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Viewing 1 to 30 of 27195
2017-06-05
Technical Paper
2017-01-1775
Mark A. Gehringer, Robert Considine, David Schankin
This paper describes recently developed test methods and instrumentation to address the specific noise and vibration measurement challenges posed by large diameter single-piece tubular aluminum propeller shafts with high modal density. The application described in this paper is a light duty truck, although the methods described are applicable to any rotating shaft with similar dynamic properties. To provide a practical example of the newly developed methods and instrumentation, rotating and non-rotating data were acquired in-situ for several propeller shafts of varying construction, including both lined and unlined shafts. Data were also acquired with and without a torsional tuned vibration absorber attached to the driveline. The example data exhibit features that are uniquely characteristic of large diameter single-piece tubular shafts with high modal density, including the particular effect of shaft rotation on the measurements.
2017-06-05
Technical Paper
2017-01-1820
Martin Sopouch, Josip Hozmec, Alessandro Cadario
This paper presents a simulation environment and methodology for noise and vibration analyses of a driven rear axle in a bus application, with particular focus on medium to high frequency range (400 Hz to 3 kHz). The workflow demonstrates structure borne noise and sound radiation analyses. The fully flexible Multi–Body Dynamics (MBD) model - serving to cover the actual mechanical excitation mechanisms and the structural domain – includes geometrical contacts of hypoid gear in the central gear and planetary gear integrated at hubs, considering non-linear meshing stiffness. Contribution of aforementioned gear stages, as well as the propeller shaft universal joint at the pinion axle, on overall axle noise levels is investigated by means of sensitivity analysis. Based on the surface velocities computed at the vibrating axle-housing structure the Wave Based Technique (WBT) is employed to solve the airborne noise problem and predict the radiated sound.
2017-06-05
Technical Paper
2017-01-1892
Yosuke Tanabe, Masanori Watanabe, Takafumi Hara, Katsuhiro Hoshino, Akira Inoue, Masaru Yamasaki
Predicting vibration of motor gearbox assembly driven by a PWM inverter in an early development stage is demanding, because the assembly is one of the dominant noise sources of electric vehicle (EV). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from mount and electromagnetic forces including carrier frequency component of inverter up to 10 kHz. By employing the techniques of structural model reduction and state space modeling, the proposed model enables to predict the vibration of assembly in operating condition to simulate with a system level EV simulator. A verification test was conducted to compare the simulation result with running test result of EV. Although the absolute value of simulation is 10 dB different from test at most, we conclude that the model can well predict the trend of the dominant order vibration caused by the electromagnetic force of motor including the carrier frequency of inverter.
2017-06-05
Technical Paper
2017-01-1891
Todd Freeman, Kelby Weilnau
Similar to the automotive industry, the expectations from customers for the noise and vibration performance of personal vehicles such as golf carts, ATV’s, and side-by-side vehicles has continued to evolve. Not only do customers expect these types of vehicles to be more refined and to have acoustic signatures that match the overall performance capabilities of the vehicle, but marketing efforts continue to focus on product differentiators which can include the acoustic and vibration performance. Due to this increased demand for acoustic and vibration performance, additional NVH efforts are often required to meet these expectations. This paper provides a sample of some of the efforts that have occurred to further refine and develop the noise and vibration signature for golf carts.
2017-06-05
Technical Paper
2017-01-1832
Giovanni Rinaldi, Jason Edgington, Brian Thom
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
2017-01-1839
Edward T. Lee
It is common for automotive manufacturers and off-highway machinery manufacturers to gain an insight of the system structural dynamics by evaluating the system inertance functions near the mount locations. The acoustic response at 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 the 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 be applied towards the transfer function set. Finite element (FE) based analysis provides a good foundation for deterministic solutions. However finite element method suffers in accuracy as the frequency increases. Many NVH problems happen to be at the mid frequency range where solving the problem with the FE-only approach falls short.
2017-06-05
Technical Paper
2017-01-1858
James Haylett, Andrew Polte
Truck and construction seats offer a number of different challenges over automotive seats in the identification and characterization of Buzz, Squeak, and Rattle (BSR) noises. These seats typically have a separate air or mechanical suspension and usually have a larger number and variety of mechanical adjustments and isolators. Associated vibration excitation tend to have lower frequencies with larger amplitudes. In order to test these seats for both BSR and vibration isolation a low-noise shaker with the ability to test to low frequency, down to 1 Hz was used. Slowly swept sine excitation was particularly helpful in understanding the seat mode shapes and nonlinearities at low frequency which showed large displacements. A typical sample set of seat BSR sounds are described in terms their time and frequency characteristics and widely used sound quality metrics.
2017-06-05
Technical Paper
2017-01-1889
Todd Tousignant, Kiran Govindswamy, Georg Eisele, Christoph Steffens, Dean Tomazic
The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle level fuel consumption. Specifically, the use of electrified propulsion systems is expected to play an increasingly important role in helping OEM’s meet fleet CO2 re-duction targets for 2025 and beyond. Electric and hybrid electric vehicles do not typically utilize IC engines for low-speed operation. Under these low-speed operating conditions, the vehicles are much quieter than conventional IC engine-powered vehicles, making their approach difficult to detect by pedestrians. To mitigate this safety concern, many manufacturers have synthesized noise (using exterior speakers) to increase detection distance. Further, the US National Highway Traffic Safety Administration (NHTSA) has provided recommendations pursuant to the Pedestrian Safety Enhancement Act (PSEA) of 2010 for such exterior noise signatures to en-sure detectability.
2017-06-05
Technical Paper
2017-01-1764
Himanshu Amol Dande, Tongan Wang, John Maxon, Joffrey Bouriez
The demand for quieter interior cabin spaces among business jet customers has created an increased need for more accurate prediction tools. In this paper the authors will discuss a collaborative effort between Jet Aviation and Gulfstream Aerospace Corporation to develop a Statistical Energy Analysis (SEA) model of a large commercial business jet. To have an accurate prediction, it is critical to accurately model the structural and acoustic subsystems, critical noise transmission paths and dominant noise sources on the aircraft. The geometry in the SEA model was developed using 3D CAD models of major airframe and interior cabin components. The noise transmission path was characterized through extensive testing of various aircraft components in the Gulfstream Acoustic Test Facility. Material definitions developed from these tests became input parameters in the SEA model.
2017-06-05
Technical Paper
2017-01-1763
Lisa Steinbach, Ercan Altinsoy, Robert Rosenkranz
In today's urban environment inhabitants are permanently exposed to elevated noise levels, which are mostly dominated by traffic noise. The current electrification of vehicles might affect the traffic noise in city centers. The aim of this work was to determine the pedestrian reaction and the annoyance of more realistic traffic situations. For this purpose both combustion and electric vehicle noise situations and mixed scenarios of both concepts were generated. The differences in the perceived annoyance were investigated with perception studies. It was found that in some cases the order of the annoyance ratings will change: a single electric vehicle, which was perceived as least annoying, was evaluated as the most annoying noise by the increase to eight vehicles. The background noise also has an impact on the perception of annoyance and the warning effect.
2017-06-05
Technical Paper
2017-01-1834
Dirk von Werne, Prasanna Chaduvula, Patrick Stahl, Michael Jordan, Jamison Huber, Korcan Kucukcoskun, Mircea Niculescu
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.
2017-06-05
Technical Paper
2017-01-1833
Bonan Qin, Jue Yang, Xinxin Zhao
Articulated engineering vehicle travels on complex road, its working condition is bad and because of the non-rigid connection between the front and rear body, additional degrees of freedom is brought in and the transverse stiffness is relatively weak. When the articulated vehicle run in a high speed along a straight line, it is easy to cause the transverse swing and the poor manipulation stability. If it is serious enough, it will lead to "snake shape" instability phenomena. This kind of instability will increase driving resistance and tire wear, the lateral dynamic load and aggravate the damage of the parts. When steering, the center of gravity will offset laterally which will lead a higher probability of rollover accident. A mathematical model for a 35t articulated dump truck with four motor-driven wheels is established in this paper, to study the condition for its stable driving and the effects of the vehicle structural parameters.
2017-06-05
Technical Paper
2017-01-1837
Paul R. Donavan, Carrie Janello
Acoustic beamforming was used to localize noise sources on heavy trucks operating on highways in California and North Carolina at a total of 20 sites. Over 1,200 trucks were measured under a variety of operating conditions including cruise on level highways, on upgrades, down degrades, low speed acceleration, and for various speeds and pavements. The contours produced by the beamforming measurements were used to identify specific source contributions under these conditions and for a variety of heavy trucks. Consistently, the highest noise levels were seen the tire-pavement interface with lessor additional noise radiated from the engine compartment. Noise from elevated exhaust stacks was only documented for less than 5% of the trucks measured. The results were further reduced to produce vertical profiles of noise levels versus height above the roadway. The profiles were normalized to the highest noise level at ground level.
2017-06-05
Technical Paper
2017-01-1890
Xingyu Zhang, Bo Yang, Manchuang Zhang, Sanbao Hu
H-Bahn ("hanging railway") refers to the suspended, unmanned urban railway transportation system. Through the reasonable platform layout, H-Bahn can be easily integrated into the existing urban transit system. With the development of urban roads, the associated rail facilities can be conveniently disassembled, moved and expanded. The track beam, circuits, communication equipment, and sound insulation screen are all installed in a box-type track beam so that the system can achieve a high level of integration and intelligence. The carriage of the modern H-banh vehicle is connected with the bogies by two hanging devices. The vehicle is always running in the box-type track beam; therefore there are less possibilities of derailment. Consequently, the key work focuses on the running stability evaluation and curve negotiation performance analysis.
2017-06-05
Technical Paper
2017-01-1855
Ramakanta Routaray
The basic function of a motorcycle frame is somewhat similar to that of the skeleton in the human body, i.e. to hold together the different parts in one rigid structure. One of the major benefits (for a motorcycle enthusiast) of using an advanced frame design lies in the sporty handling characteristics of the bike. A well designed frame can add to the joy of riding a motorcycle as the bike would feel more stable, effortless, and confident around corners, in straight lines and while braking. A well approved modeling techniques or adequate guide line principles have to be followed while designing the body and chassis in order to achieve the vibration within control. This paper depicts a methodological right approach to model the body and chassis of a two wheeler in order to control noise and vibration of the body and chassis.
2017-06-05
Technical Paper
2017-01-1783
Chris Todter, Olivier Robin, Paul Bremner, Christophe Marchetto, Alain Berry
Fluctuating surface pressure measurements using microphone arrays are still challenging, especially in an automotive context with cruising speeds around Mach 0.1. The separated turbulent boundary layer excitation and the side mirror wake flow generate both acoustic and aerodynamic components, which have wavenumbers that differ by a factor of approximately 10. This calls for high spatial resolution measurements to fully resolve the wavenumber-frequency spectrum. In SAE paper 2015-01-2325, the authors reported a micro-electro-mechanical (MEMS) surface microphone array that successfully used wavenumber analysis to quantify acoustic versus turbulence loading. It was shown that the measured surface pressure at each microphone could be strongly influenced by self noise induced by the microphone ”packaging”, which can be attenuated with a suitable windscreen.
2017-06-05
Technical Paper
2017-01-1835
Nader Dolatabadi, Ramin Rahmani, Stephanos Theodossiades, Homer Rahnejat, Guy Blundell, Guillaume Bernard
Clutches are commonly utilised in passenger type and off-road heavy-duty vehicles to disconnect the engine from the driveline and other parasitic loads. In off-road heavy-duty vehicles, fuel efficiency and start-up functionality at extended ambient conditions, such as cold start-up and low intake absolute pressure are crucial. Off-road vehicle manufacturers usually overcome the parasitic loads in these conditions by oversizing the engine. Caterpillar Inc. as the pioneer in the off-road technology has developed a novel clutch design to allow for engine downsizing while vehicle’s performance is not affected. The tribology behaviour of clutch will be crucial to start engagement in time and reach the maximum clutch capacity in the shortest possible time and the safest method in terms of dynamics. A multi-body dynamics model of the clutch system is developed in MSC ADAMS. Flywheel carries the same speed and torque as engine and represents the engine input to the clutch.
2017-06-05
Journal Article
2017-01-1762
Michael Roan, M. Lucas Neurauter, Douglas Moore, Dan Glaser
Hybrid and electric vehicles (HVs and EVs) have demonstrated low noise levels relative to their Internal Combustion Engine (ICE) counterparts, particularly at low speeds. As the number of HVs/EVs on the road increases, so does the need for data quantifying auditory detectability by pedestrians; in particular, those who are vision impaired. Manufacturers have begun to implement additive noise solutions designed to increase vehicle detectability while in electric mode and/or when traveling below a certain speed. A detailed description of the real-time acoustic measurement system, the corresponding vehicular data, development of an immersive noise field, and experimental methods pertaining to a recent evaluation of candidate vehicles is provided herein. Listener testing was completed by 24 legally blind test subjects for four vehicle types: an EV and HV with different additive noise approaches, an EV with no additive noise, and a traditional ICE vehicle.
2017-06-05
Journal Article
2017-01-1909
Joel Bruns, Jason Dreyer
The application of hydraulic body mounts between a pickup truck frame and cab to reduce freeway hop and smooth road shake has been documented in literature and realized in production vehicles. Previous studies have demonstrated the potential benefits of these devices, often through iterative prototype evaluation. Component dynamic characterization has also shown that these devices exhibit significant dependence on dynamic amplitude and preload; however, analysis of these devices has not fully addressed these dependences. This paper aims to understand the amplitude and preload dependence on the spectrally varying properties of a production hydraulic body mount. This double-pumping, three-spring mount construction has a shared compliant element between the two fluid-filled chambers. A reduced-order multi-physics model of the mount assembly is developed using parameters derived from bench testing of the different elastomeric components and the fluid system.
2017-06-05
Journal Article
2017-01-1786
Hiroshi Yokoyama, Ryo Adachi, Taiki Minato, Akiyoshi Iida
Intense tonal sound often radiates from flows around a cavity such as a sunroof or various gaps between parts of automobiles, and this sound is referred to as cavity tone. This cavity tone is due to fluid-acoustic interactions in cavity flows, where a vortex impinging at the downstream wall generates an acoustic wave and the acoustic wave propagating in the upstream direction induces another vortex near the upstream edge. The control of the cavity tone by blowing jets into the oncoming boundary layer is focused on. Moreover, the effects of the spanwise pitch of the jets on the flow and acoustic fields were investigated. To clarify the control effects on the cavity flow and tone, both low-noise wind tunnel experiments and direct aeroacoustic simulations based on the compressible Navier-Stokes equations were performed. Main experiments and computations were performed at the freestream Mach number of 0.09, where the oncoming boundary layer is laminar.
2017-06-05
Journal Article
2017-01-1825
Takenori Miyamoto, Hiroshi Yokoyama, Akiyoshi Iida
Intense tonal noise often radiates from flows around a trailing edge with an upstream kink shape such as found in an automobile bonnet, where fluid-acoustic interactions occur. It was clarified that the tonal sound became intense at a specific angle of the kink. Moreover, in order to reduce this noise, the flow was controlled by a dielectric barrier discharged plasma actuator (PA), which was attached around the kink shape. The flow and sound pressure were measured by a hot-wire anemometer and a microphone in a low-noise wind tunnel. In the flow around the model without control by the PA, vortices are shed in a separated flow between the kink and the trailing edge, and acoustic waves are radiating due to the interference of vortices with the wall. Measured coherent output power (COP) based on the simultaneous measurement of velocity fluctuations and far-field sound pressure shows that the velocity fluctuations near the trailing edge are related with the tonal acoustic radiation.
2017-06-05
Technical Paper
2017-01-1847
Asif Basha Shaik Mohammad, Ravindran Vijayakumar, Nageshwar rao.P
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. For these reasons, the noise and vibration comfort has become an important criterion in the design of the driver’s cabin and a determining factor in the acceptance and sales potential of agricultural tractors. 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.
2017-06-05
Technical Paper
2017-01-1757
Matthew Maunder, Benjamin Munday
Excitement, image and emotion are key attributes for cars, particularly those with higher power ratings. Engine sound has traditionally acted as the car’s voice, conveying these attributes to the driver and passengers along with the brand image. Engine sound also underpins the dynamic driving experience by giving instant feedback about how a car is operating, enhancing the connection between driver and vehicle. For decades, the automotive industry has engineered engine sound to achieve these benefits, thereby defining the ‘language’ of car sound. Electric vehicles deliver strong and responsive performance but naturally lack the acoustic feedback that internal combustion engines provide. While this gives advantages in terms of comfort and environmental noise, the benefits of engine sound are lost. Carefully controlled acoustic feedback brings tangible and valuable benefits both for the dynamic driving experience and to convey the brand image.
2017-06-05
Technical Paper
2017-01-1755
Frank C. Valeri, James T. Lagodzinski, Scott M. Reilly, John P. Miller
Hybrid powertrain vehicles inherently create discontinuous sounds during operation. The discontinuous noise created from the electrical motors during transition states are undesirable since they can create tones that do not correlate with the dynamics of the vehicle. The audible level of these motor whines and discontinuous tones can be reduced via common noise abatement techniques or reducing the amount of regeneration braking. One electronic solution which does not affect mass or fuel economy is Masking Sound Enhancement (MSE). MSE is an algorithm that uses the infotainment system to mask the naturally occurring discontinuous hybrid drive unit and driveline tones. MSE enables a variety of benefits, such as more aggressive regenerative braking strategies which yield higher levels of fuel economy and an overall more pleasing interior vehicle powertrain sound. This paper will discuss the techniques and signals used to implement MSE in a hybrid powertrain equipped vehicle.
2017-06-05
Technical Paper
2017-01-1814
Todd Tousignant, Kiran Govindswamy, Vikram Bhatia, Shivani Polasani, W Keith Fisher
The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle level fuel consumption. Specifically, vehicle light weighting is expected to play a key role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. Corning’s Gorilla® Glass Hybrid laminate solution offers more than 30% weight reduction compared to conventional automotive laminate. Additionally, Gorilla Glass Hybrid laminates provide improved toughness, better optics, and enables better vehicle dynamics by lowering the vehicle center of gravity. Although thin glazing offers multiple advantages, glazing weight reduction leads to an increase in transmission of sound through the laminates for certain frequencies. This paper documents a study that uses a systematic test-based approach to understand the sensitivity of interior vehicle noise behavior to changes in acoustic attenuation driven by installation of lightweight glass.
2017-05-18
Journal Article
2017-01-9678
G Agawane, Varun Jadon, Venkatesham Balide, R Banerjee
Abstract Liquid sloshing noise from an automotive fuel tank is becoming increasingly important during frequent accelerating/decelerating driving conditions. It is becoming more apparent due to significant decrease in other noise sources in a vehicle, particularly in hybrid vehicles. As a step toward understanding the dynamics of liquid sloshing and noise generation mechanism, an experimental study was performed in a partially filled rectangular tank. A systematic study was performed to understand the effects of critical parameters like fill level and acceleration/deceleration magnitude. Response parameters like dynamic pressure, dynamic force, dynamic acceleration and sound pressure levels along with high speed video images were recorded. The proposed experimental setup was able to demonstrate major events leading to sloshing noise generation. These events in the sloshing mechanism have been analysed from the dynamic sensor data and correlated with high speed video images.
2017-05-18
Journal Article
2017-01-9679
Alvaro Baleato Varela, Franz Irlinger
Abstract Lap time simulation has always been a topic of interest in the automotive industry as it summarizes the whole dynamic performance of an automobile in a single value. During the development of road and race cars, to avoid expensive testing and to prove different design solutions, it is useful to simulate the maximum performance of the vehicles. The cars are driven to their limits to exploit their capabilities, where their dynamic behaviour can be highly non-linear. The vehicle models need to replicate these characteristics as precisely as possible. Due to this, the problem of achieving the minimum lap time with a certain car around a race track is a challenging problem to solve. A method to evaluate the minimum lap time is presented, approaching the optimal solution by coupling a driver model, a simulation environment and genetic algorithms to perform the optimization. The algorithm also offers the possibility to add vehicle parameters to be optimized regarding the lap time.
2017-04-30
Book
Eduardo Galindo, David Blanco, Chris J. Brace, Edward Chappell, Richard Burke
The use of the chassis dynamometer test cells has been an integral part of the vehicle development and validation process for several decades, involving specialists from different fields, not all of them necessarily experts in automotive engineering. CHASSIS DYNAMOMETER TESTING: Addressing the Challenges of New Global Legislation (WLTP and RDE) sets out to gather knowledge from multiple groups of specialists to better understand the testing challenges associated with the vehicle chassis dynamometer test cells, and enable informed design and use of these facilities.
CURRENT
2017-04-28
Standard
J1287_201704
This SAE Standard establishes the test procedure, environment, and instrumentation for determining the exhaust sound pressure levels of motorcycles under stationary conditions. Since initial publication, it has been successfully applied to regulation and monitoring of sound pressure levels of off-highway vehicles, and that remains its recommended application. Users of SAE J1287 for the purpose of roadside enforcement of sound pressure levels for on-highway motorcycles have reported difficulties with its implementation in that application. In response, SAE J2825 was developed, and is recommended for measurement of exhaust sound pressure levels of stationary on-highway motorcycles. Care must be taken not to confuse stationary sound pressure levels with total motorcycle sound pressure levels. This test does not evaluate total motorcycle sound during operation. For this purpose, SAE J331 or SAE J47 is recommended.
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