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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
2015-01-2219
Al Ganeshkumar, Shinichi Fukuhara
Active Noise Cancellation technology is widely used in automobiles to reduce engine harmonic noise. ANC systems require one or more microphones mounted in the cabin to monitor the harmonic noise level and provide feedback to the DSP algorithm. The ideal locations for the microphones are as close as possible to the passenger seating locations and away from any wind turbulence that can hit the diaphragm of the microphone. Excessive wind turbulence on the diaphragm can cause the ANC adaptive filter weights to be perturbed enough and cause audible ‘pumping’ type artifacts. For several practical reason it’s not always possible to control the location of the microphones and hence a DSP software and/or mechanical solution often needs to incorporated in the system. This paper will primarily address the DSP software solutions to detect wind turbulence noise in ANC microphones so appropriate counter-measures can be applied to eliminate the unwanted artifacts.
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
2015-01-2225
Peng Yu, Tong Zhang, Jing Li, Shiyang Chen, Rong Guo
Faced on transient vibration of EV, considering the characteristics of the electric drive system, active and passive integrated transient vibration control method of power train mounting system was proposed. First, models of power train system and mounting system were established, modal characteristics were grasped by simulation and experiment; a feed-forward controller was constructed from the active control perspective, mounting system transient vibration and power train torsion vibration were reduced; based on this, further optimization of mounting system was conducted from a passive control perspective. Results show that the active and passive integrated control method can effectively reduce the dynamic reaction force of mounting points, improve the vibration conditions of power train and body as well.
2015-06-15
Technical Paper
2015-01-2221
Longchen Li, Wei Huang, Keda Zhu, Xiujie Tian, Richard E. Wentzel, Melvyn J. Care
The parameters such as step size and filter length have a great influence on active noise control. Simulation often achieves a good result. However, it is difficult to get a good noise reducing effect in the experimental process. This paper introduced the theory of feed-forward active noise control system with FXLMS algorithm. A simulation by using LabVIEW was designed to analyze the factors which influenced convergence and stability. Then experiments in duct system had been done and analyzed. The experimental results verified the correctness of the simulation and indicated that good primary and secondary paths could reduce the difficulty of adjusting parameters and achieve fast convergent speed and good stability. At last a simple application had been done and achieved a good result.
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
2015-01-2239
Nicholas N. Kim, Seungkyu Lee, J Stuart Bolton, Jon Alexander, Taewook Yoo, Sean Hollands
Because of the increasing concern with vehicle weight, there is an interest in lightweight materials that can serve several functions at once. Here we consider the vibration damping performance provided by an “acoustical” material (i.e., a fibrous layer that would normally be used for airborne noise control). First, earlier work related to the damping potential of fibrous, noise control materials is reviewed, and the primary damping mechanism is identified. It has been previously established that the vibration of panel structures creates a non-propagating nearfield in the region close to the panel. In that region, there is an oscillatory, incompressible fluid flow parallel to the panel whose strength decays exponentially with distance from the panel. When a fibrous medium is placed close to the panel in the region where the oscillatory nearfield motion is significant, energy is dissipated by the viscous interaction of the flow and the fibers, and hence the panel vibration is damped.
2015-06-15
Technical Paper
2015-01-2257
Ki-Chang Kim, Sang-Woo Lee, Seok-Gil Hong, Jay Kim, Gil-Jun Lee, Jae Min Choi, Yong-Jin Kim
Recently, in automobile industry, squeak and rattle (S&R) in body structure and trim parts has become a very significant issue in Initial Quality Study (IQS). In this study, a new CAE process developed by the authors to reduce S&R noises in the door system is reported. Friction-induced vibration and noise generation mechanism of a door system are studied numerically. The effect of degradation of plastics used in door trims is studied by using a model obtained from experiments. Effects of changes of material properties such as Young's modulus and loss factor, due to the material degradation as well as statistical variations are predicted using, several cases of door systems. As a new concept, the rattle and squeak index is proposed, which can be used to guide design of the body structure and trim parts. The predicted of S&R in the door system, from the proposed CAE process were compared to those obtained from the experiment.
2015-06-15
Technical Paper
2015-01-2258
Gil-Jun Lee, Kichang Kim, Jay Kim
Squeak and rattle (S&R) noises are undesirable noises caused by friction-induced vibration or impact between surfaces. While several computer programs were developed to automatically detect and rate S&R events over the years, these programs could distinguish squeak and rattle noises from each other. Because the causes of squeak noises and rattle noises are different, distinguishing two types of noises will be very useful for automotive engineers in choosing an appropriate solution to reduce S&R noises. Authors developed a new algorithm to differentiate squeak noises and rattle noises utilizing a combination of sound quality metrics. Specifically, sharpness, roughness and fluctuation strength of the noises were employed in the algorithm. A three-dimensional space defined by the maximum values of sharpness, roughness, and fluctuation strength of the noise are used to differentiate two different types of noises. The developed algorithm was applied to 86 recorded squeak or rattle noises.
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
2015-01-2334
David Bogema, Gary Newton, Mark Stickler, Chris Hocking, Frank Syred
Realistically experiencing the sound and vibration data through actually listening to and feeling the data in a full-vehicle NVH simulator remarkably aids the understanding of the NVH phenomena and speeds up the decision-making process. In the case of idle vibration, the sound and vibration of the idle condition are perceived simultaneously, and both need to be accurately reproduced simultaneously in a simulated environment in order to be properly evaluated and understood. In this work, a case is examined in which a perceived idle quality of a vehicle is addressed. In this case, two very similar vehicles, with the same powertrain but somewhat different body structures, are compared. One has a lower subjective idle quality rating than the other, despite the vehicles being so similar.
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
2015-01-2271
Yong Du Jun, Bong Hyun Park, Kang Seok Seo, Tae Hyun Kim, Myoung Jae Chae
An objective measure is proposed for seat riding comfort evaluation under low frequency (0~2 Hz) vibratory conditions which represents typical roll and pitch motions of driving motor vehicles. The related feeling due to this low frequency vehicle motion is termed ‘hold feeling’ because the seated body may tend to deviate from the defined seating position under such vehicle motion inputs. In the present study, dynamic pressure distribution measurements have been performed with a roll motion simulator at different frequencies between 0.3 and 1.0 Hz, to monitor the interface pressure change behavior of the seat-subject body. Temporal changes in body pressure in terms of the magnitude and the representative locations, and the time delay in pressure change at different regions of the seat are identified to be useful parameters for describing the subject's responses and with the subjective test results.
2015-06-15
Technical Paper
2015-01-2272
Pradeep Dinkar Jawale, E Ramachandran, Nagesh Voderahobli Karanth, Ammar Ali
Day by day, customer expectations for comfort in the vehicle interior are driving automotive manufactures to provide better environment in their vehicles. Considering the ongoing developments in diesel powered engines and vehicles in India, the necessity of noise reduction has become more relevant. In such a scenario, NVH benchmarking has become very critical for new product development. Also, given the increasing customer awareness, noise and vibration have also become indicators of overall vehicle perception and hence provide crucial inputs for NVH design, optimization and target setting. In this paper, two families of diesel powered cars in India have been evaluated for their NVH performance, both for exterior & interior noise to arrive at noise & vibration contribution relevant to passenger comfort in order to quantify contribution of powertrain, tyre, wind etc. to the overall noise and their trends are presented.
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
2015-01-2366
Golam Mainuddin, Mohamad Qatu
The mechanics of rotating machinery vibration is an interesting subject with considerable technical depth and breadth. Every rotating component has vibration issues. This is because concerns regard balancing, run-out and others. Automotive industries are always concerned to minimize noise and vibration level within comfort limit which is a key for marketing and thus industries’ business. Noise and vibration issues effect customer comfort and warranty claims, these are important to the auto industry. Light electric vehicles (EV) show different levels of NVH. Abrupt vibration and noise has been recorded for internal combustion engine during ignition. Researchers have been trying to minimize this issue to have EVs’ less noise and vibration in different conditions e.g. during startup and acceleration. To get an overall idea and to show the differences in between internal combustion engine and electric vehicle during accelerating mode, several test was run with a light electric vehicle.
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.
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