencies methods like statistical energy analysis (SEA) are particularly well suited for describing the response of a trimmed cabin due to the short wavelength response of the interior acoustic space and sound package. An accurate prediction of fluctuating surface pressures also requires an accurate model of the flow over the exterior of the vehicle.
2015-06-15
Technical Paper
2015-01-2338
Dong Guo, Quan Shi, Peng Yi
In-vehicle noise is composed of a variety of tonal (frequency-related) components and the tonal components play an important role in the improvement of interior vehicle sound quality. Much research has been focused on the suppression of sound pressure level and achieved certain positive effects. However, in some operating conditions, customers still perceive the tonal components and complain about the vehicle quality even the sound pressure level is relatively low. Therefore, a better understanding of how tonal components are perceived is necessary for automotive designers. To do so, psychoacoustics results about human hearing mechanism to tonal components are comprehensively summed in this study: human hearing response to pure tone, two tones and multiple tones. Then, well-controlled testing stimuli were generated and subjective annoyance testing was conducted. The results show agreement with former researchers’ findings.
2015-06-15
Technical Paper
2015-01-2243
Yang Liu, Pingjian Ming, Wenping Zhang, Xinyu Zhang
Turbocharger is an important part of the turbocharged diesel engine. Due to the increase of mass flow rate and pressure ratio the turbocharger, aerodynamic noise of turbocharger has become more apparent. And turbocharger noise becomes one of the major noise sources of the main engine system of the ship. In the paper, Based on Lighthill acoustic analogy theory, by using Computational fluid mechanics(CFD) and indirect boundary element method(IBEM), the aerodynamic noise prediction of marine turbocharger compressor is developed. On the basis of finite volume method, using the single stator and rotor blade passages, unsteady viscous flow in the centrifugal Compressor was simulated. The compressor’s flow characteristic was predicted and agree well with the experimental value. The flow field characteristics and frequency spectrum of the fluctuating pressure which agree well with the theoretical value were analysed.
2015-06-15
Technical Paper
2015-01-2329
Paolo Di Francescantonio, Charles Hirsch, Piergiorgio Ferrante, Katsutomo Isono
The prediction of the broadband noise generated by the flow interaction with solid bodies such as for example side mirror noise, exhaust pipe noise, or ventilation and air conditioning noise require in principle the execution of extremely high demanding unsteady CFD simulations that nowadays cannot be afforded in an industrial environment. Therefore research efforts have been focused on alternative approaches that could permit to obtain engineering accurate results with much reduced computational efforts by stochastically reconstructing the turbulent velocity field starting from a steady RANS analysis. Two main families of methods have been introduced up to now, SNGR [1], and RPM[2], but applications in industrial environment are still limited mainly due to the lack of reliability of these methods and the need to introduce some tuning parameters.
2015-06-15
Technical Paper
2015-01-2224
Yong Xu
The purpose of this study was to develop an effective active control system for improving the sound quality of vehicle engine noise. The goal of the designed system was not to decrease the sound level of the residual noise, but to adjust its quality characteristics. The sound quality of vehicle engine noise was evaluated with both of subjective and objective evaluations. Then a linear regression analysis was performed in order to expressed the subjective sound quality with measureable objective parameters. Based on the periodic properties of vehicle engine noise, a waveform, synthesized with five sine waves, was used as a reference signal in the designed active control system. The primary noise at each reference frequency was controlled by an adaptive notch filter, the taps of which were updated by the FXLMS algorithm.
2015-06-15
Technical Paper
2015-01-2327
Wind noise is one of the important NVH attributes that impacts customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic door deflection under the pressure load due to fast movement of a vehicle plays an key roll. The excessive deflection could potentially cause opened sealing gap, a.k.a. aspiration leakage, which creates a path through which the exterior aerodynamically induced noise propagates into the vehicle cabin. The dynamic door deflection can be predicted using CFD and CAE tools. This work looks into the internal pressure issue associated with the dynamic load setup during the CAE analysis. The capability of predicting the internal pressure due to high wind speed outside of a vehicle still has not been developed, and the work is based on the wind tunnel measurement involving several vehicles.
2015-06-15
Technical Paper
2015-01-2323
Abdelhakim AISSAOUI, Ravindra S Tupake, Vilas Bijwe, Mohammed Meskine, Franck Perot, Alain BELANGER, Rohit J Vaidya
F or the automotive industry, acoustic comfort is of increasing importance and changes in the market make the HVAC system noise quality a question to be addressed as early as possible during the vehicle development process. On one hand, the so-called traditional sources of annoyance such as engine, road-tires contact, exhaust systems and wind-noise have been significantly reduced for most traditional combustion engine vehicles. On the other hand, the rapid expansion of hybrid and electric vehicles and idling stop systems increases the importance of sources such as HVAC systems considered in the past as secondary. At high mass flow rate, the flow-induced contribution from the ducts and registers is the main source of noise in the mid to high frequency ranges and is more important than the HVAC structure borne and blower engine contributions.
2015-06-15
Technical Paper
2015-01-2247
Masao Nagamatsu
The sound localization methods are used for noise source detection of prototype of mechanical products including automobile engines. There are several types of sound localization methods. In middle frequency sound localization around 1kHz, which is most sensitive band for human auditory, these methods have enough resolution in reconstructed images, and are effective to localize the sound source. In high frequency sound localization, the holographic type methods take long time in measurement. To overcome this problem, I have developed the converted method of Nearfield Acoustic Holography (NAH) method, which is one of conventional holographic sound localization method. However, in low frequency sound localization, all methods do not have enough resolution in reconstructed images. I am now developing new sound localization method, Double Nearfield Acoustic Holography (DNAH) method. This method is converted method of conventional Nearfield Acoustic Holography method.
2015-06-15
Technical Paper
2015-01-2217
Guohua Sun, Tao Feng, JI XU, Mingfeng Li, Teik Lim
Current powertrain active noise control (ANC) system is not sufficient enough to track the fast engine speed variations, and yield consistent convergence speeds for individual engine order such that a balanced noise reduction performance can be achieved over a broad frequency range. This is because most of these ANC systems are configured with the standard filtered-x least mean squares (FxLMS) algorithm, which has an inherent limitation in the frequency-dependent convergence behavior due to the existing of secondary path model (electro-acoustic path from the input of control loudspeaker to the output of monitoring error microphone) in the reference signal path. In this paper, an overview is given first to compare several recently modified FxLMS algorithms to improve the convergence speed for harmonic responses such as eigenvalue equalization FxLMS (EE-FXLMS) and normalized reference LMS (NX-LMS) algorithms.
2015-06-15
Technical Paper
2015-01-2212
A. Elsawaf, H. Metered, T. Vampola, Z. Sika
This paper presents the particle swarm optimization (PSO) algorithm to search about the optimum feedback controller gains for the active mount suspension, for the first time, to reduce the transmitted vibrations to the suspended mass placed over a structure. A mathematical model and the equations of motion of the structure system with an active mount suspension are derived and simulated using Matlab/Simulink software. The proposed PSO algorithm aims to minimize the acceleration of the suspended mass as the objective function with constraint of the actuator force. System performance criteria are evaluated in both the time and frequency domains in order to count the effectiveness of the proposed controller. The simulation results reveal that the proposed feedback controller gains tuned by PSO algorithm offer a significant improvement of the vibration isolation compared with both the passive and active mount controlled using the linear quadratic regulator (LQR).
2015-06-15
Technical Paper
2015-01-2322
Bastien Ganty, Jonathan Jacqmot, Ze Zhou
At high cruising speed, the car A-pillars generate turbulent air flow. The resulting aerodynamic pressure applied on the windows significantly contributes to the total cabin noise. In order to predict this particular noise contribution, the physic of both the flow and the cabin needs to be accurately modeled. This paper presents an efficient methodology to predict the turbulent noise transmission through the car windows. The method relies on a two-step approach: the first step is the computation of the exterior turbulent field using an unsteady CFD solver (EXA PowerFlow); the second step consists in the computation of the acoustic propagation inside the cabin using a finite element vibro-acoustic solver (Actran). The simplified car cabin of Hyundai Motor Company, studied in this paper, involves aluminum skin, windows, sealant, inner air cavity and acoustic treatment (porous material, damping layer). A pure vibro-acoustic model with hammer shock excitation on a window is first built.
2015-06-15
Technical Paper
2015-01-2231
Masashi Arakawa, Miho Nakatsuka, Hiroo Yamaoka
To analyze gear transmitted vibration which occurs due to transmission error, a new prediction methodology is developed when vibration transmits through engine mounts from housing. This paper focuses on a left-hand engine mount and brackets which are assembled on a transmission housing of a compact FF vehicle connecting transmission housing to body structure. Thus a modeling technique dealing with the dynamic characteristic of mount rubber and its bracket is indispensable. A mount rubber is pre-loaded under power plant weight and undergoes from its initial shape to deformed one until reaching equilibrium state. To precisely predict a dynamic characteristic of mount rubber when the power plant is mounted in vehicle, we have to consider the deformed shape when pre-load is applied.
2015-06-15
Technical Paper
2015-01-2328
Barbara Neuhierl, Sivapalan Senthooran, Reinier Toppinga, Anke Jäger, Maarten Brink, Timo Lemke, Philippe Moron, Raghu Mutnuri
The object of the validation study presented in this paper is a generic vehicle, the so-called SAE body, developed by a consortium of german car manufacturers (Audi, Daimler, Porsche, Volkswagen). It consists of a simplified cabin whose interior can be equipped with either reverberant or partly absorbing walls. To obtain more realistic flow and pressure excitation typical for production vehicles, an a-pillar and a series rear view mirror were attached to the exterior surface. Furthermore the test object contains a glass side window, allowing noise transmission to the interior. Many experiments have been performed by the abovementioned consortium on this object in the past to investigate its behavior when exposed to fluid flow. Some of these experiments were used to validate the simulation results discussed in the present paper.
2015-06-15
Technical Paper
2015-01-2324
Hangsheng Hou, Guiping Yue
When a sunroof opens to let the fresh air in during driving, there might be several noise issues associated with it. The most common and important one is the wind throb issue, which is normally resolved by installing a wind deflector with sufficient height. However with the wind throb issue gone, other sound quality problems may surface. The most obvious one is the hissing noise, which occurs often in higher speed range. This work investigates a sunroof deflector deployment strategy considering wind throb, hissing noise and other psychoacoustic attributes that could be felt subjectively by a customer. The goal is to optimize sound quality associated with an open sunroof, potentially targeting the most NVH demanding customers in the premium vehicle segment.
2015-06-15
Technical Paper
2015-01-2325
Paul Bremner, Chris Todter, Scott Clifton
Title: Sideglass Turbulence and Wind Noise Sources Measured with a High Resolution Surface Pressure Array Authors: Paul Bremner – AeroHydroPLUS, Del Mar CA 92104 USA Chris Todter – Keppel Professional Services, San Diego CA 92107 Scott Clifton – c/o AeroHydroPLUS, Del Mar CA 92104 USA The authors report on the design and use of high resolution micro-electro-mechanical (MEMS) microphone arrays for automotive wind noise engineering. The arrays integrate both sensors and random access memory (RAM) chips on a flexible circuit board that eliminates high channel count wiring and allows the array to be deployed on automobile surfaces in a convenient “stick-on/peel-off” configuration. These arrays have application to the quantitative evaluation of interior wind noise from measurements on a clay model in the wind tunnel, when used in conjunction with a body vibro-acoustic model.
2015-06-15
Technical Paper
2015-01-2250
Masahiro Akei, Nobutaka Tsujiuchi, Akihito Ito, Takayuki Yamauchi, Daisuke Kubota
This paper describes the identification of the sound source model for the diesel engine installed on the agricultural machine by Inverse-Numerical Acoustic analysis (INA), and the noise prediction using the sound source model identified by INA. INA is a method to identify surface vibrations from surrounding sound pressures. This method is applicable for a complicated-shaped sound source like an engine. Although many studies about INA have been conducted, these past studies are the studies on improvement of the identified accuracy and noise prediction in the free sound field or hemi-free sound field. The authors predicted accurately sound pressure level of engine enclosure using sound source model identified by INA and boundary element method (BEM). However, we have not yet verified the effectiveness of sound source model against the enclosure which has an absorption material and an opening.
2015-06-15
Technical Paper
2015-01-2358
Rod Morris-Kirby, Evan Harry, Dirk Jaeger, Bernd Borgmann
Acoustic Diagnostic Network Algorithms (DNA) are experimental methods that extract airborne acoustic characteristics from a motor vehicle and decompose this information into a set of networks from which the source, path and receiver noise sources and paths can be determined. Unlike traditional transfer path analysis Acoustic DNA takes the problem into the fine detail and answers questions such as what, where and how does a vehicle system need to be changed in order to achieve any given objective. This paper describes the fundamental methodology and features together with how it has been implemented into a user friendly computer program that has been used successfully in over 50 vehicle projects within the Adler Pelzer group on a wide range of motor vehicles.
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