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Viewing 181 to 210 of 9221
2015-09-01
Journal Article
2015-01-1976
Masao Nakagawa, Mohamed Ali Ben Abbes, Toshiki Hirogaki, Eiichi Aoyama
Planetary gear sets are widely used in hybrid or electric vehicles. Although they have many advantages, they have been known to develop noise and vibration problems. There have been many reports dealing with the problems' characteristics for two-axis driving, but very few for three-axis driving. This paper reports three-axis driving performed on a developed driving stand, with driving torque measured by a high response torque sensor on each driving axis. Under these conditions it was found that the meshing frequency occurred at two kinds of frequency harmonics.
2015-08-26
Article
TECAT has developed a system to measure torque on a flexplate accurately and in-situ.
2015-08-26
Article
Helium leak detection systems are helping transmission suppliers improve quality and reduce the cost of producing new automatic transmissions.
2015-08-24
Article
Even as simulation and virtual design tools get ever more sophisticated, brick-and-mortar test facilities are as important as ever.
2015-08-24
Article
DTS' TSR data logger line includes a ±20 g sensor range.
2015-08-20
WIP Standard
AS8034C
This SAE Aerospace Standard (AS) specifies minimum performance standards for all types of Electronic Displays and Electronic Display Systems that are intended for use in the flight deck by the flightcrew in all 14 CFR Part 23, 25, 27, and 29 aircraft. The requirements and recommendations in this document are intended to apply to all installed electronic displays and electronic display systems within the flight deck, regardless of intended function, criticality, or location within the flight deck, but may also be used for non-installed electronic displays. This document provides baseline requirements and recommendations (see section 2.3 for definitions of “shall” and “should”). This document primarily addresses hardware requirements, such as electrical, mechanical, optical, and environmental. It does not address system specific functions.
2015-08-19
Article
The 2017 GT development program has begun testing in southeastern Michigan, with the exotic American supercars running “naked” as they rack up miles amid daily commuter traffic. Automotive Engineering encountered and photographed one of the off-tool prototypes recently.
2015-08-11
Article
A $2.5 million upgrade turns an existing climatic cell into one of the industry's most capable facilities for 4x4 and AWD vehicle development.
2015-08-11
Standard
J2629_201508
SAE developed this document and associated spreadsheets at the request of automobile manufacturers to help compare products from multiple suppliers using standard data presentation formats. This document includes several preferred formats for presenting acoustical data on materials, components, systems, or vehicles. These formats cover the range of acoustical tests commonly conducted in the automotive industry. These tests follow SAE and ASTM test practices as well as vehicle specific test methods. For each test, the details of samples and test conditions can be entered into an applicable electronic spreadsheet together with the acoustical results data. These data are then linked to standard graphical display(s) for each test. All manufacturers and suppliers in this industry are encouraged to present data and results in these formats.
2015-08-10
Article
Tucked within the University of Michigan's Ann Arbor campus is a glimpse of the automotive future. In this episode of SAE Eye on Engineering, Senior Editor Lindsay Brooke looks at Mcity, a new proving ground that will help automakers and suppliers develop automated and driverless car technologies.
2015-08-01
WIP Standard
ARP4462A
This recommended practice covers the procedures and method for establishing acceptance criteria when performing Barkhausen noise testing of surface-hardened steel components to detect grinding burns (metallurgical damage caused by over-heating) in bare or chromium-plated parts. Primarily for nondestructive testing of heat treated, high strength low-alloy steel parts which have been ground, in accordance with MIL-STD-866 or commercial standard, before or after chromium plating. This test method may be used as an independent test or to confirm grinding damage detected in accordance with AMS 2440 or MIL-STD-867 in bare or chromium plated components.
2015-07-29
Article
SAKOR Technologies supplies a test system for the Dream Chaser atmospheric flight control system, serving as a spacecraft emulator to test overall system performance.
2015-07-28
Article
The 6DX PRO for gathering kinematic data for research and engineering validation was designed by DTS specifically for occupant dynamics and human injury assessment.
2015-07-23
Article
Physics-based robot simulation leveraging stochastic optimization and game theory will support new NASA missions.
2015-06-30
Article
Off-highway machine mounting systems, especially the cab mounting system, significantly affect the operator comfort in the cab by providing enough damping for a good ride and isolating the structure-borne forces from traveling into the cab.
2015-06-29
WIP Standard
J1400
This SAE Recommended Practice presents a test procedure for determining the airborne sound barrier performance of materials and composite assemblies commonly installed in surface vehicles and marine products. This document is intended to provide a means of rank ordering barrier materials according to their sound transmission loss. At each test frequency the transmission loss (TL) is projected from the measured noise reduction of the test specimen using a correlation factor (CF). The respective CF for the test condition is determined as the differences between the measured noise reduction (MNR) of a homogeneous limp panel, such as lead, and its calculated field-incidence transmission loss. Latitude is permitted in certain test conditions that do not necessarily conform to all of the acoustical requirements of ASTM E 90.
2015-06-18
Article
Passenger Experience automates cabin completion processes with essential intelligent “building blocks” capturing rules, regulations, and manufacturing knowledge to automate cabin interior design, development, and delivery.
2015-06-15
Technical Paper
2015-01-2308
Yitian Zhang, David W. Herrin
Abstract The two-load method is commonly applied to determine the transmission loss for a muffler especially if an impedance tube rig is used. Although one procedure and algorithm is detailed in ASTM E2611, the quality of the transmission loss curve is dependent on several factors that are not discussed in detail in the standard. In this paper, several practical concerns are investigated including (1) the number of channels used in the measurement, (2) the selection of the reference channel, and (3) the choice of data processing algorithm (transfer or scattering matrix). Results are compared for a simple expansion chamber first, then for mufflers of other types. Recommendations are made for obtaining smoother transmission loss curves for various measurement methods.
2015-06-15
Technical Paper
2015-01-2309
David Neihguk, M.L. Munjal, Abhinav Prasad
Abstract The bias flow in Concentric Tube Resonator (CTR) is a flow-induced phenomenon in which the pressure gradient along the radial direction is produced by the kinetic energy of the flow. As a result, the flow dynamics in CTR is characterized by bias flow into the annular cavity in the upstream and outflow from the annular cavity in the downstream of the flow. This is due to the change in direction of the radial component of the bias flow at a point called the point of recovery, as a consequence of mass conservation. The pressure drop of CTR is a complex function of the momentum flux and other geometric parameters such as porosity, open area ratio, discharge coefficient of the perforated holes, bias inflow, bias outflow, grazing flow and length. In this study, numerical experiments are conducted to obtain an empirical formula for the friction factor of perforated pipes which are extensively used in automotive mufflers.
2015-06-15
Technical Paper
2015-01-2301
Maxwell Hill, Dan Luo, Mark Moeller
Abstract 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 to 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.
2015-06-15
Technical Paper
2015-01-2310
Edward Ray Green
Abstract The Sound Transmission Loss of automotive intake and exhaust components is commonly measured using the four microphone tube method per ASTM E2611 [1]. Often area adapters are used to match the component diameter to that of the tube apparatus. These area adapters affect the Sound Transmission Loss measurement, especially at very low frequencies. The use of the Transfer Matrix Technique to remove the effect of the area adapters is described. The improvements for step and cone area adapters are compared.
2015-06-15
Technical Paper
2015-01-2358
Rod Morris-Kirby, Evan Harry, Dirk Jaeger, Bernd Borgmann
Abstract 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. It answers questions such as what, where and how does a vehicle's acoustic systems 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 computer program that has been used successfully in over 50 vehicle projects within the Authors Research and Development group on a wide range of motor vehicles.
2015-06-15
Technical Paper
2015-01-2362
Todd Tousignant, Kiran Govindswamy, Mark Stickler, Ming-Ran Lee
Abstract The increasing trend toward electric and hybrid-electric vehicles (HEVs) has created unique challenges for NVH development and refinement. Traditionally, characterization of in-vehicle powertrain noise and vibration has been assessed through standard operating conditions such as fixed gear engine speed sweeps at varied loads. Given the multiple modes of operation which typically exist for HEVs, characterization and source-path analysis of these vehicles can be more complicated than conventional vehicles. In-vehicle NVH assessment of an HEV powertrain requires testing under multiple operating conditions for identification and characterization of the various issues which may be experienced by the driver. Generally, it is necessary to assess issues related to IC engine operation and electric motor operation (running simultaneously with and independent of the IC engine), under both motoring and regeneration conditions.
2015-06-15
Technical Paper
2015-01-2361
Sajjad Beigmoradi
Abstract 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
2015-01-2338
Dong Guo, Quan Shi, Peng Yi
Abstract 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
2015-01-2334
David Bogema, Gary Newton, Mark Stickler, Chris Hocking, Frank Syred
Abstract 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
2015-01-2348
Richard Kolano
Abstract This paper presents the results of a study to reduce the background noise level within a large Quiet Room located adjacent to other laboratory testing environments and below a mechanical mezzanine which houses an extensive array of mechanical and electrical equipment including banks of low-temperature chiller compressors, air handling units, and electrical switchgear that serves the entire building complex. This equipment was installed atop the concrete mezzanine floor deck without provisions for isolating vibration. As a result, structure-borne noise from that equipment travels through the floor, radiates from the underside of the floor deck, and intrudes into the Quiet Room below. This causes the background noise level within the Quiet Room to be too high for conducting low sound level measurements and studies on vehicles brought into the Quiet Room.
2015-06-15
Technical Paper
2015-01-2345
Arnaud Duval, Valérie Marcel, Ludovic Dejaeger, Francis Lhuillier, Moussa Khalfallah
Abstract The Flaxpreg is a green and light very long flax fibers thermoset reinforced sandwich, which can be effectively used as multi-position trunk loadfloor or structural floor in the passenger compartment of a vehicle. The prepreg FlaxTapes of about 120 g/m2 constituting the skins of the sandwich, are unidirectionally aligned flax fibers tapes, with acrylic resin here, easily manipulable without requiring any spinning or weaving step and thus without any negative out of plane crimping of the almost continuous flax fibers. Thanks to their very low 1.45 kg/dm3 density combined with an adaptive 0°/90°/0° orientation of the FlaxTapes (for each skin) depending on the loading boundary conditions, the resulting excellent mechanical properties allow a - 35% weight reduction compared to petro-sourced Glass mat/PUR sandwich solutions (like the Baypreg).
2015-06-15
Technical Paper
2015-01-2346
Balakumar Swaminathan
Abstract From a facility perspective, engine test cells are rarely evaluated for their vibration levels in their functional configuration. When complicated dynamic systems such as an internal combustion engine and a dynamometer are coupled together using driveshafts and coupling components, the overall system behavior is significantly different from that of the individual sub-systems. This paper details an instance where system level experimental testing and finite element analysis methods were used to mitigate high vibration levels in an engine test cell. Modal and operational test data were taken to establish baseline vibration levels at a diesel engine test cell during commissioning. Measurements were taken on all major sub-systems such as the engine assembly, dynamometer assembly, intermediate driveshaft bearing pedestal and driveshaft components.
2015-06-15
Technical Paper
2015-01-2368
Babitha Kalla, Sanjeevgouda Patil, Mansinh Kumbhar
Abstract Idle NVH (Noise Vibration Harshness) is one of the major quality parameters that customer looks into while buying the vehicle. Idle shake is undesirable vibrations generated from Engine while it is in idling condition. These low frequency vibrations affects both driver and passenger comfort. Vibrations are perceived by customer through the interfaces such as the seats, floor, and steering wheel. The frequencies of vibration felt by customer ranges between 10-30 Hz and varies based on engine configurations. There are two factors that are critical to the vehicle idle NVH quality, 1. Engine excitation force and 2. Vehicle sensitivity to excitation forces (Transfer function). Even though the engine excitation forces are governed by cylinder combustion process inside the cylinder and engine mass, it is also largely affected by how well the engine and transmission are supported on vehicle through isolators.
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