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2015-06-15
Technical Paper
2015-01-2291
Pandurang Maruti Jadhav, Sandesh A Dunung, Pravin T Nitnaware
There are many environmental issues in India. Air pollution, water pollution, garbage, vibration & noise pollution and pollution of the natural environment are all challenges for India. India has a long way to go to reach environmental quality similar to those enjoyed in developed economies. Pollution remains a major challenge and opportunity for India. The review of trends in farm practices and machinery development suggests that vibration & noise problems are still prevalent in agricultural situations, even though there has been a steady increase in the availability of materials and equipment for vibration & noise control over recent years. Diesel engine is the main source of power for agricultural equipments, such as water pump set, compressor, electric generator and tractor. Even it is one of the sources of vibration & noise in agricultural field. There is reluctance of the agricultural sector to use of vibration & noise control methods.
2015-06-15
Technical Paper
2015-01-2297
Insoo Jung, Jaemin Jin, Kwangmin Won, Seungwook Yang, Kyoungdoug Min, Hoimyung Choi
Combustion noise of diesel engine can be deteriorated by combustion characteristics that are influenced by the factors such as engnine NVH durability, driving conditions, environmental factors and fuel properties. Therefore we need to develop robust combustion noise to be insensitive to the factors. To achieve this purpose, the method for combustion characteristics prediction has been developed by means of analyzing vibration signal measured from engine cylinder block. The closed-loop control by controlling injection parameters through combustion characteristics prediction has been carried out to make combustion characteristics that we want to exhibit. We have also evaluated the effect of combustion noise and fuel consumption by applying the closed-loop control.
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
2015-01-2341
Marc Ingelmann, Holger Bickelmann
BASF supplies the automotive industry with parts made of the Micro-cellular Polyurethane Elastomer - Cellasto®, a material with unique characteristics in NVH applications. For over 50 years our automotive customers are relying on our materials, with the Jounce Bumper being our best known applications. Top mounts and coil-spring-isolators are also a key offering to the industry. A lot of functions in automotive and non-automotive products are using Cellasto® as damping element, such as armrests, seats, torque-dampers, handheld machines etc. The dynamic performance of Cellasto , combined with the ability to work in limited packages, makes it the ideal choice. The amplitude selective damping fits to the automotive requirements: small amplitudes are generating a low damping of the material; high amplitudes are increasing the damping.
2015-06-15
Technical Paper
2015-01-2361
Sajjad Beigmoradi
Nowadays, by the introduction of significant advances in automotive industries, noise, vibration and harshness (NVH), in the position of the main comfort attribute, plays a crucial role in marketing and passenger satisfaction. In order to cope NVH problems, three main actions are taken by NVH engineers for reducing perceived level of noise in cabin: Noise reduction in sources, Noise path treatment and Noise control at receiver. Among these approaches, those pertain to modification of noise pass, through structure and air, to the cabin are more prevalent in automotive applications. Accordingly, identification of noise paths that dominantly contribute to sound and vibration transfer to cabin phenomenon should be dealt with importance. In practice, engine vibration transmitted through sub-frame attachments to body can induce high level of noise and vibration to the passenger cabin.
2015-06-15
Technical Paper
2015-01-2359
Craig Reynolds, Jason Blough, Carl Anderson, Mark Johnson, Jean Schweitzer
Sound power is commonly estimated using either a reverberant chamber or an anechoic environment as described by the ISO 3741:2012 and ISO 3744:2012 standards respectively. Both methods require the volume of the noise source to be less than 1% of the chamber volume leading to a requirement of relatively large test chambers. Torque converter cavitation noise testing in an enclosed metallic test fixture violates both standards due to volume and/or space requirements. This paper describes a new method developed to accurately determine torque converter sound power through characterization of the test environment. Two types of reference noise sources were created to represent torque converter geometries and noise output. A tweeter was used to output broadband high frequency noise typical of cavitation noise. The first source consisted of the torque converter cover and tweeter only. The second used the cover and pump with a tweeter in place of the turbine, stator, and clutch.
2015-06-15
Technical Paper
2015-01-2246
Kurt Veggeberg, Mike Denton
This is an overview of the development of a portable, real-time sound camera based on FPGA (Field Programmable Gate Arrays) and digital microphones for noise source identification. The use of the FPGA technology and digital microphones provides increased performance, reduced cost and weight. This provides the capability of making interior noise measurements. Microphone arrays can be a useful tool in identifying noise sources and give designers an image of noise distribution. There are many successful applications of noise source identification systems in use in the automotive industry which will be presented. The beamforming algorithm is a classic and efficient algorithm for signal processing of microphone arrays and is the core of many microphone array systems. High-speed real-time beamforming has not been implemented much in a portable instrument because it requires large computational resources.
2015-06-15
Technical Paper
2015-01-2253
Kimitoshi Tsuji, Katsuhiko Yamamoto
It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration in advance, on virtual engine specifications and a virtual vehicle frame. In this paper, I will show the power plant model with electrical starter, battery and alternator that can predict transient torque and combustion heat results. Also vibration result with the power plant model connected to vehicle inertia model will be shown. The power plant was 1.3L 4cyl NA. The discussed vehicle was small size and 1300kg. The power plant model was realized by energy based model using VHDL-AMS. Here, VHDL-AMS is modelling language stored in IEC international standard (IEC61691-6) and can realize multi physics on 1D simulation. The modeling language supports electrical, magnetic, thermal, mechanical, fluidic and compressive fluidic domain. The model was created in house by fully VHDL-AMS and validated on ANSYS SIMPLORER.
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
2015-01-2237
Nickolas Vlahopoulos, Sergey Medyanik
Structural-Acoustic Joints for Incompatible Models in the Energy Finite Element Analysis Sergey Medyanik, Michigan Engineering Services, LLC Nickolas Vlahopoulos, University of Michigan In the EFEA method, the governing differential equations are formulated for an energy variable that has been spatially averaged over a wavelength and time averaged over a period. Differential equations are derived for all wave bearing domains within a system. Each differential equation represents a power balance over a control volume. The corresponding fundamental solutions vary exponentially with space, thus requiring only a small number of elements to capture numerically the smooth spatial variation. Joint matrices are required between the finite elements at locations where discontinuities in the primary EFEA variables exist.
2015-06-15
Technical Paper
2015-01-2280
Bernd Philippen, Roland Sottek
Transfer Path Analysis and Synthesis is a widely-used troubleshooting and engineering method in the development process of a car. An engine TPA model should include the engine mounts because they are important elements of the structure-borne paths from the engine to the driver’s ears. This allows identifying if the structure, the sound radiation or the mount is a weak point of the transmission. A mount can be characterized, e. g., by a mount attenuation function, a four-pole model, or a simple parametric mount model. If the mount characteristics are known, the influence of a different mount on the structure-borne sound can be virtually predicted without a real modification. The mount characteristics could be determined on special test rigs but the transferability to the real situation is often questionable because the same boundary conditions on the test rig and in the car are difficult to guarantee.
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
Abstract Icing conditions in cold regions of the world may cause problems for wind turbine operations, since accreted ice can reduce the efficiency of power generation and create concerns regarding ice-shedding. This paper covers modelling studies and some experimental development for an ongoing ice protection system that provides both deicing and anti-icing actions for wind turbine blades. The modelling process contained two main sections. The first part involved simulation of vibrations with very short wavelength or ultrasonic guided waves (UGW) on the blade to determine optimal excitation frequency and transducer configuration. This excitation creates horizontal shear stress at the interface between ice and blade and focuses energy at the leading edge for de-bonding ice layers.
2015-06-15
Technical Paper
2015-01-2262
Tom Knechten, Marius-Cristian Morariu, PJG van der Linden
Structural and vibro-acoustic transfer functions still form an essential part of NVH data in vehicle development programs. Excitation in the three DOFs at all body interface connection locations to target responses gives information on local dynamics stiffness and the body sensitivity for that specific path in an efficient manner. However, vehicles become more compact for fuel efficiency and production costs and to meet the market demand for urban vehicles. Alternative driveline concepts increase the electronic content and new mount locations. To achieve the optimum on road noise NVH, handling performance while conserving interior space and trunk volume requires a complex suspension layout. On top of that, customers put weight on safety and comfort systems which result to a higher packaging density. These trends imply ever limiting accessibility of the interface connections on the body structure.
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
2015-01-2259
Jan Zuleeg
Tribological contacts with plastic or polymers tend to show stick-slip and have the ability to generate noise. With the help of lubricants like bonded coatings, greases and fluids the tribological properties can be well-directed and affected. In this paper it is shown, how well known theories about polymer friction from the literature can be used for the friction of lubricants and how these findings can help in the development of new lubricants. With an adequate stick-slip test rig (Ziegler Stick-Slip test rig) it is demonstrated, how the theories can be confirmed. The introduced test methods are used in the development for lubricants for automotive applications e.g. in the interior of the car including invisible lubricants developed for Class "A" surfaces.
2015-06-15
Technical Paper
2015-01-2249
Saad Bennouna, Said Naji, Olivier Cheriaux, Solene Moreau, Boureima Ouedraogo, Jean Michel Ville
Passengers’ thermal comfort inside car cabin is mainly provided by the heating ventilation and air conditioning system (HVAC). The main part of HVAC modules is placed under the dash board. An HVAC module is a compact system composed of various elements which are subject to airflow. The interaction between airflow and these in-duct elements generates noise inside car cabin. Furthermore, the blower used to blow air inside the cabin must overcome the pressure generated by HVAC elements. Noise is created and its level is linked to flow and pressure. HVAC noise is an important issue for car makers and automotive suppliers wishing to reach passengers’ satisfaction. Furthermore thermal-engine cars are more and more silent. Also hybrid and electric car sells are expanding around the world. HVAC noise became a main issue for automotive actors. In order to reduce its HVAC noises, Valeo and partners worked to develop several methods.
2015-06-15
Technical Paper
2015-01-2238
Marina Roche, Marco Mammetti, Claudi Crifaci
Emissions and fuel consumption reduction for the year 2020 have lead to development of complex powertrain solutions, namely powersplit, electric and hybrid. The development of new concepts presents challenges for the integration in the vehicle, involving NVH among others. Electric energy flow to AC motors is controlled indeed by inverters that transform the energy from DC to AC working at frequencies around 10 kHz. Furthermore, the control of the energy flow can abruptly switch the operating strategy, inducing phenomena that are not present in combustion vehicles. Continuous wavelet transform is a relatively recent mathematical tool which allows signal decomposition into both time and frequency by convolution. On the contrary to windowed Fourier transform, it presents a minimized time support suited to the duration of the phenomena at each frequency. This characteristic makes it well-suited to for identifying transient information in non-stationary signals.
2015-06-15
Technical Paper
2015-01-2279
Giovanni Rinaldi, Chris Moon, Bret Engels
A unique Matlab-based coded engineering software tool (Time-Frequency Analyzer Core) was developed that allows users to process acquired time data to help in identifying sources and paths of noise and vibration (in the experience of the authors). The Time-Frequency Analyzer Core (TFAC) software does not replace commercial off the shelf software/hardware NV specific tools such as modal analysis, ODS, acoustic mapping, order tracking, etc., rather it aims at providing basic, yet powerful data inspection and comparison techniques in a single software tool that facilitate drawing conclusions and identifying most effective next steps. The features and advantages of using this software tool will be explained, along with a description of its application to a few different cases (automotive and off highway/agricultural).
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
2015-01-2343
Jian Pan, Yuksel Gur
OEMs are racing to develop light weight vehicles as government regulations now mandate automakers to nearly double the average fuel economy of new cars and trucks by 2025. Light weight materials such as aluminum, magnesium and carbon fiber composites are being used as structural panels in vehicle body. The reduction in weight in structural panels increases noise transmission into passenger compartment. This poses a great challenge in sound package development since simply increasing weight in sound package components to reduce interior noise is no longer an option. This paper discusses weight saving approaches to reduce noise sources, noise transmission paths, and transmitted noise into the passenger. Light weight sound package materials are introduced to treat and reduced airborne noise transmission into multi-material light weight body structure.
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
2015-01-2241
Hiromichi Tsuji, Shinichi Maruyama, Koichi Onishi
In the product development phase, the noise transfer functions (NTF) from the wheel or the tire contact patch to the passenger ear location are evaluated by the impact hammer or the ground excitation. However, no reduction of the road noise spectrum under the driving condition is occurred even if the level of the NTF peaks acquired by these methods reduces by the countermeasures on the structure. This is because the vehicle NTF of the road noise performance cannot be evaluated with the existed test equipment, such as the impact on the wheel or the 3 or 6 directional electromagnetic shaker on the ground. The cause of the issue is difficulty to excite the same structural modes coupled with acoustic modes as the one under the driving condition. Road Noise is generated by the change of random displacement input inside tire contact patch.
2015-06-15
Technical Paper
2015-01-2254
Wen-Bin Shangguan, Xiao Feng
The driving pulley in the Engine Front End Accessory Drive System (EFEAD) is usually used as a torsional vibration damper for the crankshaft. Although the crankshaft torsional vibrations are dampened, the torsional vibration is absorbed by the inertia ring of the driving pulley and then is transmitted to the EFEAD. The isolation pulley is a new device and is to reduce the belt tension fluctuation by isolating the belt transmission from the crankshaft torsional vibrations. In the isolation pulley, there are two inertia rings, one is used to damp the crankshaft vibration and another one is to drive the EFEAD. The purpose of this paper is to study design method for isolation pulley to reduce the EFEAD vibrations. An EFEAD with five-pulley system and isolation pulley is taken as studying example and a non-linear model is established to predict the dynamic response of the pulleys, tensioner motion and pulley slips.
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
2015-01-2267
Youngha Kim, Choonhyu Kim, Jaewoong Lee, Sunggi Kim
This paper describes structure borne noise reduction process that was using a combination of experimental and analytical methods. First, Major noise paths was identified using experimental Transfer Path Analysis (TPA). Next, FEA-Experimental modeling and forced response simulation were conducted using the Hybrid FEA-Experimental FRF method. Hybrid FEA-Experimental FRF-Based Substructuring (FBS) model was used along with Operational Deflection Shape (ODS) and Modal Analysis. The Hybrid FEA-Experimental model consisted of an experimental FRF representation of the body and a finite element model of sub-frame. The finite element of sub-frame is created by using Altair HyperMesh from CATIA images and dynamic analysis is carried out by using MSC Nastran. The natural frequency and frequency response function of finite element sub-frame model are compared with them of real sub-frame for the validity of applying Hybrid FBS method.
2015-06-15
Technical Paper
2015-01-2234
Giancarlo Chiatti, Ornella Chiavola, Silvia Conforto, Manfredi Amalfi
Besides pollutant emissions, fuel consumption and performance, vehicle NVH constitutes a further object during engine development and optimization. In recent years, research activity for diesel engine noise reduction has been devoted to investigate aerodynamic noise due to intake and exhaust systems and surface radiated noise. Most of the attention has been devoted to the identification and analysis of noise sources in order to evaluate the individual contribution (injection, combustion, piston slap, turbocharger, oil pump, valves) to the overall noise with the aim of selecting appropriate control strategies. Several studies have been devoted to analyze combustion process that has a direct influence on engine noise emission; the influence of injection strategies on the combustion noise has been evaluated and approaches able to separate engine combustion and mechanical noise have been presented.
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
2015-01-2363
Albert Albers, Jan Fischer, Matthias Behrendt, Dirk Lieske
The driving comfort is an important factor for buying decisions. Especially for battery electric vehicles (BEV) the acoustic quality is an elementary distinguishing feature, since the masking of an internal combustion engine (ICE) is no longer present. For the interior noise of BEV high frequency tonal orders are characteristic. They can for example be caused by the gearbox or the electric drive and strongly influence the perception and rating of the interior noise by the customer. Opposing the importance of the acoustic quality is the lack of knowledge of how to measure, analyze and predict the high frequency tonal noise generated by the dynamic torque of the electric drive. In this contribution methods for measuring, analyzing and predicting the excitation by the dynamic torque of the electric drive are presented. The dynamic torque of the electric drive up to 3.5 kHz is measured on a component test bench with the help of high frequency and high precision digital torque transducer.
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
2015-01-2301
Maxwell Hill, Dan Luo, Mark Moeller
Wind noise can be a significant event for automotive design engineers. The greenhouse glass plays an important role in the wind noise process. Robust estimates of the greenhouse glass damping are necessary for both understanding and modeling the role of the glass in the wind noise process. One unanswered question is whether the aerodynamic loads affect the window glass damping. To make this determination a method to assess the operational damping is required. The civil engineering community uses the random decrement technique to assess operational damping due wind loads. The random decrement technique has been shown to be a normalized autocorrelation function. In this paper the damping is estimated directly from the autocorrelation function. In the first section the relationship between the damping and autocorrelation function is examined for white noise excitation. A single oscillator is examined as the first case. Extension to higher modal densities is discussed.
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