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Viewing 211 to 121 of 121
2014-06-30
Journal Article
2014-01-2079
Gregor Tanner, David J. Chappell, Dominik Löchel, Niels Søndergaard
Abstract Modelling the vibro-acoustic properties of mechanical built-up structures is a challenging task, especially in the mid to high frequency regime, even with the computational resources available today. Standard modelling tools for complex vehicle parts include finite and boundary element methods (FEM and BEM), as well as Multi-Body Simulations (MBS). These methods are, however, robust only in the low frequency regime. In particular, FEM is not scalable to higher frequencies due to the prohibitive increase in model size. We have recently developed a new method called Discrete Flow Mapping (DFM), which extends existing high frequency methods, such as Statistical Energy Analysis or the so-called Dynamical Energy Analysis (DEA), to work on meshed structures. It provides for the first time detailed spatial information about the vibrational energy of a whole built-up structure of arbitrary complexity in this frequency range.
2014-06-30
Journal Article
2014-01-2081
Rainer Stelzer, Theophane Courtois, Ki-Sang Chae, Daewon SEO, Seok-Gil Hong
Abstract The assessment of the Transmission Loss (TL) of vehicle components at Low-Mid Frequencies generally raises difficulties associated to the physical mechanisms of the noise transmission through the automotive panel. As far as testing is concerned, it is common in the automotive industry to perform double room TL measurements of component baffled cut-outs, while numerical methods are rather applied when prototype or hardware variants are not available. Indeed, in the context of recent efforts for reduction of vehicle prototypes, the use of simulation is constantly challenged to deliver reliable means of decision during virtual design phase. While the Transfer matrix method is commonly and conveniently used at Mid-High frequencies for the calculation of a trimmed panel, the simulation of energy transfer at low frequencies must take into account modal interactions between the vehicle component and the acoustic environment.
2014-06-30
Journal Article
2014-01-2080
Ze Zhou, Jonathan Jacqmot, Gai Vo Thi, ChanHee Jeong, Kang-Duck Ih
Abstract The NVH study of trimmed vehicle body is essential in improving the passenger comfort and optimizing the vehicle weight. Efficient modal finite-element approaches are widely used in the automotive industry for investigating the frequency response of large vibro-acoustic systems involving a body structure coupled to an acoustic cavity. In order to accurately account for the localized and frequency-dependant damping mechanism of the trim components, a direct physical approach is however preferred. Thus, a hybrid modal-physical approach combines both efficiency and accuracy for large trimmed body analysis. Dynamic loads and exterior acoustic loads can then be applied on the trimmed body model in order to evaluate the transfer functions between these loads and the acoustic response in the car compartment.
2014-06-30
Journal Article
2014-01-2087
Ashish Shah, David Lennström, Per-Olof Sturesson, William Easterling
Abstract The increased focus and demands on the reduction of fuel consumption and CO2 requires the automotive industry to develop and introduce new and more energy efficient powertrain concepts. The extensive utilisation of downsizing concepts, such as boosting, leads to significant challenges in noise, vibration and harshness (NVH) integration. This is in conflict with the market expectation on the vehicle's acoustic refinement, which plays an increasingly important role in terms of product perception, especially in the premium or luxury segment. The introduction of the twin charger boosting system, i.e. combining super and turbo charging devices, enables downsizing/speeding in order to achieve improved fuel economy as well as short time-to-torque, while maintaining high driving dynamics. This concept requires also extensive consideration to NVH integration. The NVH challenges when integrating a roots type supercharger are very extensive.
2014-06-30
Journal Article
2014-01-2070
Jean-Baptiste Dupont, Racha Aydoun, Pascal Bouvet
Abstract The noise radiated by an electrical motor is very different from the one generated by an internal combustion engine. It is characterized by the emergence of high frequency pure tones that can be annoying and badly perceived by future drivers, even if the overall noise level is lower than that of a combustion engine. A simulation methodology has been proposed, consisting in a multi-physical approach to simulate the dynamic forces and noise radiated by electric motors. The principle is first to calculate the excitation due to electromagnetic phenomena (Maxwell forces) using an electromagnetic finite element solver. This excitation is then projected onto the structure mesh of the stator in order to calculate the dynamic response. Finally, the radiated sound power is calculated with the aid of a standard acoustic finite element method. The calculation methodology assumes a weak coupling between the different physical levels.
2014-06-30
Journal Article
2014-01-2046
Matthias Frank, Franz Zotter, Alois Sontacchi, Stephan Brandl, Christian Kranzler
Abstract When employing in-car active sound generation (ASG) and active noise cancellation (ANC), the accurate knowledge of the vehicle interior sound pressure distribution in magnitude as well as phase is paramount. Revisiting the ANC concept, relevant boundary conditions in spatial sound fields will be addressed. Moreover, within this study the controllability and observability requirements in case of ASG and ANC were examined in detail. This investigation focuses on sound pressure measurements using a 24 channel microphone array at different heights near the head of the driver. A shaker at the firewall and four loudspeakers of an ordinary in-car sound system have been investigated in order to compare their sound fields. Measurements have been done for different numbers of passengers, with and without a dummy head and real person on the driver seat. Transfer functions have been determined with a log-swept sine technique.
2014-06-20
Article
Omega’s PR-21 series of RTD (resistance temperature detector) sensors with M12 connector feature a welded 316L stainless steel housing and an integral 4-pin M12 connector for easy connection.
2014-06-12
Article
The cause of the issue was an error in the process Ford engineers used to correlate wind-tunnel testing into their Total Road Load Horsepower (TRLHP) factor that is key to the vehicle fuel economy models that are ultimately submitted to the U.S. EPA.
2014-06-11
Article
Reaction Design worked with a German premium automotive company to build cylinder-combustion simulations for a high-performance diesel engine with the goal of accurately and quickly predicting combustion performance and the effects of varied operating conditions on soot emissions.
2014-06-06
Standard
J671_201406
Description of Material—The materials classified under this specification are: a. Mastic vibration damping materials used to reduce the sound emanating from metal panels. b. Mastic underbody coatings used to give protection and some vibration damping to motor vehicle underbodies, fenders, and other parts.
2014-06-03
Article
The LC411-USBH series high-speed USB load cells from Omega connect directly to your computer and offer up to 1000 readings per second.
2014-05-31
Article
Hexagon Metrology’s Leica T-Scan 5 handheld system for laser trackers is said to operate more than 15 times faster than the previous model.
2014-05-30
Article
PCB Piezotronics’ surface microphone for R&D testing features a low-profile design ideal for testing in confined spaces and windy environments.
2014-05-30
Article
Supercritical Fluid Technologies’ SFT-250 supercritical fluid extractor is designed to perform extractions in supercritical fluid and meets the rigors of the research lab.
2014-05-20
Article
ViCANdo from Zuragon is a multimedia software tool for development, physical testing, and validation of various applications such as vehicle fleets, hybrid-electric systems, active safety systems, autonomous vehicles, and HMI systems.
2014-05-16
Standard
J1207_201405
This SAE Recommended Practice sets forth the instrumentation, environment, and test procedures to be used in measuring the silencer system effectiveness in reducing intake or exhaust sound level of internal combustion engines. The system shall include the intake or exhaust silencer, related piping, and components. This procedure is intended for engine-dynamometer testing and is not necessarily applicable to vehicle testing (see Appendix A). The effect of the exhaust or intake system on the sound level of the overall machine must be determined using other procedures. This procedure may be successively applied to various silencer configurations to determine relative effectiveness for that engine. Insertion loss for individual silencers may be calculated through measurement of the silenced and unsilenced system.
2014-05-16
Standard
J57_201405
This procedure provides for the measurement of the sound generated by a test tire, mounted on a single-axle trailer, operated at multiple speeds. The procedure describes test practices for both United States and International practices. Specifications for the instrumentation, the test site, and the operation of the test apparatus are set forth to minimize the effects of extraneous sound sources and to define the basis of reported sound levels.
2014-05-16
Standard
J1074_201405
This SAE Recommended Practice sets forth the equipment, environment, and test procedures to be used in measuring sound levels of engines. The purpose is to provide a uniform method of measuring the maximum acoustical radiation from the exterior surfaces of an engine under representative engine operating conditions. The measured sound levels will be useful in development of engines, comparison of engines, and installation of engines in various applications. The correlation of the measured engine sound levels to the various application sound levels will have to be developed.
2014-05-16
Standard
J1060_201405
This SAE Recommended Practice establishes a rating scale for subjective evaluations of noise and discomfort in motor vehicles. Through test procedures utilizing specific vehicles on specific roads, the scale may be utilized to assess the relative contributions of tires to noise and discomfort. The noise and ride comfort characteristics attributed to automotive tires have traditionally been estimated by subjectively assigning number designations (commonly on a 1 to 10 scale) to the audible and tactile sensations observed while traversing a given road course in a vehicle equipped with the tires under evaluation. Regardless of advances in objective measurements of tire properties related to noise and discomfort, subjective evaluation will continue to be necessary for the purpose of establishing the significance of such measurements.
2014-05-14
Article
Michael Duoba (SAE Member, 1993), Vehicle Test Engineer and team leader for the Advanced Powertrain Research Facility at Argonne National Laboratory, discuss his career progression and the type of work conducted at his lab.
2014-05-09
Journal Article
2014-01-9126
Nikolina Samardzic
Values of the speech intelligibility index (SII) were found to be different for the same speech intelligibility performance measured in an acoustic perception jury test with 35 human subjects and different background noise spectra. Using a novel method for in-vehicle speech intelligibility evaluation, the human subjects were tested using the hearing-in-noise-test (HINT) in a simulated driving environment. A variety of driving and listening conditions were used to obtain 50% speech intelligibility score at the sentence Speech Reception Threshold (sSRT). In previous studies, the band importance function for ‘average speech’ was used for SII calculations since the band importance function for the HINT is unavailable in the SII ANSI S3.5-1997 standard.
2014-05-09
Journal Article
2014-01-9124
David Lennström, Roger Johnsson, Anders Agren, Arne Nykänen
In the vehicle development process, targets are defined to fulfill customers' expectations on acoustic comfort. The interior complete vehicle acoustic targets can be cascaded down to system and component targets, e.g. insulation properties and source strengths. The acoustic transfer functions (ATFs) from components radiating airborne noise play a central role for the interior sound pressure levels. For hybrid vehicles fitted with an electric traction motor, the contribution of high frequency tonal components radiated from the motor housing needs to be controlled. The interior sound pressure due to an airborne motor order can be estimated by surface velocities and ATFs. This study addresses the ATFs measured from a large number of positions located around an electric rear axle drive (ERAD) and their influence on estimated interior noise. First, the magnitude variation between the individual ATFs and how it clearly can be visualized was presented.
2014-05-08
Article
The first ever Airbus A350 XWB to visit the U.S., MSN2, arrived the second week in May at McKinley Climatic Lab at Eglin Air Force base in Florida. Over several weeks the aircraft and its various systems and cabin installations will be subjected to the extreme hot and cold temperatures that the facility can sustain in a testing environment.
2014-05-08
Article
CSEG has designed, and filed a patent for, a cooling pack and fan that would allow for extreme driving conditions while downsizing the cooling pack, increasing fuel economy, and reducing costs for the OEM as well as the customers who do the driving.
2014-05-05
Journal Article
2014-01-9099
Lindsay J. Miller, Susan Sawyer-Beaulieu, Edwin Tam
Polyurethane (PU) foam is used for many automotive applications with the benefits of being lightweight, durable, and resistant to heat and noise. Applications of PU foams are increasing to include non-traditional purposes targeting consumer comfort. An example of this is the use of PU foam between the engine and engine cover of a vehicle for the purpose of noise abatement. This addition will provide a quieter ride for the consumer, however will have associated environmental impacts. The additional weight will cause an increase in fuel consumption and related emissions. More significant impacts may be realized at the end-of-life stage. Recycling PU foams presents several challenges; a lack of market for the recyclate, contamination of the foams, and lack of accessibility for removal of the material.
2014-04-30
WIP Standard
J1598
This SAE Recommended Practice is applicable to all liquid-to-gas, liquid-to-liquid, gas-to-gas, and gas-to-liquid heat exchangers used in vehicle and industrial cooling systems. This document outlines the test to determine durability characteristics of the heat exchanger from vibration-induced loading.
2014-04-30
WIP Standard
J577
This SAE Recommended Practice provides procedures, and information to conduct vibration (impact) tests on lighting devices and their components as well as other safety equipment used on vehicles.
2014-04-28
Article
AB Dynamics’ updated suspension parameter measuring machine (SPMM), the SPMM5000, is a fixed ground plane kinetics and compliance test machine that measures suspension parameters and characteristics like the SPMM4000 on which it is based.
2014-04-28
Technical Paper
2014-28-0034
Y. S. Thipse
Abstract Designers and analysts need to compare and conduct synthesis for selection of materials based on their properties involving simulation, optimization and correlation with test data. An example is that of acoustic material properties such as random and normal incidence sound absorption coefficient and sound transmission loss. The international test standards necessitate having standard operating procedures for characterization of these materials. This procedure is quite involved and addresses steps including test data acquisition, post processing, calculations, classification, report generation and most importantly, storage of such innumerable material properties in a structured manner to facilitate ease of retrieval and updating of properties. It is also highly desirable to have a synergy of the databank directly with simulation tools. Further, all of these steps need to be accurate, non-speculative and quick.
2014-04-23
Article
In a bid to deliver a system that combines quality control with process control, Hexagon introduces its 360° Smart Inline Measurement Solutions for automotive applications.
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